Abstract: A recording head 200 has a plurality of nozzle orifices aligned in a row extending in a first direction. The recording head 200 is arranged with the nozzle orifices in confrontation with a recording medium P. The recording medium P is moved in a second direction B with respect to the recording head 200. Also, ink droplets ejected from the nozzle orifices are charged to a charged amount that corresponds to deflection amount of the ink droplets. The charged ink droplets are deflected in a direction perpendicular to a main scanning line. The plurality of ink droplets ejected from the plurality of nozzle orifices impinge on the same pixel position or at a nearby position so that it is possible to impinge multiple droplets at the same pixel position or a nearby position. As a result, it is possible to back up broken nozzles and to reduce recording distortion.

Abstract: A back electrode 30 is provided at a rear surface side of a recording sheet 60. An orifice electrode 11 is attached to an orifice plate 15 of a head module 10. The orifice electrode 11, the orifice plate 15, and ink filling in a nozzle element 2 are electrically connected to the ground. The back electrode 30 has the potential corresponding to that of a charging/deflecting signal. With this configuration, the orifice electrode 11, a pressure chamber 13, and the back electrode 30 together generates an inclined electric field 85 at a position &agr; close to a center trajectory 90. A charged ink droplet is deflected greatly by the inclined electric field 85, at an early stage of the ink flight, and even greater deflection can be achieved as the flight proceeds.

Abstract: A hammer bank mounted on direct drive bearings reciprocally moves along a shaft. Springs provided at each end of the shaft supplies repulsive force to the hammer bank. When sheet feed operations for a plurality of carriage returns are performed, the hammer bank is stopped at a predetermined position away from the springs. When the reciprocal movement of the hammer bank is restarted, the hammer bank is first moved to a reverse position where the repulsive force of the spring is in the maximum. Then, the hammer bank is accelerated by utilizing the repulsive force of the spring and restarts the reciprocal movement.

Abstract: To prevent undue elevation of temperature in a hammer assembly but to maintain the maximum printing speed, when a scheduled number of drivings at which print hammers are to be driven during one scan of a manner bank which follows the currently performing scan, exceeds a first reference number, one dot line printing is completed with a plurality of scans of the hammer bank so that dot line print density in each scan of the hammer bank does not exceed, for example, 35%. If, however, high density printing exceeding 25% continues for an extended period of time more than one scan time, the printing operation is temporarily halted.

Abstract: A printer and ribbon cassette with gears for transmitting power from the drive motor of the printer to the ribbon cassette. Guides are provided for guiding the ribbon cassette in a direction perpendicular to the rotational axis of the gears, so that the ribbon cassette slides easily into place and the gears engage easily, but the gears are tightly engaged.

Abstract: In a dot line printer that prints, for example, eight lines of dots with each single scan of a hammer bank, wherein the pins of hammers for printing the first dot line and the eighth dot line or for printing the second dot line and the seventh dot line are shifted from their respective home positions to compensate for an error causing impressions of dots to be made at an unequal pitch in a sheet feed direction as a result of consecutive forward and backward movements of the hammer bank.

Abstract: A dot line printer provided with an ordinary dot density printing mode, a low dot density or draft printing mode and a high dot density printing mode. A hammer bank provided with a plurality of printing hammers is reciprocally movable in a shuttling direction for dot impressions when the hammer bank is moved through a printing region, and the moving direction of the hammer bank is reversed at a reversing region where a printing sheet is fed in a line to line direction. A shuttle cam is provided which is drivingly connected to the hammer bank. The shuttle cam has a cam profile capable of providing a cam lift characteristic approximately intermediate between a cam lift characteristics of the ordinary printing mode and that of the low dot density printing mode. A shuttling velocity of the hammer bank is changed in accordance with the selected printing mode and position of the hammer bank.

Abstract: A dot line printer for carrying out printing on a print paper while shuttling a hammer bank back and forth in a direction to traverse the print paper. To lower the peak level of the current flowed in an electromagnetic coil provided in association with a print hammer and to reduce an electric power consumption, a predetermined number of print hammers are divided, for example, into four groups A, B, C and D. The print hammers belonging to group A are arranged at a constant interval wherein three print hammers belonging to groups B, C and D are interposed between adjacent two print hammers of group A and are disposed in positions displaced toward the leftside group A hammer from their home positions defined by equally spaced apart positions between the adjacent two print hammers of group A. Currents are adapted to flow in the coils of the print hammers belonging to different groups, e.g.

Abstract: In a dot-line printer, a hammer bank carrying a plurality of dot printing hammers reciprocally moved along a printingline. Each of the printing hammers is made up of a leaf spring, one end of which is fixedly secured to the hammer bank and to another end of which a printing pin is attached. According to the invention, the plurality of dot printing hammers are separated into an odd-number group and an even-number group, in which the printing hammers in each of the odd-number and even-number groups are further separated into a predetermined number of sub-groups. The printing hammers in the odd-number group are arranged in the upper side of the printing line so that the printing pins extend downwardly and the printing hammers in the even-number group are arranged in the lower side of the printing line so that the printing pins extend upwardly.

Abstract: In a print hammer assembly for a dot line printer, print pins are attached to the tip ends of print hammers alternately displaced toward left and right by a predetermined distance from a vertical center of the print hammer, wherein comb portions of a front yoke at both sides of the plunger are made to be an equal width. With such an arrangement, the print pins are not deformed horizontally due to imbalanced magnetic force applied to the associated print hammer at the time of magnetization of a permanent magnet.

