JPH0120069B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a serial printer, and particularly to high-speed printing control thereof.

As is well known, the printing methods of serial printers include an intermittent feed printing method (hereinafter referred to as ink printing method) in which the carriage is temporarily stopped at the printing position and printing, and a continuous feed printing method in which printing is performed while the carriage is moving at a constant speed. There is a printing method (hereinafter referred to as flying printing method). Among these, the flying printing method prints while the carriage is moving, so it is expected to have faster printing speed than the ink printing method, but the spacing time must be set to the time equivalent to the longest type selection time. The printing speed was limited by this maximum character selection time, and there was a limit to how high the printing speed could be increased.

Conventionally, in order to increase the printing speed in this flying printing method, the time required to select type was divided into multiple sets, each set was assigned a different feed speed, and the number of pitches selected for type was handled accordingly. A method has been proposed in which a feed speed is selected and the carriage is fed at the selected speed to print. According to this printing method, the printing speed is not uniquely restricted by the longest type selection time, so it has the advantage of increasing the printing speed, but The following disadvantages arise because the carriage movement speed is determined by focusing only on the number of type selection pitches (type selection time).

Now, referring to Figure 1A, when issuing a movement command for the next character to be printed, the carriage movement speed before the movement command is _VH , and the carriage movement is determined by the number of type selection pitches of the character to be printed. The speed (operation command speed) is V _M (V _M < V _H ), and the carriage is
The time required to decelerate from V _H to V _M is t ₁ , the amount of carriage movement for one space is x , and the time required to decelerate from V H to V M is
When t ₂ , the following equation holds: x=V _M t ₂ + (V _H −V _M )t ₁ /2 (1). Here, if the acceleration/deceleration coefficient of the carriage is a, time t ₁ becomes t ₁ =V _H −V _M /a (2), and from equations (1) and (2), time t ₂ becomes t ₂ = x /V _M −(V _H −V _M ) ² /2aV _M (3). Similarly, referring to Figure 1B, let the carriage movement speed before the operation command be V _L (V _L < V _M ), and the time required for the carriage to accelerate from V _L to V _M is t ₃
Then, the time required to move the carriage for one space is
When t ₄ , the following equation holds: x=V _M t ₄ −(V _M −V _L )t ₃ /2 (4). Here again, if the acceleration/deceleration coefficient of the carriage is a, time t ₃ is expressed as t ₃ =V _M −V _L /a (5), and from equations (4) and (5), time t ₄ is , t ₄ =x/V _M +(V _M −V _L ) ² /2aV _M (6). Here, the difference between times t ₄ and t ₂ is calculated as follows: t ₄ - _{t 2} = (V _M - V _L ) ² + (V _H - V _M ) ² /2aV _M (7).

The motion command speed can be determined by setting it to satisfy the time t ₂ in equation (3), which is the minimum processing time among equations (3) and (6), but in the conventional method, printing is performed next. Since it is uniquely determined according to the number of selected pitches of printed characters, the time t ₄ in equation (6) must be satisfied, that is, if the time required for selecting printed characters, etc. is t ₅ , then t ₅ < t ₂ < It is necessary to set the time according to the relationship _t4 , which causes the loss time shown in equation (7).In the case of conventionally proposed printing methods, the carriage must be driven at a speed that matches the time corresponding to the number of selected pitches of type. There is a problem that it cannot be done.

SUMMARY OF THE INVENTION An object of the present invention is to provide a serial printer that eliminates the above-mentioned disadvantages and enables high-speed printing.

Therefore, when issuing a motion command for the next character to be printed, the present invention does not determine the carriage movement speed uniquely according to the number of selected pitches of the printed character, but also takes into account the carriage speed before the motion command. By setting the next moving speed of the carriage, an even higher printing speed can be obtained. That is, in the present invention, when the movement command speed is V and the required time is t, when the carriage is running at V _H in Figure 1A, x = Vt + (V _H - V) ² /2a (8) Therefore, the operation command speed V is selected so that V=(V _H −at)+√() ² −2 _H +2 (9). Similarly,
When the carriage is running at V _L as shown in Figure 1 (b), select V = (V _L + at) + √ () ² + 2 _L -2 (10).

