JP2009075558A - Liquid amount measuring device, liquid developer storage device, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid amount measuring device, a liquid developer storing device, and an image forming apparatus for accurately measuring a liquid amount.
SOLUTION: A levitation member 116Y that moves following the liquid level, and a first magnetic field generator 117Y that is arranged in the levitation member 116Y so as to be spaced apart in the moving direction of the levitation member 116Y and that faces the N pole as an opposing surface. The second magnetic field generator 118Y with the south pole facing as the opposing surface, and a position facing the opposing surfaces of the first magnetic field generator 117Y and the second magnetic field generator 118Y, are separated by a predetermined distance in the moving direction of the levitation member 116Y. A plurality of proportional output Hall elements 113Y, 114Y, and 115Y that detect magnetic fields generated by the first magnetic field generator 117Y and the second magnetic field generator 118Y, and a plurality of proportional output Hall elements 113Y and 114Y. , 115Y to measure the liquid volume.
[Selection] Figure 2

Description

  The present invention relates to a liquid amount measurement device, a liquid developer storage device, and an image forming apparatus that measure the amount of liquid toner in which toner is dispersed in a carrier liquid.

Conventionally, the float member that is formed horizontally long and moves up and down as the liquid level of the liquid developer increases and decreases is fixed at both ends, the magnetic field generator is fixed at an intermediate position between both ends, and the end portion and the intermediate position And a plurality of guide rods that are inserted into the respective ring portions to guide the vertical movement of the float member, and the magnetic field generator and the hole are moved along with the vertical movement of the float member. A float type liquid level sensor that changes the distance to the element and detects the liquid level based on the detection result of the Hall element is disclosed (see Patent Document 1).
JP 2002-14541 A

  However, in the technique described in Patent Document 1, the liquid level is measured step by step, and the insufficient amount of the liquid cannot be detected as a continuous value, and an appropriate amount cannot be supplied. Therefore, the fluctuation range of the liquid level is large, the overshoot is also large, and it takes time to reach the target concentration and liquid level. In addition, when the liquid level is high, overflow may occur when the liquid is replenished.

  In order to solve the above-described problems, an object of the present invention is to provide a liquid amount measuring device, a liquid developer storage device, and an image forming apparatus that accurately measure a liquid level.

  The liquid amount measuring device of the present invention includes a levitation member that moves following the liquid level of the liquid, a first magnetic field generator that is disposed on the levitation member and that has an N pole directed in a first direction, The first magnetic field generator is disposed on the levitation member so as to be spaced apart from the first magnetic field generator, and the first magnetic field generator is disposed at a position facing the second magnetic field generator with the S pole directed in the first direction. A plurality of proportional output Hall elements that detect the magnetic field generated by the magnetic field generator and the second magnetic field generator. Therefore, the liquid level is continuously measured by the proportional output, and the liquid deficiency is set as a continuous value. It can be detected and the liquid level of the liquid can be accurately measured.

  Moreover, since the guide part which guides the movement of the said levitation member and the control member which controls the movement of the said levitation member are provided, a limit point can be detected and an overflow etc. can be eliminated.

  Furthermore, the liquid developer storage device of the present invention includes a storage unit that stores a liquid developer containing toner particles in a carrier liquid, a floating member that moves following the liquid level of the liquid developer in the storage unit, A first magnetic field generator disposed on the levitation member and having an N pole directed in a first direction; and disposed on the levitation member spaced apart from the first magnetic field generator and in the first direction. A second magnetic field generator with the S pole facing, and a plurality of proportional output Hall elements that detect magnetic fields generated by the first magnetic field generator and the second magnetic field generator at positions facing the first direction Therefore, the liquid level of the liquid developer can be continuously measured by proportional output, and the deficiency of the liquid developer can be detected as a continuous value, and the liquid level of the liquid developer can be accurately measured. Can be measured.

  The movable member is movable between the movable member movable within the storage unit, the light emitting member, the light receiving member that receives light emitted from the light emitting member, the light emitting member, and the light receiving member. A density part having a gap part and a density measuring part for measuring the concentration of the liquid developer from the output of the light receiving member when the moving member is in the gap part and when the moving member is not in the gap part Since the measuring device is provided, it is possible to accurately adjust the desired liquid amount and concentration of the liquid developer.

  In addition, since a guide unit that guides the movement of the levitation member and a regulation member that is disposed in the measurement unit and regulates the movement of the levitation member, a limit point can be detected and an overflow or the like is eliminated. It becomes possible.

  Furthermore, the image forming apparatus of the present invention includes a developer container, a developer carrier that carries a liquid developer, and a developer supply that supplies the liquid developer stored in the developer container to the developer carrier. A member, an image carrier on which a latent image is developed by the developer carrier, a transfer body to which an image on the image carrier is transferred, a reservoir in which a liquid developer is stored, a storage unit in the storage unit A levitation member that moves following the liquid level of the liquid developer, a first magnetic field generator disposed on the levitation member and having an N pole directed in a first direction, and the first magnetic field generator on the levitation member And a second magnetic field generator with the S pole facing in the first direction, and the first magnetic field generator and the second magnetic field generation at positions facing the first direction. Liquid quantity measuring device having a plurality of proportional output Hall elements for detecting a magnetic field generated by a body Therefore, the liquid level of the liquid developer can be continuously measured by proportional output, the deficient amount of the liquid developer can be detected as a continuous value, and the liquid level of the liquid developer can be accurately measured. It is possible to form an image with high image quality.

  In addition, since the position adjustment mechanism for adjusting the position of the liquid amount measuring device in the vertical direction is provided, the degree of design freedom can be increased.

  In addition, since the liquid developer storage unit has a supply path for supplying the liquid developer to the developer container, and the plurality of proportional output Hall elements of the liquid amount measuring device are arranged in the supply path, It becomes possible to improve the detection accuracy.

  Further, a movable member movable within the storage unit, a light emitting member, a light receiving member that receives light emitted from the light emitting member, a gap portion in which the moving member can move between the light emitting member and the light receiving member, And a density measuring device having a density measuring unit that measures the concentration of the liquid developer from the output of the light receiving member when the moving member is in the gap and when the moving member is not in the gap, and the supply Since the wiring of the concentration measuring device arranged along the path is included, the number of parts can be reduced and the wiring can be stably held.

  A stirring path for collecting the liquid developer in the storage unit; a stirring propeller that stirs the liquid developer in the storage unit; and a stirring propeller shaft that rotatably supports the stirring propeller. Is arranged so as to overlap the recovery path when viewed from the stirring propeller axial direction, so that the newly recovered or replenished liquid developer can be rapidly stirred.

  In addition, since the levitation member has a facing surface that faces the proportional output Hall element, it is possible to reduce the flow of the liquid developer and improve the accuracy of each Hall element.

  In addition, since the levitation member has a rounded acute end on the opposite side of the facing surface, the liquid developer can easily flow.

  In addition, a liquid level determination unit that determines the liquid level measured by the liquid level measurement device, a liquid level control unit that controls the liquid level according to the determination result of the liquid level determination unit, and the measurement of the concentration measurement device A concentration determination unit that determines the concentration, a concentration control unit that controls the concentration of the liquid developer in the storage unit according to a determination result of the concentration determination unit, the liquid level control unit, and the concentration control unit; Therefore, the image forming apparatus can be controlled according to the liquid amount and concentration of the liquid developer, and an image can be formed with good image quality according to the state.

  In addition, when the liquid amount measured by the liquid amount measuring device is larger than a predetermined amount, the liquid level control unit includes a liquid supply amount calculating unit that prohibits the introduction of the liquid amount, and thus it is possible to eliminate overflow and the like. .

  Further, when the concentration measured by the concentration measuring device is higher than the first predetermined concentration or lower than the second predetermined concentration set lower than the first predetermined concentration, the liquid feeding amount for stopping printing by the concentration determination unit Since the calculation unit is included, an image is not formed with poor image quality.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing main components constituting the image forming apparatus according to the embodiment of the present invention. The developing units 30Y, 30M, 30C, and 30K, and the developer collection and supply devices 70Y, 70M, 70C, and 70K are disposed at the lower portion of the image forming apparatus with respect to the image forming sections of the respective colors disposed in the center of the image forming apparatus. The intermediate transfer member 40 and the secondary transfer unit 60 are disposed on the upper part of the image forming apparatus.

