JPH06115137A - Method of controlling thermal recorder - Google Patents

Abstract

PURPOSE:To make effective use of the capacity of a power source and to make a recording speed high by obtaining a one-step carriage interval corresponding to the number of time-division blocks and by feeding thermal recording paper by one step at this one-step carriage interval. CONSTITUTION:A control part 15 informs a strobe control part 23 of the number of time-division blocks at that time and also gives it instruction to start printing motions. According to the information and instruction, the strobe control part 23 reads out strobe signal data DD sequentially from a register file 21 at a prescribed time interval at the time point when a prescribed time passes after switchover of excitation of a step motor, while it makes a latch circuit 22 store the strobe signal data DD. Thereby strobe signals STB1 to STB16 corresponding to the strobe signal data DD are outputted sequentially to a thermal head device 2, and as the result, a picture corresponding to recording data DT for one line is recorded on thermal recording paper.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses a thermal head in which a large number of heating resistors are arranged at a predetermined interval in a size of an image recording width as a recording head, and an image is recorded on a thermosensitive recording paper line by line. The present invention relates to a control method of a recording device.

[0002]

2. Description of the Related Art Generally, in a thermal recording apparatus for recording an image on a thermal recording paper line by line, a thermal head having a large number of heating resistors arranged at a predetermined interval in the image recording width is used as a recording head. The heating resistor is divided into a plurality of blocks, and the recording operation is performed in a time-divisional manner on a block-by-block basis, whereby the power supply capacity required for recording can be reduced. In this case, the power supply capacity required for image recording is the capacity capable of simultaneously recording the number of black pixels included in the divided blocks.

On the other hand, the average black character ratio in a line unit of a normal office document is about 10%, and therefore the above-mentioned power supply capacity is required to print black all pixels of a block. It does not occur and the power capacity is not used efficiently.

Therefore, in order to eliminate such a situation,
A "variable speed printing method by counting the black character ratio (black pixel)" has been proposed.

In this method, when the number of data to be black-printed in the adjacent time division blocks is equal to or less than a predetermined value defined by the power supply capacity, they are driven to generate heat at the same time, so that the power supply capacity can be effectively utilized and high speed operation can be achieved. It is possible to reduce the power supply capacity while printing or maintaining the printing speed of a document having a low surplus rate at a certain level or more.

[0006]

However, such a recording method has the following disadvantages.
It is not applied to image recording means of a facsimile machine.

(A) Since the surplus rate is low and the number of time divisions is small,
When a line with a high black ratio appears after a line that is printed at high speed, the driving cycle of the stepping motor that conveys the recording paper becomes longer, causing hunting in the rotor of the stepping motor, resulting in stepping. The motor may be out of step, the recording paper may be unevenly fed, or noise may be generated. For example, in FIG. 8A, the motor drive cycle suddenly becomes longer, causing hunting in the motor rotor, which causes significant rotation unevenness. In the figure, the thick line shows the observed value of the rotational displacement of the motor rotor, the thin line shows the ideal value of the rotational displacement of the motor rotor, and the broken line shows the hunting characteristics of the motor rotor when stopped. Further, ∇ indicates the motor drive timing.

(A) Noise is remarkable because the driving cycle of the stepping motor changes frequently. For example, in FIG.
In (b), a case where the driving cycle frequently changes is shown, and in particular, an arrow indicates a portion where the speed changes sharply at the start and end of driving at the maximum speed. in this way,
In a portion where the speed change is abrupt, the reaction of the acceleration torque causes vibrations in the support and the like, which causes noise. Furthermore, since the noise level and the noise frequency change frequently, the sound quality of the noise becomes extremely annoying.

(C) Since the driving cycle of the stepping motor changes relatively arbitrarily, when the driving cycle has a specific relationship with the natural vibration cycle of the motor drive system, a remarkable noise is generated or recording paper is used. Unevenness occurs. For example, in FIG. 8 (c), due to the interaction between the motor drive cycle and the drive-type natural vibration cycle, an extremely large unevenness in feed is generated.
It occurs in a cycle four times as long as the driving cycle. Such a situation is difficult to avoid when the drive cycle changes arbitrarily.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for controlling a thermal recording apparatus that can effectively utilize the power supply capacity and can improve the recording speed.

