JP3049857B2 - Drive control device for wire dot print head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive control device for a print head, and more particularly to a drive control device for a print head. And improving the drive control of a wire dot print head that prints a character with a set of dots.

[0002]

2. Description of the Related Art Some printers provided with a wire dot type print head can move a print head and a print medium relatively at 1 × speed and 1.5 × speed. Conventionally, when printing is performed at 1.5 times speed in this type of printer, the line intersecting with the printing direction, that is, the direction of relative movement between the print head and the printing medium becomes thicker for the following reasons, and the printing quality is reduced. There was a problem.

When a plurality of dots are continuously formed in a printing direction by a wire dot type print head, FIG.
As shown in FIG. 4, at the time of the first dot formation, a fixed delay time is required after the first wire ejection command is issued from the wire driving device (after the energization is started) until the print wire actually starts to eject. Exists, whereas
When the second and subsequent dots are formed in response to the second and subsequent wire projection commands, the print wire bounces at the lead-in end and protrudes, so that there is no delay time.
Therefore, when the wire protrusion command is always issued at a constant cycle, the dot interval between the first dot and the second dot becomes narrower, and the thickness of the line intersecting with the printing direction becomes thinner accordingly.

In order to avoid this, in a conventional wire dot printer, as shown in FIG. 15, a wire protrusion command for forming the second and subsequent dots is issued in the same time as the delay time generated when the first dot is formed. Only to be delayed. In this way, when all the dots are formed, the start of the projection of the wire is delayed by the same time, and the dot interval becomes constant, thereby avoiding the line intersecting the printing direction from becoming thin.

On the other hand, when the relative moving speed with respect to the printing medium is 1.5
In the case of double, the dots constituting the character are thinned out. Since the 1 × speed is normally determined by the maximum operable cycle of the print wire, the operation cycle of the print wire cannot be increased just by increasing the relative movement speed with respect to the print medium by 1.5 times. Therefore, in the case of 1.5 times speed, dots are thinned out,
The operation cycle of the print wire is made the maximum operation cycle.

In this thinning-out, if a line intersecting the printing direction is formed by two dots arranged in the printing direction, simply thinning out one dot makes the line one dot at a time. It is formed and becomes too thin.
For this reason, the number of dots in the printing direction is kept two, and the interval between the dots is increased by 1.5 times so that the operation of the wire can be performed in time.

In the conventional print head, even in such a case, the wire protrusion command for forming the second and subsequent dots is generated with a delay time corresponding to the delay time as in the case of the 1 × speed. When the dot interval is increased by 1.5 times as described above, the line becomes slightly thicker. In addition, the line is further thickened due to the delay of the wire projection command, and the problem of deterioration in print quality occurs. I was doing it.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is possible for a print wire operated by a wire driving device to move relative to a print medium at 1 × speed and 1.5 × speed. In addition, two dots continuously arranged in the relative movement direction are referred to as the 1 × speed.
Same maximum operation in both 1.5x speed print modes
When a printed wire is formed by operating a printed wire in a possible cycle
In this case, it is created to print
Each of the two types of print data corresponding to each print mode
A print wire is operated based on each of them, and in a wire dot type printer that prints a character by a set of dots formed by the print wire, even when printing at 1.5 times speed is performed, the thickness of a line that intersects the print direction. The object of the present invention is to make it possible to obtain good print quality without excessively increasing the print quality.

[0009]

The gist of the present invention is to provide a drive control device for a wire dot print head.
A wire protrusion command to a wire driving device for forming a final dot among a plurality of dots continuously arranged in the direction of relative movement between the print medium and the print head is issued when the relative movement speed is 1 ×. Is provided with a wire protruding command generating means for issuing a signal with a delay by a predetermined delay time and issuing without delay when the speed is 1.5 times speed.

