JP2007090661A - RECORDING DEVICE, RECORDING DEVICE CONTROL METHOD, AND PROGRAM - Google Patents

Abstract

In a recording apparatus for recording an image on a recording medium by a recording head provided with a plurality of heating elements, the recording head has a function of recording an image by dividing the heating elements of the recording head into a plurality of parts, and the throughput is improved. .
A thermal printer for recording an image on a heat-sensitive roll paper by a recording head unit having a plurality of heating elements, wherein a CPU is based on recording data input from the outside. The number of heating elements to be energized is obtained, the effective value of the current flowing through the recording head unit 26 during the recording operation is obtained based on the number of heating elements to be energized, and the obtained current value is determined in advance. Based on the threshold value, the division state of the recording head unit 26 is set, and according to the division state of the recording head unit 26, the conveyance speed of the thermal roll paper by the conveyance motor 28 is set, and the recording head unit 26 Based on the divided state, the heating element is energized to record an image on the thermal roll paper.
[Selection] Figure 4

Description

  The present invention relates to a recording apparatus that records an image on a recording medium using a recording head that includes a plurality of heating elements, a control method for the recording apparatus, and a program.

2. Description of the Related Art Conventionally, in a recording apparatus that records heat on a recording medium by applying thermal energy to a recording medium by a heating element disposed in a recording head, the load on a power source increases when the number of heating elements to be energized is large. . For this problem, for example, in a recording apparatus using a battery as a power source, when the temperature of the battery rises, a method of dividing the heat generating elements of the recording head into a plurality of groups and energizing each group has been proposed ( For example, see Patent Document 1).
JP 200421044 A

  However, when recording is performed with the heating elements of the recording head divided into a plurality of groups, the timing of energization is shifted between the plurality of groups, and therefore it is undeniable that the recorded image may be disturbed. In order to prevent this, when recording by dividing the heating element, it is necessary to keep the recording medium transporting speed low, and there is a problem that throughput may be lowered.

  The present invention has been made in view of the above-described circumstances. In a recording apparatus that records an image on a recording medium using a recording head including a plurality of heating elements, the image is obtained by dividing the heating element of the recording head into a plurality of parts. The purpose is to provide a recording function and to improve the throughput.

In order to solve the above problems, the present invention provides a recording head having a plurality of heating elements that apply thermal energy to a recording medium, and a current value that flows through the recording head during a recording operation based on recording data input from the outside. Current value calculating means for calculating the recording head, a recording control means for setting a division state of the recording head based on a current value obtained by the current value calculating means, and a predetermined threshold value, and the recording head A conveyance speed control means for setting a conveyance speed of the recording medium by the conveyance motor according to the division state, and a conveyance means for conveying the recording medium based on the conveyance speed set by the conveyance speed control means, Recording means for energizing the heating element and recording an image on the recording medium based on the division state of the recording head set by the recording control means. The current value calculating means is characterized in determining the effective value of the current flowing through the recording head based on the number of heating elements to be energized.
According to this configuration, in a recording apparatus having a recording head including a plurality of heating elements that apply thermal energy to the recording medium, an effective value of the current flowing through the recording head is obtained based on the number of heating elements that are energized. Based on the effective value of the current and a predetermined threshold value, the division state of the recording head is set. Further, according to the division state of the recording head, the conveyance speed of the recording medium by the conveyance motor is set. The recording medium is conveyed based on the conveyance speed, and the heating element is energized to record an image on the recording medium based on the division state of the recording head. Can record. In particular, since the division state of the recording head is set based on an effective value that accurately reflects the current flowing through the recording head, problems such as no division when the recording head needs to be divided do not occur. Therefore, an appropriate threshold value can be set without applying an excessive load to the power source without taking measures such as providing a margin for the threshold value. As a result, it is possible to minimize the division of the recording head that causes a decrease in throughput and improve the throughput.

In the present invention, the current value calculation means may obtain a mean square value for the number of heating elements that have been energized in a plurality of past energization cycles, and obtain an effective current value based on the mean square value. . In this case, it is possible to obtain an effective value that reflects the current that actually flows through the recording head by performing a light load calculation process by the current value calculation means.
Furthermore, the transport speed control means may set the transport speed to a predetermined upper limit speed or less when the recording control means is set to divide the recording head into a plurality of parts. In this case, since the conveyance speed is suppressed when the recording head is divided, it is possible to prevent image disturbance caused by the division of the recording head.