  The image forming unit includes image carriers 10Y, 10M, 10C, and 10K, charging rollers 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 bearing members 10Y, 10M, 10C, and 10K are uniformly charged by the charging rollers 11Y, 11M, 11C, and 11K. The exposure units 12Y, 12M, 12C, and 12K irradiate modulated laser light based on the input image signal to form electrostatic latent images on the charged image carriers 10Y, 10M, 10C, and 10K. Form.

  The developing units 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, and the like, and the electrostatic latent images formed on the image carriers 10Y, 10M, 10C, and 10K are developed with liquid developers of respective colors.

  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 units 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. A fixing unit (not shown) is disposed behind the sheet material conveyance path L, and a single-color toner image or a full-color toner image transferred onto the sheet material is fused and fixed to a recording medium (sheet material) such as paper. Image formation on the final sheet material is completed.

  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 units 30Y, 30M, 30C, and 30K, and a developer container 31Y. , 31M, 31C, 31K.

  Next, the image forming unit and the developing unit will be described. FIG. 2 is a cross-sectional view showing main components of the image forming unit and the developing unit. 3 is a view for explaining the developer supply member, FIG. 4 is a view for explaining the compression of the developer by the developer compression roller 22Y, FIG. 5 is a view for explaining the development by the development roller 20Y, and FIG. 6 is an image carrier squeeze. It is a figure explaining the squeeze effect | action by the roller 13Y. Since the configurations of the image forming unit and the developing unit for each color are the same, the following description will be made based on the yellow (Y) image forming unit and the developing unit.

  The image forming unit includes, along the rotation direction of the outer periphery of the image carrier 10Y, a cleaning device including a static eliminator 16Y, an image carrier cleaning blade 17Y, and a developer recovery unit 18Y, a corona charger 11Y, an exposure unit 12Y, and a development unit. A squeeze device comprising a 30Y developing roller 20Y, an image carrier squeeze roller 13Y, and an image carrier squeeze roller cleaning blade 14Y is disposed. In the developing unit 30Y, a cleaning blade 21Y and a developer supplying roller 32Y using an anilox roller are arranged on the outer periphery of the developing roller 20Y. The stirring paddle 36Y and the developer supplying roller 32Y are placed in the liquid developer container 31Y. Contained. A primary transfer roller 51Y of the primary transfer portion is disposed along the intermediate transfer body 40 at a position facing the image carrier 10Y.

  The image carrier 10Y is a photosensitive drum made of a cylindrical member having a width wider than about 320 mm of the developing roller 20Y and a photosensitive layer formed on the outer peripheral surface. For example, the image carrier 10Y rotates in a clockwise direction as shown in FIG. To do. The photosensitive layer of the image carrier 10Y is composed of an organic image carrier or an amorphous silicon image carrier. The charging roller 11Y is disposed upstream of the nip portion between the image carrier 10Y and the developing roller 20Y in the rotation direction of the image carrier 10Y, and a bias having the same polarity as the charging polarity of the developing toner particles is applied from a power supply device (not shown). Then, the image carrier 10Y is charged. The exposure unit 12Y exposes the image carrier 10Y charged by the charging roller 11Y downstream of the charging roller 11Y in the rotation direction of the image carrier 10Y, and forms a latent image on the image carrier 10Y.

  The developing unit 30Y stirs the developer container 31Y that stores the liquid developer in a state where the toner is dispersed in a carrier liquid in an approximate weight ratio of about 25%, the developing roller 20Y that carries the liquid developer, and the liquid developer. The developer supply roller 32Y, the regulating blade 33Y, the agitation paddle 36Y, and the agitation paddle 36Y for supplying the developer to the developing roller 20Y while maintaining a uniformly dispersed state are supplied from the liquid developer reservoir 71Y described later. The liquid developer scraped by the supply unit 35Y, the developing roller cleaning blade 21Y for cleaning the developing roller 20Y, the developing roller cleaning blade 21Y, and the image carrier squeeze roller cleaning blade 14Y is collected, and a liquid developer storage unit to be described later It has a recovery screw 34Y to be sent to 71Y.

  The liquid developer accommodated in the developer container 31Y is a low concentration (about 1 to 2 wt%) and low viscosity, which is conventionally used, using Isopar (trademark: Exxon) as a carrier liquid. It is not a volatile liquid developer having volatility, but a non-volatile liquid developer having a high concentration and high viscosity and having non-volatility at room temperature. That is, in the liquid developer in the present invention, a solid having an average particle diameter of 1 μm in which a colorant such as a pigment is dispersed in a thermoplastic resin is introduced into a liquid solvent such as an organic solvent, silicon oil, mineral oil, or edible oil. It is a liquid developer having a high viscosity (about 30 to 10,000 mPa · s) which is added together with a dispersant and has a toner solid content concentration of about 25%.

  As shown in FIG. 3, the developer supply roller 32 </ b> Y is a cylindrical member, and an anilox roller having an uneven surface formed by a fine and uniform spiral groove on the surface so as to easily carry the developer on the surface. For example, as shown in FIG. 2, it rotates in the clockwise direction. The groove dimensions are such that the groove pitch is about 130 μm and the groove depth is about 30 μm. The developer supply roller 32Y supplies the liquid developer from the developer container 31Y to the developing roller 20Y. The agitation paddle 36Y and the developer supply roller 32Y may be in sliding contact with each other, but may be in a disposition relationship.

  The regulating blade 33Y is composed of an elastic blade whose surface is covered with an elastic body, a rubber portion made of urethane rubber or the like that contacts the surface of the developer supply roller 32Y, and a metal plate or the like that supports the rubber portion. The Then, the film thickness and amount of the liquid developer carried and conveyed by the developer supply roller 32Y composed of an anilox roller are regulated and adjusted, and the amount of liquid developer supplied to the developing roller 20Y is adjusted. Note that the rotation direction of the developer supply roller 32Y may be the opposite direction instead of the arrow direction shown in FIG. 2, and the regulating blade 33Y at that time requires an arrangement corresponding to the rotation direction.

  The developing roller 20Y is a cylindrical member having a width of about 320 mm, and rotates counterclockwise around the rotation axis as shown in FIG. The developing roller 20Y is provided with an elastic layer made of polyurethane rubber, silicon rubber, NBR or the like on the outer periphery of an inner core made of metal such as iron. The developing roller cleaning blade 21Y is made of rubber or the like that comes into contact with the surface of the developing roller 20Y. The developing roller 20Y is arranged downstream of the developing nip portion where the developing roller 20Y comes into contact with the image carrier 10Y in the rotation direction of the developing roller 20Y. The liquid developer remaining on the developing roller 20Y is scraped off and removed.

  The developer compression roller 22Y is a cylindrical member, and is in the form of an elastic roller configured to cover the elastic body 22-1Y as in the case of the developing roller 20Y as shown in FIG. For example, as shown in FIG. 2, it rotates clockwise in the direction opposite to the developing roller 20Y. The developer compression roller 22Y has means for increasing the charging bias on the surface of the development roller 20Y. The developer conveyed by the development roller 20Y is in sliding contact with the developer compression roller 22Y as shown in FIGS. Then, an electric field is applied from the developer compression roller 22Y side toward the development roller 20Y at the developer compression site forming the nip. The electric field applying means for the developer compression may be corona discharge from a corona discharger instead of the roller shown in FIG.

  With this developer compression roller 22Y, as shown in FIG. 4, the toner T uniformly dispersed in the carrier liquid C is moved to the developing roller 20Y side to be aggregated to form a so-called developer compressed state T ′. A part of the liquid C and a small amount of toner T ″ that is not compressed by the developer are carried and rotated in the direction of the arrow in the drawing, scraped off by the developer compression roller cleaning blade 23Y, and merged with the developer in the reservoir 31Y. On the other hand, the developer D, which is carried on the developing roller 20Y and compressed by the developer, is in a desired nip portion where the developing roller 20Y contacts the image carrier 10Y as shown in FIG. By applying an electric field, development is performed corresponding to the latent image on the image carrier 10Y, and the remaining developer D is scraped off by the developing roller cleaning blade 21Y. Is removed by by merging and re-used in the developer in the reservoir 31Y. The carrier liquid and toner that these joins are not mixed color state.