[0010]

As described above, if the wire projection command for forming the final dot is issued without delay during 1.5-times printing, lines intersecting with the printing direction are arranged in the printing direction. When dots are formed by individual dots, the wire protrusion command for forming the second dot is issued without delay.

In the case where two dots continuously arranged in the printing direction are formed at 1.5 times speed, the pitch between dots is set to 1.5 times as described above. In the drive control device according to (1), the wire protrusion command for forming the second dot is issued without delay, the dot interval is reduced by that amount, and the two dots are eventually formed. Excessive line thickness is avoided. The increase in the dot interval due to the increase in the moving distance of the print head during one dot formation period during 1.5-times printing is reduced by omitting the delay of the wire protrusion command.

The problem that the thickness of the line intersecting the printing direction becomes excessive at the time of 1.5-times printing is that the line intersecting the printing direction is formed by two dots arranged in the printing direction. Of particular importance. When printing kanji, lines are often formed by two dots even if the number of printing points is considerably large, and the same occurs when printing a small number of points when printing alphabets, numbers, and kana. . The present invention has been made mainly to solve the problem in the case where a line is formed by two dots as described above. However, when a line intersecting the printing direction is formed by four dots, the number of dots is three, and the dot pitch is 1.5.
This also occurs when the number is doubled, and in this case, the present invention can be applied.

However, if a line intersecting the printing direction is formed by three dots arranged in the printing direction, and one dot at the center is thinned out at the time of printing at 1.5 times speed, this causes Since the thickness is reduced, it is desirable that the wire protrusion command for forming the second dot is delayed as before. Therefore, only when the number of dots arranged in the printing direction is two, or only when the thickness of the line becomes excessive due to thinning at the time of 1.5-times printing, the wire protrusion command for forming the final dot is issued. It is desirable not to be delayed.

[0014]

As is apparent from the above description, according to the present invention, the effect of improving the printing quality at 1.5-times printing compared to the conventional one can be obtained. Moreover, since the object can be achieved by a simple means of omitting a delay of the wire protrusion command at the time of forming the final dot, a quality improvement effect can be obtained with almost no increase in cost.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 2 shows a main part of the wire dot printer. Reference numeral 10 denotes a platen, and the side frame 1
2 and 14 are rotatably supported. The platen 10 supports a print sheet 16 as a print medium and functions as a component of a sheet feeder that feeds the print sheet 16 in the vertical direction. Carriage guide 1 parallel to platen 10
Reference numerals 8 and 20 are provided to support the carriage 22 so as to be movable in the lateral direction along the platen 10. The carriage 22 is moved in the lateral direction by a carriage driving device 32 including a carriage driving motor 24, timing pulleys 26 and 28, a timing belt 30, and the like.

A print head 40 is mounted on the carriage 22.
Is mounted, and moves along the platen 10 as the carriage 22 moves. The print head 40 has 24 print wires (hereinafter abbreviated as wires) 42, and the tips of the wires 42 are arranged in a diamond shape as shown in FIG. The numbers in the figure indicate the numbers of the wires 42, 1 and 23, 3 and 21, and so on.
The wires 42 are arranged at the same position in the moving direction of the print head 40. By selectively protruding these wires 42 by a wire driving device 46 mainly composed of the laminated piezoelectric element 44, dots are formed at arbitrary positions of dot formation positions planned in a 24 × 24 matrix, Characters such as kanji, kana, alphabets, numbers, and symbols are printed by a set of these dots.

FIG. 4 shows a control circuit of the printer. The control circuit includes a main central processing unit (MCPU) 50 and a sub central processing unit (SCPU) 52, which are connected to two buffers 56, 58 and a gate array 60 via a gate array 54. I have. The gate array 54 includes an I / O controller 62, a buffer controller 64, an internal register 66, and a thinning device 6.
8 and a rhombus converter 70.