Furthermore, in the present invention, a predicted value calculation means for obtaining an effective value of the current flowing through the recording head based on the number of heating elements that are energized in a predetermined number of energization periods including a next energization period and a past energization period. It is good also as composition provided further. According to this configuration, since the divided state of the recording head is set based on the effective value of the current that takes into account the current flowing in the next energization cycle, the load on the power supply device can be more reliably suppressed, and Throughput can be improved by minimizing the division of the recording head.
The transport speed control means is a speed at which the currently set transport speed exceeds the predetermined upper limit speed, and the effective value of the current obtained by the predicted value calculation means exceeds a predetermined allowable value. In this case, the conveyance speed may be set to a lower speed. In this case, in preparation for the case where the recording head is divided in the subsequent energization cycle, by reducing the conveyance speed, a sudden change in the conveyance speed when the recording head is divided can be avoided and stable. Recording operation can be performed.
The recording control means may maintain the recording head in a divided state from when the recording head is set to be divided into a plurality of blocks until energization of a predetermined number of energization cycles is performed. Good. In this case, it is possible to prevent a situation in which the recording head division state is frequently changed. As a result, it is possible to prevent image disturbance due to the change in the division state of the recording head and the change in the conveyance speed associated therewith, and stable and high-quality recording can be performed.

The present invention relates to a control method for a recording apparatus including a recording head including a plurality of heat generating elements for applying thermal energy to the recording medium, and a conveying unit that conveys the recording medium at a predetermined speed, which is input from the outside. Based on the recorded data, the number of heating elements to be energized among the plurality of heating elements is determined, and the effective current flowing through the recording head during the recording operation is determined based on the number of heating elements to be energized. A value is obtained, and a division state of the recording head is set based on the obtained current value and a predetermined threshold value, and according to the division state of the recording head, the recording medium of the recording medium by the conveyance motor is set. The conveyance speed is set, and the heating element is energized to record an image on the recording medium based on the division state of the recording head.
According to this method, when recording an image on a recording medium by a recording apparatus having a recording head having a plurality of heating elements that apply thermal energy to the recording medium, an effective value that accurately reflects the current flowing through the recording head. Since the recording head division state is set based on the above, problems such as the recording head not being divided when division is required do not occur. For this reason, an excessive load is not applied to the power supply without taking measures such as providing a margin for the threshold. As a result, it is possible to minimize the division of the recording head that causes a decrease in throughput and improve the throughput.

The present invention is a program executed by a computer that controls a recording apparatus that includes a recording head including a plurality of heating elements that apply thermal energy to the recording medium, and a conveying unit that conveys the recording medium at a predetermined speed. Then, the computer determines the number of heating elements to be energized among the plurality of heating elements based on recording data input from the outside, and records based on the number of heating elements to be energized. Current value calculating means for obtaining an effective value of the current flowing through the recording head during operation, and a recording control means for setting a division state of the recording head based on the obtained current value and a predetermined threshold value A conveyance speed control means for setting a conveyance speed of the recording medium by the conveyance motor in accordance with a division state of the recording head, and a pre-set value set by the recording control means Based on the divided state of the recording head, by supplying an electric current to the heating element is characterized by operating as a recording means for recording an image on said recording medium.
According to this program, an effective value that accurately reflects the current flowing through the recording head when an image is recorded on the recording medium by a recording apparatus having a recording head that includes a plurality of heating elements that apply thermal energy to the recording medium. Since the recording head division state is set based on the above, problems such as the recording head not being divided when division is required do not occur. For this reason, an excessive load is not applied to the power supply without taking measures such as providing a margin for the threshold. As a result, it is possible to minimize the division of the recording head that causes a decrease in throughput and improve the throughput.

  According to the present invention, in a recording apparatus having a recording head including a plurality of heating elements that apply thermal energy to a recording medium, an effective value of a current flowing through the recording head is obtained based on recording data input from the outside, Since the print head division state is set based on the effective value, an excessive load is not applied to the power source, and the print head division can be minimized to improve the throughput.