  The image carrier squeeze device is disposed on the downstream side of the developing roller 20Y so as to face the image carrier 10Y and collects the excess developer of the toner image developed on the image carrier 10Y, as shown in FIG. Thus, the surface is covered with the elastic body 13aY, and the image carrier squeeze roller 13Y is formed of an elastic roller member that is slidably contacted with the image carrier 10Y. The image carrier squeeze roller 13Y is pressed and slidably contacted to clean the surface. And a cleaning blade 14Y.

  In the primary transfer unit 50Y, the developer image developed on the image carrier 10Y is transferred to the intermediate transfer member 40 by the primary transfer roller 51Y. Here, the image carrier 10Y and the intermediate transfer member 40 are configured to move at a constant speed, reducing the driving load of rotation and movement, and suppressing the disturbance effect on the visible toner image of the image carrier 10Y. Yes.

  The developer recovery and supply device 70Y stores the recovered liquid developer, supplies high concentration developer from the developer tank 74Y, and carrier liquid from the carrier liquid tank 77Y, and serves as an example of a container unit for adjusting the concentration. A liquid developer storage portion 71Y is provided.

  In the present embodiment, the liquid developer is recovered from the developing unit 30Y and the image carrier 10Y. The liquid developer recovered by the developer recovery screw 34Y of the developing unit 30Y is recovered in the liquid developer storage portion 71Y via the development unit recovery path 72Y. 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 in the liquid developer storage unit 71Y via the image carrier recovery path 73Y. Is done.

  Further, the high-concentration developer is supplied from the developer tank 74Y to the liquid developer storage portion 71Y via the developer supply path 75 and the developer pump 76. The carrier liquid is replenished from the carrier liquid tank 77Y to the liquid developer reservoir 71Y via the carrier liquid replenishment 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 etc. using gravity instead of a pump etc.

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

  Next, the operation of the image forming apparatus of the present invention will be described. Subsequently, the image forming unit and the developing unit will be described by taking the yellow image forming unit and the developing unit 30Y among the four image forming units and the developing unit as an example.

  In the developer container 31Y, the toner particles in the liquid developer have a positive charge. The liquid developer is stirred by the stirring paddle 36Y, and the developer supply roller 32Y rotates, whereby the developer container 31Y. Pumped from.

  The regulating blade 33Y is in contact with the surface of the developer supply roller 32Y and scrapes off other excess liquid developer while leaving the liquid developer in the uneven grooves of the anilox pattern formed on the surface of the developer supply roller 32Y. Thus, the amount of liquid developer supplied to the developing roller 20Y is regulated. By such regulation, the film thickness of the liquid developer applied to the developing roller 20Y is quantified so as to be about 6 μm. The liquid developer scraped off by the regulating blade 33Y falls back to the developer container 31Y due to gravity, and the liquid developer that has not been scraped off by the regulating blade 33Y forms an uneven groove on the surface of the developer supply roller 32Y. It is accommodated inside and is applied to the surface of the developing roller 20Y by being pressed against the developing roller 20Y.

  The developing roller 20Y coated with the liquid developer by the developer supply roller 32Y contacts the developer compression roller 22Y downstream of the nip portion with the developer supply roller 32Y. A bias of about +400 V is applied to the developing roller 20Y, and a bias having a polarity higher than that of the developing roller 20Y and the same polarity as the toner charging polarity is applied to the developer compression roller 22Y. For example, a bias of about +600 V is applied to the developer compression roller 22Y. Therefore, the toner particles in the liquid developer on the developing roller 20Y move toward the developing roller 20Y when passing through the nip with the developer compression roller 22Y as shown in FIG. As a result, the toner particles are gently coupled to form a film, and when developing with the image carrier 10Y, the toner particles move from the developing roller 20Y to the image carrier 10Y quickly, and the image density is improved. To do.

  The image carrier 10Y is made of amorphous silicon. The surface of the image carrier 10Y is charged to about + 600V by the charger 11Y upstream of the nip portion with the developing roller 20Y, and then the latent image is set so that the potential of the image portion becomes + 25V by the exposure unit 12Y. An image is formed. In the developing nip portion formed between the developing roller 20Y and the image carrier 10Y, the bias + 400V applied to the developing roller 20Y and the latent image (image portion + 25V, non-image portion + 600V) applied to the image carrier 10Y. According to the formed electric field, as shown in FIG. 5, the toner particles T are selectively moved to the image portion on the image carrier 10Y, whereby a toner image is formed on the image carrier 10Y. Further, since the carrier liquid C is not affected by the electric field, as shown in FIG. 5, it is separated at the exit of the developing nip between the developing roller 20Y and the image carrier 10Y, and both the developing roller 20Y and the image carrier 10Y are separated. Adhere to.

  The image carrier 10Y that has passed through the development nip passes through the image carrier squeeze roller 13Y. As shown in FIG. 6, the image carrier squeeze roller 13Y collects excess carrier liquid C and originally unnecessary fog toner T ″ from the developer D developed on the image carrier 10Y, and the toner particle ratio in the visible image The recovery capability of the surplus carrier liquid C is desired depending on the rotation direction of the image carrier squeeze roller 13Y and the difference in the peripheral speed of the surface of the image carrier squeeze roller 13Y with respect to the peripheral speed of the surface of the image carrier 10Y. The recovery capability increases when the image carrier 10Y is rotated in the counter direction, and the recovery capability increases even if the peripheral speed difference is set large. An action is also possible.

  In the present embodiment, as shown in FIG. 6, as an example, the image carrier squeeze roller 13Y is rotated with the rotation of the image carrier 10Y at substantially the same peripheral speed, and the weight ratio from the developer D developed on the image carrier 10Y is increased. The excess carrier liquid C of about 5 to 10% is collected to reduce both rotational driving loads and suppress the disturbance effect on the visible toner image of the image carrier 10Y. Excess carrier liquid C and unnecessary fog toner T ″ collected by the image carrier squeeze roller 13Y are collected from the image carrier squeeze roller 13Y to the developer container 31Y by the action of the cleaning blade 14Y. Since the surplus carrier liquid C and fog toner T ″ are collected from the dedicated isolated image carrier 10Y, the color mixing phenomenon does not occur at all locations.

  Next, the image carrier 10Y passes through the nip portion with the intermediate transfer body 40 in the primary transfer 50Y, and the primary transfer of the visible toner image to the intermediate transfer body 40 is performed. The primary transfer roller 51Y is applied with about −200 V having the opposite polarity to the charging characteristics of the toner particles, so that the toner is primarily transferred from the image carrier 10Y to the intermediate transfer member 40, and the carrier liquid is transferred to the image carrier 10Y. Only remains. On the downstream side in the rotation direction of the image carrier 10Y from the primary transfer portion, the electrostatic latent image of the image carrier 10Y after the primary transfer is erased by the static eliminator 16Y composed of an LED or the like and remains on the image carrier 10Y. The carrier liquid is scraped off by the image carrier cleaning blade 17Y and recovered by the developer recovery unit 18Y.

  The toner images on the intermediate transfer body 40, which are sequentially transferred by primary transfer of the toner images formed on the plurality of image carriers 10, are then transferred to the secondary transfer unit 60, where the intermediate transfer body 40 and the secondary transfer are transferred. It enters the nip portion with the roller 61. The nip width at this time is set to 3 mm. In the secondary transfer unit 60, −1200 V is applied to the secondary transfer roller 61 and +200 V is applied to the belt driving roller 41, whereby the toner image on the intermediate transfer member 40 is a recording medium such as paper. Transferred to (sheet material).

  However, when a sheet material supply trouble such as jam occurs, not all the toner images are transferred to the secondary transfer roll and collected, and a part of the toner image remains on the intermediate transfer body, and the normal secondary image is not recovered. Even in the transfer process, the toner image on the intermediate transfer member is not 100% secondary transferred and transferred to the sheet material, and a secondary transfer residue of several percent occurs. In particular, when a sheet material supply trouble such as a jam occurs, the toner image is transferred in contact with the secondary transfer roller 61 without the sheet material interposed, and the back surface of the sheet material is stained. In this embodiment, the secondary transfer roller 61 has a bias in the direction in which the toner particles of the liquid developer are pressed against the intermediate transfer body and a bias having the same polarity as the charging polarity of the toner particles. Apply. As a result, the toner particles of the liquid developer remaining on the intermediate transfer body 40 are pressed against the intermediate transfer body 40 so as to be in a compacted state, and the carrier liquid is collected (squeezed) on the secondary transfer roller 61 side. Cleaning of the intermediate transfer body 40 by the body cleaning blade 46 and cleaning of the secondary transfer roller 61 by the secondary transfer roller cleaning blade 62 are performed.