The gate array 54 exclusively occupies two buffers 56 and 58 during printing, but the buffer controller 64 transfers print data from one of the two buffers in response to a print timing pulse PCK from the SCPU 52 without the assistance of the MCPU 50. The data is read and expanded into pin data corresponding to each of the 24 wires 42. Therefore, MCPU
The print data 50 can store print data in the other of the buffers 56 and 58 in parallel.

At the time of storing the print data, the print data is thinned by the thinning device 68 if necessary. If the printing speed is designated as 1 × speed, the MCPU 50
Is supplied to the buffer 56 or 58 as it is. When the speed is set to 1.5 times speed, the interval between dots to be continuously printed by the same wire 42 is set to one. The print data is thinned out to be 0.5 times and stored in the buffer 56 or 58. For example, the print data illustrated in FIG. 5 is changed to the thinning data illustrated in FIG. In the drawing, circles represent data for instructing the formation of dots. The intervals between the dots continuously formed by the same wire 42 are thinned out so as to become 1.5 times, and if the dot interval is made 1.5 times as described above, the print head 40 will be 1. Even when the wire 42 is moved at 5 × speed, if the wire 42 performs a printing operation at the same cycle as that at 1 × speed, a plurality of dots continuous in the printing direction can be formed.

The pin data developed by the buffer controller 64 is shifted by a diamond converter 70 by a diamond. As described above, 24 of the print head 40
The wires 42 are arranged in a diamond shape, and pin data for one column is not executed at the same time.
If all the print data for one column is data for instructing the formation of dots, the two wires 42 are operated with a slight time delay, so
The data of one column (24 bits) is shifted so that the dot formed by 2 is consequently positioned on a vertical straight line.

The print data shifted in the shape of a diamond (diamond-shifted data) is supplied to a gate array 60, where a drive pulse for the print head 40 is generated as described later. A drive pulse for each of the laminated piezoelectric elements 44 for driving each wire 42 is created based on the print data.

Thinning device 68, buffer controller 64
7, 8 and 9 show details of the gate array 60, respectively.

First, the decimator 68 will be described. 1
Assuming that dots are formed at 1/180 inch intervals at double speed, to make the operation cycle of the wire 42 the same as that at 1 × speed when the print head 40 is moved at 1.5 times speed, , At intervals of 1/120 inch. Therefore, in the thinning device 68, a process of changing the print data before thinning that is created so that dots are formed at 1/180 inch intervals to thinned data that forms dots at 1/120 inch intervals is performed. Will be As shown in FIG.
Once changed so that dots are formed at 1/360 inch intervals, 1/120 by thinning every two dots
This is thinned data in which dots are formed at inch intervals.

For this purpose, as shown in FIG. 7, the decimation unit 68 includes a double expansion unit 80, a 6-bit shift register 82,
It comprises a comparator 84, a data latch 86 and the like.
These circuits are provided in eight systems, and data of one byte (for eight pixels) is processed in parallel. Double expander 80
Is to print the print data created so that dots are formed at 1/180 inch intervals by increasing the data of each bit by 2 bits at a time. This is a circuit that changes to data. The data latch 86 is a circuit that latches the output signal of the comparator 84 using the rising edge of the write signal WR as a latch trigger. The 6-bit shift register 82 shifts the data latch 86 one bit at a time using the falling edge of the write signal WR as a shift clock. Circuit for storing the output signal of

Since the print head 40 can print a character composed of 24 dots per column,
Three bytes of data are required for one column, and data up to six bytes before is necessary for thinning out two dots. The data latch 86 and the 6-bit shift register 82 are provided to create this data, and the comparator 84 compares the output signal of the double expander 80 with the output signal of the 6-bit shift register 82. To create the data after thinning.

