JPH0137278B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a paper feed control device for a line printer aimed at improving operability.

[Background of the invention]

FIG. 1 shows a block diagram of a paper feeding device according to the prior art.

The servo motor 1 drives four tractors 6 via a coupling 12 and a timing belt 5 to feed the printing paper 7. Encoder desk 2 is
It is mounted on the shaft of the servo motor 1 and used to control the rotation angle of the servo motor 1. Sensor 3 detects the rotation angle of encoder desk 2. Sensor amplifier 8 amplifies the output of sensor 3,
The output is applied to the paper feed drive circuit 10.

The printer control circuit 9 is connected to a paper feed drive corridor 10
is excited and further amplified by the servo amplifier 11 to control the servo motor 1. Further, the printer control circuit 9 excites a printing hammer drive circuit (not shown) to control the printing hammer (not shown).

The sensor adjust lever 4 moves the sensor 3 in the circumferential direction of the encoder desk 2 during the non-driving period of the paper feed device, thereby adjusting the servo motor 1.
It is used to shift the stop position of the paper 7, adjust the stop position of the paper 7, and align the ruled lines of the paper 7 with the printing lines of the printer.

FIG. 2 shows changes in the output of the sensor amplifier 8 with respect to changes in the position of the sensor 3. In the conventional technology,
Since it uses analog servo control technology, it operates to control the position at point _A0 of the solid line waveform in Figure 2. For example, sensor adjust lever 4
When is moved in the paper feeding direction (hereinafter referred to as the forward direction), the phase of the output of the sensor amplifier 8 advances from the solid line to the dashed line in Fig. 2, and the stable point of the servo motor 1 changes from A ₀ to A _1. As it moves, paper 7 is A ₀
The stopping position is changed by an amount equivalent to the angular displacement of A ₁ from . Furthermore, when the sensor adjust lever 4 is moved in the opposite direction to the paper feeding direction (hereinafter referred to as the backward direction), the output of the sensor amplifier 8 lags in phase from the solid line to the broken line in FIG. 2, which stabilizes the servo motor 1. Since the point moves from A ₀ to A ₂ , the paper 7 changes its stopping position by an amount corresponding to the angular displacement from A ₀ to A ₂ .

If the sensor adjustment lever 4 is used to align the ruled lines of the paper 7 and the print lines, the mechanism for moving the sensor 3 will be complicated;
Moreover, it has the disadvantage of strict manufacturing tolerances for parts. Furthermore, since the amount of movement of the sensor adjustment lever 4 cannot be accurately controlled, there is a drawback that adjustment must be made through repeated trial and error in order to align the ruled lines of the paper 7 with the print lines.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks of the prior art, facilitate the paper alignment operation, and ensure that the paper is aligned to a desired adjustment position.

[Summary of the invention]

The present invention provides that in order to change the paper stop position, it is sufficient to change the zero position of the servo control, and that in digital servo control technology, the zero position of the servo control can be changed for position control. Focusing on the fact that it is only necessary to change the count value of an up-down counter (hereinafter simply referred to as a counter), we provided a pair of switch circuits that are operated when you want to move forward or backward from the stop position, and each time the switch circuit is operated, The generated forward instruction pulse or backward instruction pulse is added to the addition input terminal or subtraction input terminal of the counter to artificially change the count value of the counter to control the zero position by servo control of the position, thereby stopping the paper. The position can be finely adjusted with simple operations.

[Embodiments of the invention]

The present invention will be explained below with reference to time charts of FIGS. 3, 6 and 7 showing examples.
Note that FIG. 6 constitutes a part of the paper feed drive circuit (hereinafter simply referred to as the drive circuit) 100, and only the parts related to the stop position adjustment of the present invention are extracted and shown.

The encoder desk 20 has a narrower slit than the slit of the encoder desk 2 shown in FIG.
Two sets of slits, for example, 384 slits, are provided per round so that they have a phase difference of 90 degrees in electrical angle.
The sensor 30 includes two sets of a light emitting element and a light receiving element so as to detect the two sets of slits of the encoder disk 20. The sensor amplifier 80 shapes the waveforms of the two outputs of the sensor 30, as shown in FIGS. 4 and 5, and outputs a forward pulse or a backward pulse depending on the timing of generation of these outputs. In Figures 4 and 5, φA,
φB is the waveform shaped output of sensor 30,
The forward pulse and backward pulse are as shown in the figure.
Each is generated when φA and φB are generated first. The forward pulse and backward pulse are applied to the subtraction input terminal and addition input terminal of the counter 16 via OR gates 22 and 21, respectively, as shown in FIG.