[0011]

According to the present invention, a thermal head having a large number of heating resistors arranged at predetermined intervals in the image recording width is used as a recording head, and an image is recorded line by line on a thermosensitive recording paper. In the method of controlling the thermal recording device, the thermal head is divided into a predetermined number of small blocks for each heating resistor, black pixels contained in the recording data are counted for each small block, and based on the count value, Within the range in which the number of black pixels recorded at the same time does not exceed a predetermined value, the plurality of small blocks are integrated into a plurality of time division blocks, and the image recording operation is executed in time division block units, while the predetermined Based on the relationship between the number of divided blocks and the one-step conveyance interval of the thermal recording paper, the one-step conveyance interval corresponding to the number of time-division blocks is obtained, and the one-step conveyance interval is obtained. In which the heat-sensitive recording paper was to convey one step by a conveying interval.

In a method of controlling a thermal recording apparatus, a thermal head having a large number of heating resistors arranged at predetermined intervals in the image recording width is used as a recording head to record an image on a thermal recording paper line by line. , The thermal head is divided into a predetermined number of small blocks for each heating resistor, the black pixels contained in the recording data are counted for each small block,
Based on the count value, the plurality of small blocks are integrated into a plurality of time division blocks, and the image recording operation is executed in units of the time division block, within a range in which the number of black pixels recorded at the same time does not exceed a predetermined value. On the other hand, based on the number of time-division blocks, the one-step conveyance interval of the thermal recording paper is set, the one-step conveyance interval is increased from the immediately preceding recording line, and the one-step conveyance interval of the immediately preceding recording line is set. When the shortest time is set, a predetermined pause time is set before recording the line.

In a method of controlling a thermal recording apparatus, a thermal head having a large number of heating resistors arranged at predetermined intervals in the image recording width is used as a recording head to record an image on a thermal recording paper line by line. , The thermal head is divided into a predetermined number of small blocks for each heating resistor, the black pixels contained in the recording data are counted for each small block,
Based on the count value, the plurality of small blocks are integrated into a plurality of time division blocks, and the image recording operation is executed in units of the time division block, within a range in which the number of black pixels recorded at the same time does not exceed a predetermined value. On the other hand, based on the number of time-division blocks, when the 1-step conveyance interval of the thermal recording paper is set and the 1-step conveyance interval is shortened, the short 1-step conveyance interval continues for a predetermined number of lines, The one-step transport interval is changed.

[0014]

Therefore, since the one-step conveyance interval is limited, the motor drive cycle (one-step conveyance interval)
Can be prevented from having a specific relationship with the natural vibration period of the motor drive system. Further, when the drive cycle is lengthened after the motor drive cycle becomes the shortest time, a constant rest period is set, so that hunting of the motor rotor is suppressed, and noise and uneven feeding of the recording paper can be eliminated. Also,
When the one-step conveyance interval becomes short, the one-step conveyance interval is shortened only when the number of lines continues for a predetermined number, so that the drive cycle is prevented from changing frequently and noise is suppressed. be able to.

[0015]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

FIG. 1 shows the construction of a recording system of a thermal recording apparatus according to an embodiment of the present invention.

In FIG. 1, the tip of the roll-shaped thermal recording paper 1 is inserted between the thermal head device 2 and the platen roller 3. The platen roller 3 is in contact with the thermal head device 2 at the position of the heating resistor array 4 of the thermal head device 2, and is rotationally driven by a step motor (not shown).

FIG. 2 shows an example of the thermal head device 2.

In the figure, the shift register 10 is 1
The recording data DT for lines is accumulated, and the recording data DT is serially transferred to the shift register 10 in synchronization with the clock CP. This shift register 1
The recording data DT for one line accumulated in 0 is output to the latch circuit 11 in parallel. Here, the recording data DT for one line is 2048 bits.