In the present embodiment, since data of 24 pins is processed for each of 8 pins, the third or sixth bit of the 6-bit shift register 82 is data for instructing dot formation. Means that a dot was formed by the target pin last time or two times before. Therefore, in the comparator 84, 6
The logical sum (OR) of the third bit and the sixth bit of the bit shift register 82 is obtained, and the logical NOT (NO) of the logical sum is obtained.
T) and the output of the double expander 80 are ANDed. Accordingly, if a dot is formed at a certain time, the value of the logical product becomes 0 at the next and subsequent printing timings, even if the output of the double expander 80 indicates the dot formation, The post-thinning data is data instructing non-formation of dots. As a result, when the double-expanded data is as illustrated in FIG.
The data after thinning shown in FIG. 2 is created.

Next, the buffer controller 64 will be described. As shown in FIG. 8, the buffer controller 64 includes a 6-byte load clock generator 90, an address counter 92, and a pin data expander 94. 6
The byte load clock generator 90 outputs 1
This circuit supplies a read signal RD to the buffer 56 or 58 and sequentially supplies six clock pulses to the address counter 92 every time the print timing pulses PCK are supplied. The read address of the print data set in advance by the MCPU 50 is loaded into the address counter 92 in response to the print timing pulse PCK. The address counter 92 is also supplied with a signal FR indicating whether the printing direction is the forward direction or the reverse direction. Each time one clock pulse is supplied from the 6-byte load clock generator 90, the address counter 92 is supplied. The address of the buffer 56 or 58 specified according to the printing direction is changed according to the printing direction, and data for the leading pin and the succeeding pin is read out from the buffer 56 or 58 by a total of 6 bytes by 3 bytes. It is sent to 94.

The data of 6 bytes each is arranged in two columns in the pin data developing unit 94 in consideration of the printing direction. A signal FR indicating the printing direction is also supplied to the pin data developing unit 94. If this signal indicates the forward direction, data of 3 bytes is arranged in one column in the order of reading, and In the case of the direction, the 3-byte data read earlier and the 3-byte data read later are reversed and arranged in two columns.

The print data expanded into the pin data as described above is subjected to rhombus conversion by the rhombus converter 70 and sent to the gate array 60. The gate array 60 includes a history determination unit 100, a history control unit 102, and a simultaneous operation control unit 10 shown in FIG.
4, a processing circuit including an ON time width storage unit 106, a delay control unit 108, a print pulse generation unit 110, and an output control unit 112 is provided for each of the 24 wires 42.

The history determination unit 100 stores the current print data and the print data before and after the current print data, and generates the print pulse HI, the current data PD, the current data PD, and the data PEN to be printed next. The data HI printed last time is supplied to the history control unit 102 to the unit 110. The history control unit 102 has the previous history, that is, the data HI printed last time is the data instructing the dot formation, or the history control unit 102 has no previous history, that is, the data printed last time is the data instructing the non-formation of the dot. Depending on whether the ON time Ta1 when there is a previous history or the ON time Ta2 when there is no previous history, an ON time value B1-
5 and the latch signal G (1-24) are supplied to the ON time width storage unit 106. In addition, the ON time value B1-5 and the latch signal G (11-14) are supplied to the simultaneous operation control unit 104.

The simultaneous operation control unit 104 has (1) 11, 1
The case where only the 3rd wire is driven simultaneously and the previous 11th and 13th wires are not driven, and (2) 12 and 14
It is determined that only the # 1 wire is driven simultaneously and the # 12 and # 14 wires are not driven, and (1), (2)
In either case, the ON time Ta3 during the simultaneous operation is selected, and the ON time values BT11 and BT12 and the latch signal G
T (11-14) is supplied to the ON time width storage unit 106, and if none of the above applies, the history control unit 102 follows the selection.

The ON time width storage unit 106 stores the ON time width data selected and supplied as described above for each of the 24 wires.

