Abstract: In an image forming apparatus, in a case where a power of the apparatus is turned from OFF to ON, a rotation drive unit rotationally drives each of a developing roller, a first conductive roller, and a second conductive roller in a state where a liquid developer supplied to a developer container by a supply device has reached a supply position, and a bias application unit applies a bias to each of the developing roller, the first conductive roller, and the second conductive roller after the developing roller rotates at least once, in the state where the liquid developer supplied to the developer container by the supply device has reached the supply position.

Abstract: A developing device includes a rotatable developer carrying member carrying a liquid developer on a carrying surface for developing an electrostatic latent image borne on an image bearing member, and an end portion restricting member, provided in contact with the developer carrying member at an end portion of the developer carrying member with respect its rotational axis direction, for restricting movement of the liquid developer in the rotational axis direction of the developer carrying member. A contact angle of the liquid developer to a side surface of the end portion restricting member on a side where the developer carrying member carries the liquid developer is larger than a contact angle of the liquid developer to the carrying surface of the developer carrying member, and the contact angle of the liquid developer to the side surface of the end portion restricting member is 45° or more.

Abstract: In an image forming apparatus, in a case where a power of the apparatus is turned from OFF to ON, a rotation drive unit rotationally drives each of a developing roller, a first conductive roller, and a second conductive roller in a state where a liquid developer supplied to a developer container by a supply device has reached a supply position, and a bias application unit applies a bias to each of the developing roller, the first conductive roller, and the second conductive roller after the developing roller rotates at least once, in the state where the liquid developer supplied to the developer container by the supply device has reached the supply position.

Abstract: An image forming apparatus includes a controller for performing a mode, in which an image portion potential is controlled during image formation so that an absolute value of the image portion potential is a first value when a resistance value of a developing roller based on a value of a current flowing between the developing roller and an electroconductive member is smaller than a predetermined value when a predetermined potential difference between the developing roller and the electroconductive member is formed during non-image formation and so that an absolute value of the image portion potential is a second value smaller than the first value when a resistance value of the developing roller based on a value of current flowing between the developing roller and the electroconductive member is not smaller than the predetermined value when the predetermined potential difference between the developing roller and the electroconductive member is formed during non-image formation.

Abstract: An image forming apparatus includes a control unit configured to execute a stop mode in which, after image forming operation is stopped, a developer bearing member is rotated for a predetermined time with a potential difference between a film forming electrode and a developer bearing member set to zero or smaller than that during image formation, and thereafter, the rotation of the developer bearing member is stopped.

Abstract: A developing apparatus includes a developer bearing member, a developer container, and a storage tank arranged within the developer container to store liquid developer to be supplied to the developer bearing member. The storage tank includes a first bottom surface including an inclined portion that is inclined downward with respect to a horizontal direction in a rotational axis direction of the developer bearing member, and a discharge port arranged on a lower end of the inclined portion of the first bottom surface. The developer container includes a second bottom surface including an inclined portion that is inclined downward with respect to the horizontal direction toward an opposite direction as the inclined portion of the first bottom surface in the rotational axis direction of the developer bearing member, and a discharge port arranged on a lower end of the inclined portion of the second bottom surface.

Abstract: A developer container is capable of supplying a liquid developer to a portion, of a surface of a cleaning roller, between a cleaning position X and a contact position Y with respect to a rotational direction of the cleaning roller. A free end of a cleaning blade is positioned in a range of 65° or more and less than 95° as a positive angle of the rotational direction of the cleaning roller when a line passing through a center of the cleaning roller and an upper end portion of the cleaning roller with respect to a direction of gravitation is at 0° (reference line G). In this case, the cleaning blade is disposed so that an angle ? between a line F perpendicular to a line E connecting the center of the cleaning roller and the free end of the cleaning blade, and the cleaning blade is in a range of 35° or more and less than 60° .

Abstract: An image forming apparatus executes a first obtain mode to obtain a resistance value of a developing roller when a potential difference between the developing roller and an electroconductive roller is generated by a second voltage generator when the developing roller carries a reference liquid developer having a known toner concentration. A second obtain mode is executed to obtain a toner concentration of the liquid developer on a surface of the developing roller based on the obtained resistance value and a detection result when a potential difference between the developing roller and the electroconductive roller is generated by the second voltage generator when the liquid developer is applied to the developing roller. During image formation, the controller controls a first voltage generator based on the obtained toner concentration so the toner concentration of the liquid developer on the surface of the developing roller is a target value.

Abstract: A developing apparatus includes a developer bearing member, a developer container configured, and a storage tank arranged within the developer container and configured to store liquid developer to be supplied to the developer bearing member. The storage tank includes a first bottom surface including an inclined portion that is inclined downward with respect to a horizontal direction in a rotational axis direction of the developer bearing member, and a discharge port arranged on a lower end of the inclined portion of the first bottom surface. The developer container includes a second bottom surface including an inclined portion that is inclined downward with respect to the horizontal direction toward an opposite direction as the inclined portion of the first bottom surface in the rotational axis direction of the developer bearing member, and a discharge port arranged on a lower end of the inclined portion of the second bottom surface.

Abstract: A developing roller is rotatable while carrying a liquid developer containing toner and a carrier liquid and contains an electroconductive agent, and includes a squeeze roller provided in contact with the developing roller through at least the carrier liquid, a voltage source capable of generating a potential difference between the developing roller and a squeeze roller, and a current detecting sensor for detecting a current passed between the developing roller and the squeeze roller. In addition, a controller controls the voltage source, and a display device outputs information on a lifetime of the developing roller. The controller outputs the information on the lifetime from the display device on the basis of a detection result by the current detecting sensor when a predetermined potential difference is generated between the developing roller and the squeeze roller by the voltage source.

