JPS6334170A - Daisy wheel printer - Google Patents

Abstract

PURPOSE:To achieve both a high print speed and a high print quality, by driving a mounted wheel by a predetermined angle through a predetermined angle driving means prior to the start of printing operation and setting the driving conditions of a rotary control means on the basis of an output from a comparison means. CONSTITUTION:An inertia moment is splitted into 1-3 groups and control conditions I-III are set for them. Furthermore, control conditions of a means 41 for driving a wheel by predetermined angle, or control conditions S having an intermediate inertia moment for a randomly selected angle, and an operating time are set. When power is turned on or a wheel is replaced, the wheel is rotated by 180 deg. from the home position on the basis of the control conditions S. Then the actual operating time is detected and compared with a preset operating time. On the basis of the comparison results, it is modified and set automatically to a drive current level satisfying the optimal control conditions being preset in a selection motor drive current control means 45.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a daisy-wheel printer that uses an open-loop controlled stepping motor to achieve high-speed printing operation and high print quality, which are essentially incompatible. In particular, by appropriately exchanging multiple types of daisy wheels with different fonts, number of fingers, etc., it is possible to print typefaces that match the content of the document you want to print, or typefaces such as symbols required for scientific literature, etc. The present invention relates to a daisy-wheel printer that achieves optimal control when selecting and using a daisy-wheel.

Specifically, when replacing the daisy wheel with the desired daisy wheel, we measure the rotational characteristics of the installed wheel, such as the rotational moment, for each daisywheel that has different weights and rotational moments due to differences in the number of fingers and the material of the wheel. The present invention also relates to a daisy-wheel printer that achieves both high print quality through high-precision control and high-speed printing operation by setting optimal control conditions based on measurement results.

In general, a daisy-wheel printer consists of a daisy wheel with type formed on the end, a rotation control means for selecting the type on this wheel, a carriage carrying the wheel, and a carriage for moving the carriage. The printer is equipped with a carriage driving means for printing, a printing hammer, and a printing hammer driving means for driving the printing hammer, and rotates the wheel to a specified position corresponding to the command character of the printing command input from the outside, and After moving the carriage to a specified position, the printing hammer is driven to strike the letters on the wheel, thereby printing out the characters corresponding to the printing command.

■Structure of a daisy-wheel printer Figure 5 is a partially exploded perspective view of the appearance of a conventionally used daisy-wheel printer. Showing the platen.

Although not particularly shown in the drawings, a daisy wheel with printed characters formed on the end is rotatably attached to the carriage 2, and a selection motor is also used as a printing hammer and a rotation control means for selecting the printed characters on the wheel. etc. are also installed.

The daisy wheel can be used depending on the content of the document you want to print.
For example, it can be replaced with wheels of various typefaces, such as typeface or italics. In addition, daisy wheels having printed characters such as special symbols and unit symbols required in scientific literature etc. are also selected and used.

Further, the carriage 2 is arranged so as to be movable in parallel with the axial direction of the platen 3, and is driven by a drive means including a space motor.

A rotatable roller for pressing the paper is attached to the platen 3 that holds the printing paper, and the loaded paper is pressed against the surface of the roller.

The printing hammer is driven by a hammer solenoid to strike the letters of the wheel onto the printing paper set on the platen 3, thereby performing a printing operation.

The daisy wheel type printer has such a configuration, and the number of fingers of the mounted daisy wheel varies depending on the type, and the weight, rotational moment, etc. vary depending on the material of the daisy wheel. Therefore, when the wheel is replaced, the control conditions of the rotation control means are actually slightly affected.

Therefore, in conventional printers, one control condition is set in advance, and a delay time corresponding to the mounted wheel is added or the operating time is changed using an external switch or the like to cope with the problem.

However, with such a method, it is impossible to set sufficient control conditions for each wheel, and problems such as load fluctuations depending on the type of print head (daisy wheel) and motor torque fluctuations occur.