Next, preferred embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a front view showing a configuration of a thermal printer 1 as a recording apparatus according to an embodiment to which the present invention is applied. 2 is a top view of the thermal printer 1, and FIG. 3 is a side view of the thermal printer 1. FIG.
The thermal printer 1 shown in FIGS. 1 to 3 accommodates a recording mechanism (not shown) and a thermal roll paper as a recording medium in an outer case 11, and the thermal roll paper is accommodated by the recording mechanism (not shown). It is conveyed while being pulled out, and heat energy is applied to the heat-sensitive roll paper to cause color development, and an image including characters is recorded.
The recording medium used in the thermal printer 1 is not limited to heat-sensitive roll paper, and is not particularly limited as long as it is a sheet having a function of developing color by heating. In addition, the number of colors that can be developed by heating is also arbitrary, and a color that develops into a single color or multiple colors can be used. In the present embodiment, as an example, a case will be described in which heat-sensitive roll paper in which heat-sensitive paper that is colored black by heating is rolled up is used.

  As shown in FIG. 1, a power switch 12 for turning on / off the power of the thermal printer 1 is disposed on the front surface of the exterior case 1 of the thermal printer 1. As shown in FIGS. 2 and 3, the thermal printer 1 is provided with a paper discharge port 13 on the upper surface of the thermal printer 1 for discharging the thermal roll paper on which an image is recorded. A lid opening button 14 is provided. The lid opening button 14 is a button for opening the upper part of the outer case 11 configured to be openable and closable. When the lid opening button 14 is pressed, the upper part of the outer case 11 is opened so that the heat-sensitive roll paper can be replenished or replaced. Next to the lid opening button 14, a control panel 15 having various indicators indicating the operating state of the thermal printer 1, switches for operating the thermal printer 1, and the like is disposed.

FIG. 4 is a block diagram illustrating a functional configuration of the control circuit unit 20 that controls each unit of the thermal printer 1. The control circuit unit 20 can be configured to include various sensors, a gate array, and the like in addition to the units illustrated in FIG. 4. For convenience of understanding, only the main units are illustrated and described here. I do.
As shown in FIG. 4, the control circuit unit 20 includes a CPU (Central Processing Unit) 21 that controls each unit of the control circuit unit 20, a logic circuit setting buffer 22 that holds various setting data input from the CPU 21, and an input from the CPU 21. A recording buffer 23 that holds the recording data to be recorded, setting data held in the logic circuit setting buffer 22, and a logic circuit 24 that drives the recording head unit 26 based on the recording data held in the recording buffer 23 (recording means) ), A power source for driving the recording head unit 26 to the logic circuit 24, and an energization control circuit 25 that outputs a pulse indicating energization timing, and a recording head unit 26 (recording head) including a plurality of heating elements. ), Pulse input indicating the power supply and operation timing to the conveyance motor 28, and CP A motor driver 27 for driving the conveying motor 28 under the control of the 21 (conveying means), and comprises the respective portions of the conveying motor 28 (conveying means) for conveying the thermal roll paper housed in the external case 11 (Figure 1).

  The control circuit unit 20 shown in FIG. 4 receives recording data for recording an image from a host computer outside the thermal printer 1. The recording data is input to the CPU 21, and the CPU 21 generates recording data for each dot line based on the input recording data and outputs the recording data to the recording buffer 23. In addition, the CPU 21 generates various setting data for driving the recording head unit 26 and outputs it to the recording buffer 23. Then, the logic circuit 24 is energized in accordance with the timing of the pulse input from the energization control circuit 25 based on the various setting data held in the logic circuit setting buffer 22 and the recording data held in the recording buffer 23. By supplying the current supplied from the control circuit 25 to the recording head unit 26, the heating elements of the recording head unit 26 are caused to generate heat. Thermal energy is applied from the heating element to the surface of the thermal roll paper, and the thermal roll paper is colored black to record an image.

Here, the logic circuit 24 has a function of dividing the heat generating element included in the recording head unit 26 into a plurality of blocks, energizing the heat generating element at different timings for each block, and recording an image. Hereinafter, an operation of dividing the recording head unit 26 will be described.
In the recording head unit 26, a plurality of heating elements are arranged in a straight line, and when an image is recorded, a heating element corresponding to the recording data among the plurality of heating elements is energized. A single straight line formed by the heating element, that is, one dot line is recorded by one energization. When there are many heating elements to be energized, the current flowing through the recording head unit 26 is large, and an excessive load may be applied to the power supply device (not shown) of the thermal printer 1. Therefore, in the thermal printer 1, the CPU 21 calculates the effective value of the current flowing through the recording head unit 26 based on the coefficient of the number of energized heating elements. The effective value of this current is calculated, for example, by obtaining a root mean square value for the number of heating elements that are energized when printing a plurality of dot lines. More specifically, the mean square value is calculated by calculating the sum of squares of the number of heating elements energized during recording of a plurality of dot lines for each dot line, and further calculating the square root after dividing by the number of dot lines. Desired.
When the effective value of the current flowing through the recording head unit 26 exceeds a predetermined threshold value, the CPU 21 generates setting data for dividing the recording head unit 26 into a plurality of blocks, and generates a logic circuit. Output to the setting buffer 22. This setting data is read by the logic circuit 24, and the logic circuit 24 energizes the heating elements at different timings for each block.

