JP2006313320A - Developer container - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developer container, wherein the viscosity of developer can be measured by decreasing the number of members disposed in the developer. <P>SOLUTION: The liquid developer container includes a holding container in which the developer is held; a stirring means that stirs the liquid developer by rotating; a driving means that supplies rotating force to the stirring means; and a time measuring means that measures time needed for the stirring means until stopping its rotation, after the supply of the rotating force by the drive means has been stopped, wherein the viscosity of the developer is determined from the time measured by the time measuring means. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a developer container for holding a developer used in a wet image forming apparatus, and more particularly to a developer container having a function of detecting the viscosity of the developer.

  As an apparatus for forming an image by transferring toner to a recording paper, a wet image forming apparatus for carrying a development by carrying a developer containing toner in a carrier liquid on the surface of a developing roller and supplying the developer to a photosensitive drum. It has been known. Since the toner used in the wet image forming apparatus is finer than the toner used in the dry image forming apparatus using powdery toner, the wet image forming apparatus generally forms a higher quality image than the dry image forming apparatus. can do.

  The density of the printed image varies depending on the density of the toner in the developer. In order to maintain the printed image with high quality, it is necessary to maintain the toner concentration in the developer at a constant value. As a method for measuring the concentration of toner in the developer, a photodetector is installed in the developer, light is irradiated from the outside of the developer container toward the photodetector, and the developer is transmitted through the photodetector. In general, a method of detecting the concentration of toner in the developer from the intensity of the light received in step (1) is employed.

Further, there is known a method for detecting the toner concentration in the developing solution by measuring the viscosity of the developing solution by utilizing the correlation between the concentration of the toner in the developing solution and the viscosity of the developing solution. For example, Patent Document 1 describes a density measuring device that measures the viscosity of a developing solution and measures the concentration of toner in the developing solution.
JP-A-10-198176

  In the above-mentioned Patent Document 1, a to-be-resisted member (cylindrical shape) that rotates is placed in a developer container in a state where the developer is stationary, and the torque acting on the to-be-resisted member is measured. An apparatus for calculating the viscosity of a developing solution and detecting a change in the concentration of toner in the developing solution is disclosed. However, disposing such a member to be resisted for measuring the viscosity in the developing solution obstructs the stirring of the developing solution.

  In addition, a commercially available viscosity sensor such as a photodetector is very expensive and has a very large volume, which causes a problem of stirring when placed in a developer container. In addition, because petroleum-based oil is used for the toner and carrier in the developer, if a sensor that uses resin-based or rubber-based parts is installed in the developer in the developer container, the sensor will be altered. There is also a problem that the detection accuracy decreases.

  In view of the above circumstances, an object of the present invention is to provide a developer container capable of measuring the viscosity of a developer with fewer members disposed in the developer.

  In order to solve the above problems, in the present invention, a holding container for holding a developing solution, a stirring unit that stirs the developing solution by rotating, a driving unit that supplies a rotational driving force to the stirring unit, and the driving unit. A time measuring unit that measures a time from when the supply of the rotational driving force is stopped until the stirring unit stops rotating, and the viscosity of the developer is calculated from the time measured by the time measuring unit. A developer container is provided.

  Therefore, according to the present invention, the viscosity of the developing solution can be determined by measuring the time until the rotation of the stirring means arranged in the developing solution stops. In order to measure the time until the rotation of the stirring means stops, it is not necessary to arrange a sensor in the developer, so the developer container of the present invention is developed with fewer members arranged in the developer. The viscosity of the liquid can be measured.

  Further, in the developer container according to the present invention, the driving unit includes a rotation shaft that transmits a rotation driving force to the stirring unit, a drive motor that rotates the rotation shaft, and the rotation shaft as a rotation center. An inertial body provided on the rotating shaft so as to rotate integrally with the stirring means, and by providing the inertial body, even after the stop of the supply of the rotational driving force by the driving means, The stirrer is capable of rotating for a long time as compared with the case where the inertia member is not provided against the resistance from the developer. In particular, the inertial body preferably has a mass that is about three times or more the mass of a member that rotates against the resistance from the developer excluding the inertial body.

