Abstract: A dot printer in which vibration is eliminated without the use of a separate counterweight. The printer includes first and second hammer banks each holding a plurality of dot printing elements. The first and second hammer banks are spaced apart from each other a predetermined distance in the direction in which a printing sheet passes. A motor and oppositely-phased drive cams reciprocate the two hammer banks in opposite directions parallel to a dot printing direction.

Abstract: Systems for discriminating among a plurality of type carriers differing in number of characters and pitch of characters are disclosed. In one circuit, the type carrier is provided with synchronizing marks and discrimination marks in addition to the usual type character marks. The synchronizing mark is located at the beginning of a set of characters, and the discrimination mark is located a predetermined distance from the synchronizing mark according to the number of characters and pitch of the particular type carrier. This distance is determined by counting type character marks. In another circuit, one or more discrimination marks are provided between type character marks at the beginning of a set of characters. The number of discrimination marks indicates the number of characters of the particular type carrier. In either circuit, a counter of only a few stages and a simple decoding circuit are all that are required to carry out the discrimination operation.

Abstract: Systems for discriminating among a plurality of type carriers differing in number of characters and pitch of characters are disclosed. In one circuit, the type carrier is provided with synchronizing marks and discrimination marks in addition to the usual type character marks. The synchronizing mark is located at the beginning of a set of characters, and the discrimination mark is located a predetermined distance from the synchronizing mark according to the number of characters and pitch of the particular type carrier. This distance is determined by counting type character marks. In another circuit, one or more discrimination marks are provided between type character marks at the beginning of a set of characters. The number of discrimination marks indicates the number of characters of the particular type carrier. In either circuit, a counter of only a few stages and a simple decoding circuit are all that are required to carry out the discrimination operation.

Abstract: A timing control device for use with a printer or the like contains a memory device storing detection signals at sequential memory locations, the number of which may be varied by adjusting the peroid of a clear signal applied to an address counter. The detection signals sequentially stored in the memory are successively read out after one period of the clear signal has elapsed, whereby a variable delay function is achieved.

Abstract: In a high speed impact printer of the type arranged to impact a plurality of print hammers against given types carried by a type carrier by energizing corresponding solenoids, the energization of given solenoid or solenoids is started from a given point of time. The given solenoid(s) is/are continuously energized for a predetermined interval which is accurately determined by digital circuitry having a counter. A memory for storing data each indicative of a place in a print line in each address thereof, is provided, where a given address of the memory is periodically read and written at a given interval in response to the output signal of the counter which periodically counts the number of clock pulses. The data stored in the memory is decoded to terminate the energization of the given solenoid(s).

Abstract: A hammer drive safety device for a line printer having a plurality of solenoid-driven hammers is disclosed, which includes a time limiting circuit for producing an output when a character print command signal is not produced for more than a predetermined duration, the plurality of detectors for detecting currents flowing through the respective solenoids, and a switch responsive to the output of the time limiting circuit and the outputs of the detector for disconnecting the solenoids from the power source.

Abstract: A magnetic interference prevention system in a printer comprising a plurality of print hammers whose hammering surfaces are disposed in a straight line and a plurality of printing magnets arranged adjacent one another to drive each of the print hammers respectively. In this system when a signal to drive a first printing magnet for a column is provided the driving of at least one of two printing magnets adjacent to the first printing magnet is inhibited for a predetermined period of time. This will prevent three adjacent printing magnets from being driven substantially at the same time.

Abstract: A printing device having a plurality of print hammers having striking surfaces arranged along a print line and print magnets provided adjacent to one another for driving the printing hammers. A magnetic interference preventing device comprises a memory for storing for each column the excitation lapse time information of the print magnets. A reader which, when exciting each print magnet is started, reads the excitation lapse time information of both print magnets adjacent to each print magnet out of the memory. The reader outputs a signal only when the excitation lapse times of both print magnets are in a predetermined range of time. An inhibitor is used for inhibiting the excitation of each print magnet when the excitation lapse times of both print magnets are within the predetermined range of time.

Abstract: A device for limiting the number of printing columns in a printer in which a group of printing data codes transferred from a data source are successively compared with a group of type codes which are determined in correspondence to the instantaneous positions of type on a type carrier, so that a type in a place where a printing data code coincides with a type code is printed. The device comprises a reversible counter adapted to subject a coincidence signal relating to said printing data code and type code and a printing completion signal for each place to addition and subtraction, respectively, so that when the count value of the reversible counter reaches a predetermined value, printing for further places is inhibited.