JPH0358919B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to a printer with corrected printing timing, in particular, to eliminate disturbances in dot printing positions that occur when printing speeds, that is, carrier movement speeds differ depending on the type of printing pattern. The present invention relates to a printer that corrects the print timing according to the following.

In general, in dot printers such as wire dot matrix printers, timing pulses corresponding to the striped pattern of the timing fence are sent from a photodetector that scans a timing fence provided to determine print timing. is obtained and a signal synchronized with the timing pulse is sent to the excitation coil of the print head. Dot printing is performed when the exciting coil is excited and a flight time (time from when the exciting coil is excited until dot printing is performed) has elapsed. A block diagram for explaining an example of the print head drive control system in a conventional printer is shown in FIG. In FIG. 1, a detector 1 optically scans the timing fence 6 shown in FIG. 2, detects, for example, a black and white striped pattern on the timing fence 6, and A timing pulse 7 (shown in FIG. 2a) corresponding to the pattern is sent to the control section 3 via the amplifier circuit 2. The control section 3 detects the rising and falling points of the timing pulse 7 and sends a print head drive panel 8 as shown in FIG. 2B to the print head 5 via the print head drive section 4. In the print head 5, the print head 5 prints dots when a predetermined flight time has elapsed after an excitation coil (not shown) is excited by the print head drive pulse 8. That is, dot printing is performed when the flight time t _f has elapsed from the rise of the print head drive pulse 8, as indicated by the x mark in FIG. 2c. It goes without saying that the print head driving pulse 8 is outputted after matching with a dot signal corresponding to a character dot pattern (not shown) to be printed in the control section 3.

The printing timing in an example of a conventional printer has been explained above.If the scanning speed of the detector 1 with respect to the timing fence 6, that is, the moving speed of the carrier is constant, the printing position interval of the dots will be constant. Generally, the moving speed of the carrier is not necessarily constant. That is,
The dot printing position interval usually differs depending on whether the printed character pattern is a kanji character, an alphanumeric character, or an image. Examples of differences in dot spacing in each of the above printed character patterns are illustrated in FIGS. 2c, d) and e. Figure 2 illustration c
is a kanji character, d is an alphanumeric symbol, or e is a dot spacing in each case of an image. For kanji, the dot spacing is the closest, and for alphanumeric characters, it is twice the dot spacing for kanji.
In the case of images, it is 3/4 of the alpha numerical value. In order to improve printing quality, the closer the dot spacing, the slower the carrier movement needs to be. Furthermore, the moving speed of the carrier is not limited to the above three types, and if the text to be printed includes kanji, alphanumeric characters, images, etc., it is necessary to switch the moving speed of the carrier. At the time of speed switching, a transient variation in the moving speed of the carrier occurs. In this way, the moving speed of the carrier is not constant, and as the moving speed of the carrier changes, the signal is transmitted from the detector 1 to the controller 3 via the amplifier circuit 2.
The pulse width of the timing pulse 7 sent to the timing pulse 7 varies as shown in FIG. 3a. Therefore, similarly to the example shown in FIG. 2, the period of the print head drive pulse 8 shown in FIG. 3B output by the control section 3 changes each time the timing pulse 7 rises and falls. The dot printing timing in the print head 5 is determined by the print head drive pulse 8 as shown by the mark c in FIG.
Since the flight time t _f has elapsed since the rise of
The printing position spacing of the dots is not kept constant. That is, due to changes in the moving speed of the carrier, the printing positions of dots are disturbed, resulting in poor quality of printed characters.

