JPH05318830A - Dot printer - Google Patents

Abstract

PURPOSE:To prevent the breaking of the uppermost sheet of paper by the printing operation of a continuous dot pattern particularly when printing is conducted on a thick form such as multiple part paper. CONSTITUTION:A dot printer is composed of a printing driver circuit 44 driving a dot pin in a printing head 2 on the basis of a dot pattern data, a motor 12 for moving a carriage driving the printing head 2 in the direction orthogonal to the direction of form-feed, and a printing-head control circuit 45 controlling a dot-printing space in the direction orthogonal to the direction of form-feed on the basis of the sensor 23 for detection of a gap changing means changing the space of a form and the printing head, and controlled so as to vary a dot printing space in response to form thickness.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a serial dot printer for printing with dot pins, and more particularly to control of printing operation for printing on so-called multi-part paper in which a plurality of paper sheets are stacked.

[0002]

2. Description of the Related Art Usually, a serial dot printer has 9 to 24 pin dot pins arranged in a row or in a staggered pattern in the vertical direction (printing line direction) of a recording paper, and is directed to a platen by a piezoelectric element or an electromagnetic solenoid. And a carriage for moving the recording head in a vertical direction, a carriage for moving the carriage equipped with the print head in a horizontal direction (print digit direction or column direction) at a predetermined speed. And a feeding means. Then, as the print operation control of this printer, the input print data is temporarily stored in the storage buffer, the print data in the print line extracted from this is expanded into a dot pattern (image data) and stored in the line buffer. It is well known to control the dot pins of the print head to drive in accordance with the dot pattern.

By the way, in such a printer,
When printing on so-called multi-part paper, such as slips, where multiple sheets are stacked and the second and subsequent sheets are copy paper, the same as when printing on only one sheet. In order to obtain print quality, it is necessary to strengthen the impact force of the driven dot pin. Therefore, conventionally, it has been considered to control so as to increase the driving force (impact force) of all the dot pins in the print head when the number of stacked sheets is large.

[0004]

However, if the impact force of the print head is increased as described above, the following inconvenience occurs. That is, as is well known, the dot pins may strike the paper through an ink ribbon arranged on the front side of the paper so that the paper can be printed in a predetermined pattern on the paper surface. A recess can be made according to the pin diameter.

The diameter of a normal dot pin is 0.2 m, and the spacing (pitch) P of printing dots is 1/180 inch.
If it is (0.141 mm) or 1/160 inch (0.159 mm), when printing a continuous dot pattern in the horizontal direction (column direction), which is represented by horizontal ruled lines, as shown in FIG. Adjacent dots 100 overlap each other. As a result, there is a problem that the paper of the horizontally long dot pattern portion is torn.

Particularly, since the back side of the first sheet (the uppermost sheet in the stack of sheets) of the multi-part sheet is supported by the second and subsequent sheets, the back side is supported by the hard platen. High-density printing (high-duty printing), such as the horizontal ruled line printing operation described above, or most of the printing area is occupied by the printing dot area (the density of the dot pattern is high) compared to a single sheet of paper At times, there is a problem that paper breakage is particularly likely to occur.

It is an object of the present invention to solve this problem and to provide a printer in which paper breakage does not easily occur even when multi-part paper is used.

[0008]

In order to achieve the above object, a printer according to a first aspect of the present invention comprises a print driving means for driving dot pins in a print head based on dot pattern data, and a paper feed direction. Print head moving means for driving the print head in the direction, the paper thickness detecting means for detecting the paper thickness, and the dot printing interval in the direction intersecting the paper feeding direction based on the detection by the paper thickness detecting means. The control unit is configured to control the dot printing interval according to the sheet thickness.

According to another aspect of the present invention, the print driving means drives the dot pins in the print head based on the dot pattern data, the print head moving means drives the print head in a direction intersecting the paper feeding direction, and the paper. The sheet thickness detecting means for detecting the thickness, and the print head drive control means for controlling the drive of the dot pin based on the detection of the sheet thickness detecting means. The strength of the drive pulse of the dot pin is controlled for every other dot in the column direction of the dot pattern data.

