Abstract: A recording head ejects ink using nozzles. A control unit determines nozzles corresponding to an image to be printed and causes the recording head to eject ink from the nozzles. A correction processing unit detects an ejection malfunction nozzle and performs a correction process corresponding to the ejection malfunction nozzles. The correction processing unit causes a secondary adjacent nozzle of the ejection malfunction nozzle to perform ink ejection with a first ink ejection amount if ink ejection of a primary adjacent nozzle of ejection malfunction nozzle is performed earlier than ink ejection of the secondary adjacent nozzle and causes the secondary adjacent nozzle to perform ink ejection with a second ink ejection amount if ink ejection of the primary adjacent nozzle is performed later than ink ejection of the secondary adjacent nozzle. Here, the second ink ejection amount is smaller than the first ink ejection amount.

Abstract: An image forming apparatus includes a recording head, a control unit, and a correction processing unit. The recording head is configured to eject ink corresponding to an image to be printed, using arranged nozzles. The control unit is configured to determine nozzles corresponding to the image to be printed, correspondingly to a position of a print sheet, and cause the recording head to eject ink from the nozzles. The correction processing unit is configured to detect an ejection malfunction nozzle and perform a correction process corresponding to the ejection malfunction nozzles. Further, if the number of the detected ejection malfunction nozzles exceeds a predetermined upperlimit value, the correction processing unit preferentially sets as a target of the correction process an ejection malfunction nozzle that ejects an ink droplet earlier than nozzles corresponding to two adjacent dots of a dot corresponding to the ejection malfunction nozzle.

Abstract: An ejection malfunction nozzle detecting unit prints plural test patterns on a print sheet using a recording head, and detects ejection malfunction nozzles on the basis of scanned images of the plural test patterns. The plural test patterns are line-shaped or band-shaped images for which a correction process has been performed at plural nozzle positions with a predetermined period. The nozzle positions of the plural test patterns are specified with offset positions different from each other. Further, the ejection malfunction nozzle detecting unit (a) determines a test pattern that densities at periodical ejection malfunction positions have been corrected among the plural test patterns on the basis of density distributions of scanned image of the test patterns, and (b) stores as ejection malfunction nozzle data an offset position of the determined test pattern into a storage device.

Abstract: An image forming apparatus includes a recording head, a control unit, an ejection malfunction detecting unit, and an ejection malfunction nozzle determining unit. The recording head ejects ink corresponding to an image to be printed, using arranged nozzles. The control unit determines nozzles corresponding to the image and causes the recording head to eject ink from the nozzles. The ejection malfunction detecting unit (a) prints a first test pattern on a print sheet using the recording head, and (b) detects a density defect due to ejection malfunction in a scanned image of the first test pattern. The ejection malfunction nozzle determining unit (a) prints a second test pattern using the recording head if the density defect is detected by the ejection malfunction detecting unit, and (b) does not perform printing of the second test pattern if no density defects are detected by the ejection malfunction detecting unit.

Abstract: A control unit causes a recording head to eject ink from nozzles corresponding to an image to be printed. An ejection malfunction nozzle detecting unit prints a test pattern using the recording head, and detects an ejection malfunction nozzle on the basis of a scanned image of the test pattern. The test pattern includes plural test pattern images such that in each of the plural test pattern images a dot is not formed at a dot position of a target nozzle set as a non ejection nozzle, and the target nozzles of the plural test pattern images are sequentially shifted by one nozzle in a primary scanning direction. Further, the ejection malfunction nozzle detecting unit determines an ejection malfunction nozzle on which ejection deviation occurs, on the basis of density decreasing amounts of respective density decrease parts in the plural test pattern images in the scanned image.