Printer control circuit (hereinafter simply referred to as control circuit)
Reference numeral 9 receives print data and paper feed line feed data transferred from a host device (not shown), generates a signal to drive the print hammer via a print hammer drive circuit (not shown), and issues a paper feed command FEED corresponding to the number of command line feeds. is sent to the drive circuit 100. Further, when receiving a line feed pulse signal (described later) transferred from the drive circuit 100, and receiving a number of line feed pulse signals equal to the number of command line feeds, the control circuit 9 outputs the paper feed command.
Stop the occurrence of FEED.

The drive circuit 100 receives a paper feed command from the control circuit 9.
In response to FEED, a signal is generated to drive the servo motor 1 via the servo amplifier 110 to start paper feeding. Similar to normal servo control, the drive circuit 100 performs speed feedback control until the paper 7 advances near a predetermined position, and after the paper 7 advances near the predetermined position, that is, the paper feed command FEED is executed.
After the occurrence of the error has stopped, the process moves to position feedback control. Note that such speed feedback control is a well-known technique and is not directly related to the present invention, so drawings and explanations thereof will be omitted.

The counter 16 counts forward pulses applied to the subtraction input terminal, and the count value is, for example, -20.
, the line feed pulse signal is generated and sent to the control circuit 9 via a decoder (not shown).
It is assumed that when the paper 7 is line-feeded by one line, 24 encoder pulses, that is, forward pulses are generated from the sensor amplifier 80). Counter 16 is also -24
This will be explained as a 24-decimal counter that returns to 0 when it counts up to 0.

As shown in the time chart of FIG. 7, when three line feed pulse signals are generated in response to a paper feed command to feed three lines, the generation of the paper feed command FEED is stopped and position control is started. The load value of the load data circuit 15 (in this embodiment, the value is +4) is loaded into the counter 16 by the counter load signal whose logical value becomes 1 when the paper feed command FEED stops generating, and the count value of the counter 16 is It becomes 4. The load value of the load data circuit 15 indicates the distance between the position of the paper 7 and the line feed stop position when the generation of the paper feed command FEED stops, and the load value corresponds to the slit of the encoder desk 20, that is, the number of forward pulses generated. This is the converted value.

A pulse width modulation circuit 17 that receives the count value of the counter 16 converts it into a pulse width corresponding to the count value and outputs the pulse width, and after moving to position control, the AND gate 23 , 24 to the servo amplifier 110. AND gate 23 is counter 1
When the count value of 6 is positive, the logical value becomes 1, indicating that the advance is in progress, and the advance signal and the paper feed command.
A gate is opened by a detent signal whose logical value becomes 1 when the generation of FEED stops, and a forward correction signal is generated to cause the servo motor 1 to move forward. When the count value of the counter 16 is negative, the AND gate 24 has a logic value of 1, which indicates that the servo motor 1 is moving backward, and opens the gate in response to the backward signal and the detent signal, and generates a backward correction signal that causes the servo motor 1 to move backward. do. Therefore, counter 1
6 generates a forward correction signal or a backward correction signal via the pulse width modulation circuit 17 and AND gates 23 and 24 until the count value reaches 0, and performs servo control to stop the paper 7 at a predetermined line feed position.

The servo amplifier 110 amplifies the power of the forward correction signal so that the servo motor 1 rotates in the forward direction, and the servo amplifier 110 amplifies the power of the backward correction signal so that the servo motor 1 rotates in the backward direction. .

The above is related to paper feed control during normal printing, and the method for adjusting the stop position of the paper 7 when printing is stopped according to the present invention will be described below.

Switch circuits 13 and 14 are provided to adjust the position of paper 7, and each time they are operated, they generate one forward instruction pulse or one backward instruction pulse. These pulses are applied to the addition input terminal and the subtraction input terminal of the counter 16 through an AND gate 18 and an OR gate 21 whose other input is the detent signal, and an AND gate 19 and an OR gate 22 whose other input is the detent signal. can be added respectively. For example, if the switch circuit 13 is
When the forward command pulse is generated once after being operated twice,
The AND gate 18 performs a logical product with the detent signal, and the forward instruction pulse is applied to the addition input terminal of the counter 16 via the OR gate 21, so the count value of the counter 16 becomes +1, indicating that a position error has occurred. Equivalent to. Since the count value of the counter 16 is not 0, the pulse width modulation circuit generates a forward correction signal via the AND gate 23 and controls the servo motor 1 so that the count value of the counter 16 becomes 0. As a result, the paper 7 is advanced by 1/384 rotation of the servo motor 1,
The stopping position of the paper 7 will be changed. 7th
The figure shows a case where the switch circuit 13 is operated once to generate one forward instruction pulse. When the switch circuit 14 is operated to generate a backward instruction pulse, the backward instruction pulse is applied to the subtraction input terminal of the counter 16 via the AND gate 19 and the OR gate 22, and the count value of the counter 16 becomes -1. Therefore, the position servo control is performed in the same way as described above, a backward correction signal is generated, the paper 7 is moved backward, and the stop position is changed. In addition, the seventh
In the figure, the position error value during the detent period (9) is
This shows the count value of the counter 16, which is the same as the up-down counter 16 in (6), and is shown to make it easier to understand the count value of the counter 16 during position servo control.