  Further, the time measuring means stops the rotation of the stirring means by measuring the time from when the supply of the rotational driving force by the driving means is stopped until the inertial body reaches a predetermined rotational speed. It is characterized by detecting this.

  Specifically, the inertial body has a disk shape, and light detection positions and non-light detection positions are alternately arranged along a circumferential direction, and the light detection position and the non-light detection position are detected by light detection means. By detecting the above, the rotation period of the inertial body is measured.

  Furthermore, the light detection position is a hole formed so as to penetrate the inertial body, and the non-light detection position is a surface of the inertial body. In this case, the light detection means is a pair of a light emitting element and a light receiving element provided near the front surface and the back surface of the inertial body and at positions where the light detection position and the non-light detection position pass. It is characterized by that.

  Alternatively, the light detection position is a position that reflects light on the inertial body, and the non-light detection position is a position that does not reflect light on the inertial body. The light detection position and the non-light detection position are located on a peripheral surface of the inertial body. In this case, the light detection means receives light emitted from the light emitting element and the light emitting element reflected by the light detection position provided in the vicinity of the position where the light detection position and the non-light detection position pass. And a light receiving element.

  Further, the driving means further functions to transmit the rotational driving force only to the rotational direction in which the stirring means rotates and not to transmit the rotational driving force in the opposite rotational direction to the stirring means and the inertial body. A one-way clutch is provided. Alternatively, the time measuring means may alternatively measure the time from when the supply of the rotational driving force by the driving means is stopped until the back electromotive force generated in the driving motor reaches a predetermined value. The time until the rotation of the stirring means stops is measured.

  In addition, the developer container of the present invention includes a temperature measurement unit that measures the temperature of the developer, and develops based on the time measured by the time measurement unit and the temperature measured by the temperature measurement unit. It is characterized by detecting the viscosity of the liquid.

  ADVANTAGE OF THE INVENTION According to this invention, the developer container which can reduce the member arrange | positioned in a developing solution and can measure the viscosity of a developing solution can be provided.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a side sectional view showing a configuration of the wet printer 100. The wet-type printer 100 is an apparatus for forming an image by carrying a developer containing toner in a carrier liquid on the surface of a developing roller. Character / image information input from an external device such as a computer is converted into a laser beam. It is an apparatus that prints and outputs on recording paper P1 by the electrophotographic method used.

  The wet printer 100 is formed on a photosensitive drum by laser scanning unit (Laser Scanning Unit, hereinafter abbreviated as LSU) 30 for outputting laser light modulated according to character / image information, and irradiation of the laser light. A developing unit 50 that develops the electrostatic latent image by electrophotography to generate a toner image, a transfer unit 70 that transfers the toner image developed by the developing unit 50 onto the recording paper P1 at a transfer position, and a transport mechanism And a fixing unit 80 for fixing the toner image transferred onto the recording paper P1 conveyed by the recording paper P1 and a conveying unit 90 for conveying the recording paper P1.

  The developing unit 50 carries a holding roller 51, a metering roller 52 for metering the developer, a metering roller blade 52a for uniformizing the developer on the surface of the metering roller 52, and a developer supplied from the metering roller 52. An electrostatic latent image is formed by the developing roller 53, the developing roller cleaning blade 53 a that scrapes and removes the developer from the surface of the developing roller 53, the developing roller charging corona 54 that charges the developing roller 53, and the laser light from the LSU 30. The photosensitive drum 55, the photosensitive drum charging corona 57 that uniformly charges the surface of the photosensitive drum 55, the squeezed roller 58 that recovers the carrier liquid from the photosensitive drum 55, and the residual developer generated in the developing unit 50 are put into the wet printer 100. It has a screw 59 for returning it to the arranged developer container (not shown).

  The developer supplied from the developer container holding the developer via the developer pipe 49 is supplied from above the rolling contact portion between the holding roller 51 and the metering roller 52. The developer measured by the measuring roller 52 is applied to the developing roller 53. On the other hand, in the photosensitive drum 55, the surface of the drum charged with a uniform potential by the charging corona 57 for the photosensitive drum is irradiated with laser light, and the irradiated portion has a potential lower than the uniform potential. The portion where the potential is reduced compared to this uniform potential is an electrostatic latent image. The toner of the developer applied to the developing roller 53 is charged and is attracted to the electrostatic latent image portion of the photosensitive drum 55. Thus, the electrostatic latent image is developed to form a toner image.