  To explain with a specific example, when recording an image by dividing the heat generating elements into two in the recording head section 26 in which 512 heat generating elements are arranged in a line in the recording head section 26, 512 heat generating elements Are divided into two blocks of 256 from the center. Then, the logic circuit 24 energizes one of these two blocks and energizes the other block after the energization is completed. In this case, the current flowing through the recording head unit 26 can be suppressed to the extent that 256 heat generating elements generate heat.

Further, the CPU 21 sets the conveyance speed of the thermal roll paper by the conveyance motor 28 according to the division state of the recording head unit 26, and drives the conveyance motor 28 by the motor driver 27 according to the set conveyance speed. .
When the recording head unit 26 is divided, each block is energized at different timings, so that one dot line is recorded in a plurality of times. Since the thermal roll paper continues to be conveyed even while the recording head unit 26 is energized, if the thermal roll paper is conveyed at a high speed, the color development position shift of the thermal roll paper is increased due to the difference in the energization timing of each block. May cause disturbance. For this reason, the CPU 21 suppresses the conveyance speed of the thermal roll paper to a predetermined upper limit speed or less when the heating element is divided into a plurality of blocks in a recording control process (FIG. 6) described later.

FIG. 5 is a timing chart showing a change in energization state when the recording head unit 26 is divided. In FIG. 5, (a) shows the energization start pulse output from the energization control circuit 25, (b) shows the energization state of the first energized block among the divided blocks, and (c) shows the division. The energization state of the block to be energized later is shown.
In FIG. 5, a period for recording one dot line is defined as an energization cycle P, and cycles t−1, t, and t + 1 are the t−1th dot line (dot line t−1) and the tth dot, respectively. This refers to the energization cycle for recording the line (dot line t) and the t + 1th dot line (dot line t + 1).

As shown in FIG. 5A, when a pulse indicating energization start timing is input from the energization control circuit 25 to the logic circuit 24, the logic circuit 24 records the dot line t. As shown in (b), the heating element of one of the blocks divided into two is energized.
Here, the logic circuit 24 energizes the heating elements of the block to be energized by further dividing into history energization and main energization. The main energization is an energization operation for energizing the heat generating element that is not energized at the period t-1 with the period t, and a predetermined current flows through the heat generating element. On the other hand, the history energization is an energization operation for continuously energizing the heating element energized at the cycle t-1 at the cycle t. In this history energization, since the temperature of the heat generating element is high at the start of energization, a current smaller than that in the case of the main energization is supplied to the heat generating element in order to prevent the heat generating element from generating heat beyond the desired temperature range.
Thereafter, as shown in FIG. 5C, the logic circuit 24 performs history energization and main energization for the heating elements of the other block.

Further, as shown in FIG. 5B, after the history energization and the main energization of the one block are executed, the CPU 21 detects the current mi flowing to the recording head unit 26 by the history energization in the period Q1, and the main current. A current ni flowing in the recording head unit 26 by energization is obtained. Furthermore, after executing the energization and main energization of the other block, the CPU 21 performs the current pi that has flowed to the recording head unit 26 by the energization of history and the current qi that has flowed to the recording head unit 26 by the energization in the period Q2. And ask. These currents mi, ni, pi, qi are easily obtained from the number of heating elements that are energized in the history energization and the main energization, for example.
After the dot line t is recorded at the period t, the CPU 21 divides the recording head unit 26 when the next dot line t + 1 is recorded at time T2, and the thermal roll paper by the transport motor 28. A recording control process for setting the conveyance speed is executed. This recording control process is executed every time a recording operation of one cycle (one dot line) is performed.
Details of the recording control process will be described below.

