Abstract: An image forming apparatus includes a recording head, a water-repellent transfer belt, a pattern formation controller, a read unit, and a detection unit. The recording head has a plurality of nozzles aligned in a given direction, and ejects droplets of a liquid therefrom. The pattern formation controller directs each of the plurality of nozzles to eject the liquid to form a detection pattern on the transfer belt. The detection pattern has multiple droplets ejected from each of the plurality of nozzles sequentially arranged and spaced apart from each other both in the given direction and in a direction orthogonal to the given direction. The read unit includes a light emitting element and a light receiving element, and reads the detection pattern to output a read result. The detection unit detects a defective nozzle according to the read result.

Abstract: An adjustment pattern, which is composed of a reference pattern made of plural independent liquid droplets and a pattern to be measured made of plural independent liquid droplets ejected under an ejection condition different from the reference pattern, is formed on a water-repellent conveying belt. Then, light is applied to the adjustment pattern to receive the regular reflection light from the adjustment pattern, so that the adjustment pattern is scanned. The distance between the respective patterns is measured based on the measured result. Finally, liquid droplet ejection timing of the recording head is corrected based on the result thus measured.

Abstract: A development device includes a toner carrier including first and second groups of electrodes, a toner supplier, and an electrical field generator to generate an electrical field for causing toner to hop along the surface of the toner carrier. The electrical field generator includes a positive-phase pulse voltage generation circuit, a negative-phase pulse voltage generation circuit, a first DC power source for supplying a bias for setting a peak value of pulse voltages, a second DC power source to output a variable voltage having a polarity identical to a polarity of toner charge, a first diode having an anode and a cathode connected to a lower potential side of the positive-phase pulse voltage generation circuit and an output terminal thereof, and a second diode having an anode and a cathode connected to the lower potential side of the positive-phase pulse voltage generation circuit and an output terminal thereof.

Abstract: A disclosed image forming apparatus includes a recording head configured to jet liquid droplets; a pattern forming unit configured to form, on a water-repellent surface of a water-repellent sheet member, an adjustment pattern used for correcting shifts in landing positions of the liquid droplets, wherein the adjustment pattern includes plural liquid droplets that are separated from each other, and the water-repellent surface having a water-repellent property is formed on at least a part of a surface of the water-repellent sheet member; a reading unit including a light emitting unit configured to irradiate light onto the adjustment pattern and a light receiving unit configured to receive specular reflection light from the adjustment pattern; and a landing position correction unit configured to correct, based on a reading result obtained by the reading unit, the shifts in the landing positions of the liquid droplets that are jetted from the recording head.

Abstract: A disclosed developing device includes a toner carrying member having electrodes, a toner supply unit supplying the toner to the toner carrying member, and a hopping electric field generator unit generating electric field to cause the toner hopping on the toner carrying member by applying a pulse voltage to the electrodes. The hopping electric field generator unit includes a pulse voltage generator circuit generating the pulse voltage, a first direct-current power source supplying bias to the pulse voltage generator circuit for regulating a peak value of the pulse voltage, and a second direct-current power source having a same polarity with a toner charging polarity, and outputting a variable voltage level. The hopping electric field generator unit controls the peak value of the pulse voltage by changing an output of the first power source and a mean thereof by changing an output of the second power source.

Abstract: An image forming device, including a toner bearer including plural linear electrodes located at a first regular pitch in a crosswise direction thereof, flying a toner on the surface thereof between the plural linear electrodes with a pulse voltage thereto to form a floating toner layer; and a substrate including plural hole-electrode combinations arranged in a longitudinal direction of the linear electrodes, each formed of a through-hole and a hole-adjacent electrode located close to the through-hole, wherein the floating toner layer is formed in an area facing the through-hole, and a toner passes through only the through-holes facing a desired image from the floating toner layer with a record on or off voltage, and the plural hole-electrode combinations are lined at a second regular pitch in a crosswise direction of the toner bearer, and the second regular pitch is an integral multiple of the first regular pitch.