  Next, the cleaning device for the intermediate transfer member 40 will be described. When a sheet material supply trouble such as a jam occurs, all the toner images are transferred to the secondary transfer roller 61 and are not collected, but a part of the toner image remains on the intermediate transfer body 40. Further, in the normal secondary transfer process, the toner image on the intermediate transfer member 40 is secondarily transferred 100% and is not transferred to the sheet material, and a secondary transfer residue of several percent is generated. The two types of unnecessary toner images are collected by an intermediate transfer member cleaning blade 46 and a developer collecting unit 47 arranged so as to contact the intermediate transfer member 40 for the next image formation. During such non-transfer, a bias is applied to the secondary transfer roller 61 so as to press the residual toner on the intermediate transfer member 40 against the intermediate transfer member 40.

  Next, the liquid amount measuring device 110Y will be described. As shown in FIG. 2, the liquid amount measuring device 110Y includes a float supporting member 111Y, a regulating member 112Y, a first Hall element 113Y, a second Hall element 114Y, a third Hall element 115Y as an example of a proportional output Hall element, It has a float 116Y, a first magnetic field generator 117Y and a second magnetic field generator 118Y as an example of a levitation member.

The float support member 111Y is a member that movably supports the float 116Y from above the liquid level in the liquid developer storage portion 71Y to a substantially bottom portion below the liquid level. The upper restriction member 112aY is upward and the lower restriction member is downward. 112bY is provided, and a first Hall element 113Y, a second Hall element 114Y, and a third Hall element 115Y are sequentially provided from the bottom with a predetermined distance therebetween.
The first Hall element 113Y, the second Hall element 114Y, and the third Hall element 115Y are proportional output Hall elements whose output voltage changes with respect to the magnetic flux density. In the present embodiment, the distance between the Hall elements is 30 mm.

  The float 116Y floats on the liquid surface and is movable relative to the float support member 111Y depending on the liquid surface position. The float 116Y includes a first magnetic field generator 117Y below and a second magnetic field generator 118Y above a predetermined distance. .

  The first magnetic field generator 117Y and the second magnetic field generator 118Y are provided so as to move facing the hall elements 113Y, 114Y, 115Y as the float 116Y moves. The first magnetic field generator 117Y and the second magnetic field generator 118Y are arranged so that the N pole and the S pole are reversed. In the present embodiment, magnetic field generators 117Y and 118Y having a diameter of 5 mm, a length of 6 mm, and 4000 gauss are arranged with a distance of 20 mm.

  A method for converting the output of each Hall element 113Y, 114Y, 115Y when the liquid amount measuring apparatus 110Y having such a configuration is actually operated to a distance will be described.

  FIG. 7 is a diagram showing a table for converting the outputs of the hall elements 113Y, 114Y, and 115Y into distances. FIG. 7A is a first table showing the relationship between the output voltage of each Hall element when the S pole is sensed and the distance, and FIG. 7B is the output voltage of each Hall element when the N pole is sensed. FIG. 7C is a third table showing the relationship between the output voltage of each Hall element and the distance when the inverted N pole is sensed.

  FIG. 8 is a flowchart for converting the output of each Hall element 113Y, 114Y, 115Y into a distance.

  First, in step 1, it is determined whether the outputs of all the Hall elements 113Y, 114Y, 115Y are 2.5V (ST1).

  If the outputs of all the Hall elements 113Y, 114Y, 115Y are 2.5V in Step 1, the previous measurement result is used as the liquid surface position in Step 11 (ST11), and the process ends. If the outputs of all the Hall elements 113Y, 114Y, 115Y are not 2.5V in Step 1, it is determined in Step 2 whether the output of the first Hall element 113Y is less than 2.5V (ST2).

  If the output of the first Hall element 113Y is smaller than 2.5V in Step 2, the liquid level position is the value obtained from the first table for the distance to the output of the first Hall element 113Y in Step 12 (ST12), and the process ends. To do. In Step 2, when the output of the first Hall element 113Y is larger than 2.5V, in Step 3, the output of the first Hall element 113Y is larger than 2.5V and the output of the second Hall element 114Y is 2.5V. It is determined whether it exists (ST3).

  If the condition in Step 3 is satisfied, in Step 13, the liquid surface position is set to a value obtained by adding the distance to the output of the first Hall element 113Y to the value obtained from the second table by 10 mm (ST13), and the process ends. If the condition in Step 3 is not satisfied, it is determined in Step 4 whether the output of the first Hall element 113Y is greater than 2.5V (ST4).

  If the condition in Step 4 is satisfied, in Step 14, the liquid surface position is set to a value obtained by adding 20 mm to the value obtained from the third table for the distance to the output of the first Hall element 113Y (ST14), and the process ends. If the condition in Step 4 is not satisfied, it is determined in Step 5 whether the output of the second Hall element 114Y is smaller than 2.5V (ST5).

  If the condition in Step 5 is satisfied, in Step 15, the liquid surface position is set to a value obtained by adding 30 mm to the value obtained from the first table for the distance to the output of the second Hall element 114Y (ST15), and the process ends. If the condition in Step 5 is not satisfied, it is determined in Step 6 whether the output of the second Hall element 114Y is greater than 2.5V and the output of the third Hall element 115Y is 2.5V (ST6).

  If the condition in step 6 is satisfied, in step 16, the liquid surface position is set to a value obtained by adding the distance to the output of the second hall element 114Y to the value obtained from the second table by 40 mm (ST16), and the process ends. If the condition in Step 16 is not satisfied, it is determined in Step 7 whether the output of the second Hall element 114Y is greater than 2.5V (ST7).

  If the condition in Step 7 is satisfied, in Step 17, the liquid level position is set to a value obtained by adding the distance to the output of the second Hall element 114Y to the value obtained from the third table by 50 mm (ST17), and the process ends. If the condition in Step 7 is not satisfied, it is determined in Step 8 whether the output of the third Hall element 115Y is smaller than 2.5V (ST8).

  If the condition in step 8 is satisfied, in step 18, the liquid surface position is set to a value obtained by adding the distance to the output of the third hall element 115Y to the value obtained from the first table by 60 mm (ST18), and the process ends. If the condition in Step 8 is not satisfied, it is determined in Step 9 whether the output of the third Hall element 115Y is greater than 2.5V and the output of the second Hall element 114Y is 2.5V (ST9).

  If the condition in Step 9 is satisfied, in Step 19, the liquid surface position is set to a value obtained by adding 70 mm to the value obtained from the third table for the distance to the output of the third Hall element 115Y (ST19), and the process ends. If the condition in step 9 is not satisfied, an error is determined in step 10 (ST10), and the process ends.

  FIG. 9 is a diagram showing a result of executing the flowchart shown in FIG. As shown in FIG. 9, the liquid level position corresponding to the output of each Hall element 113Y, 114Y, 115Y can be obtained.

  With such a liquid amount measuring device 110Y, the number of components is small, the cost can be kept low, and a long distance can be detected, so that the system can be stopped from being stopped.

  As another embodiment, a concentration measuring device 120Y as shown in FIG. 10 may be provided.

  As shown in FIG. 10, the concentration measuring device 120Y includes a stirring propeller shaft 121Y, a transparent propeller 122Y as an example of a moving member, a stirring propeller 123Y as an example of a stirring member, a motor 124Y, and a concentration measuring unit 130Y. Have

  The stirring propeller shaft 121Y is a member that is provided with a transparent propeller 122Y and a stirring propeller 123Y coaxially and is rotated by a motor 124Y.

