JP2933315B2 - Print density adjustment device - Google Patents

Description

Detailed Description of the Invention [Table of Contents] Overview Industrial field of application Conventional technology Problems to be solved by the invention Means to solve the problem Action Embodiment Effects of the invention [Overview] Printing density in an impact type dot printer If the print is thin, increase the impact force and limit the temperature rise of the head to prevent the power supply capacity from increasing.If the print is thin, increase the impact force applied to the pins and reduce the printing speed. The purpose of the present invention is to provide a printer that does not need to increase the power supply capacity by limiting the temperature rise of the head, and to drive the pins with an impact force corresponding to the amount of energy supplied to the windings of the head, and to apply a force to the carrier. By performing the space operation, the printing device that detects the timing of driving each pin and prints out the printing density. Instructing means for instructing switching, and when the amount of energy supplied to each winding for a certain period of time is increased by a predetermined amount based on the instruction of the instruction means, or when the temperature sensor reaches the predetermined temperature by the operation. Is detected, the amount of energy supplied to each of the windings for a certain period of time is controlled by control means for changing the space speed of the carrier or by limiting the number of windings of the simultaneously driven head, thereby instructing to increase the print density. The configuration is such that the control is performed so as to be substantially equal to the case where the processing is not performed.

[Industrial applications]

The present invention relates to an impact-type dot printer, particularly when printing is performed with an impact force that is normally used, when the print density is low, the impact force is increased, the temperature rise of the head is limited, and the power supply capacity is not increased. And a print density adjustment method.

An impact-type dot line printer that has multiple heads and performs printing in a shuttle system is a group of dots that correspond to the character pattern by driving the pins provided on the head with a paper and ribbon interposed between the platen and the head. By
Printing is performed by forming characters, but when the number of copies increases,
Insufficient impact force of individual pins results in thin printing.

In this case, it is desirable to increase the impact force given to the pins to increase the print density. However, in order to increase the impact force, it is necessary to increase the amount of energy supplied to the head.

However, even if the amount of energy supplied to the head is increased, it is necessary that the temperature of the head does not exceed the limit, the printing speed is extremely reduced, and the power supply capacity is not insufficient.

[Conventional technology]

FIG. 6 is a diagram illustrating an example of an impact type dot line printer.

When the printer is viewed from above, a plurality of heads 2 are arranged facing the platen 1, and a ribbon 3 and a sheet 6 indicated by a dotted line exist between the platen 1 and the head 2.

The plurality of heads 2 are mounted on the same carrier (not shown).
The pin (not shown) is projected in the direction of the ribbon 3 with a predetermined impact force while reciprocating in the direction of the arrow (3), and printing is performed on the paper 6 set between the platen 1 and the ribbon 3.
That is, the head 2 is provided with a plurality of pins, respectively.
In addition, a driving winding for driving the pin is provided for each pin. Then, a drive current is applied to the windings of only the pins selected corresponding to the character pattern, so that the ribbon is driven to project in the direction of the ribbon 3.

The ribbon 3 is moved in the direction of arrow C by a roller 5 driven and rotated by a motor (not shown) in accordance with the space operation of the head 2, pulled out from the ribbon cassette 4, and moved between the head 2 and the paper 6. An operation of passing through and returning to the ribbon cassette 4 is performed.

Conventionally, when such an impact type dot line printer performs printing on a plurality of sheets simultaneously, the printing becomes thin. Therefore, the operator has reduced the gap between the head 2 and the platen 1, that is, the gap, from an appropriate value to increase the impact force applied to the paper 6.

[Problems to be solved by the invention]

As described above, conventionally, when the print density is low, the gap is narrower than an appropriate value. However, in this method, since a large number of heads are arranged, when the space between the ribbon 3 and the head 2 becomes narrow,
The frictional force between the head 2 and the ribbon 3 increases, so that the running of the ribbon 3 and the carrier for transporting the head 2 are likely to be hindered, a ribbon jam occurs, and the pins of the head 2 are caught on the ribbon 3. Also, the pin was broken, which was an obstacle factor.