Optimal control conditions for variations in drive conditions etc. cannot be obtained.

In other words, even if character selection is completed and the wheel is moved to that position due to load fluctuations on the print head or motor torque fluctuations, vibrations remain in the print head, so the printing operation is continued until the vibrations attenuate. I can't.

In particular, with open-loop control, the actual travel distance of the wheel is not fed back, so it is necessary to set a delay time in advance to make the printing operation wait until the vibrations of the print head have almost certainly damped, and the printing speed decreases further.

■Control unit of open-loop control system FIG. 6 is a functional block diagram showing an example of the configuration of the main parts of the control unit that performs the open-loop control system for the daisy-wheel type printer shown in FIG. 11 is a CPU, 12 is a ROM, 13 is a RAM, 14 is a power supply, 15 is a 5EL (selection motor) driver, 16 is a HAM (hammer solenoid) driver,
17 is an R/F (ribbon feed motor) driver, 1
8 is L/F C line feed motor) driver, 1
9 is sp (space motor) driver, 20 is SEL
(Selection) Motor, 21 is HAM (hammer)
Solenoid, 22 is R/F (ribbon feed) motor,
23 is L/F C line feed) motor, 24 is SP
(Space) indicates a motor.

The SEL motor 20 is a motor that selects characters on the daisy wheel and is driven by the SEL driver 15.

RAM solenoid 21 activates a print hammer to strike selected characters on the wheel and is driven by HAM driver 16.

The R/F motor 22 is a motor for feeding the printing ribbon, and is driven by the R/F driver 17.

The L/F motor 23 is a motor that rotates the platen for line feeds, etc., and is driven by the L/F driver 18.

The SP motor 24 is a motor for carriage feeding.
It is driven by the SP driver 19.

The CPU II stores necessary data in the ROM12 and RAM13.
control each of these parts.

The ROM 12 stores data such as control programs, and the RAM 13 stores print data and the like. In addition,
The power supply 14 supplies necessary power to each of these parts.

In this way, with a daisy-wheel printer.

Rotate the wheel to the specified position corresponding to the command character of the print command input from the external host system,
After the carriage 2 is moved to a specified position, the printing hammer hits the printed characters on the wheel to print out the characters corresponding to the printing command.

Incidentally, in the daisy-wheel type printers shown in FIGS. 5 and 6, the printing speed is set for each machine, such as the number of characters per second.

When this printing speed is high, the selection operation for selecting type must also be performed at high speed.

(2) Selection operation for selecting printed characters As already explained, in a daisy wheel type printer, a selection operation is performed to select the printed characters provided at one end of the finger of the wheel.

In the selection operation, the rotation direction and amount of movement are calculated from the relationship between the current print position and the next print position.

In this case, the number of positions around the daisy wheel is 2.
It is possible to set any number of all-around positions, regardless of whether it is a power of or not, and whether it is an even number or an odd number, and can be changed arbitrarily within the settable range. Devices for controlling the rotation of daisy wheels are known.

Moreover, the rotation control device for this wheel rotates at 20 speeds per second.
It can be used in printers that perform printing operations at high speeds, such as character to 80 characters.

In order to enable such high-speed rotational control, the shortest number of movement steps and In addition to realizing a calculation means for instructing the direction of rotation, the type carrier has a different number of circumferential steps due to a change in the type of printing matrix due to a change in typeface, etc.
The configuration allows the set of the number of all-around positions to be changed arbitrarily within a settable range.

FIG. 7 is a block diagram showing a control system of an impact printer having a conventional daisy wheel. In one drawing, 31 is a judgment circuit for input data, 32 is a calculation circuit for the rotation direction and the number of rotation positions, and 321 is a calculation circuit. 32 is a current position register provided in the calculation circuit 32, 33 is a selection motor control circuit, 331 is a position subtraction counter provided in the control circuit 33, and 34 is a selection motor , 35 is a daisy wheel consisting of a rotating body having a type head on its circumference, 36 is a selection sensor, 37
1 shows control circuits of each control system for other components of the printer.

