Liquid developing device, liquid developing method, and printer including the device

A liquid developing device comprising:

• four storage tanks which respectively store fours colors, yellow, cyan, magenta, and black, of inks, each including a toner and a carrier, for use in developing an electrostatic latent image formed on a photoconductor;
• four ink supply pumps which respectively send the four colors of inks from the respective storage tanks;
• four concentration sensors which respectively measure toner concentrations of the respective four colors of inks to be sent to said photoconductor;
• four storage-amount sensors which respectively measure amounts of four colors of inks stored in the respective storage tanks;
• four concentrated-ink supply pumps which respectively send four colors of inks from ink cartridges to the respective storage tanks each of which stores a same color of ink as a color of a concentrated ink stored in one of four ink cartridges;
• a carrier supply pump which sends a carrier to the storage tanks from a carrier cartridge storing a carrier;
• four ink discharge pumps which respectively discharge excessive inks from the respective storage tanks to a discharge cartridge;
• and
• a controller which controlls each of said concentrated-ink supply pumps, said carrier supply pump and said ink discharge pumps, so as to retain a predetermined level of the toner concentrations of the inks stored in the respective storage tanks and a predetermined amount of the inks stored therein, based on a measurement value form each of said concentration sensors and a measurement amount of each of said storage-amount sensors.

A liquid developing method comprising:

• supplying an ink from a storage tank, storing an ink including a toner and a carrier and for use in developing an electrostatic latent image formed on a photoconductor, to said photoconductor;
• developing said photoconductor with the ink supplied by said supplying;
• measuring a toner concentration of the ink which is to be sent to said photoconductor by said supplying;
• measuring an amount of ink stored in said storage tank;
• and
• controlling the toner concentration of the ink stored in said storage tank and the amount of the ink, by supplying said storage tank with a concentrated ink and a carrier, and discharging an excessive ink from said storage tank, while developing the photoconductor by said developing, based on a measurement value measured by said measuring the toner concentration and a measurement amount measured by said measuring the amount.

A liquid developing method comprising:

• supplying four kinds of inks, each of which includes a toner and a carrier, for use in developing an electrostatic latent image formed on a photoconductor, respectively from four storage tanks to the photoconductor;
• developing the photoconductor with each of the four inks which are supplied by said supplying;
• measuring a toner concentration of each of the inks to be supplied to the photoconductor by said supplying;
• measuring an amount of each of the four inks included respectively in the storage tanks;
• controlling the toner concentration of each of the four inks stored respectively in the storage tanks and the amount of each of the four inks, by supplementing each of the storage tanks with a concentrated ink and a carrier, and by discharging an excessive ink from each of the storage tanks, while developing the photoconductor by said developing, based on the measurement value measured by said measuring the toner concentration and the measurement amount measured by said measuring the amount.