  Next, a density detection method using the density measuring unit 130Y and the transparent propeller 122Y will be described. 11 is an enlarged view of the vicinity of the transparent propeller 122Y in FIG. 2, FIG. 12 is an enlarged view of the gap portion, FIG. 13 is a diagram showing a change in the signal output from the density measuring light receiving element 132Y, and FIG. 14 is a density measuring light receiving element. FIG. 15 is a system diagram of the transmission type density measurement unit 130Y, and FIG. 16 is a system diagram of the reflection type density measurement unit 130Y. The graph shows the relationship between the 132Y output voltage and the liquid developer concentration.

  As shown in FIG. 11, the transparent propeller 122Y is supported by the stirring propeller shaft 121Y and is made of a flat plate member such as a rotatable rectangle. The gap 130cY between the first member 130aY and the second member 130bY of the concentration measuring unit 130Y. It has a structure that passes through the inside intermittently. The first member 130aY or the second member 130bY can move, and the distance 130cY can be changed. Further, the distance of the gap 130cY can be varied depending on the color of the liquid developer.

  Next, a simple principle of the concentration detection method will be described. FIG. 12 is an enlarged view of the gap portion, and FIG. 13 is a diagram showing a change in a signal output from the density measuring light receiving element 132Y. When the transparent propeller 122Y is not positioned between the light emitting LED 131 and the density measuring light receiving element 132Y as shown in FIG. 12A, the density measuring light receiving element 132Y has a small value Fo in the graph shown in FIG. The signal is output. When the transparent propeller 122Y is positioned between the light emitting LED 131 and the density measuring light receiving element 132Y as shown in FIG. 12B, the density measuring light receiving element 132Y has a large value Fi in the graph shown in FIG. The signal is output. In the present embodiment, a value for obtaining a density value is selected for each color. For example, black averages the value Fi to obtain a density value, and cyan averages the value Fo to obtain a density value.

  FIG. 14 is a graph showing the relationship between the output voltage of the density measuring light receiving element 132Y and the liquid developer concentration. FIG. 14A shows the relationship between the output voltage of the density measuring light receiving element 132Y in black and the liquid developer concentration, and FIG. 14B shows the output voltage of the density measuring light receiving element 132Y in cyan and the liquid development. The relationship with the agent concentration is shown.

  In the transmission type density measuring unit 130Y as shown in FIG. 15, a light emitting LED 131Y as an example of a density measuring member and a density measuring light receiving element 132Y are arranged facing each other with a gap 130cY interposed therebetween. On the light emitting LED 131Y side, a light emission intensity measuring light receiving element 133Y as a second light receiving element is arranged.

  With such a structure, the light emitted from the light emitting LED 131Y passes through the liquid developer on the light emitting LED 131Y side from the transparent propeller 122Y, the liquid developer on the density measuring light receiving element 132Y side from the transparent propeller 122Y and the transparent propeller 122Y, It has an optical path received by the density measuring light receiving element 132Y and an optical path received by the light emitting intensity measuring light receiving element 133Y without passing through the transparent propeller 122Y or the liquid developer.

  The light emitting LED 131Y, the density measuring light receiving element 132Y, and the light emitting intensity measuring light receiving element 133Y are each connected to the CPU 134Y. The light emitting LED 131Y is connected to the CPU 134Y via the amplifier 135Y, the density measuring light receiving element 132Y is connected to the CPU 134Y via the first A / D converter 136Y, and the light emitting intensity measuring light receiving element 133Y is connected to the second A / D converter 137. To the CPU 134Y.

  In the reflection type density measuring unit 130Y as shown in FIG. 16, a light emitting LED 131Y, a density measuring light receiving element 132Y, and a light emitting intensity measuring light receiving element 133Y are arranged on one side with respect to the gap 130cY. A reflective film 140Y is disposed on the other side of the gap 130cY.

  With such a structure, the light emitted from the light emitting LED 131Y passes through the liquid developer on the light emitting LED 131Y side, the transparent propeller 122Y, and the liquid developer on the reflective film 140Y side from the transparent propeller 122Y, and is reflected by the reflective film 140Y. An optical path that passes through the liquid developer on the reflective film 140Y side, the transparent propeller 122Y, and the liquid developer on the density measuring light receiving element 132Y side from the transparent propeller 122Y and is received by the density measuring light receiving element 132Y, and the transparent propeller 122Y And a light path that passes through the liquid developer on the light emitting LED 131Y side and is received by the light receiving element 133Y for light emission intensity measurement.

  The light emitting LED 131Y, the density measuring light receiving element 132Y, and the light emitting intensity measuring light receiving element 133Y are each connected to the CPU 134Y. The light emitting LED 131Y is connected to the CPU 134Y via the amplifier 135Y, the density measuring light receiving element 132Y is connected to the CPU 134Y via the first A / D converter 136Y, and the light emitting intensity measuring light receiving element 133Y is connected to the second A / D converter 137Y. To the CPU 134Y.

  Next, a detection method of the concentration measuring apparatus 120Y having such a configuration will be described. FIG. 17 is a diagram illustrating a detection flowchart of the concentration measuring apparatus 120Y.

  First, in step 21, the light emitting LED 131Y is turned on (ST21). Subsequently, at step 22, the light intensity of the light emitting LED 131Y is measured by the light receiving element 133Y for measuring light emission intensity (ST22).

  Next, in step 23, the correction value α is calculated (ST23). The correction value α is obtained by comparing the reference value of the light emitting LED 131Y stored in advance with the measured value measured by the light receiving element 133Y for measuring light emission intensity.

  Next, in step 24, the density is measured by the density measuring light receiving element 132Y (ST24).

  Subsequently, in step 25, the CPU 134Y executes density correction to determine the density of the liquid developer (ST25). The density of the liquid developer is obtained from the product of the density measuring light receiving element 132Y measured in step 24 and the correction value α obtained in step 23.

  Next, in step 26, it is determined whether the concentration of the liquid developer is lower than a concentration reference value stored in advance (ST26). When it is determined that the developer is thin, the high-concentration developer is supplied from the developer tank 74Y to the liquid developer reservoir 71Y via the developer supply path 75Y and the developer pump 76Y.

  If it is not determined in step 26 that it is light, it is determined in step 27 whether the concentration of the liquid developer is higher than the concentration reference value stored in advance (ST27). If it is determined that the concentration is high, the carrier liquid is supplied from the carrier liquid tank 77Y to the liquid developer storage portion 71Y via the carrier liquid supply path 78Y and the carrier liquid pump 79Y.

  By controlling in this way, the concentration of the liquid developer in the liquid developer reservoir 71Y becomes substantially constant.

  Next, control of the developer pump 76Y and the carrier liquid pump 79Y will be described. The control amount of the developer pump 76Y or the carrier liquid pump 79Y is controlled according to the toner amount of the liquid developer or the shortage amount of the carrier liquid amount.

  First, the toner amount and the carrier liquid amount of the liquid developer are calculated by the liquid amount measuring device 110Y and the concentration measuring device 120Y shown in FIG. Then, a deficiency with respect to the target values of the toner amount and carrier liquid amount of the liquid developer stored in advance is calculated.

  FIG. 18 is a diagram showing the rotational speeds and DUTY values of the developer pump 76Y and the carrier liquid pump 79Y with respect to the toner amount or the carrier liquid shortage amount. As shown in FIG. 18, the developer pump 76Y and the carrier liquid pump 79Y keep the rotational speed constant up to the upper limit DUTY value, and change the DUTY value according to the shortage amount. After reaching the upper limit DUTY value, the rotational speed is increased according to the shortage amount.

  Next, the control with respect to the priority of the control in the printing state will be described. FIG. 19 is a diagram illustrating the control priority with respect to the liquid amount and concentration of the liquid developer in the liquid developer storage portion 71Y.

  As shown in FIG. 19, the liquid amount priority mode for controlling the developer recovery and supply device 70Y according to the measurement result of the liquid amount measurement device 110Y, and the developer recovery and supply device 70Y according to the measurement result of the density measurement device 120Y. A density priority mode to be controlled. Further, when the liquid amount measured by the liquid amount measuring device 110Y is larger than the first predetermined amount, the liquid amount priority mode is set and the introduction of the liquid amount is prohibited.