In order to avoid such an adverse effect, it is conceivable to set a higher drive current to be applied to the winding and to always apply an excessive impact force to the pin. However, in this method, power consumption is increased, and a means for preventing the temperature of the head 2 from rising is required, so that there is a problem that the cost is increased and the consumption of the platen is accelerated.

In view of the above problems, the present invention increases the impact force applied to the pins when the operator recognizes that printing is light, increases the printing density, and reduces the printing speed.
It is an object of the present invention to provide a printer that suppresses a temperature rise of the head 2 within a limit and does not require an increase in power supply capacity.

[Means for solving the problem]

 FIG. 1 is a block diagram showing the principle of the present invention.

When the control unit 7 develops a character pattern for one line on the RAM 8 based on the print data provided from the host device via the interface circuit 9, it sends the character pattern to the head 2 via the head control circuit 11 to perform printing.

At this time, simultaneously, the control means 7 drives the space motor 16 via the space control circuit 14 to move the carrier 15,
After the head 2 mounted on the carrier 15 is positioned at a predetermined printing position, a space operation for moving the head 2 together with printing is performed.

Then, the space control circuit 14 detects the position of the head 2 from the carrier 15 and sends a timing for supplying energy to the windings of the head 2 to the head control circuit 11.

When printing of one line is completed, the control means 7 drives a line feed motor 18 via a line feed control circuit 17 to feed the paper.

The instruction means 10 sends a signal to the control means 7 by an operation of the operator, and gives an instruction to increase the print density. Upon receiving this instruction, the control means 7 controls the increasing means 12 of the head control circuit 11 to increase the amount of energy supplied to the winding of the head 2 by a predetermined amount.

Further, when the instruction means 10 gives an instruction to increase the print density, the control means 7 controls the space control circuit 14 to reduce the space speed to a predetermined speed. When the space speed is reduced, the timing at which the energy is supplied to the winding of the head 2 is delayed due to the decrease in the space speed. Is determined in advance by an experiment or the like so as to be substantially equal to the average of the total energy amounts of.

Further, when the instruction means 10 gives an instruction to increase the print density, the control means 7 monitors the temperature sent by the sensor 13 through the head control circuit 11, and determines that the temperature of the head 2 is a predetermined temperature, that is, the allowable limit. When the value is reached, the space control circuit 14 is controlled to reduce the space speed to a predetermined speed in the same manner as described above.

When the control means 7 reads the character pattern for one line developed on the RAM 8 and sends it to the head control circuit 11, when the instruction means 10 gives an instruction to increase the print density, the control means 7 The number of windings is limited to a predetermined number.

In general, in an impact type dot line printer, the number of windings of the head 2 and the printing density of each line which are simultaneously excited for power supply protection are limited, and when the number of windings driven simultaneously is larger than a predetermined value, divided printing is performed. However, the amount of energy supplied to the windings to increase the printing density by using this function is increased, and the number of windings (pins) of the head 2 driven at the same time is reduced. Control is performed so that the power is substantially equal.

[Action]

With the above-described configuration, the increasing means 12 can control the head 2 when the instruction means 10 instructs to increase the print density.
In order to increase the amount of energy supplied to the winding, the impact force of the pin driven by the winding can be increased, and the printing density can be increased.

By the way, when the instruction means 10 instructs to increase the print density, the increasing means 12 increases the amount of energy supplied to the windings of the head 2 as described above. When the mechanism is moved up faster and the winding burnout prevention mechanism of the head 2 provided in the impact type dot line printer is operated, the printing speed is extremely reduced.

This reduces the number of windings of the head 2 driven simultaneously,
This is because the printing of one line is performed by multiple space operations and the printing of one character is performed by dividing it into multiple times.To prevent an extreme decrease in printing speed, the operation of this winding burnout prevention mechanism must be performed. Need to be prevented.

In order to prevent the operation of the winding burnout prevention mechanism, the average amount of energy supplied to the head 2 in a certain period of time may be made substantially equal to the case where the print density is increased and the case where normal printing is performed. . For this reason, the present invention prevents the printing speed from being extremely lowered by reducing the space speed.