Abstract: A printing hammer assembly is provided having a plurality of hammer springs arrayed side by side at a predetermined pitch in a shuttling direction of a hammer bank. A front yoke is provided in front of the hammer springs, and a plurality of rectangular grooves are formed at an upper portion of the front yoke so as to receive therein corresponding rectangular plungers provided at the hammer springs. A gap is defined between a side wall of the groove and a side wall of the plunger. The gap is sufficiently large for tolerating inaccurate assembly of the hammer springs and the front yokes. Further, a subordinate front yoke is provided on the front yoke at a position of an array of the grooves.

Abstract: In a dot matrix line printer, a pair of pin tractors for feeding a print paper are operatively connected to a paper feed motor, and a tension roller mechanism disposed beneath a platen is operatively connected to a separately provided drive motor. To eliminate a paper slack which may occur when the feeding of the print paper is stopped after creating many blank lines, the drive motor is energized for a short period of time immediately before the paper feeding is ended. The tension roller mechanism which is made up of a plurality of rollers pulls the print paper in a direction opposite the paper feeding direction to thus prevent the print paper from slackening.

Abstract: A dot line printer with a paper feed time controlling capability includes a hammer bank accommodating a plurality of print hammers, a shuttle mechanism for shuttling the hammer bank back and forth along a print line, and a sheet feeding mechanism for feeding a sheet of paper in a direction perpendicular to the direction in which the hammer bank shuttles. When a first predetermined amount of a line space feeding is to be carried out after completion of one line printing, a hammer bank reversing time is prolonged. When more than the first predetermined amount of the line space feeding but less than a second predetermined amount of line space feeding is to be carried out, it is carried out during an extended period of time including both the hammer bank reversing time and the subsequent hammer bank scanning time without prolonging the hammer bank reversing time.

Abstract: A hammer bank assembly including a hammer base, a plurality of leaf spring type printing hammers, permanent magnets, a comb yoke and electromagnetic coils. The comb yoke has a base portion positioned on the permanent magnets and police portions secured by the base portion and extending from the base portion toward the rear faces of the printing hammers. The pole portions are made of a material capable of providing highly saturated magnetic flux density, and the base portion comprising a plurality of metal plates laminated together and containing another material which provides low saturated magnetic flux density.

Abstract: In a shuttle dot line printer including a hammer bank shuttling back and forth at a given speed in a direction to transverse a sheet of print paper while turning around at two opposite ends, and an endless ink ribbon uni-directionally moving through a space between the hammer bank and the sheet of print paper, the ink density of the characters printed when the hammer bank is moving in the direction opposite to the ink ribbon is lowered. To prevent such occurrence, the ink ribbon is moved at a low speed lower than a regular speed when the moving direction of the hammer bank is opposite to that of the ink ribbon. On the other hand, when the moving direction of the hammer bank is same as that of the ink ribbon, the ink ribbon is moved at the regular speed after a predetermined period of time has been expired when the hammer bank turns around at one end and starts moving in the same direction as the ink ribbon.

Abstract: A dot line printer having ink ribbon guides for stabilizing running performance of an ink ribbon. A dot line printer includes a hammer bank, a shuttle mechanism, a platen and ink ribbon guides. The hammer bank has print hammers for forming a plurality of dot impressions. The shuttle mechanism has one side positioned adjacent to one end of the hammer bank for reciprocally moving the hammer bank. The platen is adapted for bearing dot impression force, and a part of the ink ribbon is positioned at an ink ribbon path extending along the platen. The ribbon guides have a first guide positioned adjacent to another end of the hammer bank, and a second guide positioned adjacent to another side of the shuttle mechanism. The ink ribbon guides guide travel of the ink ribbon at the ink ribbon path. The ribbon guides further include a third ink ribbon guide positioned between the hammer bank and the shuttle mechanism for further guiding travel of the ink ribbon at the ink ribbon path.

Abstract: A dot-line printer has a hammer bank carrying a plurality of printing hammers arranged in groups, each group having a predetermined number of printing hammers displaced from one another by predetermined numbers of dot-lines in the direction of paper feed. A shuttle mechanism causes the hammer bank to undergo reciprocating shuttle movements with a reversing period between successive shuttle movements. A character line, covering a predetermined number of dot-lines, is printed over a plurality of shuttle movements, a paper feed mechanism causing the paper to move a predetermined number of dot-lines in the reversing period between shuttle movements. A number of blank dot-lines separate a printed character line from the beginning of the first dot-line of the next character line to be printed.

Abstract: An auxiliary ribbon separator for use on a dot-line printer is positioned to prevent vertical ribbon displacement in the presence of upward forces such as caused by perforations on continuous feed paper. The auxiliary separator is located so that the ribbon is guided past an end of a front yoke. The front yoke serves as a course ribbon guide and is a component of the electro-magnetic assembly of the print head associated with the printer. The auxiliary separator may be shaped so as to facilitate loading of the ribbon in the printer.

Abstract: A printing mechanism is provided with a counter-balanced hammer bank such that the hammer bank and a counterweight are oppositely reciprocated by a pair of cams mounted on a vertically oriented cam shaft. Vibration of the printer even at high speed can be eliminated by completely dynamically balancing the system.