In addition, in the present invention, in addition to the selection time of the printed character, etc., which is the target of the movement command, and the carriage speed before the movement command, the printed character, etc. of one or more characters, etc. after the character, etc., which is the target of the movement command, is determined. The method is characterized in that the operating speed of the carriage is set based on relative relationships such as selection time. As will be described later, this makes it possible to further increase the flying printing speed. Hereinafter, one embodiment of the present invention will be described in detail.

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

In the figure, the carriage feeding drive unit 26 is equipped with a carriage feeding motor, and the carriage is fed by this motor. A position signal generator 27 is directly or indirectly coupled to the rotating shaft of the carriage feed motor. The position signal generator 27 is composed of, for example, a slit that rotates in response to the rotation of a motor, and a light emitting/light receiving element placed oppositely across the slit, and generates a pseudo sine wave position signal P in response to the movement of the carriage. Occur. The position signal P is input to a step signal generation circuit 29 to generate a step signal C indicating a unit movement amount (one step) of the carriage, and is input to a subtraction counter 30. The subtraction counter 30 is configured such that the required space movement amount of the carriage is initially set by an external processing device (not shown) at the start of operation, and this is sequentially subtracted by the step signal C. In other words, the subtraction counter 30 indicates the amount of remaining space movement of the carriage. The output of the counter 30 is sent to a flying speed determination circuit 20, a position signal switching circuit 31, an increment speed indicating circuit 32,
The speed is supplied to the one-stroke character position discrimination circuit 34, etc.
These will be described later.

On the other hand, the position signal P generated by the position signal generator 27 is input to the speed signal generation circuit 28, and the actual speed signal V _P of the carriage is generated. The actual speed signal V _P is connected to the analog speed instruction signal V _A and the subtraction circuit 2.
4, and the difference signal is amplified by a power amplifier 25 and applied to a carriage feed drive section 26, thereby controlling the speed of the carriage. That is, the subtraction circuit 24, the power amplifier 25, the carriage feed drive section 26, the position signal generator 27, and the speed signal generation circuit 28 constitute a speed servo control system, which controls the carriage at the speed indicated by the analog speed instruction signal V _A. The movement speed of is controlled. The present invention is to set the analog speed instruction signal V _A to an optimal value. This will be explained below.

Now, the data such as the next character to be printed that comes from the external processing device is decoded by the decoder circuit 11, and if it is print data, the print current value storage unit 1
3, and information on the number of pitches selected for the printed character and various operations (for example, up/down shift) associated with the selected printed character for the printed character data is provided to the required time determination circuit 16. If the incoming data is space data that does not involve printing, the space signal is directly input to the required time determining circuit 16. On the other hand, when function data other than print data and space data (excluding CR and TAB) is decoded by the decoder circuit 11, it is also given to the required time determination circuit 16 through the register 14 and is also sent to the function operation control circuit 15.
is input, and after the current operation is completed, a predetermined function operation is executed.

The required time determination circuit 16 divides the time required for a type selection operation, etc. when a printing operation is involved, into several levels, and determines a predetermined required time level based on information such as the number of type selection pitches given.
The result is stored in the first register 17. or,
In the case of a space signal or the like that does not involve a printing operation, the data is stored in the first register 17 as is.
In the same manner, the required time information for subsequent arriving data is also stored in the second and third registers 18 and 19 in sequence. That is, in the embodiment, the first register 17
Carriage operating speed (hereinafter referred to as
To determine V _A (also called flying speed), the time information of the following two data is referred to. The registers 17, 18, and 19 are, for example, shift registers, and when the operation on the data in the first register 17 is completed, the contents of the second register 18 are transferred to the first register 17, and the contents of the third register 19 are transferred to the second register 18. and move to the third register 1
9, subsequent time information is newly stored. The contents of these registers 17, 18, and 19 are the output of the flying speed indication circuit 21, which indicates whether the carriage is currently stopped or running, and if so, what the speed level is.
Both V _D and V D are applied to the flying speed determination circuit 20 . The flying speed determination circuit 20 selects the first register 17 based on the count value of the subtraction counter 30.
The end point of the operation for the data before the data is known, and at the end of the operation, the first to third registers 17, 1
8 and 19 and the output of the flying speed instruction circuit 21 (that is, the carriage speed before issuing the operation command according to the data in the first register) V _D , the first
The flying speed level associated with the data in the register 17 is selected, and the selected speed information is passed through the flying speed instruction circuit 21 and becomes new speed instruction information V _D for the carriage. The flying speed determination circuit 20 sets the flying time of the hammer based on printing pressure information when the printing pressure is varied depending on the printing surface area of the type and copy control information from the copy control switch that controls the distance between the platen and the type. The output of the hammer flying time determination circuit 33 (hammer flying time information) is also input.
This is used when the speed level of the carriage needs to be determined in consideration of the hammer flying time. Further, space movement amount information is also input to the flying speed determination circuit 20, but this is because when the space movement amount is variable, it is necessary to adjust the obtained speed instruction information V _D.