The latch circuit 11 stores the recording data DT for one line applied to the heating resistor array 4, and the recording data output from the shift register 10 at the timing when the latch signal LT is applied. Import DT. The recording data DT output from the latch circuit 11 is output to the gate circuit 12 in parallel.

The gate circuit 12 receives the recording data DT output from the latch circuit 11 at one input end (non-inversion) thereof.
It consists of 2048 AND circuits which are divided into 16 drive blocks (small blocks), each of which is added to, and the other input end (inversion) of this AND circuit corresponds to each drive block. The strobe signals STB1 to STB16 (non-logic) are added. The output signal of the gate circuit 12 is applied to the switch circuit 13 in parallel.

The switch circuit 13 is composed of 2048 switch elements which are turned on by the ON output signal from the gate circuit 12, and each switch element which is turned on is
A drive current is supplied to the corresponding heating resistors of the heating resistor array 4.

Therefore, the strobe signals STB1 to SB1
During the period when TB16 is being output, the gate circuit 12 at the position where the data "1" representing the black print is stored in the latch circuit 11 is turned on, and the switch circuit 13 at that position is turned on. A drive current is supplied to the heating resistors of the heating resistor array 4 at the black printing position, and the thermosensitive recording paper 1 at the black printing position is heated to develop black color.

FIG. 3 shows an example of the control system of the thermal recording apparatus shown in FIG.

In the figure, a control section 15 controls the operation of the thermal recording apparatus, and outputs a clock CP and a latch signal LT to the thermal head apparatus 2 in synchronization with the output of the recording data DT. To do. Mechanical part 16
Is a mechanical portion of this heat-sensitive recording apparatus, such as a step motor that drives the platen roller 3 to rotate. The external interface circuit 17 connects the thermal recording device to an external device that uses the thermal recording device as a recording device,
It is for exchanging various signals such as recording data DT and control signals.

The parallel / serial converter 18 is for converting the recording data DT transferred in parallel through the internal bus 19 into serial data, and the output data thereof is the recording data DT as the thermal head device 2.
The counter 20 is added to the counter 20.

The counter 20 of the recording data DT
The number of data “1” is counted, and the count value is output to the control unit 15 via the internal bus 19. Further, the counter 20 clears the count value of the counter 20 to 0 each time the recording data DT of each drive block is started to be transferred.

The register file 21 stores 16-bit strobe signal data DD representing a combination of strobe signals STB1 to STB16 for each time division block (described later), and can store 32 pieces of strobe signal data DD. It has a capacity. The output data of the register file 21 is added to the latch circuit 22.

The latch circuit 22 has a register file 21.
It stores the strobe signal data DD output from the thermal head device 2 in the bit order as strobe signals STB1 to STB16.

The strobe signal control unit 23 includes a control unit 15
The strobe signal DD output from the control unit 15 is stored in the storage area of the register file 21 at the sequential position (address) designated by the control unit 15, and the strobe signal data DD stored in the register file 21 is stored in the storage area of the register file 21.
When data of one line is recorded, the data is sequentially read at predetermined time intervals and stored in the latch circuit 22.

The recording operation for one line of this thermal recording apparatus will be described below.

For example, when the control unit 15 has finished transferring the recording data DT of the nth line to the thermal head device 2, the recording data DT of the nth line is stored in the shift register 10 of the thermal head device 2. Have been accumulated. Further, in this state, the recording data DT of the nth line
Strobe signal data DD representing a combination of the strobe signals STB1 to STB16 corresponding to each time division block when printing is printed by the control unit 15 and stored in the register file 21.

First, the latch signal LT is output from the control unit 21 (see FIG. 4C), and the recording data DT of the nth line accumulated in the shift register 10 of the thermal head device 2 is changed to the thermal head device. 2 latch circuit 11
(See FIG. 4D).