Since the wires 42 for forming one column of dots are arranged in a diamond shape as described above, the delay control unit 108 is provided to delay the print timing signal by a time corresponding to the position of each wire. The print timer has a built-in delay timer and supplies a print timing pulse corrected for each wire to the print pulse generator 110. The delay control unit 108 controls the print timing pulse P
Each time CL is input, the delay timer is reset to start counting. The basic clock of the built-in timer is selected according to the moving speed of the carriage 22, and the delay control unit 108 counts the count value DRT of the built-in timer.
M1-3 is compared with the values set by the 12 addresses, and if they match, the TDL signal is turned on, and if they do not match, the TDL signal is turned off. Two wires 42 such as No. 1 and No. 23 and No. 3 and No. 21 are provided at the same position with respect to the moving direction of the carriage 22, and these two wires 42 have a common delay time. To get
It suffices if 12 types of delay time can be set.

The print pulse generator 110 is a circuit for generating a print pulse based on the various signals created as described above. As shown in FIG.
It has. Timer comparator 120 includes timers 122 and 1
24, and is selected by the history control unit 102 or the simultaneous operation control unit 104 based on the print data PEN to be printed next supplied from the history determination unit 100 and the print data HI printed last time. ON time Ta
1, 2, 3 and a preset delay time T
b, the combination of the brake pulse start time Tc and the brake pulse end time Td is determined, and the print pulse HA is generated in synchronization with the signal TDL supplied from the delay control unit 108 when the current print data PD is ON.

FIG. 1A shows a case where the printing speed is 1 × speed. When the print data HI printed last time is data instructing non-formation of a dot, that is, when the first print pulse is issued, the delay time Tb is not given, and the power is supplied for the power supply time Ta2. On the other hand, if the print data HI printed last time is data instructing the formation of dots, that is, if the energization is for the second or subsequent time, a delay time Tb is given, and energization for the energization time Ta1 is performed. Will be If the print data PEN to be printed next is data instructing non-formation of dots, that is, if energization is final,
After the energization for the energization time Ta1, the brake pulse is generated from the time when the brake pulse start time Tc elapses to the time when the brake pulse end time Td elapses without giving a delay time.

FIG. 1B shows the case where the printing speed is 1.5 times the speed. Also in this case, the first dot and the second and subsequent dots of the continuously formed dots are formed by the energizing time Ta2 without delay time and the energizing time Ta1 with delay time Tb, respectively, at 1 × speed. Is the same as the case of (1), except that the last dot is formed with the energization time Ta1 without delay time.
It is different from the case of double speed.

As described above, in the case of 1.5 times speed, the last dot is formed with the energizing time Ta1 without the delay time, so that the print head 4 during the delay time Tb.
The dot interval becomes narrower by the distance that 0 moves. In the case of 1.5 × speed, the distance the print head 40 moves during the printing cycle is 50% of that in the case of 1 × speed. However, since no delay time is given at the second energization, the printing period of the printing cycle is reduced. The increase in the moving distance of the print head 40 between the two dots is reduced, and the width of the vertical line formed by the two dots is close to the case of 1 × speed.

For example, if the printer is capable of printing 150 characters per second, each of which is assigned a character column of 24 columns and a space column of 3 columns, a total of 27 columns, the dot pitch is 1/18.
At 1 × speed, which is 0 inches, the print head 40 moves 150 × 27 × 25.4 / 180 = 572 millimeters per second. In addition, the delay time from the start of energization to the actual start of wire protrusion when forming the first dot is 60 seconds.
If it is μs, the delay time Tb given at the time of forming the second and subsequent dots is 60 μs.

When printing is performed at 1.5 times speed, the dot pitch is 1/120 inch, that is, 2 dots.
5.4 / 120 millimeters, (25.4 / 1
20) − (25.4 / 180) = 0.071 mm longer, but 1.5 × 5 by omitting the delay time of 60 μs when forming the final dot.
72 × 60 × 10 ⁻⁶ = 0.051 mm shorter, and eventually the thickness of the vertical line formed by two consecutive dots only needs to be 0.071−0.051 = 0.02 mm thicker. Become. If a delay time of 60 μs is given as before, originally 25.4 / 180 =
The vertical line which should be 0.141 mm becomes 0.071 mm thick and increases by almost 50%, while the apparatus of this embodiment only increases by 0.02 mm and increases by 14%. It only needs to be done.