The speed instruction information V _D newly instructed by the flying speed instruction circuit 21 passes through the flying/increment switching circuit 22 and is converted into an analog speed instruction signal V _A by the digital/analog conversion circuit 23. The speed instruction signal V _A is input to the subtraction circuit 24
is subtracted from the actual carriage speed signal V _P at
The difference signal is given to the carriage feed drive unit 26 via the power amplifier 25, and the carriage
Controlled to the speed indicated by V _A. In parallel with this,
In the printing position discrimination circuit 34, it is necessary to drive the hammer several steps before the carriage passes the printing position based on the speed instruction information V _D of the flying speed instruction circuit 21 and the hammer flying time information of the hammer flying time discrimination circuit 33. When the subtraction counter 30 reaches a predetermined count value, a printing signal is output. This printing signal is further finely adjusted by a printing command position fine adjustment circuit 35, and by issuing a printing command at a predetermined timing, flying printing is performed on the data in the first register 17. The printing command position fine adjustment circuit 35 uses the hammer drive carriage position obtained by the printing position discrimination circuit 34 and the step signal C.
This is a circuit that corrects for deviations from the position of the carriage and variations in the carriage traveling speed during flying operation. Space movement amount information is also input to the printing position determination circuit 34, but this is because when the space movement amount is variable, it is necessary to change the output timing of the printing signal accordingly.

On the other hand, if the next operation signal does not arrive during the flying printing operation, the flying speed determination circuit 20 determines that the printing mode is increment mode, and switches the flying/increment switching circuit 22 to the ink printing mode. That is, as a result, the ink speed instruction circuit 32
is connected to the digital-to-analog conversion circuit 23. Increment speed instruction circuit 32 is subtraction counter 3
0 is input, and speed instruction information of a speed pattern corresponding to the number of remaining steps of the carriage is output.In the increment mode, the carriage is controlled to decelerate according to a predetermined speed pattern. Then, when the carriage approaches the next stop position (printing position), the ink speed instruction circuit 32 instructs zero as the speed information. At the same time, the position signal switching circuit 31 is activated, and the position signal P is applied to the carriage feeding drive unit 26 through the subtraction circuit 24 and the power amplifier 25, and the carriage stops at the printing position. After the carriage stops, a printing command is issued after waiting for the completion of operations such as character selection, but the configuration necessary for this is omitted in FIG. Further, the flying/increment switching circuit 22 can be operated arbitrarily by an external switching signal, thereby allowing the device to operate in either flying or increment mode.

Next, the effects of the present invention will be explained in more detail using specific numerical examples.

Assume now that the relationship between the carriage traveling speed and the speed switching position when the carriage is controlled in the incremental mode is as shown in FIG. The corresponding carriage position signal (signal P in FIG. 2) is shown in FIG. 4A, and the speed switching timing pulse is shown in FIG. 4B. As shown in FIGS. 3 and 4, it is assumed that the speed signal is switched by a timing pulse generated at 5/8 of each step of the position signal. FIG. 4 illustrates the operation of five steps, and shows that there is a discrepancy between the actual operating point of each step and the subtraction counter 30 of FIG.

Here, the time per step and the hammering command position at the _V3 to _V7 levels shown in FIG. 3 are determined as shown in FIG. Other speeds are omitted because they are not directly related to the present invention. In FIG. 5, _V7 is the flying speed of the carriage used when only space is operated without printing, and _V3 to _V6 are the traveling speeds of the carriage used when performing flying printing. The hammering command position in Figure 5 indicates how many steps before the hammer is ready to start, assuming that the time from when the hammer starts to when it collides with the platen is 3.5ms. In the flying mode, the carriage is supposed to reach the corresponding travel speed by these steps. For example, the printing position determination circuit 34 in FIG.
is V ₄ carriage running speed, counter 3
A printing signal is output when the remaining step of 0 is "3". Note that these values are calculated assuming that 12 steps are required to perform a space operation for one character.