FIG. 6 is a flowchart showing an outline of the recording control process.
During the execution of the recording control process, the CPU 21 functions as a current value calculation unit, a recording control unit, a conveyance speed control unit, and a predicted value calculation unit.
In the recording control process, the CPU 21 calculates an effective current value Irms (t) for N dot lines that have been recorded including the dot line t (N is a positive integer) (step S11). The effective value Irms (t) is the mean square value of the number of heating elements energized during the recording of the N dot lines, the current mi, ni, pi, qi, the energization cycle, the energization pulse width, various coefficients, etc. It is calculated | required by performing the arithmetic processing based on.
Subsequently, the CPU 21 determines the currently set thermal paper roll conveyance speed (step S12), and executes the low speed process (FIG. 7) when the conveyance speed is less than 141 mm / s (millimeter / second). In the case of 141 mm / s, medium speed processing (FIG. 8) is executed, and in the case of exceeding 141 mm / s, high speed processing (FIG. 9) is executed.
After executing the low speed process, the medium speed process, and the high speed process, the CPU 21 determines the number of divisions of the recording head unit 26 (one division or two divisions in the example of the present embodiment) and the thermal roll paper. A conveyance speed is determined (step S16). In step S 16, setting data corresponding to the division state of the recording head unit 26 set in the low speed process, the medium speed process, and the high speed process is generated and output to the logic circuit setting buffer 22. In step S16, when the conveyance speed determined by the low speed process, the medium speed process, and the high speed process is within a range determined in advance according to the specifications of the thermal printer 1, it corresponds to the conveyance speed. A control signal is generated and output to the motor driver 27. After execution of step S16, the CPU 21 ends this process.
Here, the names of low-speed processing, medium-speed processing, and high-speed processing are all given to indicate whether the processing speed is low or high compared to 141 mm / s, which is the criterion for determination in step S12. It does not include any more significance.

FIG. 7 is a flowchart showing in detail the low speed process executed in step S13 of FIG.
In the low speed process, the CPU 21 first changes the transport speed of the transport motor 28 to a speed one step higher than the current setting (step S21). Subsequently, the CPU 21 determines whether or not the recording head unit 26 is divided into two at the present time, that is, when the dot line t is recorded (step S22). Here, when the recording head unit 26 is divided into two (step S22; Yes), the CPU 21 sets the division state of the recording head unit 26 as being divided into two and sets the conveyance speed of the thermal roll paper in step S21. The speed is changed by one step higher (step S23), and this process ends.

On the other hand, when the recording head unit 26 is not divided into two (step S22; No), the CPU 21 calculates a predicted effective value Irms (t + 1) of the current flowing through the recording head unit 26 for the dot line t + 1 to be recorded next. (Step S24). In this step S24, an arithmetic expression similar to that for obtaining the effective value Irms (t) is used, for example, N dots including the dot line t + 1 and (N-1) dot lines recorded in the past. For the line, a calculation process based on the root mean square value of the number of heating elements energized during recording is executed.
Then, the CPU 21 determines whether or not the predicted effective value Irms (t + 1) exceeds a predetermined allowable value Irms (step S25). Here, the allowable value Irms is a threshold value set with a sufficient margin to reduce the load on the power supply device of the thermal printer 1 as described above.
If the predicted effective value Irms (t + 1) is equal to or less than the allowable value Irms (step S25; No), the CPU 21 sets the division state of the recording head unit 26 to 1 division (not divided), and the conveyance speed to step S21. In step S26, the conveyance speed changed by one step is set (step S26), and the process is terminated.

  When the predicted effective value Irms (t + 1) exceeds the allowable value Irms (step S25; Yes), the CPU 21 determines to divide the print head unit 26 into two (step S27). Thereafter, the CPU 21 sets the division state of the recording head unit 26 to two divisions, sets the conveyance speed to the conveyance speed changed by one step in step S21 (step S28), and ends this process.

  According to this low-speed process, when the conveyance speed of the thermal roll paper is less than 141 mm / s, the conveyance speed can be increased while maintaining an excessive load on the power supply device of the thermal printer 1. Throughput can be improved. In addition, the division state of the recording head unit 26 is set in consideration of not only the effective value of the current related to the dot line t for which recording has been completed but also the predicted effective value related to the dot line t + 1 to be recorded next. For this reason, by predicting the current when the next dot line is recorded and dividing the recording head unit 26 only when necessary, recording can be performed accurately and without waste.