The input data includes operation instructions for the daisy wheel 35 and operation instructions for other components of the printer, which are determined by the determination circuit 31. In the case of an instruction to operate the daisy wheel 35, the fixed address on the daisy wheel 35 of the type to be printed next is outputted from the determination circuit 31 as designated position information.

In the next rotation direction and rotation position number calculation circuit 32,
All-around position number register 321 and current position register 3
22 and this specified position information, in order to move the daisy wheel 35 to a predetermined position in a short time, it is determined whether it should be rotated clockwise or counterclockwise, and the daisy wheel 35 is moved. Calculate the number of exponent positions.

After outputting these data from the calculation circuit 32, the specified position information is transferred to the current position register 322. Note that if the current position and the designated position match, there is no need to move the daisy wheel 35, and therefore an operation prohibition signal is output.

The selection motor control circuit 33 receives the information on the rotational direction and the number of rotational positions output in this way.
The selection motor 34 is rotated in a specified direction to start the rotation of the daisy wheel 35 connected to its rotating shaft, and the position subtraction counter 331 is set to " by the signal from the selection sensor 36 attached to the motor 34. Rotate until it reaches 0''.

8 is a detailed block diagram of an example of a circuit for calculating the rotational direction and number of rotational positions used in the rotation control device of FIG. 7. In the drawing, A is a register that indicates the current position, and B is a designated position. C is the register that stores the number of full-circle positions, D is the data of the half-circle position number, E is the subtraction circuit, F is the addition circuit, and G is the number of moving positions when rotating counterclockwise. data, H
2 shows a subtracting circuit, 2 shows a subtracting circuit, and J shows a gate circuit that performs logic processing.

The calculation circuit shown in FIG. 8 has an 8-bit configuration, and up to 255 predetermined positions of characters to be printed can be set in register C.

Then, up to 255, any type of type, for example, the alphabet, is arranged clockwise on the daisy wheel in the order of A, B, C1, etc., and each type has A=OO000000, B= 00000001,
Binary code addresses such as C=00000010, . . . are given.

Next, the operation of this calculation circuit will be explained. First, the contents of the designated position register B are subtracted from the contents of the current position register A by a subtraction circuit E.

That is, A-B=E output is obtained, and if this E output is all "o", then A=
Since it is B, a rotation operation prohibition signal is output from the 8AND circuit.

If A<B, a carry occurs and the contents of the full-circle position number register C are input to the next adder circuit F as addition data.

Then, the E output and the addition data controlled by the carry of the subtraction circuit E are added by the addition circuit F, and data G is output.

Note that if A>B, no carry occurs, so
The next addition data to the addition circuit F becomes 0'', and the E output of the subtraction circuit E becomes data G as is.

This data G represents the number of positions to be moved when a rotating body such as a daisy wheel rotates counterclockwise.

Next, data D indicating the number of half-round positions is subtracted from data G by a subtraction circuit H.

If G<D, a carry occurs, and the OR circuit outputs “0” which instructs counterclockwise rotation via the inverter.
' is obtained, and the gate circuit J is activated by the output of the OR circuit to output data G as the number of positions moved in the counterclockwise direction.

In the case of G>D, since no carry occurs, the output of the inverter becomes '1'', which instructs clockwise rotation. In this case, the gate circuit J is a gate that selects the output of the subtraction circuit I. is opened and the total position number register C
The output obtained by subtracting the data G from the contents of is obtained, which indicates the number of positions moved in one clockwise direction. Note that the case of G=D is similar to the case of G>D.

In this way, by using the calculation circuit shown in FIG. 8, the rotation direction and the number of moving positions can be obtained.

The following Figures 9 (1) to (3) show the correspondence between the letter position and address code when 16, 15, and 14 letters are distributed on the circumference of a rotating body such as a daisy wheel. FIG.