  If the density measured by the density measuring device 120Y is higher than the first predetermined density or lower than the second predetermined density set lower than the first predetermined density, printing is stopped. When the concentration measured by the concentration measuring device 120Y is lower than the first predetermined concentration and higher than the second predetermined concentration, and the liquid amount measured by the liquid amount measuring device 110Y is lower than the first predetermined liquid amount, the second predetermined liquid amount If it is higher, the density priority mode is set, and a carrier liquid or a high-concentration developer is introduced according to the density and the liquid amount.

  For example, up to a certain amount of liquid, priority is given to the concentration. When the concentration is high, the carrier liquid is supplied from the carrier liquid tank 77Y to the liquid developer storage unit 71Y, and when the concentration is low, the high concentration developer is used as the developer. The liquid is stored in the reservoir 71Y of the liquid developer from the tank 74Y. Also, when giving priority to the amount of liquid, when the amount of liquid exceeds a predetermined amount, priority is given to the amount of liquid, and charging of the carrier liquid and the high-concentration developer is stopped regardless of the concentration. Printing continues. When the concentration is higher than the first predetermined concentration, lower than the second predetermined concentration set lower than the first predetermined concentration, or when the liquid amount is outside a certain range, the printing is stopped.

  Further, the developer concentration at the development nip may be controlled by controlling the speed of the developer compression roller 22Y or the developer supply roller 32Y according to the detected density.

  20 to 23 are diagrams showing another embodiment of the liquid amount measuring device 110Y and the concentration measuring device 120Y in the liquid developer storing portion 71Y. 20 is a perspective view of another embodiment, FIG. 21 is a sectional view of the other embodiment, FIG. 22 is a view of the other embodiment as viewed from below, and FIG. 23 is a schematic view of the other embodiment. The liquid amount measuring device 110Y and the concentration measuring device 120Y arranged in the liquid developer storage unit 71Y measure the liquid level and concentration of the liquid developer, as shown in FIG. In the present embodiment, the first Hall element 113Y, the second Hall element 114Y, and the third Hall element 115Y are developed for supplying the liquid developer from the liquid developer storage portion 71Y to the supply portion 31bY of the developer container 31Y. It distributes to the agent supply path 81Y.

  First, the liquid amount measuring device 110Y that is a liquid level sensor will be described. The liquid amount measuring device 110Y includes a float supporting member 111Y, a regulating member 112Y, a first Hall element 113Y as an example of a proportional output Hall element, a second Hall element 114Y, a third Hall element 115Y, and a float as an example of a floating member. 116Y, a first magnetic field generator 117Y, and a second magnetic field generator 118Y.

  The float support member 111Y supports the float 116Y so as to be movable from the liquid level in the yellow liquid developer reservoir 71Y to a measurable position below the liquid level. The regulating member 112Y is arranged in the concentration measuring unit 130Y of the concentration measuring device 120Y, and prevents interference between the float 116Y and the concentration measuring unit 130Y.

  The first Hall element 113Y, the second Hall element 114Y, and the third Hall element 115Y are provided in order from the bottom at a predetermined distance via a bracket or the like in the developer supply path 81Y.

  The first Hall element 113Y, the second Hall element 114Y, and the third Hall element 115Y are proportional output Hall elements whose output voltage changes with respect to the magnetic flux density. In the present embodiment, the distance between the Hall elements is 30 mm.

  The float 116Y floats on the liquid surface and is movable relative to the float support member 111Y depending on the liquid surface position. The float 116Y includes a first magnetic field generator 117Y below and a second magnetic field generator 118Y above a predetermined distance. . The first magnetic field generator 117Y and the second magnetic field generator 118Y are provided so as to move facing the hall elements 113Y, 114Y, 115Y as the float 116Y moves. The first magnetic field generator 117Y and the second magnetic field generator 118Y are arranged so that the N pole and the S pole are reversed. In the present embodiment, the first magnetic field generator 117Y faces the Hall elements 113Y, 114Y, and 115Y with the S pole facing the first direction, and the second magnetic field generator 117Y faces the N pole in the first direction. The Hall elements 113Y, 114Y, and 115Y are opposed to each other. The magnetic field generators 117Y and 118Y having a diameter of 5 mm, a length of 6 mm, and 4000 gauss are arranged with a distance of 20 mm.

  When the liquid level of the liquid developer changes, the float 116Y moves, and the distances between the first magnetic field generator 117Y and the second magnetic field generator 118Y and the Hall elements 113Y, 114Y, 115Y change. Due to this change in distance, the magnetic field detected by each Hall element 113Y, 114Y, 115Y changes, and the liquid level can be obtained from the detection value of each Hall element 113Y, 114Y, 115Y.

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

  Since the concentration measuring unit 130Y is substantially the same as the structure shown in FIGS. 11 and 12, the description of the same contents is omitted.

  The concentration measuring unit 130Y has a case formed of an insulating member such as plastic. The case has a gap 130cY, and the transparent propeller 122Y is supported by the stirring propeller shaft 121Y and is made of a flat plate member such as a rotatable rectangle, and includes a first portion 130aY and a second portion 130bY of the concentration measuring unit 130Y. It has a structure that passes through the gap 130cY intermittently. In addition, the 1st part 130aY or the 2nd part 130bY can move, and the clearance gap 130cY distance can be changed. Further, the distance of the gap 130cY can be varied depending on the color of the liquid developer.

  Further, the light emitting device has a light emitting LED 131Y, a density measuring light receiving element 132Y, a light emitting intensity measuring light receiving element 133Y, and the like, and these wirings 138Y are arranged in the developer supply path 81Y. The density measuring light receiving element 132Y, the light emission intensity measuring light receiving element 133Y, and the like are supported by the electrically floating metal plate 139Y, and the electrical influence on the density measuring unit 130Y can be reduced.

  Furthermore, the liquid amount measuring device 110Y and the concentration measuring device 120Y have a position adjusting mechanism 150Y that can adjust the height as a whole, and the whole position can be aligned, thereby increasing the degree of freedom in design.

  As shown in FIG. 22, when the embodiment is viewed from below, the agitation propeller 123Y rotates clockwise, and the developing unit recovery path 72Y, the image carrier recovery path 73Y, the developer supply path 75Y, and the carrier liquid It is arranged so as to overlap with at least one of the openings of the supply path 78Y. As a result, the newly collected or replenished liquid developer is rapidly stirred.

  Further, the float 116Y has a substantially fan-shaped cross section, and the end 116aY on the opposite side of each Hall element 113Y, 114Y, 115Y has a rounded acute angle so that the liquid developer can easily flow. Is formed. Further, the surface 116bY opposite to the end portion 116aY is opposed to each Hall element 113Y, 114Y, 115Y to reduce the flow of the liquid developer and to improve the accuracy of each Hall element 113Y, 114Y, 115Y. It has become.

  FIG. 24 is a block diagram showing the relationship between the liquid amount measurement device 110Y and the concentration measurement device 120Y and the developer recovery and supply device 70Y according to the present invention.

  The liquid level determination unit 210 determines whether or not the liquid volume measured by the liquid volume measuring device 110Y is greater than a predetermined volume. When the liquid level determination unit 210 determines that the liquid volume measured by the liquid volume measuring device 110Y is larger than the predetermined volume, the liquid supply volume calculation unit 200 enters the liquid volume priority mode and the liquid level control unit 201 to the pump motor control unit 230. Is output to prohibit the charging of the liquid developer. The pump motor control unit 230 prohibits the operation of pump motors such as the developer pump 76Y and the carrier liquid pump 79Y, and prohibits the introduction of the liquid developer. Therefore, it is possible to eliminate overflow and the like.

  The density measured by the density measuring device 120Y is determined by the density determination unit 220 to be higher or lower than the first predetermined density and the second predetermined density. When the density determination unit 220 determines that the density measured by the density measuring device 120Y is higher than the first predetermined density or lower than the second predetermined density that is lower than the first predetermined density, the density control unit 202 sets the density priority mode. Stop printing. Therefore, an image is not formed with poor image quality.

  As described above, the image forming apparatus according to the present invention develops according to the liquid amount priority mode for controlling the developer recovery and supply device 70Y according to the measurement result of the liquid amount measurement device 110Y and the measurement result of the density measurement device 120Y. A concentration priority mode for controlling the agent recovery and supply device 70Y, and a liquid amount priority mode and a concentration priority mode are selected by the liquid supply amount calculation unit 200 as a selection unit. Accordingly, the image forming apparatus can be controlled, and an image can be formed with good image quality according to the state.