The present invention aims to solve the above-mentioned drawbacks, and by correcting the timing pulse in accordance with the moving speed of the carrier, dot printing is always performed at the correct printing position, thereby ensuring high quality printing. The aim is to provide a printer that can be obtained. Therefore, the present invention includes a detector that scans a timing fence and outputs a timing pulse corresponding to the timing fence, and drives a print head in synchronization with the timing pulse from the detector. The printer is equipped with a correction circuit that corrects the timing pulse and outputs a correction pulse having synchronization corresponding to the scanning speed of the detector, and the correction circuit is compatible with a plurality of types of printing patterns. The pulse time of the timing pulse at the highest scanning speed among the scanning speeds of the detector predetermined in advance is provided as a reference pulse time,
The difference between the pulse time of this pulse time and the pulse time of the above timing pulse at other scanning speeds is counted during the pulse time of the current timing pulse.
A counter that measures under up mode and measures the time given correspondingly to the time difference by count up mode during the pulse time of the next timing pulse to generate a delay time. The present invention is characterized in that the correction pulse is generated after the delay time from the counter has elapsed. This will be explained below with reference to the drawings.

Fig. 4 is an explanatory diagram for explaining the preconditions of the present invention, Fig. 5 is a block diagram of an embodiment of the invention, and Fig. 6 explains the configuration and operation of an embodiment of the correction circuit shown in Fig. 5. FIG. 7 is a block diagram of another embodiment of the present invention, and FIG. 8 is an explanatory diagram for explaining the configuration and operation of another timing pulse generation circuit shown in FIG.

As explained at the beginning of this specification, the moving speed of the carrier in the printer varies depending on the character pattern to be printed, that is, alpha anonymous, kanji, image, etc., but generally the moving speed in the case of alpha anonymous printing is is the maximum. In the present invention, the above-mentioned moving speed in the case of alphanumeric printing is set as a reference speed and is set as _v0 , and even at the moving speed _V0 , the distance L of one pattern of the timing fence 6 shown in FIG.
Let T ₀ be the time required to advance. Then, let t ₁ be the time required to travel the distance L at another certain moving speed v ₁ . Now, as with the conventional printers described in connection with FIGS. 1 to 3, prints are output at the same timing synchronized with the timing pulse whether the moving speed is v ₀ or v ₁ . Assuming that printing is performed by the print head drive pulse 8, the dot printing position when the above-mentioned moving speed is v ₀ is as shown by the mark a in FIG. The position is a distance v ₀ t _f from the rising point of . On the other hand, when the moving speed is v ₁ , the position is a distance v ₁ t _f as shown by the x mark b in FIG. 4. In other words, when the above moving speed is v ₀ and
The printing position differs by a distance l from the case of _v1 .
Even when the above-mentioned moving speed is v ₁ , in order to make the dot printing position the same as when the moving speed is v ₀ , as shown by the x mark b in Fig. 4, the above-mentioned moving speed is
As shown in FIG. 4, the generation timing of the print head drive pulse 8' at v ₁ may be delayed by a correction time Δt, which will be described later, than the print head drive pulse 8 at the above-mentioned moving speed v ₀ . . That is, the correction time Δt is the time required to travel the distance l shown in FIG. 4b at the moving speed v ₁ . _{To explain the above} correction time _{Δt in more detail , in FIG .} △t=t _f (v ₀ /v ₁ -1) ...(1) Also, the distance L, moving speed v ₀ , v ₁ and time mentioned above
The following equation holds true from the relationship between t ₀ and t ₁ .

L=v ₀ t ₀ = v ₁ t ₁ ...(2) From equation (2) v ₀ /v ₁ =t ₁ /t ₀ ...(3) From equations (1) and (3) △t=t _f (t ₁ /t ₀ -1) t _f /t ₀ (t ₁ -t ₀ ) ...(4) In general, the above flight time t _f travels the above distance L in the case of the above alphanumeric printing. Since the time required for t is selected to be equal to t ₀ , the following equation holds from equation (4) above. That is, △t=t ₁ −t ₀ ...(5) As explained above, the present invention generates print head drive pulses in response to fluctuations in the moving speed of the carrier so as to satisfy the above equation (5). I'm trying to correct the timing.