[0010]

According to the present invention, the paper thickness detecting means can determine whether the total thickness of the paper is thick or thin. According to the structure of claim 1, when the printing gap is large, in other words, when printing is performed on a thick paper such as a multi-part paper, a horizontal (column direction) like a horizontal ruled line is printed. By widening the dot spacing in the column direction in a dot pattern of two or more continuous dots, it is possible to print under the condition that the adjacent dots in the horizontal direction are reduced or not overlapped.
Damage to the thinnest paper of the multi-part paper is reduced, and the inconvenience of paper tear does not occur.

According to the second aspect of the invention, when printing on multi-part paper as in the case of the above, the leading dots in two or more dot patterns that are continuous horizontally like a horizontal ruled line are printed with a strong impact force, Since the second dot is printed with a weak impact force, consecutive dots are printed alternately with a strong and weak impact force.
Compared to printing with continuous strong force, damage to paper is less and paper tear does not occur. On the contrary, when the total paper thickness is thin like one paper, it continues in the column direction. Even if high-density printing (high-duty printing) such as a dot pattern, narrowing the dot spacing in the horizontal direction (column direction), or printing with the same impact force, it is applied to the paper. Since there is little damage, there is an effect that paper tear does not occur.

[0012]

EXAMPLE Next, an example in which the present invention is applied to a serial type dot printer as an impact printer will be described. 1 and 2, reference numeral 1 denotes a platen rotatably supported on left and right side plates 3a and 3b of a frame of a printing apparatus, and a print head 2 facing the platen 1.
Is mounted on a carriage 4, and the carriage 4 is mounted on a guide shaft 5 arranged along the surface of the platen 1 so as to be slidable in the axial direction thereof, and an auxiliary guide arranged parallel to the guide shaft 5. A rearward U-shaped guide groove of the rear portion of the carriage 4 is fitted on the shaft 6 so as to be slidable along the axis and capable of moving toward and away from the surface of the platen 1.

An eccentric shaft 5a protruding from the left and right ends of the guide shaft 5 is rotatably supported on the left and right side plates 3a and 3b, and a driven gear 9 meshing with a fan gear 7 mounted on one of the eccentric shafts 5a and The driving force from the step motor 8 is transmitted through the driving gear 10, and the gap between the nose portion 2a of the print head 2 mounted on the carriage 4 and the platen 1 (printing is performed according to the rotation angle of the guide shaft 5). The gap) is configured to be wide and narrow. Print head 2
The dot pins (not shown) in FIG. 9 are dot pins of 9 to 24 pins arranged in a row or in a zigzag pattern in the feeding direction of the recording paper P (vertical direction of the recording paper (printing line direction)). The dot pin is configured to be driven to project toward the platen by a drive source 44 (see FIG. 4) such as a piezoelectric element or an electromagnetic solenoid.

Further, as shown in FIG. 3, a rotary plate 18 having a large number of slits formed in the driven gear 9 and the like at regular intervals in the circumferential direction is provided so as to rotate integrally with the driven gear 9. The number of forward and reverse rotation steps of the step motor 8 is calculated by associating with an encoder 19 such as a photo interrupter capable of detecting blocking / passing of light by the slit across the both sides of the rotary plate 18. , The print gap can be set to a predetermined value.

Further, as shown in FIG. 3, the guide shaft 5
The adjustment lever 20 attached to the right end eccentric shaft 5a is a manual adjustment mechanism that adjusts the print gap to an optimum value according to the sheet thickness by rotating the adjustment lever 20. The midway portion of the adjusting lever 20 is made to face the vertically long guide groove 22 in the scale plate 21. The scale plate 21 is engraved with a number display along the longitudinal groove 22. When the adjusting lever 20 is set to the number "1" (a state where the paper thickness is thin), the light-shielding type lever sensor 23 is turned on.
On the other hand, when printing on multi-part paper, the lever sensor 23 is turned off when the adjusting lever 20 is turned downward in FIG. 3 to match the numbers “2” to “4”.

As described below, in the first embodiment, when the print gap is small (when printing on one or two sheets of recording paper), the normal print pitch [1/180
Inch (0.141 mm) or 1/160 inch (0.159 mm)] is controlled to print at a narrow print pitch, but when the print gap is large (when printing on multi-part paper), 1/120 inch The print mode is switched so that the print is performed at a wide pitch such as (0.217 mm).