FIG. 8 is a flowchart showing in detail the medium speed process executed in step S14 of FIG.
In the medium speed process, the CPU 21 determines whether or not the recording head unit 26 is divided into two at the time point when the dot line with the period t is recorded (step S31).
Here, when the recording head unit 26 is divided into two (step S31; Yes), the CPU 21 determines whether or not 30 dot lines have been recorded after being divided into two (step S32). If the number of dot lines recorded after the division into two is less than 30, the CPU 21 sets the division state of the recording head unit 26 as two divisions and sets the conveyance speed as the current conveyance speed (141 mm / s). (Step S33), the process is terminated.
On the other hand, when the number of dot lines recorded after being divided into two reaches 30 (step S32; Yes), the CPU 21 sets the number of divisions of the recording head unit 26 to 1 and resets the counter (step S34). This counter counts the number of dot lines to be recorded after the recording head section 26 is divided into two. After resetting the counter, the CPU 21 proceeds to step S35.
If the division state of the recording head unit 26 is one division at the start of the medium speed process (s31; No), the CPU 21 proceeds directly to step S35.

In step S35, the CPU 21 determines whether or not the effective value Irms (t) of the current obtained in step S11 (FIG. 6) exceeds the allowable value Irms.
When the effective value Irms (t) exceeds the allowable value Irms, the CPU 21 determines to divide the recording head unit 26 into two (step S36). Thereafter, the CPU 21 sets the division state of the recording head unit 26 to two divisions, sets the conveyance speed to 141 mm / s (step S37), and ends this process.

If the effective value Irms (t) does not exceed the allowable value Irms (step S35; No), the CPU 21 changes the conveyance speed of the thermal roll paper by one step (step S38), and the dot line t + 1 to be recorded next. The predicted effective value Irms (t + 1) is calculated (step S39). Then, the CPU 21 determines whether or not the predicted effective value Irms (t + 1) exceeds the allowable value Irms (step S40).
When the predicted effective value Irms (t + 1) is equal to or smaller than the allowable value Irms (step S40; No), the CPU 21 sets the division state of the recording head unit 26 to one division, and the conveyance speed is increased by one step in step S38. The transport speed is set (step S41), and this process is terminated.
On the other hand, when the predicted effective value Irms (t + 1) exceeds the allowable value Irms (step S40; Yes), the CPU 21 sets the transport speed by the transport motor 28 to a speed one step lower (step S42). Here, since the conveyance speed is increased in step S38 and then decreased in step S42, the original conveyance speed (141 mm / s) is obtained. Thereafter, the CPU 21 sets the division state of the recording head unit 26 to one division, sets the conveyance speed to 141 mm / s (step S43), and ends this process.

  According to this medium speed processing, when the conveyance speed of the thermal roll paper is 141 mm / s, that is, the upper limit speed when the recording head unit 26 is divided into two, the division state of the recording head unit 26 is divided into one. After that, the recording head unit 26 is divided into two only when the effective value of the current exceeds the allowable value. For this reason, the recording head section 26 is divided only when necessary, so that accurate and wasteful recording can be performed. Further, when the recording head unit 26 is divided into two, the division state is not changed until 30 dot lines are recorded after the division into two, so that the division state is not frequently changed, and a stable recording operation can be realized. . In particular, since it is possible to reliably prevent image disturbance due to a change in the division state of the recording head unit 26 and a frequent change in the conveyance speed associated therewith, stable and high-quality recording can be performed. Furthermore, since the division state is set by taking into consideration not only the effective value of the current relating to the dot line t for which recording has been completed but also the predicted effective value relating to the dot line t + 1 to be recorded next, the recording head is only necessary. The section 26 can be divided, and recording can be performed accurately and without waste. In addition, when there is no need to divide into two, the conveyance speed is changed one step higher, so that it is possible to improve the throughput while maintaining an excessive load on the power supply device of the thermal printer 1.

  FIG. 9 is a flowchart showing in detail the high-speed processing executed in step S15 of FIG. This high-speed processing is executed when the conveyance speed of the thermal roll paper exceeds 141 mm / s, that is, when the upper limit speed when the recording head unit 26 is divided into two is exceeded. Accordingly, when the high-speed processing is executed, the division state of the recording head unit 26 is always one division.

In the high-speed processing, the CPU 21 determines whether or not the effective value Irms (t) of the current obtained in step S11 (FIG. 6) exceeds the allowable value Irms (step S51).
Here, when the effective value Irms (t) exceeds the allowable value Irms, the CPU 21 changes the conveyance speed to a one-step lower speed (step S52), and proceeds to step S57 described later.