That is, the control means 7 lowers the space speed of the space control circuit 14 when the instruction means 10 gives an instruction to increase the print density. The head control circuit 11 sends an exciting current to the winding of the head 2 according to the excitation timing sent by the space control circuit 14, so that the average of the total amount of energy supplied to the head 2 can be reduced by the reduced space speed. Thus, the temperature rise of the head 2 can be suppressed within the limit.

In addition, the control means 7 controls the sensor 13 to notify the fact that the temperature rise of the head 2 has reached the permissible limit value. By reducing the space speed at this point, the printing speed is reduced as much as possible. Can be prevented.

This is because, in an actual use state, as the winding burnout prevention mechanism of the head 2 operates, it is less likely that characters having a high print density are continuously printed.

Further, the control means 7 further increases the print density by
Since the maximum number of windings of the simultaneously driven head 2 is reduced by the amount of energy supplied to the windings of the head 2, the maximum power consumption can be made equal to that in normal printing. Therefore, it is possible to prevent the power supply capacity from increasing in order to increase the print density.

〔Example〕

FIG. 2 is a block diagram of a circuit showing one embodiment of the present invention.

1 have the same functions. The processor 19 reads out the program stored in the ROM 20 and operates. When a character pattern corresponding to one line is developed on the RAM 8 based on print data given from the host device via the interface circuit 9, the head 2 passes through the head control circuit 11. And print it out.

At this time, simultaneously, the processor 19 drives the space motor 16 via the space control circuit 14, moves the carrier 15, and positions the head 2 mounted on the carrier 15 at a predetermined printing position. A space operation for moving with printing is performed.

Then, the space control circuit 14 detects the position of the head 2 from the carrier 15 and sends an excitation timing for supplying energy to the winding of the head 2 to the head control circuit 11.

When printing of one line is completed, the processor 19 drives the line feed motor 18 via the line feed control circuit 17 to feed the paper.

When the switch 22 provided on the operator panel 21 is pressed, the processor 19 recognizes that the instruction is to increase the print density, and controls the increasing means 12 of the head control circuit 11 to supply the print signal to the winding of the head 2. Energy amount to be increased by a predetermined amount.

The switch 22 is a digital switch for inputting multi-stage digital values corresponding to a desired density.

FIG. 3 is a block diagram illustrating an example of a head control circuit, and FIG. 4 is a diagram illustrating the operation of FIG.

FIG. 3A shows a case in which the amount of energy supplied to the winding of the head 2 is increased by increasing the supply time of the current supplied to the winding of the head 2.

Enter "1" as data for driving the winding 32 of the head 2 from the terminal A _1, the terminal B as described above, as shown from the space control circuit 14 to the excitation timing of the 4 (a), the excitation timing input. When the excitation timing is inputted from the terminal B, the timer 23 sends out a predetermined time "1" to the AND circuit 24 as shown in the timer output of FIG. While sending
"1" is sent to the transistor 28.

Thus, the transistor 28 is turned on, the exciting current flows through the transistor 28 from the power supply V _D through a winding 32 of the head 2, to generate a constant voltage at resistor 30. This voltage is sent to the operational amplifier 26, where it is compared with the reference voltage sent from the reference voltage generating circuit 34.

The operational amplifier controls the base potential of the transistor so that the potential between the resistor 30 and the transistor is equal to the potential generated by the reference voltage generating circuit. Therefore,
The operational amplifier 26 applies a constant current determined by the reference voltage to the winding 32
Is controlled to flow.

A plurality of heads (for example, 24
Windings 32 to 33 are provided, and the 24 windings 32
Also, the head control circuit 11 is provided with transistors 28 to 29, operational amplifiers 26 to 27, and AND circuits 24 to 25 corresponding to. That is, in response to winding 33, the transistor 29 resistor 31, and an operational amplifier 27 and the AND circuit 25, the operation except that input data for driving the winding 33 from terminal A _N, the same is that for details Description is omitted.

When the switch 22 on the operator panel 21 is pressed, a signal for thickening the printing is input to the timer 23 via the terminal C.
When this signal is input, when the excitation timing is input to the terminal B, the timer 23 sets the time for sending "1" to the AND circuit 24 for a predetermined time as shown in the timer output of FIG. Lengthen.

That is, the time during which the current supplied to the partial windings 32 to 33 indicated by hatching in the timer output flows is increased. This makes it possible to adjust the print density as desired by the operator.