In the second embodiment, when the print gap is small, control is performed so that all dot pattern data are printed with the dot drive pulse having the same strength.
When the printing gap is large, the strength of the dot drive pulse is controlled every other row in the dot pattern data. The timing belt 13 is fixed to the lower surface of the carriage 4 or the like, and the timing belt 13 is attached to the one side plate 3a or the like and the pulley 11a and the other side plate 3b.
The carriage 4 is wound around a pulley 11b attached to the output shaft of a carriage motor 12 such as a step motor which can be rotated forward and backward, and the carriage 4 is moved in the longitudinal direction of the platen 1 (width direction of recording paper, digit direction of printing, It is configured to reciprocate along the print column direction).

Further, the platen 1 is rotated through the gear group 15 by the power of the paper feed drive motor 14, and
The recording paper P, which is a continuous multi-part paper that is conveyed by a tractor unit 16 that is a pin tractor driven by the drive motor 14, is sent to a roller pair (not shown) via a guide passage 17. , It passes through one platen and is discharged to the outside of the machine on the downstream side.

An ink ribbon supplied by a ribbon cassette (not shown) is interposed between the recording paper P and the print head 2 so as to move appropriately in a direction substantially parallel to the moving direction of the carriage 4. FIG. 4 shows the control device 3 of the present invention.
A functional block diagram of a computer as 0 is shown, and a central processing unit (CPU) 32, a read only memory (ROM) 33, a read / write memory (RAM) 34 and an input / output circuit (input / output interface) connected by a bus 31 are shown. 35, a print head control circuit 45 and the like.

Reference numeral 36 is a receiving buffer for receiving print data or the like from a host computer (not shown) which is a higher-level device, and 37 is a character of a commonly used Kanji such as the first level Kanji and the second level Kanji. A read-only character generator (character generator, font RO) in which character patterns other than Kanji such as patterns, letters, numbers, hiragana and katakana characters and codes for designating them are stored in advance.
M) and 39 are work memories in which a control signal for controlling the operation of the mechanical portion of the printing device can be read and written.

Reference numeral 40 is a carriage motor drive circuit for driving the carriage motor 12, and reference numeral 41 is a paper feed motor drive circuit for driving the paper feed drive motor 14 (step motor) for feeding the recording paper P by line. In addition to various processing programs, the ROM 33 stores excitation timing data (pulse rate) of the carriage motor 12, energization time data (response frequency) of a drive source 44 such as an electromagnetic solenoid that operates each dot pin in the print head 2. It is stored.

In the RAM 34, a pointer area (both not shown) is set in addition to a work area for storing various data by an initialization process performed at the time of startup, and a read pointer P1 and a read pointer P1 to be described later are set in the pointer area. The write pointer P2 is set. Font ROM3
Reference numeral 7 stores basic dot patterns corresponding to the various characters and figures. For example, if the basic dot pattern is a matrix of [24 × 24], the data for one column is 3 bytes and the data for 24 lines is 1 character (graphic).
The dot pattern data of the
7 is stored in a predetermined area.

The print head control circuit 45 includes a print head drive control circuit 46 and an energizing circuit 47.
7 is a power transistor 47 for energizing each drive source 44.
a and an AND gate 47b connected to its base terminal. The print head drive control circuit 46 forms a dot pattern from the image buffer 43 at each moving step in the print direction (column direction) of the print head 2 synchronized with the drive of the carriage motor 12 based on the timing signal Sti from the input / output circuit 35. In response, the dot recording signal Sd (high active) is output to the AND gate 47b. The energization circuit 47 prints based on the energization command signal EN input from the input / output circuit 35 to one terminal T1 of the AND gate 47b and the dot recording signal Sd input from the image buffer 43 to the other input terminal T2. Each time the head 2 is moved, the drive source 44 is selectively energized for a predetermined time to print a dot matrix character or graphic of a predetermined size.