If the effective value Irms (t) does not exceed the allowable value Irms (step S51; No), the CPU 21 changes the conveyance speed of the thermal roll paper by one step (step S53), and the dot line t + 1 to be recorded next. The predicted effective value Irms (t + 1) is calculated (step S54). Then, the CPU 21 determines whether or not the predicted effective value Irms (t + 1) exceeds the allowable value Irms (step S55).
When the predicted effective value Irms (t + 1) exceeds the allowable value Irms (step S55; Yes), the CPU 21 sets the transport speed to a one-step lower speed (step S56), and proceeds to step S57. By the processing in step S56, the conveyance speed is increased again in step S53 and then decreased again, so that the original conveyance speed is obtained.
When the predicted effective value Irms (t + 1) is equal to or smaller than the allowable value Irms (step S55; No), the CPU 21 proceeds to step S57 as it is.
In step S57, the CPU 21 sets the division state of the recording head unit 26 to one division, sets the conveyance speed, and ends this processing.

According to this high-speed processing, when the conveyance speed of the thermal roll paper exceeds 141 mm / s, the conveyance speed is reduced when the effective value of the current relating to the dot line t exceeds the allowable value.
When the recording head unit 26 is divided into two, recording cannot be performed at a speed exceeding 141 mm / s. Therefore, when the recording head unit 26 is divided into two in the future, it is necessary to reduce the conveyance speed. For this reason, if the conveyance speed is changed to a low value in the high-speed processing, a sudden change in the conveyance speed can be suppressed when the recording head unit 26 is divided thereafter.
In addition, even when the predicted effective value related to the dot line t + 1 to be recorded next exceeds the allowable value, the conveyance speed is rapidly changed when the recording head unit 26 is divided into two in the future by reducing the conveyance speed. Can be suppressed. Further, even if the conveyance speed exceeds 141 mm / s, if the effective value of the current does not exceed the allowable value, the conveyance speed is further increased, so that an excessive load is not applied to the power supply device of the thermal printer 1. Throughput can be further improved.

  As described above, the thermal printer 1 according to the embodiment to which the present invention is applied records the recording data input to the CPU 21 from the outside when an image is recorded on the thermal roll paper by the recording head unit 26 including a plurality of heating elements. Based on this number, the number of heating elements that are energized during recording is obtained, the effective value of the current flowing through the recording head unit 26 is obtained based on this number, and the division state of the recording head unit 26 is set based on this effective value. To do. For this reason, the division state of the recording head unit 26 can be appropriately set based on the effective value that accurately reflects the current that actually flows through the recording head unit 26. As a result, the load applied to the power supply device of the thermal printer 1 does not occur when the recording head unit 26 needs to be divided, without causing a problem such as not being divided, and without taking measures such as giving a margin to the allowable value. Can be kept below a predetermined level. Since the division of the recording head unit 26 can be stopped to the minimum necessary, the unnecessary division is performed and the throughput does not decrease. Thus, according to the thermal printer 1, it is possible to improve the throughput while suppressing the load on the power supply device.

  The embodiment described above shows one embodiment of the present invention, and it is needless to say that the embodiment can be arbitrarily modified and applied within the scope of the present invention. For example, in the low speed process, the medium speed process, and the high speed process of the above embodiment, the process is performed using the same allowable value Irms. However, the present invention is not limited to this, and the low speed process is performed. Different tolerance values may be used for the medium speed processing and the high speed processing. Further, for example, in the above-described embodiment, the case where the recording head unit 26 is divided into two as necessary has been described. However, the present invention is not limited to this, and a larger number (for example, four divisions, eight divisions, etc.). It is of course possible to divide the The arrangement of the heating elements in the recording head unit 26 is arbitrary, and all the heating elements may be arranged in a straight line, or may be arranged in a plurality of rows. Furthermore, the present invention can be applied not only to a recording apparatus having an independent outer case 11 like the thermal printer 1 but also to a recording apparatus incorporated in another device. In addition, the present invention uses a non-colored sheet such as plain paper as a recording medium, contacts an ink ribbon to which ink that melts by heating adheres to the sheet, and applies thermal energy to the ink ribbon to record an image. It can also be applied to a so-called thermal transfer type recording apparatus. Furthermore, using a non-colored sheet such as plain paper as a recording medium, an ink ribbon to which ink sublimated by heating is attached is disposed close to the sheet, and thermal energy is applied to the ink ribbon to record an image. The present invention can also be applied to a so-called thermal sublimation type recording apparatus. In addition, the specific configuration of the recording mechanism section and the detailed configuration of the heat-sensitive roll paper transport mechanism and the like can be changed as appropriate without departing from the spirit of the present invention.