  The liquid developer storage device according to the present invention includes a liquid developer storage unit 71Y, a liquid amount measurement device 110Y, a concentration measurement device 120Y, and the like.

  As described above, the liquid amount measuring device 110Y according to the present embodiment is arranged on the float 116Y that moves following the liquid surface of the liquid and the first magnetic field with the N pole directed in the first direction. The generator 117Y and the second magnetic field generator 118Y, which is arranged on the float 116Y and spaced apart from the first magnetic field generator 117Y and has the S pole in the first direction, are positioned opposite to each other in the first direction. , And having a plurality of proportional output Hall elements 113Y, 114Y, 115Y for detecting the magnetic fields generated by the first magnetic field generator 117Y and the second magnetic field generator 118Y, the liquid level is continuously measured by the proportional output, The liquid deficiency can be detected as a continuous value, and the liquid level of the liquid can be accurately measured.

  Further, since the float supporting member 111Y for guiding the movement of the float 116Y and the restricting member 112Y for restricting the movement of the float 116Y are provided, the limit point can be detected, and overflow or the like can be eliminated.

  Furthermore, the liquid developer storage device of the present invention includes a storage unit 71Y that stores a liquid developer containing toner particles in a carrier liquid, and a float 116Y that moves following the liquid level of the liquid developer in the storage unit 71Y. And the first magnetic field generator 117Y with the N pole directed in the first direction and the float 116Y spaced apart from the first magnetic field generator 117Y and in the first direction. A plurality of proportional output holes for detecting the magnetic fields generated by the first magnetic field generator 117Y and the second magnetic field generator 118Y at a position facing the first magnetic field generator 118Y with the S pole facing the first direction. Since the elements 113Y, 114Y, and 115Y and the liquid amount measuring device 110Y are provided, the liquid level of the liquid developer is continuously measured by a proportional output, and the deficiency of the liquid developer can be detected as a continuous value. , It is possible to accurately measure the liquid level of the liquid developer.

  In addition, the transparent propeller 122Y movable within the storage unit 71Y, the light emitting LED 131Y, the light receiving element 132Y for density measurement that receives light emitted from the light emitting LED 131Y, and the transparent propeller between the light emitting LED 131Y and the light receiving element 132Y for concentration measurement. Density measurement for measuring the density of the liquid developer from the output of the density measuring light receiving element 132Y when the gap Y is movable and the transparent propeller 122Y is in the gap 130aY and when the transparent propeller 122Y is not in the gap 130aY. Therefore, the liquid developer can be accurately adjusted to a desired liquid amount and density.

  In addition, since the float supporting member 111Y for guiding the movement of the float 116Y and the regulating member 112Y arranged in the concentration measuring unit and regulating the movement of the float 116Y are provided, the limit point can be detected, and an overflow or the like can be detected. Can be eliminated.

  Further, in the image forming apparatus of the present invention, the developer container 31Y, the developer carrier 20Y that carries the liquid developer, and the development that supplies the liquid developer stored in the developer container 31Y to the developer carrier 20Y. An agent supply member 32Y, an image carrier 10Y on which a latent image is developed by the developer carrier 20Y, a transfer body 40 to which an image on the image carrier 10Y is transferred, and a storage unit 71Y for storing a liquid developer. , A float 116Y that moves following the liquid level of the liquid developer in the reservoir 71Y, a first magnetic field generator 117Y that is disposed on the float 116Y and that has the N pole directed in the first direction, and the float 116Y Are spaced apart from the first magnetic field generator 117Y and the second magnetic field generator 118Y having the S pole directed in the first direction and the first magnetic field generator 117Y at a position facing the first direction. And second magnetic field generation Since it has a plurality of proportional output Hall elements 113Y, 114Y, 115Y for detecting a magnetic field generated by 118Y and a liquid amount measuring device 110Y, the liquid level of the liquid developer is continuously measured by a proportional output, The shortage of the liquid developer can be detected as a continuous value, the liquid level of the liquid developer can be accurately measured, and an image can be formed with good image quality.

  In addition, since the position adjusting mechanism 150Y as a position adjusting mechanism for adjusting the position of the liquid amount measuring device 110Y in the vertical direction is provided, the degree of freedom in design can be increased.

  In addition, a supply path 81Y for supplying the liquid developer from the liquid developer storage portion 71Y to the developer container 31Y is provided, and a plurality of proportional output type Hall elements 113Y, 114Y, 115Y are arranged in the supply path 81Y. The accuracy can be improved.

  In addition, the transparent propeller 122Y movable within the storage unit 71Y, the light emitting LED 131Y, the light receiving element 132Y for density measurement that receives light emitted from the light emitting LED 131Y, and the transparent propeller 122Y moves between the light emitting LED 131Y and the light receiving element 132Y for density measurement. A density measuring unit 130Y that measures the concentration of the liquid developer from the output of the density measuring light receiving element 132Y when the possible gap 130aY and the transparent propeller 122Y are in the gap 130aY and when the transparent propeller 122Y is not in the gap 130aY. And the concentration measuring device wiring 138Y arranged along the supply path 81Y, the number of parts can be reduced and the wiring 138Y can be stably held. It becomes possible.

  In addition, a recovery path for collecting the liquid developer to the storage unit 71Y, a stirring propeller that stirs the liquid developer in the storage unit, and a stirring propeller shaft that rotatably supports the stirring propeller, When viewed from the direction of the stirring propeller shaft, the liquid developer is arranged so as to overlap the recovery path, so that the newly recovered or replenished liquid developer can be rapidly stirred.

  Further, since the float 116Y has a facing surface that faces the proportional output Hall elements 113Y, 114Y, and 115Y, the flow of the liquid developer can be reduced and the accuracy of the Hall elements 113Y, 114Y, and 115Y can be improved. It becomes possible.

  Further, the float 116Y has a rounded acute end on the opposite side of the opposing surface, so that the liquid developer can easily flow.

  Further, the liquid level determination unit 210Y that determines the liquid amount measured by the liquid level measurement device, the liquid level control unit 201Y that controls the liquid amount according to the determination result of the liquid level determination unit 210Y, and the concentration measurement device 120Y A concentration determination unit 220Y that determines the measured concentration, a concentration control unit 202Y that controls the concentration of the liquid developer in the storage unit 71Y according to the determination result of the concentration determination unit 220Y, a liquid level control unit 201Y, and a concentration control The image forming apparatus can be controlled according to the liquid amount and concentration of the liquid developer, and an image can be formed with good image quality according to the state.

  Further, when the liquid amount measured by the liquid amount measuring device is larger than the predetermined amount, the liquid level control unit has a liquid supply amount calculating unit that prohibits the introduction of the liquid amount, so that overflow or the like can be eliminated.

  Further, when the concentration measured by the concentration measuring device is higher than the first predetermined concentration or lower than the second predetermined concentration set lower than the first predetermined concentration, the liquid amount calculation unit that stops printing by the concentration determination unit Therefore, an image is not formed with poor image quality.

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 unit. It is a perspective view of a developer supply member. It is a diagram for explaining the compression of the developer by the developer compression roller 22Y. It is a figure explaining the development by the developing roller 20Y. It is a figure explaining the squeeze effect | action by the image carrier squeeze roller 13Y. It is a figure which shows the table which converts the output of each Hall element 113,114,115 into distance. It is a flowchart which converts the output of each Hall element 113,114,115 into distance. It is a figure which shows the result of having performed the flowchart shown in FIG. It is the figure which provided the liquid quantity measuring device 110 and the density | concentration detection means 120. FIG. FIG. 3 is an enlarged view of the vicinity of a transparent propeller 122 in FIG. 2. It is an enlarged view of a clearance gap part. It is a figure which shows the change of the signal which the light receiving element 132Y for density | concentration measurement outputs. It is a graph which shows the relationship between the output voltage of light receiving element 132Y for density | concentration measurement, and a liquid developer density | concentration. FIG. 3 is a system diagram of a transmission type concentration measurement unit 130. 3 is a system diagram of a reflection type density measuring unit 130. FIG. It is a figure which shows the detection flowchart of the density | concentration detection means. It is a figure which shows the rotational speed and the DUTY value of the developer pump 76 and the carrier liquid pump 79 with respect to the insufficient amount of toner or carrier liquid. It is a figure which shows the control priority with respect to the liquid quantity and density | concentration of the liquid developer in the storage part 71Y of a liquid developer. FIG. 12 is a perspective view of another embodiment in a liquid developer storage portion 71Y. It is sectional drawing of other embodiment in the storage part 71Y of a liquid developer. It is the figure which looked at other embodiment in the storage part 71Y of a liquid developer from the downward direction. FIG. 11 is a schematic view of another embodiment in the liquid developer storage portion 71Y. FIG. 4 is a block diagram showing the relationship between a liquid amount measuring device 110Y and a concentration measuring device 120Y and a developer recovery and supply device 70Y according to the present invention.