In this embodiment, when three or more dots are continuously formed at 1.5 times speed, the provision of the delay time Tb is omitted only when the last dot is formed. However, the provision of the delay time Tb may be omitted when forming all the second and subsequent dots. In the former case, the interval between the last dot and the preceding dot is shorter by the delay time, whereas in the latter case, the interval between the first dot and the second dot is shorter by the delay time. This is because there is no apparent difference in the printing result.

In this embodiment, the digital circuit determines whether or not to provide a delay time when forming the last dot at 1.5 times speed. However, it may be configured by software. It is possible. For example, the CPU pre-reads the data at the next print timing to determine whether or not to provide a delay time.

In this embodiment, the wire is driven by the wire driving device 46 mainly composed of the laminated piezoelectric element 44. However, the wire of the print head provided with the wire driving device mainly composed of the solenoid is used. The present invention can be applied to a drive control device. Although not specifically exemplified, it goes without saying that the present invention can be implemented in various modified and improved forms based on the knowledge of those skilled in the art.

[Brief description of the drawings]

FIG. 1 is a graph showing a comparison of power supply states of a wire driving device when 1 × speed printing and 1.5 × speed printing are performed in a print head drive control device according to an embodiment of the present invention.

FIG. 2 is a plan view schematically showing the periphery of a print head of a printer including the print head drive control device of the embodiment.

FIG. 3 is a view conceptually showing the arrangement of the leading ends of print wires in the print head.

FIG. 4 is a block diagram of the print head drive control device.

FIG. 5 is a diagram showing an example of a character printed at 1 × speed by the print head drive control device.

FIG. 6 is a diagram showing a state in which dots of the character are thinned out in order to print at 1.5 times speed.

FIG. 7 is a block diagram illustrating a configuration of a thinning device of the print head drive control device.

FIG. 8 is a block diagram showing a configuration of a buffer controller of the print head drive control device.

FIG. 9 is a block diagram showing a configuration of a gate array of the print head drive control device.

FIG. 10 is a diagram for explaining thinning by the thinning device of FIG. 7;

11 is a diagram for explaining thinning by the thinning device in FIG. 7;

FIG. 12 is a diagram for explaining thinning-out by the thinning-out device in FIG. 7;

FIG. 13 is a diagram for explaining a print pulse generator of the gate array of FIG. 9;

FIG. 14 is a diagram for explaining a problem when a delay time is not given when printing at 1.5 × speed by a conventional print head drive control device.

FIG. 15 is a diagram for explaining a case where a delay time is given at 1.5 × speed printing by a conventional print head drive control device.

[Explanation of symbols]

 Reference Signs List 22 carriage 40 print head 42 print wire 44 laminated piezoelectric element 45 wire driving device 100 history judgment unit 102 history control unit 106 ON time width storage unit 110 print pulse generation unit

Claims (1)

(57) [Claims] A print wire operated by a wire driving device is movable relative to a print medium at 1 × speed and 1.5 × speed, and two print wires are continuously arranged in the relative movement direction. Dot with the 1x speed
Same maximum operation in both 1.5x speed print modes
When a printed wire is formed by operating a printed wire in a possible cycle
In this case, it is created to print
Each of the two types of print data corresponding to each print mode
In a drive control device of a wire dot type print head that prints a character by a set of dots formed thereby, a print wire is operated based on each of the plurality of dots continuously arranged in the direction of the relative movement. Is issued with a delay of a predetermined delay time when the relative moving speed is 1 ×, and when the relative moving speed is 1 ×, and when the speed is 1.5 ×. A drive control device for a print head, characterized in that a projection command generating means for issuing a projection command without delay is provided.