1 is a front view of a thermal printer according to an embodiment of the present invention. It is a top view of a thermal printer. It is a side view of a thermal printer. It is a block diagram which shows the functional structure of the control circuit part of a thermal printer. 6 is a timing chart illustrating an energization operation to a recording head unit. It is a flowchart which shows a recording control process. It is a flowchart which shows the process at the time of low speed. It is a flowchart which shows the process at the time of medium speed. It is a flowchart which shows the process at the time of high speed.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Thermal printer (recording apparatus), 20 ... Control circuit part, 21 ... CPU (Current value calculation means, Recording control means, Conveyance speed control means, Predicted value calculation means), 22 ... Logic circuit setting buffer, 23 ... Recording buffer , 24 ... logic circuit (recording means), 25 ... energization control circuit, 26 ... recording head section (recording head), 27 ... motor driver (conveyance means), 28 ... conveyance motor (conveyance means).

Claims (8)

A recording head comprising a plurality of heating elements for applying thermal energy to the recording medium;
Current value calculating means for obtaining a current value flowing through the recording head during a recording operation based on recording data input from the outside;
Recording control means for setting a division state of the recording head based on a current value obtained by the current value calculating means and a predetermined threshold value;
A conveyance speed control means for setting a conveyance speed of the recording medium by the conveyance motor according to a division state of the recording head;
Conveying means for conveying the recording medium based on the conveying speed set by the conveying speed control means;
Recording means for energizing the heating element and recording an image on the recording medium based on the division state of the recording head set by the recording control means,
The current value calculating means obtains an effective value of the current flowing through the recording head based on the number of heating elements to be energized;
A recording apparatus.   2. The current value calculating means obtains a root mean square value for the number of heating elements that have been energized in a plurality of past energization cycles, and finds an effective current value based on the mean square value. The recording device described.   3. The conveyance speed control unit, when the recording control unit is set to divide the recording head into a plurality of divisions, sets the conveyance speed to a predetermined upper limit speed or less. Recording device.   The apparatus further comprises predicted value calculation means for obtaining an effective value of the current flowing through the recording head based on the number of heating elements to be energized in a predetermined number of energization periods including a next energization period and a past energization period. The recording apparatus according to claim 1.   The transport speed control means is a speed at which the currently set transport speed exceeds the predetermined upper limit speed, and the effective value of the current obtained by the predicted value calculation means exceeds a predetermined allowable value. 5. The recording apparatus according to claim 4, wherein the conveying speed is set to a lower speed.   The recording control unit maintains the divided state of the recording head from when the recording head is set to be divided into a plurality of blocks until energization of a predetermined number of energization cycles is performed. The recording apparatus according to claim 1. A control method for a recording apparatus, comprising: a recording head including a plurality of heat generating elements that apply thermal energy to a recording medium; and a conveying unit that conveys the recording medium at a predetermined speed.
Based on the recording data input from the outside, the number of heating elements to be energized among the plurality of heating elements is obtained, and based on the number of heating elements to be energized, flows to the recording head during the recording operation. Find the effective value of the current,
Based on the obtained current value and a predetermined threshold value, the division state of the recording head is set,
The conveyance speed of the recording medium by the conveyance motor is set according to the division state of the recording head, and the heating element is energized to record an image on the recording medium based on the division state of the recording head. thing,
A control method for a recording apparatus. A program executed by a computer that controls a recording apparatus that includes a recording head including a plurality of heat generating elements that apply thermal energy to the recording medium, and a conveying unit that conveys the recording medium at a predetermined speed,
The computer,
Based on the recording data input from the outside, the number of heating elements to be energized among the plurality of heating elements is obtained, and based on the number of heating elements to be energized, flows to the recording head during the recording operation. A current value calculating means for obtaining an effective value of the current;
Recording control means for setting the division state of the recording head based on the obtained current value and a predetermined threshold value;
A conveyance speed control means for setting a conveyance speed of the recording medium by the conveyance motor according to a division state of the recording head;
Recording means for energizing the heating element to record an image on the recording medium based on the division state of the recording head set by the recording control means;
A program characterized by operating as

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