Abstract: An image forming apparatus comprises a toner-bearing member that bears toner and makes the toner clouded thereon. A toner passage control device including plural widthwise lines of toner passage holes in a printing medium conveyance direction is provided. Each of the toner passage holes includes a control electrode that controls passage of the toner through each of the toner passage holes toward a printing medium. a control pulse proving device provides a control pulse to the control electrode to operate. The control pulse applied to the control electrode of the one of the plural lines is different from that applied to the control electrode of the other one of the plural lines.

Abstract: An image forming apparatus includes a recording head, a water-repellent transfer belt, a pattern formation controller, a read unit, and a detection unit. The recording head has a plurality of nozzles aligned in a given direction, and ejects droplets of a liquid therefrom. The pattern formation controller directs each of the plurality of nozzles to eject the liquid to form a detection pattern on the transfer belt. The detection pattern has multiple droplets ejected from each of the plurality of nozzles sequentially arranged and spaced apart from each other both in the given direction and in a direction orthogonal to the given direction. The read unit includes a light emitting element and a light receiving element, and reads the detection pattern to output a read result. The detection unit detects a defective nozzle according to the read result.

Abstract: A disclosed image forming apparatus for forming an image on a recording medium being conveyed includes: a recording head discharging droplets; a pattern forming unit forming an adjustment pattern for detecting displacement of landing positions of droplets on a water-repellent member, the adjustment pattern including a minimum block pattern for each detection item and being formed with plural droplets independent of one another; a reading unit including a light emitting unit projecting a light onto the adjustment pattern and a light receiving unit receiving a regular reflection light from the adjustment pattern; and a landing position correcting unit correcting the landing positions of the droplets discharged from the recording head based on a result of reading by the reading unit.

Abstract: An image forming apparatus is provided with a carriage in which recording heads having nozzles for ejecting liquid droplets are mounted and is configured to form an image on a recording medium being transported. The image forming apparatus includes a pattern forming unit that forms an impact position displacement adjustment pattern formed of plural independent liquid droplets on a water repellent member; a reading unit that includes a light emitting unit for emitting light onto the adjustment pattern and a light receiving unit for receiving specular reflection light from the adjustment pattern; and an impact position correcting unit that corrects an impact position of a liquid droplet to be ejected from the recording head based on a read result by the reading unit. The reading unit is disposed on the carriage and is arranged close to the side of a guide member that guides movement of the carriage.

Abstract: An adjustment pattern, which is composed of a reference pattern made of plural independent liquid droplets and a pattern to be measured made of plural independent liquid droplets ejected under an ejection condition different from the reference pattern, is formed on a water-repellent conveying belt. Then, light is applied to the adjustment pattern to receive the regular reflection light from the adjustment pattern, so that the adjustment pattern is scanned. The distance between the respective patterns is measured based on the measured result. Finally, liquid droplet ejection timing of the recording head is corrected based on the result thus measured.

Abstract: A disclosed image forming apparatus includes a recording head configured to jet liquid droplets; a pattern forming unit configured to form, on a water-repellent surface of a water-repellent sheet member, an adjustment pattern used for correcting shifts in landing positions of the liquid droplets, wherein the adjustment pattern includes plural liquid droplets that are separated from each other, and the water-repellent surface having a water-repellent property is formed on at least a part of a surface of the water-repellent sheet member; a reading unit including a light emitting unit configured to irradiate light onto the adjustment pattern and a light receiving unit configured to receive specular reflection light from the adjustment pattern; and a landing position correction unit configured to correct, based on a reading result obtained by the reading unit, the shifts in the landing positions of the liquid droplets that are jetted from the recording head.

Abstract: A disclosed liquid-jet device includes a liquid-jet head configured to jet liquid droplets; a pattern formation control unit configured to control the liquid-jet head and thereby to form a test pattern composed of separate liquid droplets on a water-repellent part; a detecting unit including a light-emitting element configured to illuminate the test pattern on the water-repellent part and a light-receiving element configured to receive specularly reflected light from the illuminated test pattern and to output a detection signal proportional to the received specularly reflected light; and a landing position adjusting unit configured to adjust landing positions of the liquid droplets based on the detection signal from the light-receiving element.