The carriage drive circuit 40 is an input / output circuit 35.
Each phase of the carriage motor 12 is energized in a predetermined sequence (for example, two-phase excitation method) in synchronization with the pulse signal Spc input from the. That is, the input / output circuit 35 uses
A pulse signal Spc having a steady speed or a high speed is created based on the excitation timing data 33, and the carriage drive circuit 44 drives the carriage motor 12 at a steady speed or at a high speed (for example, at a steady speed) in synchronization with the pulse signal Spc. 1. Double speed). Therefore, in this embodiment,
At the steady speed of the carriage motor 12, the print head 2 can record (print) continuous dots at a pitch of [1/180 (inch)] in the column direction, and at high speed,
Continuous dots can be printed at a pitch of [1/120 (inch)]. The paper feed drive circuit 41 also drives the paper feed drive motor 14 based on the pulse signal Spi input from the input / output circuit 35.

Next, in accordance with the thickness of the recording paper P, based on the detection of the gap changing means for changing the gap between the paper and the print head 2, the paper feed direction (printing line direction) is orthogonal to the direction. A means for controlling the dot printing interval to be changed between a normal narrow printing pitch and a wide printing pitch will be described. As a means to change the print pitch
Here, the basic dot pattern is set to a narrow print pitch [1 /
180 (inch)], while the basic dot pattern and the same pattern as the basic dot pattern are half the dot pitch [1/360 (inch)] of the basic dot pattern as described later. By arranging them in the direction (column direction, column direction) so as to be arranged, a reference dot pattern having a double dot density with respect to the basic dot pattern is created, and dots continuous from the reference dot pattern in the column direction are formed. Among them, a dot pattern which is thinned out by a predetermined number of dots at a predetermined interval and remains (in this embodiment, a dot pattern obtained by omitting 2 dots following the dot in the head row for every three consecutive dots) is printed. Therefore, the printing pitch is [1/120 (inch)]
To make it wider.

As a means for this, a thinning circuit 42 described later is provided. That is, the control device 30 is connected to the thinning circuit 42 connected to the data bus 31a and the control line (not shown) in the bus 31, and the address bus 31b and the control line (not shown) in the bus 31. And an image buffer 43 connected to the data bus 31c via a thinning circuit 42.

As shown in FIG. 5, the thinning circuit 42 is a circuit unit 42a composed of a well-known shift register 50, a D flip-flop 51, and logic elements 53 to 56.
42h is the number of data buses 31a (eight in this embodiment)
It is a gate array provided only. In the apparatus of this embodiment, since the basic dot pattern is 24 dots in the vertical direction (printing line direction) as described above, it is necessary to perform thinning-out by the above-mentioned eight thinning-out circuit units 42a to 42h.
Each thinning circuit unit 42 per column (24 dots)
It is necessary to operate a to 42h three times. That is, for example, the thinning circuit unit 42a connected to the data bus D0
Each time the write signal WR is input, the drive signals of the first dot pin, the ninth dot pin, and the seventeenth dot pin of the print head are sequentially processed.

Therefore, for example, the thinning circuit unit 42
In a, when the dot thinning command signal DL2 (high active) is input from the input / output circuit 35, the CPU 3
The write signal WR from 2 is input to the shift register 50, and the data is input from the font ROM 37 via D0 of the data bus 31a. Shift register 50 and D
The output of the flip-flop 51 is printed before printing one line.
NOR gate 53 because it is reset to low level
Becomes a high level, and a signal input from the font ROM 37 via D0 of the data bus 31a (which is multiplied by n in the column direction for each dot with respect to the original data by the processing described later) is supplied to the AND gate 52. Pass as it is.

After that, a signal is similarly input twice, which is drive data for the ninth dot pin and the seventeenth dot pin, respectively. The shift register 50 changes its state when the write signal WR falls, and the D flip-flop 51 changes its state when it rises and changes its output. Therefore, the D flip-flop 51 is
The data input to the shift register 50 is determined immediately before the operation of the shift register 50 (more precisely, before the low time of the write signal WR). Since a method for determining the timing of data transfer using the D flip-flop 51 is known, the description using the timing chart and the like will be omitted.

Next, the input data becomes the first dot pin drive data again. For the subsequent data, the previous output data appears in Q3 of the shift register 50. Therefore, if the previous output data is high level (dot ON), the output of the NOR gate 53 will be low level, and the AND gate 52 will be in the cutoff state, regardless of whether the input data is high level or low level. The output data becomes low level (dot OFF). Also, the first of the next
When the drive data is input to the dot pin (when data is input after three times), the shift register Q6 is at the high level, so that the output of the NOR gate 53 is also off and the output data is at the low level. In this way, the target print dot pins (first
The previous and previous drive data of the dot pin) is output, and the output data is at the low level regardless of the input data (whether or not the input data is present), whichever is the high level (dot ON).