  The transfer unit 70 includes an intermediate transfer roller 71 and a secondary transfer roller 73. A voltage having a polarity opposite to that of the toner is applied to the intermediate transfer roller 71, and the toner image on the surface of the photosensitive drum 55 is primarily transferred to the surface of the intermediate transfer roller 71 at the rolling contact portion between the photosensitive drum 55 and the intermediate transfer roller 71. The The secondary transfer roller 73 is installed at a position facing the intermediate transfer roller 71 across the conveyance path of the recording paper P1, and a voltage having a reverse polarity higher than that of the intermediate transfer roller 71 is applied. Therefore, the toner image is sucked in the direction of the secondary transfer roller 73, and the toner image transferred to the surface of the intermediate transfer roller 71 is transferred to the recording paper P1 at the rolling contact portion with the secondary transfer roller 73.

  The fixing unit 80 is installed at a position opposed to the heat roller 81 that heats the recording paper P1 and the heat roller 81 across the conveyance path, and a press roller 82 that presses the recording paper P1 between itself and the heat roller 81. It consists of and. By this fixing unit 80, the toner image on the recording paper P1 is fixed on the recording paper P1 by heating and pressing.

  The transport unit 90 includes a roll shaft 91 on which a roll-shaped recording paper P1 is installed, a paper feed driving roller 93 that transports the recording paper P1, a paper feed driven roller 94 that is in rolling contact with the paper feed drive roller 93, and a paper feed drive roller 93. Drive motor 95 and paper feed sensor 97. The recording paper P1 is conveyed by the paper feed driving roller 93, and the timing at which the LSU 30 emits light is calculated by the control unit of the wet printer 100 with reference to the time when the recording paper P1 passes the paper feed sensor 97. Since the timing at which the LSU 30 emits light is controlled based on when the recording paper P1 passes the paper feed sensor 97, printing can be performed at an appropriate position on the recording paper P1.

  Next, the arrangement of the developer container holding the developer will be described. FIG. 2 is a side sectional view of the wet printer 100 observed from the back direction of FIG. The wet printer 100 includes a developer container 3A for supplying developer to the developing unit 50, a developer preliminary container 5 for supplying developer to the developer container 3A, and a carrier liquid preliminary container 7 for supplying carrier liquid to the developer container 3A. And a developer replenishment pump 9 used for transporting the developer from the developer preliminary container 5 to the developer container 3A, and a developer circulation pump 11 for transporting the developer from the developer container 3A to the developing unit 50.

  The developer container 3A includes a holding container 3 that holds the developer and a stirring device 4 that has a function of stirring the developer. When the amount of the developing solution in the holding container 3 is reduced below a predetermined amount, a preliminary developing solution is supplied from the developing solution preliminary container 5 to the holding container 3. During the operation of the wet printer 100, the developer in the holding container 3 is conveyed to the developing unit 50 by the developer circulation pump 11. The discharge port of the developer circulation pump 11 is connected to the developer pipe 49.

  The developing solution in the holding container 3 and the developing solution preliminary container 5 is configured so that about 30% is toner and the remaining about 70% is carrier liquid. An image to be printed becomes dark when the toner ratio is high, and light when the toner ratio is low. The toner concentration of the developer in the holding container 3 is determined by supplying the developer from the developer preliminary container 5 to the holder 3 and the carrier liquid from the carrier liquid preliminary container 7 to the holder 3. The toner density is adjusted to be constant, and the quality of the printed image is kept constant. Note that the developer containers (3B, 3C, 3D) of the present invention described later have a mechanism for measuring the viscosity of the developer. By measuring the viscosity of the developer, the concentration of the developer is indirectly determined. The wet printer 100 can adjust the concentration of the developer by using the concentration of the developer obtained from the developer container.