FIG. 5 shows a block diagram of an embodiment of the present invention,
Reference numerals 1 to 5 in the figure correspond to those in FIG.
Reference numeral 3-1 denotes a correction circuit which is provided in the control section 3 and corrects the timing pulse from the amplifier circuit 2 in response to fluctuations in the moving speed of the carrier. Further, FIG. 6 is an explanatory diagram for explaining the configuration and operation of the fifth illustrated correction circuit 3-1, and reference numerals 9 and 10 in the figure are monostables, and the rising or falling edge of the pulse signal input 11 and 12 are counters, 13 and 14 are flip-flops, 15 and 16 are AND circuits, 1
7 represents a NOT circuit, 18 represents an OR circuit, and CL represents a clock signal.

In the present invention, as shown in FIG. 5, the control section 3 is provided with a correction circuit 3-1 as shown in FIG. It is being In the present invention, the printing timing is corrected based on the moving speed _v0 of the carrier in alphanumeric printing. Hereinafter, correction of printing timing in the present invention will be specifically explained with reference to FIG. 6. It should be noted that the explanation of the parts other than the correction circuit 3-1 will be omitted since they are no different from the conventional device described above.

The above correction circuit 3-1 illustrated in FIG.
In the configuration diagram showing the configuration of the monostable 9
The timing pulse a shown in FIG. 6 is input from the amplifier circuit 2 to 10 and 10. The timing
The pulse waveform of pulse a has a pulse width, that is, time t 1 between time T ₁ and time T ₂ , time t ₂ between time T ₂ and time T ₃ , ..., time T ₅ in response to fluctuations in the moving speed of _the carrier.
The time t ₀ between T 6 and T ₆ is different from each other. The time t ₀ indicates the pulse time of the timing pulse in the case of the above-mentioned alphanumeric printing, that is, when the carrier moves at the reference speed v ₀ . When timing pulse a is input to the monostables 9 and 10, the monostable 9
At each rising edge of timing pulse a, a one-shot signal as shown in FIG. Also, Monostable 10
At each rising edge of timing pulse a, a one-shot signal as shown in FIG. The above counters 11 and 1
2 starts counting by each of the one-shot signals mentioned above, and the counting is carried out by the clock signal CL. Note that the counters 11 and 12
The circuit counts up while the input signal applied to each U/D terminal is at a low level, and counts down while it is at a high level. Also,
Counters 11 and 12 have a count upper limit value determined at the time of counting up, and the upper limit value is a clock count value corresponding to time _t0 . When the count exceeds the upper limit value, the count returns to the "0" value and continues to count up again from the "0" value.

As explained above, the monostable 9 captures the rising edge of the timing pulse a at time _T1 and loads the one-shot signal as shown in FIG. Start up. What happens is that the U/D terminal of the counter 11 is connected to the not circuit 1.
This is because the low level is loaded via 7. That is, the counter 11 starts counting up from time _T1 in response to the clock signal CL, and at the same time as time _t0 elapses, that is, at time _T'1 , the count value temporarily returns to "0" and starts from the "0" value. Continue counting up. Then, when time _T2 is reached, the U/D terminal, which had been at a low level until then, is reversed and becomes a high level, so that the counter 11 starts counting down. Assuming that the count value immediately before the countdown is N, the count value N is equal to the time △t, that is, the time (t ₁
−t ₀ ). Therefore, the count value reaches "0" at time T' ₂ when time △t, that is, time (t ₁ - t ₀ ) has passed after N counts after the start of the countdown, that is, from the countdown start time T ₂ . Carry as shown in Figure 6d.
d is sent from the counter 11 to the AND circuit 15. At this time, it is sent to the AND circuit 15.
At this time, since the other input of the AND circuit 15, that is, the output of the NOT circuit 17, is at a high level,
The AND circuit 15 becomes conductive and outputs a pulse signal immediate correction pulse f as shown in FIG. 6 via the OR circuit 18. Note that the ENB signal A is output from the flip-flop 13 by the output of the AND circuit 15.
is sent to the counter 11, and the counter 11 stops counting. Then, at time _T3 , the counter 11 starts counting again as described above.

On the other hand, the monostable 10 captures the falling edge of the timing pulse a at time _T2 and loads a one-shot signal as shown in FIG. Thereafter, in the same manner as described for the counter 11 described above, the sixth counter at time T' ₃ when time Δt', that is, time (t ₂ −t ₀ ) has elapsed from time T ₃ .
A correction pulse as shown in FIG. f is output.