Abstract: An image forming apparatus includes a control unit configured to execute a stop mode in which, after image forming operation is stopped, a developer bearing member is rotated for a predetermined time with a potential difference between a film forming electrode and a developer bearing member set to zero or smaller than that during image formation, and thereafter, the rotation of the developer bearing member is stopped.

Abstract: A developing device includes a developer carrying member (41) rotating while carrying a liquid developer on a carrying surface (41b) and an end portion restricting member (46) for restricting movement of the liquid developer, carried on the carrying surface (41b), to an outside of the carrying surface (41b). A contact angle between the end portion restricting member (46) and the liquid developer is set so as to be larger than a contact angle between the carrying surface (41b) of the developer carrying member (41) and the liquid developer. By this, when the developer carrying member (41) is separated from the end portion restricting member (46), deposition of the liquid developer in a large amount in the neighborhood of an end (41c) of the carrying surface (41b) is prevented.

Abstract: A developer container 53 is capable of supplying a liquid developer to a portion, of a surface of a cleaning roller 58, between a cleaning position X and a contact position Y with respect to a rotational direction of the cleaning roller 58. A free end of a cleaning blade 56 is positioned in a range of 65° or more and less than 95° as a positive angle of the rotational direction of the cleaning roller 58 when a line passing through a center of the cleaning roller 58 and an upper end portion of the cleaning roller 58 with respect to a direction of gravitation is at 0° (reference line G). In this case, the cleaning blade 56 is disposed so that an angle ? between a line F perpendicular to a line E connecting the center of the cleaning roller 58 and the free end of the cleaning blade 56, and the cleaning blade 56 is in a range of 35° or more and less than 60°.

Abstract: A toner concentration adjusting means capable of adjusting a toner concentration, an electroconductive member provided in contact with a developing roller through a liquid developer, a voltage applying means capable of generating a potential difference between the developing roller and the electroconductive member, a current detecting means for detecting a current flowing through between the developing roller and the electroconductive member, and a controller capable of controlling the toner concentration adjusting means and the voltage applying means are provided, and the controller adjusts the toner concentration of the liquid developer on a surface of the developing roller by the toner concentration adjusting means (step S17, 18) depending on a change in detection result by the current detecting means (step S14) when a predetermined potential difference is generated between the developing roller and the electroconductive member by the voltage applying means.

Abstract: During non-image formation, a setting mode in which a predetermined potential difference is generated by a first voltage applying means (step S5) and depending on a detection result by a current detecting means (step S8), a developing contrast and a fog-removing voltage are set is executable, and during image formation, the potential difference set in the setting mode is generated by at least one of a second voltage applying means, a charging means and an exposure means (steps S9, S10).

Abstract: A developing roller which is rotatable while carrying a liquid developer containing toner and a carrier liquid and which contains an electroconductive agent, a squeeze roller provided in contact with the developing roller through at least the carrier liquid, a voltage source capable of generating a potential difference between the developing roller and a squeeze roller, a current detecting sensor for detecting a current passed between the developing roller and the squeeze roller, a controller capable of controlling the voltage source, and a display device capable of outputting information on a lifetime of the developing roller are provided, and the controller outputs the information on the lifetime from the display device on the basis of a detection result by the current detecting sensor (steps S5 to S8) when a predetermined potential difference is generated between the developing roller and the squeeze roller by the voltage source (steps S2, S4).

Abstract: A high-density area of a low-reflectance patch image is accurately detected. There is an image forming apparatus that detects the density of a patch image by radiating light from a laser oscillator 701 and receiving reflected light reflected off the patch image using a line sensor 704. The density of a black patch image 720 having a low reflectance is detected from the difference between the position at which reflected light from a yellow patch image 710 is received and the position at which reflected light from a superimposed toner image that is transferred in such a manner that the yellow patch image 730 is superimposed on the top of the black patch image 720 is received.

Abstract: A toner image height measurement apparatus capable of accurately measuring heights of toner images of respective colors with a relatively simple construction and without being affected by toner colors. With motion of an image carrier, there occurs a change in reflection light amount detected by a photodiode of the height measurement apparatus in timing when laser light having been irradiated onto the image carrier starts to be irradiated onto or intercepted by a toner image and in timing when the laser light having been irradiated onto the toner image starts to be irradiated onto the image carrier. Based on a principle that these timings vary according to a toner image height, the height measurement apparatus detects the timing when the reflection light amount changes by a predetermined amount, thereby detecting the toner image height.

Abstract: A high-density area of a low-reflectance patch image is accurately detected. There is an image forming apparatus that detects the density of a patch image by radiating light from a laser oscillator 701 and receiving reflected light reflected off the patch image using a line sensor 704. The density of a black patch image 720 having a low reflectance is detected from the difference between the position at which reflected light from a yellow patch image 710 is received and the position at which reflected light from a superimposed toner image that is transferred in such a manner that the yellow patch image 730 is superimposed on the top of the black patch image 720 is received.

Abstract: A toner image height measurement apparatus capable of accurately measuring heights of toner images of respective colors with a relatively simple construction and without being affected by toner colors. With motion of an image carrier, there occurs a change in reflection light amount detected by a photodiode of the height measurement apparatus in timing when laser light having been irradiated onto the image carrier starts to be irradiated onto or intercepted by a toner image and in timing when the laser light having been irradiated onto the toner image starts to be irradiated onto the image carrier. Based on a principle that these timings vary according to a toner image height, the height measurement apparatus detects the timing when the reflection light amount changes by a predetermined amount, thereby detecting the toner image height.