Based on the above data, FIG. 6 specifically classifies the time required for various operations associated with printing operations (type selection operations, etc.) into five levels. In Figure 6, "space" means that the incoming data is only a space operation and does not involve printing, and "A" means that the incoming data is the same character as the previously printed character, or the time required for type selection, etc. Those within 8 ms belong to this group, and "B" means that the required time is 8 ms.
~13ms, "C" is 13ms ~ 20ms, "D" is 20m
s~30ms. A shift operation accompanying a type selection operation in the case of a type wheel having a plurality of stages of type, such as a cylinder type or petal type, is also considered to belong to one of these types.

According to the conventional method, the required time is classified as shown in FIG. 6, and the carriage traveling speed corresponding to each incoming data is determined based on this classification. However, in the embodiment of the present invention shown in FIG. Even if the time discrimination circuit 16 determines that the incoming data belongs to group B, the traveling speed of the carriage before issuing the speed command and the first to third registers 1
One of the flying printing speeds V ₃ to V ₆ shown in FIG. 5 is selected depending on the relative relationship with the required time of the subsequent arrival data of 7, 18, and 19. Note that _V7 is assigned to space operations that do not involve printing.

Based on the data in FIGS. 5 and 6, the required time and number of steps required for each speed change of the flying control are determined as shown in FIG. 7. In addition, each value in Fig. 7 is calculated using the following formula when the carriage is brought to speed V _N from a stop: Required time: t = V _N /a Required number of steps: x = V _N ² /2a When changing from V _M to V _N , the time required: t=|V _M −V _N |/a The number of steps required: x=|V _M ² −V _N ² |/2a It is calculated using the following formula. Here, a represents the acceleration/deceleration of the carriage, and a=0.26 steps/ ^ms2 . Various operation examples will be explained below.

1 If both the 1st and 2nd registers are spaces: In this case, it is further determined whether the 3rd register contains data for the next operation instruction, and if there is data, it instructs the speed of V ₇ , and if there is no data. In the case of , it enters a 2-space increment operation. In other words, the vehicle is run at the speed of _V7 up to the 15th step of the remaining 24 steps corresponding to 2 spaces, then the speed command is changed from _V7 to _V6 , and then the remaining 7 steps are performed. V ₆ at the step →
V ₅ , V ₅ →V ₄ in 4 steps, V ₄ → in 2 steps
V ₃ , gradually decelerates from V ₃ to V ₂ in one step and stops. Here, the contents of the 1st to 3rd registers and the data two places ahead are determined.If the flying speed of _V7 is set, to stop the carriage, _V7 must be decelerated to _V6 . This is because more than 15 steps of points are required, that is, 16 steps.

2 When the first register is a space and the second register belongs to groups A and B: Regardless of the presence or absence of data in the third register
Indicate V ₆ . The operations for the required times A and B are started at the same time as the speed command for the space of the first register. In other words, the traveling speed of the space is
When V ₇ is set, the number of steps required to decelerate from V ₇ to V ₆ is 7.5 steps from Figure 7 A, so
It is necessary to give the _V6 speed command 12.5 steps before the hammering command position in Figure 5, which is 5 steps before the hammering command position. Here, 12.5 steps is more than 12 steps for one space, so the _V6 speed command is issued two spaces in advance.

On the other hand, when this command is issued, the time required to move 2 spaces is 3.89 + 0.70 x (24 - 7.5) = 15.44 ms, and as shown in Figure 6, the required time groups A and B are shorter than this. belong to

Then, if the carriage was stopped, V ₆
The time required to issue the speed command for two spaces is 5.49 + 0.7 x (24 - 3.9) = 19.56 ms, which also belongs to time groups A and B.

3 When the first register is a space and the second register belongs to group C: When there is no data in the third register, a 2-space increment operation is performed so that the carriage can be stopped within a 2-space operation. If data is available, the carriage travel speed before issuing the command is
Depending on whether it is V ₇ to _{V 3} , the time required to move 2 spaces is 20 m for group C.
In order to make it more than s, the traveling speed is V ₇
The speed command is V ₄ when the speed is V 4 , and V ₅ when the speed is V ₆ to stop. These calculations are performed using FIGS. 7 and 6. FIG. 8 shows the required time for each.