The same applies to the drive data of the ninth dot pin and the seventeenth dot pin input to the thinning circuit unit 42a, and the same applies to the other thinning circuit units 42b to 42h. The description is omitted. Each thinning circuit unit 42a-
In 42h, when the 1-dot thinning-out command signal DL1 (high active) is input, the dots are thinned out from every two consecutive dots. Further, the write signal WR is input through one of the control lines, and after the write signal WR is input to the shift register 50, when the data on the data bus 31a becomes stable, the data is input to the AND gate 52. The bus timing is predetermined so as to be input. When the write signal WR from the CPU 32 is input, the image buffer 43 stores the data input from the thinning circuit 42 at the address designated by the CPU 32. Therefore, when the CPU 32 writes data to a predetermined address of the image buffer 43, the data actually written to the address becomes the data thinned out by the thinning circuit 42.

Next, referring to the subroutine flowchart of FIG. 7, the reference dot pattern creation processing executed by the control device 30 will be described. When print data is input from a host computer (not shown) and a signal that the gap is wide is input based on the detection of the thickness of the print paper, first, the font ROM 37 in which the basic dot pattern corresponding to the print data is stored. The leading address in the area of is set to the read pointer P1 (S
1) Then, the start address of a predetermined area of the image buffer 43 for storing the printing dot pattern is set in the write pointer P2 (S2). Next, the counter C1 for counting the number of columns is set to the number L (24 in this embodiment) of columns forming a dot matrix of a predetermined size (S3), and then the counter C2 for counting the number of writings is set to a predetermined number. n (2 in this embodiment) is set (S
4). Subsequently, in step S5, data of 3 addresses, that is, data of 3 bytes = 1 column (in the case of 24 pins) is read from the address of the font ROM 37 designated by the read pointer P1, and then in step S6, the data of the write pointer P2 is read. Writing from the designated address of the image buffer 43 to the area of 3 addresses. That is, the CPU 32 outputs the thinning command signal DL2 from the input / output circuit 35 to the thinning circuit 42.
And the write signal WR and the data are sequentially output to the thinning circuit 42 three times, thereby writing 3 bytes of data to consecutive predetermined addresses of the image buffer 43. Therefore, the thinning circuit 4 is provided at the predetermined address.
The data thinned out by 2 is written. Then, the write pointer P2 is incremented three times (S7),
The counter C2 is decremented once (S8), and the process proceeds to step S9. In step SS9, it is determined whether or not the value of the counter C2 is 0, and when it is not 0 (S9, n
o), and returns to step S6. When the value of the counter C2 is 0 (S9, yes), the read pointer P1 is incremented three times (S10), and the counter C1 is decremented once (S11).

Next, in step S12, it is determined whether or not the value of the counter C1 is 0 (S12), and when the value of the counter C1 is not 0 (S12, no), the process returns to step S4. When the value of the counter C1 is 0 (S12, yes), this process ends. As a result of this processing, for example, with respect to the basic dot pattern as shown in FIG. 8A, the reference dot pattern shown in FIG. 8B has the basic dot pattern and the horizontal direction (column direction). , The column direction) is formed as a pattern (overlapping) with the basic dot pattern shifted by 1 pitch. Then, in the thinning circuit 42, for each dot row of the reference dot pattern, three consecutive dots in succession from the first row among the continuous dots existing in the dot row are followed by the dots in the first row. The remaining dot pattern obtained by thinning out two dots is created (FIG. 8C), and the pattern is stored in the image buffer 43.
Is stored at a predetermined address of.

When printing is carried out at high speed (1.5 times the steady printing speed in the embodiment) based on the printing dot pattern created in this way, the dot pitch is 1/1 in steady printing.
If 180 (inch), high speed printing is 1.5 x 1/180 = 1
It is possible to print with a dot pattern with a dot pitch of / 120 (inch). Next, the operation of this device will be described. In the main routine of the control system of the present apparatus (see FIG. 6), when the feeding is instructed, the feeding is performed (M1), and then the thickness of the fed sheet is measured (M
2).