Explanation of symbols

  10Y, 10M, 10C, 10K ... photosensitive body (image carrier), 11Y, 11M, 11C, 11K ... corona charger, 12Y, 12M, 12C, 12K ... exposure unit, 13Y ... image carrier squeeze roller, 14Y ... cleaning Blade, 16Y ... Static eliminating device, 17Y ... Photoconductor blade, 18Y ... Photoconductor cleaning liquid recovery unit, 20Y, 20M, 20C, 20K ... Developing roller (developer carrier), 21Y ... Developing roller blade, 30Y, 30M, 30C , 30K ... development unit, 31Y, 31M, 31C, 31K ... developer container, 31aY ... recovery unit, 31bY ... supply unit, 32Y, 32M, 32C, 32K ... developer supply roller (developer supply member), 33Y ... development Agent regulating blade (developer regulating member), 34Y ... recovery screw, 35Y ... communicating portion, 36Y ... agitated Paddle, 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, DESCRIPTION OF SYMBOLS 50 ... Primary transfer part, 51 ... Primary transfer roller, 60 ... Secondary transfer unit, 61 ... Secondary transfer roller, 62 ... Secondary transfer roller blade, 63 ... Secondary transfer roller cleaning liquid collection part, 70Y ... Developer collection Replenishing device, 71Y... Storage section, 72Y... Developing unit recovery path, 73Y... Image carrier recovery path, 74Y... Developer tank, 75Y .. developer replenishing path, 76Y ... developer pump, 77Y. ... carrier liquid supply path, 79Y ... carrier liquid pump, 81Y ... developer supply path, 82Y ... developer supply pump 110Y: Liquid level measuring device, 111Y: Float support member, 112Y ... Restriction member, 113Y ... First Hall element (proportional output type Hall element), 114Y ... Second Hall element (proportional output type Hall element), 115Y ... 3rd Hall element (proportional output type Hall element), 116Y... Float (floating member), 117Y... 1st magnetic field generator, 118Y ... 2nd magnetic field generator, 120Y ... concentration detecting means, 121Y ... stirring propeller shaft, 122Y. Transparent propeller (moving member), 123Y ... stirring propeller, 124Y ... motor, 130Y ... concentration measuring unit, 130aY ... gap, 131Y ... light emitting LED (concentration measuring member, light emitting member), 132Y ... light receiving element for concentration measurement (concentration measuring member) , Light receiving member), 133Y... Light receiving intensity measuring light receiving element (concentration measuring member, second light receiving member), 134Y... CPU, 35Y ... amplifier, 136Y ... No. 1A / D converter, 137Y ... No. 2A / D converter, 138Y ... wiring, 139Y ... metal plate, 140Y ... reflective film, 150Y ... position adjusting mechanism

Claims (15)

A floating member that moves following the liquid level;
A first magnetic field generator disposed on the levitation member and having an N pole directed in a first direction;
A second magnetic field generator disposed on the levitation member apart from the first magnetic field generator and having an S pole directed in the first direction;
A plurality of proportional output Hall elements that detect magnetic fields generated by the first magnetic field generator and the second magnetic field generator at positions facing the first direction;
A liquid quantity measuring device characterized by comprising: A guide for guiding the movement of the levitation member;
A regulating member that regulates the movement of the floating member;
The liquid quantity measuring device according to claim 1, comprising: A reservoir for storing a liquid developer containing toner particles in the carrier liquid;
A levitation member that moves following the liquid level of the liquid developer in the reservoir,
A first magnetic field generator disposed on the levitation member and having an N pole directed in a first direction;
A second magnetic field generator disposed on the levitation member apart from the first magnetic field generator and having an S pole directed in the first direction;
as well as,
A plurality of proportional output Hall elements that detect magnetic fields generated by the first magnetic field generator and the second magnetic field generator at positions facing the first direction;
A liquid quantity measuring device having
A liquid developer storage device comprising: A movable member movable within the reservoir;
A light emitting member;
A light receiving member that receives light emitted from the light emitting member;
A gap portion in which the moving member can move between the light emitting member and the light receiving member;
A concentration measuring unit that measures the concentration of the liquid developer from the output of the light receiving member when the moving member is in the gap and when the moving member is not in the gap;
The liquid developer storage device according to claim 3, further comprising: a concentration measuring device having: A guide for guiding the movement of the levitation member;
A regulating member that is disposed in the measurement unit and regulates the movement of the levitation member;
The liquid developer storage device according to claim 4. A developer container;
A developer carrying member carrying a liquid developer;
A developer supply member for supplying the liquid developer stored in the developer container to the developer carrier;
An image carrier on which a latent image is developed by the developer carrier;
A transfer body onto which an image on the image carrier is transferred;
A reservoir in which liquid developer is stored;
A levitation member that moves following the liquid level of the liquid developer in the reservoir,
A first magnetic field generator disposed on the levitation member and having an N pole directed in a first direction;
A second magnetic field generator disposed on the levitation member apart from the first magnetic field generator and having an S pole directed in the first direction;
as well as,
A plurality of proportional output Hall elements that detect magnetic fields generated by the first magnetic field generator and the second magnetic field generator at positions facing the first direction;
A liquid quantity measuring device having
An image forming apparatus comprising: The image forming apparatus according to claim 6, further comprising a position adjusting mechanism that adjusts a vertical position of the liquid amount measuring apparatus. A supply path for supplying the liquid developer from the liquid developer reservoir to the developer container;
The image forming apparatus according to claim 6, wherein a plurality of the proportional output Hall elements of the liquid amount measuring device are arranged in the supply path. A movable member movable within the reservoir,
Luminous member,
A light receiving member that receives light emitted from the light emitting member;
A gap portion in which the moving member can move between the light emitting member and the light receiving member,
as well as,
A concentration measuring device having a concentration measuring unit that measures the concentration of the liquid developer from the output of the light receiving member when the moving member is in the gap portion and when the moving member is not in the gap portion;
Wiring of the concentration measuring device arranged along the supply path;
The image forming apparatus according to claim 6, further comprising: A collection path for collecting the liquid developer to the storage unit;
An agitation propeller for agitating the liquid developer in the reservoir;
A stirring propeller shaft that rotatably supports the stirring propeller;
Have
The image forming apparatus according to claim 6, wherein the stirring propeller is disposed so as to overlap the recovery path when viewed from the axial direction of the stirring propeller. The image forming apparatus according to claim 6, wherein the levitation member has a facing surface facing the proportional output Hall element. The image forming apparatus according to claim 6, wherein the levitation member has a rounded acute-angled end on the opposite side of the facing surface. A liquid level determination unit for determining the liquid volume measured by the liquid volume measuring device;
A liquid level control unit that controls the amount of liquid according to the determination result of the liquid level determination unit;
A concentration determination unit for determining the concentration measured by the concentration measuring device;
A concentration control unit that controls the concentration of the liquid developer in the storage unit according to the determination result of the concentration determination unit;
Selection means for selecting the liquid level control unit and the concentration control unit;
The image forming apparatus according to claim 6, further comprising: 14. The liquid supply amount calculation unit according to claim 6, further comprising: a liquid supply amount calculating unit that prohibits the liquid amount from being input by the liquid level control unit when the liquid amount measured by the liquid amount measuring device is larger than a predetermined amount. The image forming apparatus described. When the concentration measured by the concentration measuring device is higher than the first predetermined concentration or lower than the second predetermined concentration set lower than the first predetermined concentration, the liquid amount calculation unit that stops printing by the concentration determination unit The image forming apparatus according to claim 6, further comprising:

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