Also, time T ₅ at timing pulse a
In the case of a timing pulse having a time t ₀ from T _{6 to T 6} , i.e. in the case of the above-mentioned alphanumeric printing, a correction pulse is generated synchronously with the above-mentioned timing pulse.

As explained above, the correction circuit 3 in the present invention
-1, the timing pulse from the detector 1 is corrected in accordance with the variation in the moving speed of the carrier, resulting in a correction pulse as shown in FIG. A correction pulse is generated that can perform timing correction that satisfies the following. In the embodiment shown in FIG. 6, the embodiment is configured to generate correction pulses f corresponding to the rising and falling edges of the timing pulse a inputted from the detector 1 via the amplifier circuit 2. It is shown. However, as mentioned at the beginning of this specification, the positional spacing of dot printing is changed depending on the type of character pattern to be printed, that is, Chinese characters, alphanumeric characters, and images. Therefore, in the case of the kanji shown in FIG. 2c, it is sufficient to follow the timing of the correction pulse f shown in FIG. 6, and as shown in FIG. 2d,
In the case of an alphanumeric character in which one dot is printed for every two dots of the above-mentioned kanji, the correction pulse f can be changed by providing a binary counter, flip-flop, etc. (not shown) in the control section 3. It's easy to make it one against one. but,
As in the case of image printing shown in FIG. 2e, it is not easy to achieve a printing interval of 3/4 of that of alphanumeric printing. Correction of the print timing in the case of image printing according to the present invention will be described next. That is, FIG. 7 shows a block diagram of another embodiment of the present invention, in which numerals 1 to 5 and 3-1 correspond to those in FIG. 5, and 3-2 is another timing pulse generation circuit. This shows what creates the timing pulse for image printing. Further, FIG. 8 shows an explanatory diagram for explaining the configuration and operation of the timing pulse generation circuit 3-2 shown in FIG.
21 represents a shift register, 21 to 23 represent counters, and 24 represents an OR circuit.

Another embodiment of the present invention is as shown in FIG.
In addition to the correction circuit 3-1 shown in FIG. 6, the control section 3 is provided with a separate timing pulse generation circuit 3-2, which has a function of generating timing pulses for image printing, and other configurations. The operation is no different from the embodiment shown in FIG. Hereinafter, correction of print timing in the case of image printing in the present invention will be explained with reference to FIG.

The above-mentioned different timings shown in FIG.
In the block diagram showing the configuration of the pulse generation circuit 3-2, a correction pulse f from the correction circuit 3-1 is inputted to the shift register 20 via a not circuit 19. The inputs are illustrated in Figure 8a.
In the shift register 20, the shift panel b shown in FIG. 8b, which has been shifted by one clock of the clock signal CL, is the counter 2.
Sent to 1. Furthermore, the shift pulse c shown in FIG. Now, a shift pulse b 1 obtained by shifting pulse a ₁ of the above-mentioned inverted pulse a by one clock in the shift register 20 is transferred to the counter ₂₁ .
When loaded into the counter 21, the counter 21 counts.
Start up and count up to the next shift pulse _b2 . 1/2 of the count value, ie, x/2, is stored in a register (not shown). Then, the contents of the register are loaded into the counter 22 by the shift pulse _c2 , and the counter 22 starts counting down from the load value x/2. Then, in the counter 22, when the count value reaches the "0" value due to the counter down, carry d ₂ is outputted and the OR circuit 24
is sent to the counter 23 via. In this way, the above operation is repeated. That is, the next carry d ₃ is sent to the counter 23 at a timing delayed by 1/2 or Y/ ₂ of the count value between the shift pulse c ₃ and the shift pulses b ₂ and b 3 in the counter 22 . In this way, the counter 23 receives shift pulses c ₁ , c ₂ , c ₃ , . . . and carries d ₁ , d ₂ ,
d ₃ , ... are input alternately. The counter 23, which is a ternary counter, receives input of carry d ₁ , shift pulse c ₂ and carry d ₂ , and then inputs 3
When the th carry d ₂ is input, another timing pulse e ₁ is output. Furthermore, when the shift pulses c ₃ , carry d ₃ and the third input pulse, the shift pulse c ₄ , are input, the next timing pulse e ₂ is output. That is, the separate timing pulse generating circuit 3-2 shown in FIG. 8 generates a different timing pulse having a period 1.5 times as long as the correction pulse f shown in FIG. 6, as shown in FIG. 8e.
It can output pulses. In the embodiment shown in FIG. 8, a case has been described in which the separate timing pulse has a period 1.5 times that of the correction pulse, but the invention is not limited to this, and the counter loaded into the counter 22 2
By appropriately selecting the output 1, a desired timing pulse can be obtained.