This process will be described in detail. First, the print head 2 is retracted to a predetermined position. The predetermined position is the time when the encoder 19 deviates from the position of the slit of the rotary plate 18 and no pulse is output from the encoder 19. Then, from that position, the print head 2
The print head 2 is moved forward until the leading end of the sheet comes into contact with the mounted recording paper P and stops. And the print head 2
The thickness of the printing paper is obtained from the driving amount of the motor 8 required until the stop of the printing.

Then, the optimum print gap is obtained from the print paper thickness by referring to a look-up table, and the print head 2 is retracted again based on the optimum print gap to obtain the optimum print gap. Further, when the adjusting lever 20 of the manual adjusting mechanism is operated, the thickness of the printing paper is determined by the position of the adjusting lever 20. That is, the thickness of the printing paper and the printing gap generally have a deep relationship, and the thickness of the paper desired by the user can be estimated from the manually set value of the printing gap.

Next, it is judged whether or not the thickness of the paper is a predetermined value or more (M3). As the predetermined value, a thickness of about 3 multi-part sheets is used. If the result of the determination is no (M3, no), then 1/180 (
Printing is executed with a dot interval of inch (that is, a state where adjacent dots slightly overlap each other) (M4). That is, DL
Both 1 and DL2 output low level signals,
By inputting normal print data (1/180 inch dot pitch), printing with 1/180 inch dot pitch can be obtained.

If the result of the above determination is that the value is equal to or greater than the predetermined value (M3, yes), the adjacent dot is smaller than the dot interval [1/180 (inch)] in the normal printing performed in step M4. Increase the interval [1/120 (inch)] (M5). On the other hand, if it is in the copy strengthening mode, DL2 outputs a high (High level) signal and either DL1 can be used), and the created 1/360 inch dot pitch reference dot pattern is input ( M
13). Then, the dot pitch of 1/120 inch is printed. In this case, the adjacent dots do not overlap each other, so that the printing is not damaged.

DL1 is set high and DL2 is set low.
By inputting normal print data (1/18 inch dot pitch), 1/90 inch dot pitch printing can be performed.
Even if it is in copy enhancement mode,
1/90 inch without switching to 1/120 inch dot pitch
It goes without saying that printing is performed at inch dot pitch.

As described above, when the print gap is wide, in other words, when printing multi-part paper, by widening the print interval, paper breakage is unlikely to occur even with continuous dot patterns such as horizontal ruled lines. .. The embodiment of FIG. 9 detects the paper thickness, and when the paper thickness is equal to or larger than a predetermined thickness,
Instead of the process of step M5 of the above-described embodiment, the strength of the drive pulse of the dot pin is controlled for every other dot in the column direction of the dot pattern data. For example, when at least two dots are continuous dots, the dots in the first row are printed with a strong impact force, such that the odd-numbered dots are strong and the even-numbered dots are weak in order from the dots in the first row. A strength control circuit 60 is shown which alternately performs strength control of the impact force by printing with a weak impact force at subsequent dot portions and then with a strong impact force.

The strength control circuit 60 includes a D flip-flop 62, an RS flip-flop 63 and a logic element 64.
˜70, a first timer 71 and a second timer 72. The line buffer 61 develops the print data received by the receive buffer 36 into print dot images for each line. Then, from the line buffer 61 to D
Data is input to the D terminal of the flip-flop 62 for each dot, while the clock pulse CP is input to the clock input terminal C (negative edge trigger type).

An output signal is output from the Q terminal (high active) of the D flip-flop 62 at a timing delayed by one dot of the dot pattern of the line buffer 61. The AND gate 64 receives the data signal of the current dot from the line buffer 61 and the signal of the timing delayed by the 1 dot from the Q terminal, so that two dot patterns continue in the column direction (column direction). The AND gate 64 has a high (High level) output when it is on, and has a Low (Row level) output otherwise.

The output of the AND gate 64 is input to the S terminal (set terminal) of the RS flip-flop 63, and the clock pulse CP is input to the clock input terminal C (negative edge trigger type) of the RS flip-flop 63. In the Q terminal, the first one of the two data that is lined up is always high (ON), and the second is low (OFF). High, low, high, low alternate (however, in the middle High, sometimes high) signal is output. Then, the Q-bar terminal outputs a (NOT) signal that is the reverse of the output of the Q terminal. The OR gate 65 receives the signal from the Q terminal and the high or low signal from the strength control terminal PP. Here, during normal printing operation that does not add strength,
This is a level signal, and it is a low level signal during printing operation in which strength is alternately applied.