Abstract: An ejection malfunction nozzle detecting unit prints a test pattern on a print sheet using the recording head, and detects an ejection malfunction nozzle on the basis of a density distribution of a scanned image of the test pattern. Here, a resolution of the scanned image is lower than a resolution of the test pattern printed on the print sheet using the recording head. Further, a correction processing unit (a) stores into a predetermined storage device history data that indicates the ejection malfunction nozzle for which the correction process was performed, (b) refers to the history data and detects as an additional correction nozzle a nozzle included in the history data, among nozzles corresponding to a predetermined pixel range that includes a pixel corresponding to the detected ejection malfunction nozzle, and (c) performs the correction process for the detected ejection malfunction nozzle and the additional ejection malfunction nozzle.

Abstract: A black-generation-and-UCR processing unit generates image data of a black ink color from image data of chromatic ink colors of the image and adjusts values of the image data of the chromatic ink colors correspondingly to generation of the image data of the black ink color. An image outputting unit causes a printing device to perform printing based on the image data. A print condition adjustment unit derives an ink coverage of the image on a print sheet, determines a black generation ratio corresponding to the ink coverage, and causes the black-generation-and-UCR processing unit to perform generation of the image data of the black ink color with the determined black generation ratio. The ink coverage indicates a ratio of ink usage amounts of the chromatic ink colors and the black ink color to a predetermined maximum value, for a pixel for which ink is ejected in the image.

Abstract: An ejection malfunction nozzle detecting unit prints a test pattern and detects ejection malfunction nozzles on the basis of a scanned image of the test pattern. The ejection malfunction nozzle detecting unit classifies the ejection malfunction nozzles into periodical nozzles that periodically appear with a specific period in a primary scanning direction and non-periodical nozzles other than the periodical nozzles; for the periodical nozzles, stores the specific period and an offset as the ejection malfunction nozzle data into a storage device, and for the non-periodical nozzles, stores the ejection malfunction nozzle data that individually indicates positions of the non-periodical nozzles into the storage device. A correction processing unit performs the correction process for the periodical nozzles on the basis of the specific period and the offset, and the correction process for the non-periodical nozzles on the basis of the positions of the non-periodical nozzles.

Abstract: A first pump of small capacity and a second pump of large capacity are connected directly with each other and are driven by a variable-speed motor. The rotational speed of the variable-speed motor is controlled by a control device. In a first mode, a first discharge line of the first pump and a second discharge line of the second pump are disconnected with each other, making the first pump unloaded. With the first pump in the unloaded state, a constant-horsepower operation is performed, where the discharge fluid is brought into a high pressure by relatively small torque. In a second mode, the first discharge line and the second discharge line are connected with each other by a switching valve. With the first and second discharge lines in the connected state, a constant-horsepower operation is performed, where a high flow rate of discharge fluid is discharged at relatively low rotational speed.

Abstract: A first pump of small capacity and a second pump of large capacity are connected directly with each other and are driven by a variable-speed motor. The rotational speed of the variable-speed motor is controlled by a control device. In a first mode, a first discharge line of the first pump and a second discharge line of the second pump are disconnected with each other, making the first pump unloaded. With the first pump in the unloaded, state, a constant-horsepower operation is performed, where the discharge fluid is brought into a high pressure by relatively small torque. In a second mode, the first discharge line and the second discharge line are connected with each other by a switching valve. With the first and second discharge lines in the connected, state, a constant-horsepower operation is performed, where a high flow rate of discharge fluid is discharged at relatively low rotational speed.

Abstract: There is provided an autonomous inverter-driven hydraulic unit in which a command pressure and command flow rate do not need to be inputted from outside and a pressure and flow rate can be autonomously controlled without requiring any input signal wire. A target horsepower calculation unit 25 of a controller 11 judges which of a plurality of regions a point representing a present operating state belongs to and calculates a target horsepower represented by a point on a target pressure-flow rate characteristic line based on the present pressure and present flow rate. A comparison unit 28 calculates a deviation of this target horsepower and a present horsepower received from a present horsepower calculation unit 26, inputs a control signal representing this deviation to the inverter 3 and controls a rotational number of a variable-speed motor 2 so that the present horsepower coincides with the target horsepower.