Figure 9 (1) shows a number on the circumference that is a power of 2, for example 1
A case of 16 positions in which 6 type characters are arranged is shown.

FIG. 1O is a diagram showing the outputs of registers A to D, subtraction circuits E, H, and I, data G, and the output of the calculation circuit in the case of 16 positions.

For example, from the current position IF (print C) to the specified position (print J)
When moving to , the result is as shown in (4-1) in FIG. 10, and the output of the calculation circuit is clockwise rotation, and the number of movements is 7 positions.

Similarly, from the current position If (printed character C) to the specified position (printed character N)
When moving to , it becomes (4-2) in Figure 1O,
Furthermore, the current position! ! ! (Printed character N) to the specified position l1l (Printed character C), (4-3) in Figure 10, the current position! ! (Print character N) to the designated position (Print character J) is as shown in (4-4) in FIG. 10.

In this way, according to the rotation control device shown in FIG. 7, the rotational direction and number of movement positions required for rotational movement to the specified position in the shortest time can be obtained, and the optimum rotational control for various specified positions can be achieved. It will be done.

Also, as shown in Figure 9 (2), the number of positions on the entire circumference is 2.
In the case of an odd number that is not a power of, for example, 15 positions,
The number of half-circle positions will be.

Furthermore, as shown in Fig. 9 (3), if the number of positions on the entire circumference is an even number that is not a power of 2, for example 14 positions, the number of half-circle positions will be 7, and the current position it (printed C)
When moving from to the specified position (printed J), use the
Rotate counterclockwise in the same way as in 1).

In the cases of these FIGS. 9(1) to (3), the 10th As shown in the figure, the rotational direction and the shortest number of moving positions are calculated, and rotation control is performed.

As explained in detail in sections (1) to (2) above, in daisy wheel printers, wheels have traditionally been replaced, and various wheels are used depending on the number of fingers, materials, etc.

In this case, when compared to closed loop control,
When the selection operation for type selection is performed using an oven loop-controlled step motor, which has an extremely simple control circuit configuration and is inexpensive, the load changes depending on the type of daisy wheel (print head) installed. The motor torque may change, or the drive conditions may change, making it impossible to perform optimal control as envisioned at the time of design.

In particular, if the load on the print head or the motor torque fluctuates, vibrations will remain in the print head even after the character selection operation is completed, and the printing hammer cannot be driven until the vibrations are damped. was there.

Purpose Therefore, in the daisy-wheel type printer of this invention,
These disadvantages in conventional wheel-changeable printers include the drive conditions of the selection motor being different depending on the type of wheel installed, and the motor torque fluctuating, causing vibrations in the print head after the type selection operation is completed. This solves the inconvenience that the printing speed decreases due to the residual amount, and that printing quality deteriorates when the printing speed is forcibly increased. 5 Even in high-speed printing operations such as 60 characters/second, the daisy wheel achieves both high printing speed and high printing quality by always enabling type selection operations under optimal control conditions. The purpose is to provide a type printer.

For this purpose, the daisy-wheel type printer of the present invention includes a daisy wheel in which type is formed at the end and is configured to be replaceable as a whole, and an opening for selecting the type on the wheel. comprising a rotation control means using a loop-controlled stepping motor, a carriage on which the wheel is mounted, a carriage driving means for moving the carriage, a printing hammer, and a printing hammer driving means for driving the printing hammer, In the conventional method, the wheel is rotated to a specified position corresponding to the command character of the print command inputted from the outside, and then the characters on the wheel are hit with the print hammer to print out the characters corresponding to the print command. In a daisy-wheel type printer, a predetermined angle drive means for moving the housing by a predetermined angle from a home position to a preset target position, and a required operation time to reach the target position by the predetermined angle drive means are measured. a required time measuring means; a control condition table storing preset control conditions for each wheel;
Comparing means for comparing the time measured by the required time measuring means and the contents of the control condition table is provided, and before the start of the printing operation, the wheel mounted by the predetermined angle driving means is driven by a predetermined angle, and the The driving condition of the rotation control means is set based on the output of the comparison means.