Next, the control unit 21 switches the excitation of the step motor (see FIG. 4 (e)), and the step motor is driven by one step, whereby the conveyance of the thermal recording paper 1 for one step is started. It

At the same time, the control unit 15 notifies the strobe control unit 2 of the number of time-division blocks at that time and instructs the strobe control unit 2 to start the printing operation. As a result, the strobe control unit 23 sequentially reads the strobe signal data DD from the register file 21 at a predetermined time interval when a predetermined time has elapsed from the switching of the excitation of the step motor, and the strobe signal data is stored in the latch circuit 22. Remember DD.

As a result, the strobe signals STB1 to STB16 (FIG. 4) corresponding to the strobe signal data DD are generated.
(F) to (i)) are sequentially output and output to the thermal head device 2, and as a result, an image corresponding to the recording data DT for one line is recorded on the thermal recording paper 1.

Further, the control unit 21 includes the strobe control unit 2
3 is notified to start the printing operation, the next (n +
1) The record data DT of the line is transferred to the parallel / serial converter 18 as parallel data of a predetermined number of bits, and according to the bit timing of the serial record data DT output from the parallel / serial converter 18. , Clock CP is output. This allows
The print data DT of the (n + 1) th line is transferred / stored in the shift register 10 of the thermal head device 2.

Further, the control unit 21 has 128 bits (16
Counter 2 each time the recording data DT of (byte) is output.
When the count value of 0 is input and the input is completed, the counter 20 is cleared to 0. As a result, the control unit 2
1 relates to the recording data DT of the (n + 1) th line, and 1
The number of black prints from the th drive block to the 16 th drive block is detected.

Then, based on the detected black print number of each drive block, the drive cycle of the step motor in the recording cycle of the (n + 1) th line (hereinafter referred to as the line cycle) and the thermal head device 2 While determining the time-division drive mode, the strobe signal data DD stored in the register file 21 is formed and sequentially transferred to the register file 21.

In this way, when the image recording operation of the nth line is being executed, the control unit 15 controls the next (n +
1) Preparations are made for the image recording operation of the line.

FIG. 5 and FIGS. 6A and 6B show an example of processing of one line recording cycle executed by the controller 15.

First, the counter i is initialized to 0 (process 101), and the print data DT (128 bits) of the i-th drive block of the print line at that time is transferred to the thermal head device 2 (process 102). The count value of the counter 20 at that time is input, and the count value is substituted into the variable n (i) as the number of black characters (process 103).

Next, the value of the counter i is incremented by 1 (process 104), and it is checked whether the value of the counter i is equal to 16 (decision 105). When the result of determination 105 is NO, the process returns to step 102, and the transfer operation of the print data DT of the next drive block is executed.

When the result of determination 105 is YES, it means that the transfer of the recording data DT for one line has been completed. At this time, the variable n (i) (i = 0 to
In 15), the number of black characters of the i-th drive block is stored.

At this time, the value of the counter i is initialized to 0 and the value of the counter j is initialized to 1 (process 106).
The following operation sets the strobe signal data DD and the line cycle at the time of recording on that line.

First, the value of the counter i is substituted into the variable k (process 107). Next, it is checked whether or not the value of the counter i is 16 (decision 108), and when the result of the decision 108 is NO, it means that the process for the drive block of that line has not been completed, so the variable n
It is checked whether the added value of (i-1) and the variable n (i) exceeds 128 (decision 109).

When the result of judgment 109 is NO,
Since one time division block has not been extracted yet, the value of the variable n (i-1) is added to the value of the variable n (i) to update the value of the variable n (i) (process 110), and the counter i
The value of is incremented by 1 (process 111), and the process returns to the determination 108.

When the result of the judgment 109 is YES, the extraction of one time division block has been completed, so the jth strobe signal data DD (j) (= stb).
(J)) is calculated (process 112). By this process,
As the value of the strobe signal data DD (j), a value in which data "1" is set at the bit position of the time division block extracted at that time is stored. Then, the calculated strobe signal data DD (j) is stored as the j-th element of the register file 21 (process 113). Also, judgment 1
When the result of 08 is YES, the process proceeds to process 112.

