US 4,034,842 AGranted

Arrangement for driving a printing head along a printing line

AssigneeIng. C. Olivetti & C., S.p.A.

InventorFelice Giacone

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Abstract

An arrangement for driving a printing head along a printing line of a recording medium comprises a reversible direct-current electric motor which is coupled to the head for moving the latter forwards and backwards along the printing line. The head prints only during the forwards movement and during this movement the motor is supplied with a first voltage which causes the forwards movement of the head at a first substantially constant velocity. After the printing of a last character the head is moved away from the recording medium by an electromagnet and the motor is supplied with a second voltage which causes the backwards movement of the head at a second substantially constant velocity, greater than the first velocity. During the backwards movement of the head two rollers advance the recording medium and held it tensioned in correspondence with the printing line.

Claims9

Dependent claims

An arrangement for driving a printing head along a printing line of a recording medium, comprising:

a reversible direct-current electric motor coupled to said head for the driving thereof at a speed substantially proportional to the supply voltage to said motor and energized through opposite supply voltages for moving said printing head in a forward movement and in a backward movement along said printing line, wherein said head is positioned at rest at a rest extremity of the printing line, from which the head starts for the forward movement and to which the head returns at the end of the backward movement;
driving means for causing said printing head to print only during said forward movement defining a printing stage thereof;
voltage generating means having a first, a second terminal and a third terminal and feeding to said first terminal a first substantially constant voltage, to said second terminal a second substantially constant voltage, of opposite polarity with respect to said first voltage and of greater magnitude than said first voltage and to said third terminal a third substantially constant voltage of the same polarity and of smaller magnitude than said second voltage;
first switching means actuatable by said driving means for supplying said first voltage to said motor during said printing stage to move said head forward along the printing line at a first velocity;
second switching means actuatable by said driving means for supplying to said motor said second voltage, to move said head backward along the printing line at a second velocity greater than said first velocity;
and
third switching means selectively actuable by said driving means for supplying to said motor said third voltage when the head is arriving at the rest extremity of the printing line during the backward movement thereof thereby giving to said head a slow final approach to said rest extremity for an exact positioning thereof.

4 more elements

An arrangement for driving a printing head along a printing line of a recording medium, comprising:

a reversible direct-current electric motor coupled to said head for the driving thereof at a speed substantially proportional to the supply voltage to said motor and energized through opposite supply voltages for moving said printing head in a forward movement and in a backward movement along said printing line;
feedback-speed means for generating a feed-back speed voltage proportional to the speed and to the sense of rotation of the motor;
driving means for causing said printing head to print only during said forward movement defining a printing stage thereof;
voltage generating means having a first and a second terminal and feeding to said first terminal a first substantially constant voltage and to said second terminal a second substantially constant voltage, of opposite polarity with respect to said first voltage and of greater magnitude than said first voltage and comprising voltage divider means connected to said first and second terminals for feeding said first and second voltages;
first switching means actuatable by said driving means for supplying said first voltage to said motor during said printing stage to move said head forward along the printing line at a first velocity;
second switching means actuable by said driving means for supplying to said motor said second voltage, to move said head backward along the printing line at a second velocity greater than said first velocity;
wherein said first and second switching means comprise a first and a second electronic switch, said first and second switches each having a first connector connected to the corresponding one of said first and second terminals;
and
an operational amplifier having an output connected to said motor for the driving thereof, a first input connected to a second connector of said first and second switches for receiving the first and second voltages therefrom, and a second input connected to said feedback-speed means for receiving the feedback-speed voltage therefrom.

6 more elements

An arrangement for driving an electrothermal type printing head along a printing line of a recording medium, comprising:

a reversible direct-current electric motor coupled to said head for the driving thereof at a speed substantially proportional to the supply voltage to said motor and energized through opposite supply voltages for moving said printing head in a forward movement and in a backward movement along said printing line;
driving means for causing said printing head to print only during said forward movement defining a printing stage thereof;
voltage generating means having a first and a second terminal and feeding to said first terminal a first substantially constant voltage and to said second terminal a second substantially constant voltage, of opposite polarity with respect to said first voltage and of greater magnitude than said first voltage;
first switching means actuatable by said driving means for supplying said first voltage to said motor during said printing stage to move said head forward along the printing line at a first velocity;
second switching means actuatable by said driving means for supplying to said motor said second voltage to move said head backward along the printing line at a second velocity greater than said first velocity;
and
advancing means for advancing said recording medium transversely with respect to said printing line and holding a portion of said recording medium tensioned in correspondence with said printing line, said advancing means comprising a pair of draw rollers rotatably supported in a parallel relationship, means for holding said recording medium substantially adherent to said rollers wherein said rollers locate said portion of said recording medium therebetween with one of said rollers having a diameter larger than the other, and rotating means for rotating said rollers at a same angular speed for causing the roller having the larger diameter to pull said portion of recording medium jointly with the advancing thereof.

4 more elements

An arrangement for driving a printing head along a printing line of a recording medium, wherein said head is, at rest, positioned at a rest extremity of the printing line, from which the head starts for a forward movement and to which the head returns at the end of a backward movement, said arrangement comprising:

a reversible direct-current electric motor coupled to said head and energizable through opposite voltages for moving said printing head in said forward and backward movements along said printing line;
control means for causing said printing head to print only during said forward movement defining a printing stage thereof;
first supplying means actuatable for supplying a first voltage to said motor during said printing stage to move said head forward along the printing line at a first velocity;
second supplying means actuatable for supplying to said motor a second voltage, of opposite polarity with respect to said first voltage, and of greater magnitude than said first voltage, to move said head backward along the printing line at a second velocity greater than said first velocity;
third supplying means actuatable for supplying to said motor a third voltage, of the same polarity and of smaller magnitude than said second voltage when the head is arriving at the rest extremity of the printing line during the backward movement thereof;
driving means operated by said control means for selectively actuating said first, said second and said third supplying means;
feedback-speed means for generating a feedback speed voltage proportional to the speed and to the sense of rotation of the motor;
voltage divider means having three terminals feeding said first, said second and said third voltage, said first, said second and said third supplying means comprising a first, a second and a third electronic switch respectively, each one having a first connector connected to a corresponding one of said three terminals and a second connector;
and
an operational amplifier having an output connected to said motor for the driving thereof, a first input connected to the second connector of said first, second and third switches for receiving the first, the second and the third voltage therefrom, and a second input connected to said feedback-speed means for receiving the feedback-speed voltage therefrom.

7 more elements

Dependencies are inferred from the claim text.