Next, embodiments of the daisy-wheel type printer of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a functional block diagram showing a detailed configuration of an embodiment of a control section for setting control conditions for character selection of each wheel in a daisy-wheel type printer of the present invention. 41 is a wheel predetermined angle driving means, 42 is a required time measuring means, and 43 is a control condition table.

Reference numeral 44 indicates a required time comparison means, and 45 indicates a selection motor drive current control means.

The control unit for setting control conditions for wheel type selection shown in Figure 1 is a part added to a conventional daisy-wheel type printer, and the normal control operation is as shown in Figure 6 above. It is basically the same as loop control.

The wheel predetermined angle driving means 41 rotates the wheel by 180@ from the home position, for example, prior to starting the printing operation P, such as when the power of the printer is turned on or when the wheel is replaced by opening the cover. It is forcibly driven in a type selection mode with a preset movement amount.

The required time measuring means 42 is a wheel predetermined angle driving means 4.
The actual operation time of the wheel rotation operation performed by No. 1, that is, the type selection mode operation according to a preset amount of movement, is measured.

The control condition table 43 is a table that stores optimal control conditions determined for each wheel. For example, as shown in FIG. remembered.

The required time comparing means 44 compares the operation time measurement result obtained by the required time measuring means 42 and the control condition table 4.
The time of the optimum control condition for each wheel stored in 3 is compared with the time of the optimum control condition for each wheel, and the comparison result is outputted for selecting the optimum control condition for that wheel.

The selection motor drive current control means 45 sets the drive current of the selection motor according to the optimum control condition for the wheel outputted from the required time comparison means 44. For this purpose, the selection motor drive current control means 45 stores the current value and the like selected based on the output of the comparison result.

Note that the output of the selection motor drive current control means 45 is given to a control means for controlling the drive of the selection motor, that is, a selection motor control means similar to the conventional one.

FIG. 2 is a flowchart illustrating a procedure for setting control conditions for wheel type selection in the daisy-wheel type printer of the present invention.

FIG. 3 is a diagram showing an example of distribution for setting optimal control conditions in the daisy-wheel type printer of the present invention.

FIG. 3 shows a case where the optimum control conditions are set based on the moment of inertia as the operating characteristics of each wheel.

In the case of daisy wheels, the weight varies depending on the type of daisy wheel, that is, depending on the typeface and other differences.

When the weight changes, the moment of inertia also changes.

Therefore, as shown in Fig. 3, for example, it is divided into three groups, and control conditions ■ to ■ are set corresponding to each group.
The unit of this moment of inertia is “Xl 0-2g-cs・
sec" J and uses wheels in the range of 24 to 40.

That is, the moment of inertia is divided into groups 1 to 3, and control conditions I to control conditions (2) for these groups are set so that the boundaries of each group overlap.

Further, the control conditions to be performed by the wheel predetermined angle driving means 41 shown in FIG. 1, ie, the control conditions having an intermediate moment of inertia for any selected angle, and the operating time are set in advance.

In the example in Figure 3, 32 x 10-2g-cs ・se
The control condition is to rotate a wheel having a moment of inertia of 180 @ (here, control condition S), and the operating time is 50 m5ec.

Then, as shown in the flowchart of FIG. 2, when the power is turned on or when the wheel is replaced, it is rotated 180@ from the home position according to the control condition S.

In this case, if the moment of inertia of the wheel mounted on the printer is 32×10 −2 g−1·sec”, the actual operating time should also be 50 m5 ec.

FIG. 4 is a characteristic diagram showing an example of the relationship between operating time and selection angle for character selection in the daisy-wheel type printer of the present invention. In FIG. 6, the horizontal axis indicates operating time and the vertical axis indicates selection angle.