  Since the developer used in the wet printer 100 has a relatively high viscosity, if it is left as it is, it becomes a semi-solid and loses its fluidity. Therefore, the developer is stirred by the stirring device 4 in the developer container 3A. The holding container 3 has a side opening 6. An opening is formed on the extension line of the shaft of the screw 59 (see FIG. 1) in the developing unit 50 described above, and the opening is connected to the side opening 6 through a pipe. That is, the developer conveyed by the screw 59 is configured to be returned to the developer container 3 from the side opening 6.

  Hereinafter, the developer container of the embodiment of the present invention will be described. FIG. 3 is a perspective view showing the developer container 3B of the first embodiment of the present invention. Note that all of the developer containers of the embodiments described below are replaced with the developer container 3A shown in FIG. The developer container 3 </ b> B includes a holding container 103 and a stirring device 104. 3 shows a part of the holding container 103 removed so that the inside of the holding container 103 of the developer container 3B can be observed. The holding container 103 has a cylindrical shape, the bottom is closed, and the top is open. The stirring device 104 includes a drive motor 119, a rotating shaft 113 rotated by the driving motor 119, an agitating unit 111 fixed to one end of the rotating shaft 113 so that the rotating shaft 113 is the center of rotation, and the rotating shaft 113. It has a flywheel 115 as an “inertia” arranged near the drive motor 119 so as to be the center of rotation, a one-way clutch 117 provided at the upper center of the rotation of the flywheel 115, and a photo sensor 121. The stirring unit 111 stirs the developer by rotating in the direction of arrow A in the figure.

  The rotating shaft 113 includes an upper rotating shaft 113a and a lower rotating shaft 113b. The upper rotating shaft 113a is directly connected to the drive motor 119. The lower rotating shaft 113b can rotate independently of the upper rotating shaft 113a, and is connected to the upper rotating shaft 113a via a one-way clutch 117. The flywheel 115 is fixed to the lower rotary shaft 113b. The one-way clutch 117 transmits only the rotation in the direction of arrow A in the figure from the upper rotating shaft 113a to the lower rotating shaft 113b. That is, when the upper rotating shaft 113a rotates in the direction of arrow A in the figure by the rotational driving force of the drive motor 119, the lower rotating shaft 113b rotates integrally with the upper rotating shaft 113a via the one-way clutch 117. However, for example, when the upper rotating shaft 113a rotates in the reverse direction, the rotational driving force is not transmitted to the lower rotating shaft 113b, and only the upper rotating shaft 113a rotates idly. That is, even if the upper rotating shaft 113a is in a non-rotating state due to the stop torque of the drive motor 119, the lower rotating shaft 113b is freely rotatable in the direction of arrow A in the figure.

  When stirring the developer, the drive motor 119 rotates the rotary shaft 113 in the direction of arrow A. As a result, the developer is also rotated in the direction of arrow A and stirred. The flywheel 115 is provided with a plurality of slits 115a. The slits 115 a extend along the radial direction of the flywheel 115 and are provided at equal intervals in the rotational direction of the flywheel 115. The slit 115 a is a hole formed so as to penetrate from the front surface to the back surface of the flywheel 115. The photosensor 121 has a U-shape, and is arranged such that one end (end portion 121 a) is located near the front surface of the flywheel 115 and the other end (end portion 121 b) is located near the back surface of the flywheel 115. A light source such as an LED is installed on the flywheel side of the end 121a, and a light receiving element is installed on the flywheel side of the end 121b. While the flywheel 115 is rotating, the light receiving element of the photosensor 121 can receive light from the LED while the slit 115 a passes through the photosensor 121.

  Next, a method for measuring the viscosity of the developer will be described. After the drive motor 119 is driven for a predetermined time and the drive motor 119 is turned off (that is, after the rotation of the drive motor 119 is stopped), the stirring unit 111, the rotating shaft 113b, the flywheel 115 (hereinafter referred to as the inertial rotation unit) ) Continues to rotate due to inertial force. Thereafter, the inertial rotating part is stopped by the resistance of the developer. The flywheel 115 widely includes members that apply a rotational inertial force to the inertial rotation unit. Moreover, it is preferable that the mass of the flywheel 115 is set to about 3 times or more the mass of the inertial rotating unit other than the flywheel 115. At this time, a one-way clutch 117 is provided between the flywheel 115 and the drive motor 119 so that the resistance force of the drive motor 119 does not affect the force for stopping the inertial rotation unit. The one-way clutch 117 prevents the stop torque of the drive motor 119 from preventing smooth rotation of the inertial rotation unit after the rotation of the drive motor 119 is stopped.