Next, the value of the counter i is incremented by 1 (process 114), and it is checked whether the value of the counter i is 16 or more (decision 115). If the result of determination 115 is NO, it means that the processing has not been completed for all the drive blocks in this line, so the value of the counter j is incremented by 1 (step 116), the process returns to step 107, and the next drive is performed. Execute the process for the block.

When the result of the determination 115 is YES, the process relating to the strobe signal data DD is completed, so the line cycle is set.

First, based on the following Table 1, the value of the line period L corresponding to the time-division block number j is obtained (process 11).
7). However, in this case, the recording time of one time division block is 0.95 (msec).

[0052]

[Table 1]

Here, it is checked whether or not the line period L'of the previous line is equal to this line period L (decision 11).
8). When the result of determination 118 is YES, the process waits until the recording cycle of the previous line ends (NO in determination 119).
loop). When the recording cycle of the previous line ends and the result of determination 119 becomes YES, the motor excitation switching process is executed (process 120), the strobe output process of the strobe control unit 23 is started (process 121), and one line worth is processed. Ends the operation.

When the result of judgment 118 is NO, it is checked whether or not the line cycle L'is larger than the line cycle L (judgment 122). If the result of determination 122 is YES, it means that the line cycle is changing in the direction of shortening, and the value of the counter k is incremented by 1 (process 123), and the value of the counter k is larger than the predetermined value NC. Check whether (decision 124).

When the result of judgment 124 is NO,
In order to avoid frequent line cycle changes, this process is terminated without changing the line cycle. Also, judgment 1
When the result of 24 is YES, the line cycle is changed because there is no influence of the change of the line cycle. That is, the value of the counter k is cleared to 0 (process 125),
It waits until the recording cycle of the previous line ends (NO loop of decision 126). Judgment when the recording cycle of the previous line ends 12
If the result of 6 is YES, the line period at the time of recording of the line is changed to the line period L obtained at that time (process 127), and the process proceeds to process 120 to switch the excitation of the motor and the strobe signal. Execute output operation.

When the result of judgment 122 is NO, it is checked whether or not the line period L'of the preceding line is the minimum time (decision 128). The result of judgment 128 is YE
At S, if the line cycle is suddenly extended in the next line, the motor rotor of the step motor may cause hunting as described above. Therefore, the process waits until a predetermined time that can suppress hunting elapses (process 129). ), The line period at the time of recording of the line is changed to the line period L obtained at that time (process 130), and the process proceeds to process 120 to switch the excitation of the motor and output the strobe signal.

In this way, in this embodiment, when the number of time division blocks increases and the line period becomes longer than that of the preceding line, the line period is changed after a certain amount of time has passed, so the motor rotor It is possible to suppress the occurrence of hunting in the
It is possible to suppress noise generation and uneven feeding of the thermal recording paper.

When the number of time-division blocks decreases and the line period becomes shorter than that of the preceding line, the line period is shortened only when a predetermined number of such lines continue. It is possible to suppress the situation in which the cycle is frequently changed and suppress the noise generation of the step motor.

In this case, the line period corresponding to the number of time division blocks is set so that the line period of 5 to 10 (msec), which has a specific relationship with the natural vibration period of the motor drive system, is not set. Since Table 1 is configured, it is possible to avoid a situation in which a significant noise or a remarkable uneven feeding of the recording paper occurs.

By the way, in the above-mentioned embodiment, the pause time for avoiding the influence of hunting is set only when the line period becomes longer from the state of the shortest time, but when the line period becomes longer, It is also possible to always set a predetermined rest time. An example of rotor displacement in this case is shown in FIG.

The present invention can be applied in the same manner to a thermal recording apparatus having a structure other than that shown in the above-mentioned embodiment. Further, the number of heating resistors (2048), the number of drive blocks (16), the number of simultaneous drives (128), and the number of time division blocks (16) of the thermal head device are not limited to these.