As is clear from the characteristic diagram in Figure 4, if the moment of inertia is 40 x 10-2 g-cm・sec, the control is too effective and the actual operating time is 50 m5 ec.
For example, the operating time is 53 m5ec.

On the other hand, if it is 25 Complete.

Therefore, this actual operating time is detected and compared with a preset operating time, in this case 5Qmsec.

Then, with the wheel returned to its home position, the drive current value is automatically set to the optimal control condition preset in the selection motor drive current control means 45, for example, based on the comparison result of the actual operating time. Change/set.

Various methods have been used to drive the selection motor. For example, a method is known in which a high current is excited when starting or stopping the drive, and the drive current is lowered when the speed is constant. However, even with such a driving method, it is sufficient to set optimal control conditions according to the rotational characteristics such as the moment of inertia of the wheel, and it is not necessarily necessary to simply change only the value of the driving current.

In this way, in the daisy-wheel type printer of the present invention, before starting the printing operation, the operating characteristics such as the moment of inertia of the mounted wheel are actually measured,
Based on the actual measurement results, preset optimal control conditions are selected and set.

In the explanation of the above embodiment, the moment of inertia is used as the operating characteristic of each wheel, and the actual operating time obtained due to the difference in the moment of inertia is compared with the standard operating time to determine the drive current value of the selection motor. The case of setting is described.

However, the operating characteristic does not necessarily have to be the moment of inertia, and other characteristics may be used.

Furthermore, a method has been described in which the standard is 50 m5ec and one of the control conditions (1) to (2) is selected depending on the measurement result of the operating time.

However, such time comparisons can also be performed simply. For example, if the measured actual operating time is 49 m5
If it is less than or equal to ec, select control condition ■; if it is greater than or equal to 51m5ec, select control condition I; if neither of these is the case,
Control condition (2) may be set to perform a selection operation for selecting printed characters.

Furthermore, it is also possible to set the entire control condition including the previous control condition S to this control condition (2) as a standard control condition.

Therefore, according to the daisy-wheel type printer of the present invention, the optimum control conditions corresponding to the type of wheel mounted are automatically set, and the optimum control conditions are used to perform the actual character selection operation and drive of the printing hammer. The printing operation is performed by

Therefore, even if you replace the wheel with a different number of fingers, weight, etc. due to differences in typefaces, etc., the optimum control conditions for the selection motor will always be set, and the printing operation will be executed according to these optimum control conditions. Vibration and the like are prevented, and high-speed printing operation and high-quality printing can be obtained.

Moreover, the daisy-wheel type printer of this invention
The same effect can be obtained not only against load fluctuations due to wheel replacement, etc., but also against motor torque fluctuations.
For example, even if the moment of inertia of the mounted wheel is a standard value, if the actual operating time changes due to variations in the drive characteristics of the motor, control conditions should be selected according to the measurement results. For example, in practice, optimal control conditions will be automatically set.

Therefore, not only the load fluctuation due to the type of wheel but also the motor torque fluctuation are corrected at the same time, and a high-speed and high-quality printing operation is realized.

As explained in detail above, the daisy-wheel type printer of the present invention includes a daisy-wheel in which type is formed at the end and the entire structure is replaceable;
Rotation control means using an oven loop-controlled stepping motor for selecting type characters on the wheel, a carriage on which the wheel is mounted, a carriage driving means for moving the carriage, a printing hammer, and driving the printing hammer. After rotationally moving the wheel to a designated position corresponding to the command character of the print command input from the outside, the print hammer drives the printed characters on the wheel to issue the print command. In a conventional daisy-wheel type printer that prints out characters corresponding to a required time measuring means for measuring the required operation time;
A control condition table for storing preset control conditions for each wheel, and comparison means for comparing the time measured by the required time measuring means with the contents of the control condition table, and before starting the printing operation, The mounted wheel is driven by a predetermined angle by the predetermined angle driving means, and the driving condition of the rotation control means is set based on the output of the comparing means.