Incidentally, the timer 23 is configured so that a time corresponding to the multi-level density information given via the switch 22 can be set via the terminal C.

FIG. 3B shows a case where the amount of energy supplied to the winding of the head 2 is increased by increasing the current value supplied to the winding of the head 2 proposed by the present invention. The same effect as the method of increasing the current supply time shown in FIG. 3A is obtained, and since the cycle is fixed, circuits such as the timer 23 are simplified.

The same reference numerals as those in FIG. 3 (a) indicate those having the same functions. Transistor 36 is the voltage on the base through a resistor from the power supply V _C is applied to short-circuit the resistor R ₃ turned on. Therefore, the reference voltage delivered to the operational amplifier 26 to 27, when the voltage across the Zener diode 35 and V _Z, the resistance of the V _Z
A voltage divided by R ₁ and R _2. That is, reference voltage = R ₂ / (R ₁ + R ₂ ) × V _Z.

Therefore, as shown in the excitation timing of FIG.
Due to the excitation timing input to the terminal B, a constant current determined by the reference voltage shown by the equation flows through the windings 32 to 33 as shown in the winding current of FIG. 4B.

When the switch 22 on the operator panel 21 is depressed, a signal for thickening the printing is input to the transistor 36 via the terminal C. That is, since a signal for grounding the base of the transistor 36 is input, the transistor 36 is turned off, and the reference voltage sent to the operational amplifiers 26 to 27 is (R ₂ + R ₃ ) / (R ₁ + R ₂ + R ₃ ) × V _Z ...

Since the reference voltage obtained by the expression is higher than the reference voltage obtained by the expression, the voltage generated in the resistors 30 to 31 becomes higher by the increase thereof, and the operational amplifiers 26 to 27 become windings 32 to 33.
The current that flows through is increased by the increased amount. That is, as shown by the winding current in FIG. 4 (b), a current larger by the amount indicated by the oblique line than the current value indicated by the winding current flows.

The processor 19 controls the space control circuit 14 to reduce the space speed to a predetermined speed when the switch 22 is pressed and an instruction to increase the print density is issued.

 FIG. 5 is a diagram for explaining a decrease in heat generation of a winding.

When performing normal printing, a current to be printed with a normal impact force is supplied to the windings 32 to 33 of the head 2 based on the excitation timing corresponding to the normal space speed, as shown in the excitation timing, as shown in the winding current. Is done.

When the switch 22 is depressed, as shown in the excitation timing, the winding current or the current or the current value in which the supply time becomes longer as shown in the above, based on the excitation timing which is slower than the excitation timing by the reduced space speed. Is supplied to the windings 32-33.

That is, the excitation timing is determined by the pulse output of the position detection sensor provided on the carrier 15, and
Since the pulse interval changes in the same manner as the pulse interval corresponding to the moving speed of 15, the interval between the excitation timings becomes wider in conjunction with the decrease in the carrier speed.

When the printing density is increased as described above, the space speed is reduced to increase the transmission interval of the excitation timing. However, the average amount of energy supplied to the head 2 in a fixed time is equal to the energy required for printing at a normal density. The space velocity is set in advance to be approximately equal to the average of the amounts.

Also, when the switch 22 is pressed down to give an instruction to increase the print density, the processor 19 monitors the temperature sent by the sensor 13 through the head control circuit 11 and when the temperature of the head 2 reaches the allowable limit value. Controlling the space control circuit 14,
The space speed is reduced to a predetermined speed.

Further, the processor 19 reads out the character pattern of one line developed on the RAM 8 and sends it to the head control circuit 11. When the switch 22 is depressed and an instruction to increase the print density is issued, the heads simultaneously driven are read. The number of windings of No. 2 is limited to a predetermined number.

That is, when the number of windings driven at the same time is larger than a predetermined value, a plurality of (for example, 24) heads 2 (for example, 24) are increased by increasing the amount of energy supplied to the windings to increase the printing density by using the function of performing divided printing. By reducing the number of dot pins to be driven, the number of windings of the simultaneously driven heads 2 is reduced, and the power consumption is controlled to be substantially equal.