[0062]

As described above, according to the present invention,
Since the one-step transport interval is limited, it is possible to prevent the drive cycle of the motor (one-step transport interval; line cycle) from having a specific relationship with the natural vibration cycle of the motor drive system. Further, when the drive cycle of the motor is set to the shortest time and then the drive cycle is lengthened, a constant rest period is set, so that hunting of the motor rotor is suppressed,
Noise and uneven feeding of recording paper can be eliminated. Further, when the one-step conveyance interval becomes short, the one-step conveyance interval is shortened only when the number of lines continues for a predetermined number of times, so that it is possible to prevent the drive cycle from changing frequently and to reduce noise. The effect that it can be suppressed is obtained.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a configuration example of a transport system of a thermal recording apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram showing an example of a thermal head device.

FIG. 3 is a block diagram showing an example of a control system of the thermal recording apparatus of FIG.

FIG. 4 is an operation waveform diagram for explaining the operation of one line of the apparatus of FIG.

5 is a flowchart showing a part of a processing example of an operation for one line of a control unit of the apparatus of FIG.

6 is a flowchart showing another part of the processing example of the operation for one line of the control unit of the apparatus of FIG.

7 is a graph showing another example of the operation of the apparatus shown in FIG.

FIG. 8 is a graph for explaining the inconvenience of the conventional device.

Claims (3)

[Claims] 1. A method of controlling a thermal recording apparatus, wherein a thermal head having a large number of heating resistors arranged at predetermined intervals in an image recording width is used as a recording head, and an image is recorded line by line on a thermal recording paper. , The thermal head is divided into a predetermined number of small blocks for each heating resistor, the black pixels included in the recording data are counted for each small block, and the number of black pixels simultaneously recorded is determined based on the counted value. In the range of not exceeding a predetermined value, while integrating the above plurality of small blocks into a plurality of time division blocks,
While the image recording operation is performed for each time-division block, the one-step conveyance interval corresponding to the number of time-division blocks is determined based on the relationship between the predetermined number of division blocks and the one-step conveyance interval of the thermal recording paper. A method of controlling a heat-sensitive recording apparatus, characterized in that the heat-sensitive recording paper is fed one step at the one-step feeding interval. 2. A method of controlling a thermal recording apparatus, wherein a thermal head having a large number of heating resistors arranged at predetermined intervals in the image recording width is used as a recording head, and an image is recorded line by line on a thermal recording paper. , The thermal head is divided into a predetermined number of small blocks for each heating resistor, the black pixels included in the recording data are counted for each small block, and the number of black pixels simultaneously recorded is determined based on the counted value. In the range of not exceeding a predetermined value, while integrating the above plurality of small blocks into a plurality of time division blocks,
While the image recording operation is performed for each time-division block, the one-step conveyance interval of the thermal recording paper is set based on the number of time-division blocks, and the one-step conveyance interval from the immediately preceding recording line becomes long, and A method for controlling a thermal recording apparatus, wherein when a one-step conveyance interval of a recording line immediately before that is set to the shortest time, a predetermined pause time is set before recording of the line. 3. A method of controlling a thermal recording apparatus, wherein a thermal head having a large number of heating resistors arranged at predetermined intervals in an image recording width is used as a recording head, and an image is recorded line by line on a thermal recording paper. , The thermal head is divided into a predetermined number of small blocks for each heating resistor, the black pixels included in the recording data are counted for each small block, and the number of black pixels simultaneously recorded is determined based on the counted value. In the range of not exceeding a predetermined value, while integrating the above plurality of small blocks into a plurality of time division blocks,
While the image recording operation is performed for each time-division block, the one-step conveyance interval of the thermal recording paper is set based on the number of time-division blocks, and when the one-step conveyance interval is shortened, the short one-step conveyance interval is set. The method for controlling a thermal recording apparatus is characterized in that the one-step conveyance interval is changed on the condition that a predetermined number of lines continue.