Effects Therefore, according to the daisy-wheel type printer of the present invention, when a wheel whose weight, moment of inertia, etc. differs depending on the typeface or the number of fingers is replaced with a desired wheel for printing, the speed of that wheel is always the same. The control conditions for the selection motor that are optimal for selection drive will be automatically set.

Therefore, load fluctuations due to differences in print head types,
Even if variations in motor torque or drive conditions occur, the optimum control conditions are immediately set, and once the type selection operation is complete, the printing hammer can be driven, increasing printing speed. At the same time, high quality printing can be obtained.

Furthermore, when driving a stepping motor using open-loop control without a feedback system, there is no need to add a delay time depending on the type of wheel, as is the case with conventional methods, and it can be easily adjusted against fluctuations in the motor's drive characteristics. , and the corresponding controls are performed simultaneously, so that the control circuit of the selection motor can be configured even more easily.

Furthermore, the process of selecting and setting these optimal control conditions is
Since it is easy to implement using software, it can be realized by making some changes to the control circuit of conventional daisy-wheel printers, and it has many excellent effects such as cost reduction. can get.

[Brief explanation of drawings]

FIG. 1 is a functional block diagram showing the detailed configuration of an embodiment of a control section for setting control conditions for character selection of each wheel in a daisy-wheel type printer of the present invention. A flowchart for explaining the procedure for setting the control conditions for wheel type selection in the daisy-wheel type printer of the present invention, FIG. FIG. 4 is a characteristic diagram showing an example of the relationship between operating time and selection angle for character selection in the daisy-wheel type printer of the present invention; FIG. 5 is a diagram showing an example of the relationship between type selection operation time and selection angle; A perspective view showing the external appearance of the daisy-wheel printer in a partially exploded state; FIG. 6 is a functional diagram showing an example of the configuration of the main parts of the control unit that performs the open-loop control method for the daisy-wheel printer shown in FIG. 5. FIG. 7 is a block diagram showing a control system of an impact printer having a conventional daisy wheel, and FIG. 8 is an example of a calculation circuit for the rotation direction and number of rotational positions used in the rotation control device shown in FIG. 7. The detailed block diagram of Figure 9 (1) to (3) shows the character positions and addresses when 16, 15, and 14 characters are respectively placed on the circumference of a rotating body such as a daisy wheel. FIG. 10 is a diagram showing the outputs of registers A to D, subtraction circuits E, H, and circuit, and the output of data G and calculation circuit in the case of 16 positions. In the drawing, 41 is a wheel predetermined angle driving means;
2 is a required time measuring means, 43 is a control condition table, 44
45 is selection motor drive current control means. Ya'ya 1zo8-ichisakon 2 Figure East Exit Wholesale 粂碕o8L勺はお 31! l IJI during operation: v* see God 4 figure arm 5 figure

Claims (1)

[Claims] A daisy wheel having typefaces formed at its ends and having a structure that is entirely replaceable; a rotation control means using an open-loop-controlled stepping motor for selecting the typefaces of the wheel; and a carriage on which the wheel is mounted. , a carriage driving means for moving the carriage, a printing hammer, and a printing hammer driving means for driving the printing hammer, and the wheel is moved to a designated position corresponding to a command character of a printing command inputted from the outside. In a daisy wheel type printer that rotates and moves, and then hits the type on the wheel with the printing hammer to print out characters corresponding to a print command, the wheel is moved from a home position to a preset target position. a predetermined angle drive means for moving the wheel by a predetermined angle; a required time measurement means for measuring the required operation time for the predetermined angle drive means to reach the target position; and a control condition table that stores preset control conditions for each wheel. and a comparing means for comparing the time measured by the required time measuring means and the contents of the control condition table, and the wheel mounted by the predetermined angle driving means is moved by a predetermined angle before starting the printing operation. A daisy wheel type printer, characterized in that the drive condition of the rotation control means is set based on the output of the comparison means.