  For example, when an inexpensive stepping motor is used as the drive motor 119, the stop torque (force for maintaining a stationary state) is very strong depending on the stepping motor, and therefore, the inertia rotating part and the drive motor 119 are combined. If so, the inertial rotating part stops immediately due to the influence of the stop torque. However, by installing the one-way clutch 117, transmission of the stop torque of the drive motor 119 can be eliminated, so that the drive motor 119 can be selected from many types of motors including inexpensive stepping motors.

  FIG. 4 is a graph schematically showing the relationship between the time from when the drive motor 119 is turned off until the inertial rotating portion stops and the viscosity of the developer. The horizontal axis indicates the time until the inertial rotating part stops, and the vertical axis indicates the viscosity of the developer. As shown in the graph, the time until the inertial rotating portion stops and the viscosity have a correlation that can be approximated to a linear function indicating that the viscosity of the developer is lower as the stop time is longer. Therefore, the viscosity of the developer can be determined by measuring the time until the inertial rotating part stops by collecting the relationship between the time until the inertial rotating part stops and the viscosity of the developer as data. It can be detected. Further, there is a correlation between the viscosity of the developer and the temperature of the developer, and generally, the viscosity tends to decrease as the temperature of the developer increases. For example, a, b, and c in FIG. 4 indicate the stop time and viscosity characteristics when the developer is A ° C, B ° C, and C ° C (A <B <C), respectively. Therefore, the viscosity of the developer can be measured more accurately by measuring the measured value and the temperature of a thermometer installed in contact with the developer inside the developer container.

  FIG. 5 is a timing chart showing the operation of the photosensor before and after the drive motor 119 is turned off. In this figure, the photosensor is on when the light receiving element is receiving light, and off is when the light receiving element is not receiving light. Depending on the system configuration, the photosensor is on when the light receiving element is receiving light. When not receiving light, it may be turned off when the light receiving element is receiving light. When the drive motor 119 is turned on (that is, when the drive motor 119 supplies a rotational driving force to the rotating shaft 113), the inertial rotating part rotates at a constant speed, so that the photosensor is a slit. It is turned on / off at a period according to the geometric arrangement of 115a. t1 indicates the time required for the slit 115a that first passes through the photosensor to pass through the photosensor after the drive motor 119 is turned off. t2, t3, and tn indicate passage times of the second, third, and nth slits 115a, respectively. ts is a predetermined constant, and if the photo sensor does not switch off even after the time ts has elapsed since the photo sensor was turned on, it is considered that the flywheel 115 has been stopped. That is, when the flywheel 115 becomes below a predetermined rotational speed, it is considered that it has stopped. Then, the time from when the drive motor 119 is turned off to when the time ts elapses after the photosensor is turned on is detected as the time tc required to stop the rotation of the inertial rotation unit.

  Similarly, T1 indicates the time taken from when the photosensor is first turned off to when it is turned on after the drive motor 119 is turned off (the interval from the first slit 115a to the next slit 115a). Time corresponding to). T2, T3, and Tn indicate the passage times of the second, third, and nth slits 115a, respectively. Ts is a predetermined constant. If the photosensor does not turn on even after the time Ts has elapsed since the photosensor was turned off, it is considered that the flywheel 115 has been stopped. The time from when the drive motor 119 is turned off to when the time ts elapses after the photosensor is turned off may be detected as the time Tc required to stop the rotation of the inertial rotation unit. Note that a control circuit for detecting tc and Tc, an arithmetic circuit for calculating viscosity, and the like may be provided in the photosensor 121, or provided inside the wet printer 100 outside the developer container 3B. It may be done.

