JPS59138480A - Paper feed controller for printer - Google Patents

Abstract

PURPOSE:To obtain a paper feed controller for printer in which a platen can be easily rotated manually by the operator, by a method wherein the second holding force stronger than the first holding force for maintaining a stop position is exerted on a rotor. CONSTITUTION:When a signal A of A-phase where the rotor of a pulse motor 3 is stopped is set in a Low condition and other signals B, C, D are set in a High condition, the first holding force corresponding to an electric current i1 is generated between a winding C1 and a salient pole of the rotor corresponding to the winding C1. A counter 6 outputs to a driving circuit 5 a signal F which is normally High and becomes Low three times at an interval of T2 in a period T1. When the signal F becomes Low, the second holding force equal to the first holding force plus a force corresponding to an electric current i2 is generated. The operator rotates the platen with a light touch, and stop the rotation of the platen at a desired position. Thereafter, the rotor receives the second holding force, a force is exerted on both the winding corresponding to A-phase and the projected pole of the rotor, and the position of the rotor is automatically corrected to be an initial A-phase position.

Description

[Detailed description of the invention] [Field of invention] The present invention relates to improvements in paper feed control devices for printers.

[Technical background of the invention]

In a printer that uses a pulse motor in a paper feeding mechanism, such as a serial printer, when paper feeding is not being performed, the rotor of the pulse motor is stopped at a certain electrical phase. By passing a constant current through the winding corresponding to this phase, a holding force was generated between the stator and rotor of the pulse motor to prevent the rotor from rotating easily at 5KL. Therefore, conventionally, a mechanical clutch was provided between the pulse motor and the 7"5 tensioner, and when the operator manually rotated the platen, the mechanical clutch was declutched and the platen knob was rotated. However, after the operator manually rotates the platen in this way, the rotor's stop position is
Usually does not match the original electrical phase position. For this reason, conventionally, a large current was passed through the winding corresponding to the original phase to strengthen the holding force so that the rotor stopping position coincided with the electrical phase position.

[Problems with background technology]

As described above, in conventional printers, when the operator manually rotates the platen, the operator has to press the knob of the platen in the axial direction, which is complicated. Furthermore, conventional printers were expensive because they were equipped with mechanical clutches with complicated structures.

Further, conventional printers require a relatively large power supply even when paper feeding is stopped.

[Purpose of the invention]

The present invention has been made in view of the above drawbacks, and its purpose is to:
To provide a paper feed control device for a printer which has no mechanical clutch between a paper feed pulse motor and the platen and controls the platen of the printer so that an operator can easily manually rotate the platen.

[Summary of the invention]

Therefore, in the present invention, when the rotor of the paper feed pulse motor of the printer stops rotating in the negative phase, a first
a first holding force generating means for causing a current to flow through a winding corresponding to the negative phase in order to apply a holding force to the rotor;
After the rotor is manually rotated through the platen with a first holding force applied thereto, a second holding force stronger than the first holding force is applied so that the rotor stops in the negative phase. In order to give the rotor a holding force of -
A paper feed control device for a printer is created, comprising: a second holding force generating means for causing current to flow through a winding corresponding to the phase;
The above objective was achieved.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram of a paper feed control device for a printer that is an embodiment of the present invention. Reference numeral 1 in the figure is a CPU that generally controls the entire printer using this device. 2 is CP
, Ul stores the programs used.

3 is a pulse motor that feeds the paper. The rotation of the pulse motor 3 causes a platen (not shown) to rotate. 4 is a motor control circuit, 5 is a drive circuit, and 6 is a counter. CPU1. The memory 2, motor control circuit 4 and counter 6 are connected by a common bus 7, and the drive circuit 5 is
Signals can be applied from the motor control circuit 4 and the counter 6 via signal lines 8.9, respectively. The motor control circuit 4 is controlled by the CPUI,
A pulse signal with a timing necessary to drive the windings of the pulse motor 3 is outputted to the drive circuit 5 via the signal line 8. The drive circuit 5 supplies power to each winding of the pulse motor 6 based on a signal given from the motor control circuit 4.

Counter 6 is here a programmable counter,
A counter whose counting function can be specified by a program. It is assumed that the function of this counter 6 is set by a program so as to output a signal F as described later.

Further, the pulse motor 3 used in this embodiment is a four-phase pulse motor (each phase is a human phase, a B phase, a C phase, and a D phase).