Abstract: An ink jet printing apparatus includes an ink jet head having a plurality of nozzles for respectively ejecting ink drops, a plurality of ink chambers communicating with the nozzles, and a plurality of electromechanical conversion elements corresponding to the respective nozzles. The volume of the ink chamber of the non-drive channel is increased by the influence of the drive channel adjacent thereto, and thereby undesired ejection of the ink drop occurs. To solve this problem, a drive energy set for ejecting the ink drop is applied to the piezoelectric elements of the drive chambers n−1, n+1 and a reduced drive energy set for not ejecting the ink drops is applied to the piezoelectric element of the non-drive channel n.

Abstract: In a printing apparatus, a printer control unit transmits image data to an engine control unit for a respective one of a plurality of bands sent by a host computer. The image data of the respective one of the plurality of bands defines a pattern of "M" dots by "N" lines related to an image of a corresponding band where both "M" and "N" denote an integer. The printer control unit transmits a band information command to the engine control unit prior to the transmission of the image data. The band information command includes a band height, a print start dot position and a print end dot position, the band height indicative of a quantity of the image data transmitted, the print start dot position indicative of a position of a print start dot with respect to all the "N" lines in the image, and the print end dot position indicative of a position of a print end dot with respect to all the "N" lines in the image.

Abstract: An ink jet recording apparatus capable of automatically changing a mode of recording operation to fit to a newly installed recording head unit, when at least one interchangeable recording head unit is replaced.

Abstract: A minimum per-time voltage-increase gradient during a time a driving voltage is being increased is not less than 1/8 a maximum per-time voltage-increase gradient during said time the driving voltage is being increased. A driving-voltage increase amount which the driving voltage is increased during a time, within a predetermined time, during which a per-time voltage-increase gradient is maintained at a maximum voltage is not less than 1/2 of a full driving-voltage increase amount which the driving voltage is increased during said predetermined time. When the driving voltage is decreased, a per-time voltage-decrease gradient when said voltage decrease is started is sharper than an average per-time voltage-decrease gradient, and a per-time voltage-decrease gradient when said voltage decrease is ended is less sharp than the average per-time voltage-decrease gradient.

Abstract: An ink jet printing head includes: a plurality of piezoelectric actuators arranged in rows on a substrate, each row including first piezoelectric elements and second piezoelectric elements which are alternately arrayed along the row, the first piezoelectric elements being actuatable to apply a compressive force to ink in accordance with print signals, the second piezoelectric elements being fixed and not actuated; and an ink chamber unit which includes ink chambers located above the first piezoelectric elements and containing ink.

Abstract: An ink jet recording apparatus includes a recording head for ejecting droplets of ink and a driving circuit for driving the recording head. The recording head includes a base, a plate on which a plurality of openings are formed; an ink chamber to be filled with ink being formed between the base and the plate; and heater elements, provided in the ink chamber so as to face the openings of the plate, each of which heater elements supplies heat energy to ink adjacent thereto so that the air bubble is generated on each of the heater elements and so that the air bubble grows toward a corresponding one of the openings. An area of each of the openings of the plate is greater than an area each of the heater elements. When the driving circuit activates each of the heater elements, a droplet of ink is ejected due to the air bubble from the corresponding one of the openings of the plate.

Abstract: An ink jet printer includes a pump which pressurizes an ink to be supplied to a nozzle, which projects an ink jet. When the ink pressure which is supplied to the nozzle exceeds a given value or when the deflection of the ink jet is improper, pressure oscillations are applied to the nozzle by alternately and repeatedly driving and ceasing to drive the pump in order to remove a plugging of the nozzle. If the repeated operation does not result in a reduced ink pressure, the nozzle is connected to a low pressure ink vessel, causing the pressure prevailing within the nozzle to be reduced.