  FIG. 6 is a perspective view showing a developer container 3C according to the second embodiment of the present invention. Note that members that are the same as those included in the developer container 3B shown in FIG. 3 are given the same reference numerals, and descriptions thereof are omitted. The developer container 3 </ b> C includes a holding container 103 and a stirring device 204. The stirring device 204 includes a drive motor 119, a rotation shaft 113 (rotation shafts 113a and 113b), a stirring unit 111, and a flywheel 215 disposed near the drive motor 119 so that the rotation shaft 113 is a rotation center. A one-way clutch 117 and a reflection sensor 221 are provided. The stirring unit 111 stirs the developer by rotating in the direction of arrow A in the figure.

  The flywheel 215 has a disk-like shape, and markings 215a are provided at equal intervals on the circumferential end portion thereof. For example, the marking 215a is formed so that the peripheral surface of the flywheel 215 having a relatively light color is painted black. That is, the peripheral surface of the flywheel 215 has a relatively low light reflectance at a position where the marking 215a exists, and a relatively high light reflectance at a position where the marking 215a does not exist. The reflection sensor 221 is disposed in the vicinity of the peripheral surface of the flywheel 215. The reflection sensor 221 has a function of irradiating light and a function of receiving reflected light. The reflection sensor 221 is turned off when it receives light and turned on when it does not receive reflected light. When the flywheel 215 rotates and the marking 215a passes through the reflection sensor 221, the reflected light is not received and the reflection sensor 221 is turned on. When the marking 215a does not pass through the reflection sensor 221, the reflection sensor 221 is turned off.

  The time from when the drive motor is turned off to when the flywheel 215 stops (time until the predetermined rotational speed is reached) is calculated by the same method as described with reference to FIG.

  Next, a method for measuring the viscosity of the developer using the back electromotive force generated in the drive motor after the drive motor is turned off will be described. FIG. 7 is a perspective view showing a developer container 3D according to the third embodiment of the present invention. Similar to FIG. 6, the same members as those included in the developer container 3B shown in FIG. 3 are denoted by the same reference numerals, and the description thereof is omitted.

  The developer container 3D includes a holding container 103 and a stirring device 304. The agitator 304 is fixed to one end of the rotation shaft 313 such that the rotation shaft 313 is rotated by the drive motor 319 and is disposed through the drive motor 319 and the rotation shaft 313 is the rotation center. And a flywheel 315 fixed to the other end of the rotating shaft 313 (above the drive motor 319) so that the rotating shaft 313 is the center of rotation.

  Even after the drive motor 319 is turned off and the stirring of the developing solution is stopped, the stirring unit 311, the rotating shaft 313, and the flywheel 315 (hereinafter referred to as an inertia rotating unit) continue to rotate due to the inertial force. The inertial rotating portion rotates for a short time against the resisting force of the developer and the stop torque of the drive motor 319 and then stops. During this time, a counter electromotive force is generated in the drive motor 319 by the rotational force of the inertial rotating unit.

  FIG. 8 is a graph showing the relationship between the elapsed time after the drive motor 319 is turned off and the back electromotive force generated in the drive motor 319. The horizontal axis indicates the elapsed time since the drive motor 319 is turned off, and the vertical axis indicates the counter electromotive force generated in the drive motor. In the present embodiment, the state where the voltage of the back electromotive force is Vc is regarded as the state where the inertial rotating unit is stopped. Then, an elapsed time tc until the voltage Vc is reached is detected. By obtaining the relationship between tc and the viscosity of the developer in advance, the viscosity of the developer is detected by detecting the time tc from when the drive motor is turned off until the inertial rotating unit is deemed to have stopped. can do.

  Note that the viscosity of the developer and the toner concentration in the developer have a substantially linear proportional relationship, so the toner concentration in the developer can be detected by detecting the viscosity of the developer. It becomes. Therefore, the toner density of the developer can be adjusted to a constant level by replenishing the developer container with an appropriate amount of the developer from the developer preliminary container and the carrier liquid from the carrier liquid preliminary container. Can be kept constant.

  Further, according to the developer container of the present invention, various viscosity measurement ranges can be set easily and inexpensively by changing the material and shape (inertia) of the flywheel. Further, since there is no need to arrange a viscosity sensor or an optical sensor in the developing solution, sensors of various materials can be selected without worrying about the influence due to the contact of the developing solution.