4 When the first register is a space and the second register belongs to group D: The operation in this case is the same as in 3 above, and the third
The respective required times when there is data in the register are as shown in FIG. If there is no data, the ink operation for 2 spaces is performed as in 2 and 3 above.

5 When the first register belongs to group A: Determine whether or not there is data in the second register, and if there is data, issue a _V6 speed command. FIG. 10 shows the time required in this case depending on the traveling speed of the carriage before the command is given. When there is no data in the second register, the operation for the data in the first register is an increment operation of one space. Note that if the data before the command is a space and an operation such as character selection has already been started, processing is performed in accordance with 2 above.

6 When the first register belongs to group B: When there is data in the second register, the speed command based on the carriage running speed before the command and the required time are as shown in FIG. When there is no data in the second register, an increment operation for one space is performed as in 5 above. Furthermore, when the data before the command is a space, processing is performed according to 2 above.

7 When the first register belongs to group C: If there is data in the second register, issue a speed command of _V3 . In this case, the required time depending on the carriage traveling speed before the command is as shown in FIG. If there is no data in the second register, the increment operation for one space is performed as in 5 and 6 above. In addition, if the data before the command is a space and an operation such as character selection has already started, please refer to step 3 above.
Processed by

8. When the first register belongs to group D: When the data in the first register belongs to group D, the required time is 30 ms. On the other hand, even if flying printing, which takes the longest time (stop → V ₃₎ , is performed, the time is 25.98 ms, which is less than 30 ms, and flying printing is impossible. Therefore, in this case, inking operation for one space is performed, and printing is performed after stopping.

As described above, according to the present invention, it is possible to obtain a more optimal and faster printing speed than the conventionally proposed methods, and the effect is great.
It should be noted that most of the configuration shown in FIG. 2 can be configured by, for example, a microprocessor, and in this case, the above-mentioned control can be easily realized by a combination of hardware and software.

[Brief explanation of drawings]

Fig. 1 is a diagram explaining the relationship between the carriage speed before an operation command and the time required for one carriage space, Fig. 2 is a block diagram showing an embodiment of the present invention, and Fig. 3 is a normal carriage increment control. Fig. 4 shows the carriage position signal and speed switching timing signal, and Fig. 5 shows the time required per step for each speed level and the hammer command position. 6 is a diagram showing a specific example of each required time group of command operation, FIG. 7 is a diagram showing a specific example of the required time and required number of steps for each speed change of flying control, and FIG. to 12th
The figure is a diagram for explaining an example of control according to the present invention. 11...Decoder, 12...Print selection pitch number and up/down shift judgment circuit, 13...Print current value storage device, 14...Function register, 15
... Function operation control circuit, 16 ... Required time determination circuit, 17, 18, 19 ... Register,
20...Flying speed discrimination circuit, 21...Flying speed instruction circuit, 22...Flying/increment switching circuit, 23...Digital/analog conversion circuit, 24...Subtraction circuit, 25...Power amplifier, 26...Carriage Feed drive unit, 27...Position signal generator, 28...Speed signal generation circuit, 29
. . . Step signal generation circuit, 30 . . . Subtraction counter, 31 . . . Position signal switching circuit, 32 .
Print command position fine adjustment circuit.

Claims (1)

[Claims] 1. In a serial printer that performs operations such as printing and spacing by continuously inputting operation command signals such as type codes and space codes and driving a carriage along printing lines on a recording medium, a means for determining the time required for a type selection operation, a spacing operation, etc. (hereinafter referred to as required operation time) in response to a given operation command signal; and a means for sequentially holding the operation command signal for each time before and after the end of the operation in response to the previous operation command signal.
means for determining the carriage drive speed for the operation period of the next operation command signal based on the carriage drive speed at that time and the required operation time information corresponding to the plurality of operation command signals held at that time. A serial printer. 2. A hammer command position corresponding to the carriage drive speed is determined, and the carriage drive speed is determined in response to the input operation command signal so that the change in the carriage drive speed can be completed at the determined position. The serial printer described in item 1.