Therefore, each time the switches in the switch circuits 13 and 14 are operated, the servo motor 1 rotates by 1/384 rotation in the forward or backward direction to rotate the paper 7.
You will be able to adjust the stopping position of the 1/384 rotation of the servo motor 1 corresponds to, for example, 0.174 mm in terms of the amount of movement of the paper 7, and is an appropriate adjustment unit in light of the resolution that can be visually determined. Therefore, by operating the switches in the switch circuits 13 and 14 twice, the paper 7 can be moved by 0.174×2=0.348 mm. Similarly, the desired amount of adjustment can be reliably adjusted by changing the number of times the switch circuits 13 and 14 are operated.
In order to prevent the switches of the switch circuits 13 and 14 from being pressed down by mistake when adjustment is not desired, it is desirable that the switches be recessed from the surface of the cover to be accessed.

〔Effect of the invention〕

As described above, according to the present invention, the paper feed command
In a paper feed control device that performs servo control so that the count value of a counter that is loaded with a predetermined value becomes 0 when the generation of FEED stops, a pair of switch circuits that are operated when it is desired to advance or retreat the paper stopping position are used. A forward instruction pulse or a backward instruction pulse generated each time the switch circuit is operated is applied to the addition input terminal or subtraction input terminal of the counter, and the zero position of the servo control is forcibly changed to stop the paper. I adjusted the position, so
Adjustment operations become easier and the paper can be reliably stopped at a desired stop position. Furthermore, since the forward instruction pulse and backward instruction pulse are not input to the counter unless the paper feed command FEED has stopped generating, the switch circuit may be erroneously operated during normal paper feeding. Even if the paper is stopped, the paper stop position will not change.

[Brief explanation of drawings]

Figure 1 is a block diagram of a conventional paper feeding device, Figure 2 is a waveform diagram showing the relationship between the rotation angle of the servo motor and the output of the sensor amplifier when the position of the sensor in Figure 1 is changed, and Figure 3 is A block diagram of a paper feeding device showing an embodiment of the present invention, and FIGS. 4 and 5 are time charts showing the output of the encoder sensor when the servo motor is rotating in the forward direction and backward direction, respectively. FIG. 6 is a block diagram showing the main part of the present invention, and FIG. 7 is a time chart for explaining the paper feeding operation. In the figure, 1 is a servo motor, 6 is a tractor, 7 is printing paper, 9 is a printer control circuit, 1
3 and 14 are switch circuits, 15 is a load data circuit, 16 is an up/down counter, 17 is a pulse width modulation circuit, 20 is an encoder desk, 30 is a sensor, 80 is a sensor amplifier, 100 is a paper feed drive circuit, and 110 is a servo amplifier. It is.

Claims (1)

[Claims] 1. An encoder desk mounted on the shaft of a servo motor that drives a tractor to feed paper, and a pair of sensors that generate detection outputs with a phase difference each time the desk rotates by a predetermined angle. and a sensor amplifier that takes the detection output of the sensor as input and generates a forward pulse or a backward pulse corresponding to a predetermined rotation angle when the servo motor moves forward or backward, and subtracts the forward pulse and backward pulse of the sensor amplifier, respectively. An up-down counter that has input and addition input and generates a line feed pulse signal every time a predetermined number of forward pulses are counted; It has a printer control circuit that stops generation of the paper feed command, and a load data circuit that loads a predetermined value into the up-down counter using a counter load signal that is generated at the timing when the generation of the paper feed command stops. A paper feed control device for a line printer, which controls the rotational direction and rotation amount of the servo motor so that the count value becomes 0, and controls the paper stop position, and is operated when the paper is to be moved forward or backward. , one input is a pair of switch circuits that generates one forward instruction pulse and one backward instruction pulse each time the operation is performed, and a detent signal that is generated at the timing when the generation of the paper feed command stops;
A pair of gate circuits each having the forward instruction pulse and the backward instruction pulse as inputs of the other, and apply the forward instruction pulse and the backward instruction pulse to an addition input terminal and a subtraction input terminal of the up-down counter, respectively. Paper feed control device for line printers.