It is a sectional side view which shows the structure of a wet printer. It is the sectional side view which observed the wet printer from the back direction of FIG. It is a perspective view which shows the developing solution container of 1st embodiment of this invention. It is a graph which shows roughly the relationship between time until an inertia rotation part stops, and the viscosity of a developing solution. It is a timing chart which shows operation of a photosensor before and after a drive motor is turned off. It is a perspective view which shows the developing solution container of 2nd embodiment of this invention. It is a perspective view which shows the developing solution container of 3rd embodiment of this invention. It is a graph which shows the relationship between the elapsed time after a drive motor was turned off, and the counter electromotive force which generate | occur | produces in a drive motor.

Explanation of symbols

3A, 3B, 3C, 3D Developer container 103, 203, 303, Holding container 4, 104, 204, 304 Stirrer 5 Developer preliminary container 50 Developer unit 70 Transfer unit 80 Fixing unit 90 Transport unit 100 Wet printer 111 Stirrer 113,313 Rotating shaft 115,215,315 Flywheel 115a Slit 117 One-way clutch 119,319 Drive motor 121 Photo sensor 215a Marking 221 Reflection sensor

Claims (13)

A holding container for holding the developer,
Stirring means for stirring the developer by rotating;
Driving means for supplying a rotational driving force to the stirring means;
Time measurement means for measuring the time from when the supply of rotational driving force by the driving means is stopped until the rotation of the stirring means is stopped,
A developer container, wherein the viscosity of the developer is determined from the time measured by the time measuring means. The driving means includes
A rotating shaft for transmitting a rotational driving force to the stirring means;
A drive motor for rotating the rotating shaft;
An inertial body provided on the rotating shaft so as to rotate integrally with the stirring means, with the rotating shaft as a rotation center;
By providing the inertial body, even after the supply of the rotational driving force by the drive means is stopped, the stirring means is against the resistance from the developer, compared with the case where the inertial body is not provided. The developer container according to claim 1, wherein the developer container can be rotated for a long time.   3. The developer container according to claim 2, wherein the inertia member has a mass that is about three times or more the mass of a member that rotates against the resistance from the developer excluding the inertia member.   The time measuring means measures that the rotation of the stirring means has stopped by measuring the time from when the supply of rotational driving force by the driving means is stopped until the inertial body reaches a predetermined rotational speed. The developer container according to claim 2, wherein the developer container is detected.   The inertial body is disk-shaped, and alternately arranges light detection positions and non-light detection positions along the circumferential direction, and detects the light detection positions and the non-light detection positions by light detection means. The developer container according to claim 4, wherein the rotation period of the inertial body is measured by   6. The developer container according to claim 5, wherein the light detection position is a hole formed so as to penetrate the inertial body, and the non-light detection position is a surface of the inertial body.   The light detection means is a pair of a light emitting element and a light receiving element provided near the front and back surfaces of the inertial body and at positions where the light detection position and the non-light detection position pass. The developer container according to claim 6.   6. The developer container according to claim 5, wherein the light detection position is a position that reflects light on the inertial body, and the non-light detection position is a position that does not reflect light on the inertial body. .   The developer container according to claim 8, wherein the light detection position and the non-light detection position are located on a peripheral surface of the inertia body.   A light-receiving element provided near the position where the light detection position and the non-light detection position pass, and a light-receiving element that receives light emitted by the light-emitting element reflected by the light detection position; The developer container according to claim 8 or 9, characterized by comprising:   The driving means further functions to transmit the rotational driving force to the stirring means and the inertial body only in the rotational direction in which the stirring means rotates, and not to transmit the rotational driving force in the opposite rotational direction. The developer container according to claim 2, further comprising:   The time measuring means measures the time from when the supply of rotational driving force by the driving means is stopped until the back electromotive force generated in the driving motor reaches a predetermined value, whereby the stirring means rotates. 4. The developer container according to claim 2, wherein a time until the stop is measured. Temperature measuring means for measuring the temperature of the developer,
Detecting the viscosity of the developer based on the time measured by the time measuring means and the temperature measured by the temperature measuring means;
The developer container according to any one of claims 1 to 12.

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