Furthermore, in the embodiments shown in FIGS. 5 to 8 above, the correction circuit 3-1 and the separate timing/pulse generation circuit 3-2 are provided in the control section 3, but the present invention is not limited to this. Not a thing,
For example, although not shown, it may be provided between the amplifier circuit 2 and the control section 3.

As explained above, according to the present invention, by providing a correction circuit that corrects the timing pulse in response to fluctuations in the moving speed of the carrier, it is possible to always print dots at the correct printing position, Accordingly, it is possible to provide a printer with corrected printing timing so that high-quality printing can be obtained. Since the correction circuit is not designed to provide a fixed or semi-fixed time delay, it is highly flexible in providing the desired time delay. It's summery. Furthermore, by providing a separate timing pulse generation circuit that shifts the cycle of the correction pulse corrected by the correction circuit, it is possible to use one timing fence to produce kanji, alphanumeric characters, and images. It is possible to provide a printer with corrected printing timing that can perform high-quality printing in any printing pattern.

[Brief explanation of drawings]

FIG. 1 is a block diagram for explaining an example of a print head drive control system in a conventional printer; FIGS. 2 and 3 are explanatory diagrams for explaining the print head drive control operation shown in FIG. 1; FIG. 4 is an explanatory diagram for explaining the preconditions of the present invention, and FIG. 5 is a block diagram of an embodiment of the present invention.
FIG. 6 is an explanatory diagram for explaining the configuration and operation of one embodiment of the correction circuit shown in FIG. 5, FIG. 7 is a block diagram of another embodiment of the present invention, and FIG. An explanatory diagram for explaining the configuration and operation of an embodiment of a timing pulse generation circuit is shown. In the figure, 1 is a detector, 2 is an amplifier circuit, 3 is a control unit, 3-1 is a correction circuit, and 3-2 is a different timing
a pulse generation circuit; 4 is a print head drive unit;
5 is a print head, 9 and 10 are monostables, 11, 12 and 21 to 23 are counters, 13 and 14 are flip-flops, 1
5 and 16 are AND circuits, 17 and 19 are NOT circuits, 18 and 24 are OR circuits, and 20 is a shift register.

Claims (1)

[Claims] 1. A detector is provided that scans a timing fence and outputs a timing pulse corresponding to the timing fence, and the print head is driven in synchronization with the timing pulse from the detector. The printer is provided with a correction circuit that corrects the timing pulse and outputs a correction pulse having synchronization corresponding to the scanning speed of the detector, and the correction circuit corresponds to a plurality of types of printing patterns. The pulse time of the timing pulse at the highest scanning speed among the predetermined scanning speeds of the detector is provided as a reference pulse time, and the pulse time of the timing pulse at the highest scanning speed among the scanning speeds of the detector determined in advance is provided as a reference pulse time, and the pulse time of the timing pulse at the time of the reference pulse time and other scanning speeds is provided as a reference pulse time. The difference between the pulse time of the timing pulse is measured under the count-up mode during the pulse time of the current timing pulse, and the time given corresponding to the time difference is calculated as the next timing pulse. a counter that generates a delay time by measuring in a countdown mode during the pulse time, and is configured to generate the correction pulse after the delay time from the counter has elapsed. A printer with corrected printing timing.