FIG. 2 shows a part of the drive circuit 5 shown in FIG. 1, and is a circuit diagram around the winding corresponding to the physiognomy.
(The same applies to the other B, C, and D phases, so illustrations are omitted). Tr is a PNP type transistor, Tr,
is an NPN type transistor, -1 is a resistor, Dl is a diode, 11 is an inverter, and C1 is a winding corresponding to the A phase of the pulse motor 3. A voltage VA is applied to the anode terminal of the diode through a resistor A, and the emitter terminal of the Y transistor Tr is directly connected to the transistor Tr! A voltage VB is applied to the base terminals of each via a resistor. A signal F is applied to the base terminal of the transistor Tri via a resistive island, and a signal F is applied to the input terminal of the inverter I0. Here, the signal F is a signal supplied from the counter 6 shown in FIG. 1 via the signal line 9. Signal A is a signal created based on a signal supplied from motor control circuit 4 via signal line 8 . transistor Tr,
The collector terminal of is connected to the anode terminal to the diode, and the output terminal of the inverter Tr is connected to the transistor Tr.
is connected to the base terminal of. Diode D, and D2
The cathode terminal of is connected, and the connection point thereof is grounded via a resistor R3 and connected to one end of the winding C1. The collector terminal of the transistor Tr is connected to the other end of the winding C1, the emitter terminal of the transistor Tr is grounded, and the base terminal of the transistor Tr is grounded via a resistor. Note that the emitter terminal and base terminal of the transistor Tr1 are connected via a resistor.

The above is a description of the circuit around the winding corresponding to the human phase, but the same applies to the other B, C, and D phases. However, in each circuit, input signals B and C are used instead of input signal A shown in FIG.

It becomes D. Note that the input signal F shown in FIG. 2 is similarly input to each circuit.

The operation of the apparatus of this embodiment configured as described above will be explained with reference to the timing chart of FIG.

Signals A, B, C, and D shown in FIG. 3 are excitation signals generated by the drive circuit 5 based on signals output from the motor control circuit 4 via the signal line 8. When these signals are \Low', current will flow through the corresponding windings. As mentioned above, the signal F is applied to the counter 6.
This is the signal output from. These signals A, B, C,
D and F are 5V and I (high#, Low when Ov).
〃.

First, let's assume that the rotor stops at the human face.
At this time, the signal person is 'Low'. Next, if this signal A is kept in a low state and the other signals B, C, and D are set as Machida ghI, the transistor Tr shown in FIG. Between the line C4 and the corresponding salient pole of the rotor, there is a through flow i, VC
A corresponding first holding force is generated.

In this state, the counter 6 outputs the signal F shown in FIG. 3 to the drive circuit 5 via the signal line 9.

This signal F is normally ηghIL? ! Yes, period T1
It is a signal that becomes 3 marks Low /l at intervals of T in the range.

Here, the period T is the period when the - salient pole of the rotor of the pulse motor 3 moves from one winding to the next on the stator side when the operator rotates the platen knob at a normal speed. It is assumed that the time required to do this is set. When the signal F output from the counter 6 is applied to the base terminal of the transistor Tr1 via the resistor as shown in FIG.
It becomes ON only when it is Low'. In other words, the signal F is '
When it becomes Low', a force corresponding to the current is added to the first holding force between the winding corresponding to the human phase of the pulse motor 3 and the corresponding salient pole of the rotor. A second holding force is generated.

From the above, when the operator manually rotates the platen, the first holding force acts between the stator and rotor of the pulse motor 6, but this force is weak. Therefore, the operator can rotate the platen with a light touch. After the rotation of the platen is stopped at a position desired by the operator, the rotor of the pulse motor 3 receives a second holding force, which is strong. Therefore,
Forces act on the windings corresponding to the human phase and the salient poles of the rotor, and the position of the rotor is automatically corrected to the original electrical phase (human phase) position.

In the above example, the signal F generates three pulses within the period T, but in general, n pulses (n>1) may be used. Furthermore, as another means, one pulse may be applied such that the addition of these n pulses provides the same electric power as the electric power applied to the winding of the pulse motor 6.

〔Effect of the invention〕

As explained above, according to the present invention, there is no need to provide a multi-fiber mechanical clutch in the printer. Therefore, the cost of the printer can be reduced.

Furthermore, when manually rotating the platen, the operator does not need to perform operations such as pressing down on the knob of the platen in the axial direction as in the past, and can quickly and easily rotate the platen. Furthermore, the printer using the present invention requires less power to generate the holding force when paper feeding is stopped. Furthermore, when the operator manually rotates the platen, the holding force is weak, so the noise is low.

[Brief explanation of drawings]

FIG. 1 is an overall block diagram of the device of the present invention, FIG. 2 is a diagram showing 11 parts of the drive circuit shown in FIG. 1, and FIG. 6 is a timing chart for explaining the operation of the device of the present invention. be. 1...CPU, 2...Memory, 3...Pulse motor, 4...Motor control circuit, 5...Drive circuit, 6...Counter agent Patent attorney Nori Haka So 1 person) 11- Mu Ku ω 0 0

Claims (1)

[Claims] When the rotor of the paper feed pulse motor of the printer stops rotating in the negative phase, a first holding force is applied to the rotor so that the rotor maintains the stopped position in the negative phase. Therefore, after the rotor is manually rotated with the first hold force applied to it, the rotor is rotated manually. In order to apply a second holding force stronger than the first holding force to the rotor so that the rotor stops at the negative phase, a second holding force is generated that causes current to flow through the winding corresponding to the negative phase. 1. A paper feed control device for a printer, comprising: means.