〔The invention's effect〕

As described above, the present invention can increase the print density when the operator deems it necessary, and prevents the print head temperature from increasing when the print density is increased, thereby preventing the print speed from extremely lowering. Further, since it is not necessary to unnecessarily increase the power supply capacity, an economical impact type dot line printer can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram of the principle of the present invention, FIG. 2 is a block diagram of a circuit showing an embodiment of the present invention, FIG. 3 is a block diagram for explaining an example of a head control circuit, and FIG. FIG. 5 is a diagram for explaining a decrease in heat generation of a winding, and FIG. 6 is a diagram for explaining an example of an impact type dot line printer. In the figure, 1 is a platen, 2 is a head, 3 is a ribbon, 4 is a ribbon cassette, 5 is a roller, 6 is paper, 7 is control means, 8 is RAM, 9 is an interface circuit, 10 is instruction means, and 11 is a head. Control circuit, 12 is an increasing means, 13 is a sensor, 14 is a space control circuit, 15 is a carrier, 16 is a space motor, 17 is a line feed control circuit, 18 is a line feed motor, 19 is a processor, 20 is a ROM, 21 is an operator panel, 22 is a switch, 23 is a timer, 24 and 25 are AND circuits, 26 and 27 are operational amplifiers, 28, 29 and 36 are transistors, 30, 31 are resistors, 32 and 33 are windings, 34 is a reference voltage generation circuit, 35 Is a Zener diode.

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Satoshi Yoshino 1015 Ueodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Inside Fujitsu Limited (56) References JP-A-59-212276 (JP, A) JP-A-61-11258 (JP, A) JP-A-56-47884 (JP, A) JP-A-60-228157 (JP, A) JP-A-56-163545 (JP, U)

Claims (3)

(57) [Claims] 1. A method of driving each pin by driving each pin with an impact force corresponding to the amount of energy supplied to each winding of the head and causing a carrier mounting the head to perform a space operation. A printing device that detects timing and prints serially, comprising: instruction means for instructing switching of print density; and a predetermined amount of energy supplied to each winding of the head based on the instruction of the instruction means. Increasing means for increasing, and control means for changing the space velocity of the carrier based on the instruction of the instruction means, wherein when the instruction means gives an instruction to increase the print density, winding of the selected head is performed. The amount of energy supplied to the head is increased to increase the impact force of the pin to perform printing. A print density adjusting device, wherein the space speed of the carrier is reduced to a predetermined speed so as to be substantially equal to a case where the indicating means does not give an instruction to increase the print density. 2. A sensor for detecting a temperature of a head, wherein each pin is driven by an impact force corresponding to an amount of energy supplied to each winding of the head, and a space operation is performed on a carrier on which the head is mounted. A printing device that detects the timing of driving each pin and performs printing in a serial manner, comprising: instructing means for instructing switching of print density; and Increasing means for increasing the amount of energy supplied to the winding by a predetermined amount; and the sensor detects that the temperature of the head has risen to the predetermined temperature after the instruction means instructs to switch the print density. Control means for changing the space velocity of the carrier, and when the instructing means instructs to increase the print density, the carrier is supplied to the selected winding of the head. The amount of energy supplied to the head for a certain period of time when the sensor detects that the temperature of the head has reached a predetermined temperature while increasing the amount of energy and increasing the impact force of the pin to cause printing. Wherein the space speed of the carrier is reduced to a predetermined speed so that the average of the distance is substantially equal to the case where the instruction means does not issue an instruction to increase the print density. 3. A printing apparatus for performing printing by driving each pin with an impact force corresponding to an amount of energy supplied to each winding of a head, and instructing means for instructing switching of print density, Increasing means for increasing the amount of energy supplied to each winding of the head by a predetermined amount based on the instruction of the instruction means, and controlling means for limiting the number of windings of the head driven simultaneously to a predetermined number. When the instruction means instructs to increase the print density, the amount of energy supplied to the selected winding of the head is increased, the impact force of the pin is increased, and printing is performed. The number of windings of simultaneously driven heads is limited so that the average amount of energy supplied to the head is substantially equal to the case where no instruction to increase the print density is given. Character density adjustment device.