Then, the output signal of the OR gate 65 and the signal at the timing delayed by one dot of the dot pattern of the line buffer 61 are input to the AND gate 68, and the output of the AND gate 68 is set to about 200 μm. It is input to the dot pin drive switch element 73 via the timer 71 and the OR gate 70 having a long time length. On the other hand, the output of the Q bar terminal of the RS flip-flop 63 and the signal from the strength control terminal PP via the inverter 66 are input to the AND gate 67. The output signal of the AND gate 67 and the signal at the timing delayed by one dot of the dot pattern of the line buffer 61 are input to the AND gate 69, and the output of the AND gate 69 is output for a short time length of about 100 μm. It is input to the dot pin driving switch element 73 via the timer 72 and the OR gate 70.

In this configuration, if yes in step M3, the strength control terminal PP is set to low (Ro level), and if no, it is set to high (High level). When a low level signal is output from the strength control terminal PP, that is, when the strength printing control is executed, the first dot (third dot, fifth dot, About ...) RS flip-flop 63
The dot pin drive switch element 73 is operated for a long period of time via the AND gate 68 and the timer 71 in accordance with the output from the Q terminal to print with a strong impact force, and the second dot from the first among the consecutive dots is printed. Four
As for the th dot, ..., The dot pin driving switch element 73 is operated for a short time via the AND gates 67 and 69 and the timer 72 in accordance with the output from the Q bar terminal in the RS flip-flop 63, and a weak impact is exerted. The printing is driven by alternating impact forces, such as printing with force.

In the printing operation without intensity, the intensity control terminal PP is set to high (High level), the output of the OR gate 65 and the signal at the timing delayed by one dot of the dot pattern of the line buffer 61. And are input to the AND gate 68. When the output of the AND gate 68 is a high (High level) signal, it becomes a strong signal, and the dot pin driving switch element 73 is operated for a long time through the timer 71 having a length of about 200 μm, and continuously. Print with the same strong impact. In this case, the output of the Q bar terminal of the RS flip-flop 63 is directly output from the AND gate 67, and the AND gate 69
Since it is not output to the timer 72, the timer 72 is deactivated.

[Brief description of drawings]

FIG. 1 is a schematic plan view of a printer.

FIG. 2 is a schematic perspective view of a printer.

FIG. 3 is a perspective view of a printing gap changing unit.

FIG. 4 is a functional block diagram of a control device.

FIG. 5 is a reference dot pattern creation circuit diagram.

FIG. 6 is a flowchart of a main routine of a printing operation.

FIG. 7 is a flowchart of a subroutine for creating a reference dot pattern.

FIG. 8 is an example of thinning printing.

FIG. 9 is a control circuit diagram of the strength of a print dot pin.

FIG. 10 is an example of a conventional print dot.

[Explanation of symbols]

 1 Platen 2 Print Head 4 Carriage 12 Carriage Drive Motor 14 Paper Feed Drive Motor 30 Central Processing Unit 40, 41 Drive Circuit 42 Thinning Circuit 60 Strength Control Circuit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location B41J 25/308 8804-2C B41J 3/12 C 25/30 K

Claims (2)

[Claims] 1. A print driving means for driving a dot pin in a print head based on dot pattern data, a print head moving means for driving the print head in a direction intersecting with a paper feeding direction, and a paper thickness for detecting a paper thickness. And a control means for controlling a dot printing interval in a direction intersecting with the paper feeding direction based on the detection of the paper thickness detecting means, and a control for changing the dot printing interval according to the paper thickness. Dot printer characterized by doing 2. A print driving means for driving a dot pin in the print head based on dot pattern data, a print head moving means for driving the print head in a direction intersecting with a paper feeding direction, and a paper thickness for detecting a paper thickness. And a print head drive control means for controlling the drive of the dot pins based on the detection of the paper thickness detection means. When the paper thickness is a predetermined thickness or more, the dot pattern data in the column direction A dot printer characterized by controlling the driving pulse of the dot pin for every other dot.