JP2014034148A - Printing device and method for controlling print head thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide means for preventing burning of a driving element even when a temperature threshold is set to a relatively high temperature.SOLUTION: A printing device includes a print head having a plurality of wire pins and a plurality of driving elements for driving the wire pins by an electromagnetic force, selectively projects a wire pin by the driving element, and performs printing in a medium via an ink ribbon. The printing device includes protective operation means for regulating the printing operation of the print head to protect each driving element, and determination means for calculating a count value of the driving history of each driving element by a predetermined method and comparing the calculated count value with a predetermined threshold value to determine the necessity of execution of the protective operation means.

Description

  The present invention relates to a printing apparatus such as a printer that prints print data on a medium, and a method for controlling the print head.

  A conventional dot impact printer has a print head that selectively protrudes a plurality of wire pins with a drive element using electromagnetic force and prints on a medium via an ink ribbon, and a temperature sensor is used to drive the drive element of the print head. If the temperature detected by the temperature sensor is determined to be high, the print speed of the print head is set to low speed, and if it is determined to be medium temperature, the print speed is set to medium speed to Temperature rise is prevented. (For example, refer to Patent Document 1).

JP-A-9-76568 (paragraphs 0023-0026, FIG. 6)

  However, in the conventional printer, the temperature control for preventing the temperature rise of the drive element of the print head is performed using the temperature detected by one temperature sensor provided in the print head. For example, a specific drive If the frequency of use of the element and its surrounding drive elements is very high, the temperature difference between the temperature detected by the temperature sensor and the temperature of the specific drive element becomes large. The temperature is set at a relatively low temperature, and in the case of normal Kanji / Kana mixed character printing, the temperature is excessively controlled even though the frequency of use of each drive element is relatively low. There is a problem in that the number of characters printed in the printer is reduced and printing efficiency is lowered.

For this reason, when the temperature threshold is set to a relatively high temperature, there is a problem in that the drive element may be burned out when the specific drive element and its surrounding drive elements are used very frequently.
The present invention has been made to solve the above problems, and an object of the present invention is to provide means for preventing burning of a drive element even when the temperature threshold is set to a relatively high temperature. .

  In order to solve the above problems, the present invention comprises a print head having a plurality of wire pins and a plurality of drive elements that drive the wire pins by electromagnetic force, and the wire pins are selectively projected by the drive elements, In a printing apparatus that performs printing on a medium via an ink ribbon, a protection operation unit that regulates a printing operation of the print head to protect the drive elements, and a count value related to a drive history of each of the drive elements. And a determination unit that calculates by a predetermined method and compares the calculated count value with a predetermined threshold value to determine whether or not the protection operation unit needs to be executed.

  As a result, according to the present invention, the temperature of the target drive element becomes a dangerous temperature even when the print data frequently used only for the target drive element and its peripheral elements is repeatedly printed. Before, the printing operation of the print head can be shifted to the protection operation, and the effect that the burnout of the driving element can be prevented is obtained.

1 is a block diagram illustrating a printer connected to a host device according to a first embodiment. Explanatory drawing which shows the printing mechanism of the printer of Example 1. Explanatory drawing which shows the external appearance of the print head of Example 1. FIG. Explanatory drawing which shows the print head of Example 1. FIG. Explanatory drawing which shows arrangement | positioning of the drive element of the printing head of Example 1. FIG. Explanatory drawing which shows the printing operation of the printer of Example 1. 7 is a flowchart illustrating update processing of the count value N of the printer according to the first embodiment. 1 is a flowchart illustrating print processing of the printer according to the first embodiment. The graph which shows the experimental result for the setting of the count threshold value etc. of Example 1 Explanatory drawing which shows the start setting value of Example 1. Explanatory drawing which shows the difference in operation by the start setting value of Example 1. Explanatory drawing which shows the setting method of the influence coefficient of Example 1. Explanatory drawing which shows the setting method of the temperature threshold value of Example 1. Explanatory drawing which shows the increase in the number of printed characters by the temperature threshold value of Example 1. FIG. 9 is a block diagram showing a printer connected to a host device of Embodiment 2. Explanatory drawing which shows the printing mechanism of the printer of Example 2. FIG. Explanatory drawing which shows the gap correction value with respect to the gap scale of Example 2. Explanatory drawing which shows the difference in operation | movement by the clearance gap equivalent to the gap scale of Example 2. FIG. Flowchart showing print processing of the printer of Embodiment 2.

  Embodiments of a printing apparatus and a method for controlling the print head according to the present invention will be described below with reference to the drawings.

A printer as a printing apparatus according to the present embodiment will be described below with reference to FIGS. 4 is a cross-sectional view taken along the line AA in FIG. 3, and FIG. 5 shows the arrangement of the drive elements D viewed from the direction of arrow B in FIG.
In FIG. 1, reference numeral 100 denotes a printer as a printing apparatus.
A control unit 1 of the printer 100 is connected to a personal computer 2 or the like as a host device via an external interface (not shown). Each unit in the printer 100 is controlled based on print data received from the personal computer 2 or the like. It has a function of controlling and executing printing processing and the like.

Reference numeral 3 denotes a storage unit as a storage unit of the printer 100, which stores a program executed by the control unit 1, various data used for it, processing results by the control unit 1, and the like, and temporarily stores received print data. Is done.
A character generator 4 is connected to the control unit 1 and the storage unit 3 and has a function of generating the excitation timing of each drive element D for each row based on the print data stored in the storage unit 3. doing.
A drive circuit 5 has a function of supplying drive power for driving the print head 6, the print head drive motor 7, and the medium transport motor 8 according to a command signal from the control unit 1.
A temperature sensor 9 is built in the center of the print head 6 (see FIG. 4), and has a function of outputting the head temperature T, which is the internal temperature of the print head 6, to the control unit 1.

In FIG. 2, reference numeral 11 denotes a carriage on which the print head 6 is mounted, which is guided by a columnar rail 12 installed in a direction orthogonal to the transport direction of the printing paper P as a medium, and is a print head drive motor. The mounted print head 6 is moved along the rail 12 to the printing position by the drive belt 13 formed of an endless belt driven so as to be able to reciprocate by 7.
Reference numeral 14 denotes a platen which is arranged in parallel with the rail 12 so as to be opposed to the print head 6, receives a blow of the wire pin 6 a of the print head 6, and is rotated by the medium transport motor 8 to transport the paper P in the transport direction. To do.

The print head 6 of this embodiment has 24 wire pins 6a provided for each dot, and is configured as shown in FIGS.
The drive element D of the print head 6 is provided for each individual wire pin 6a, and is formed in a cylindrical shape surrounding the core 16a by using a columnar core 16a having a magnetic field response and resin or the like, and a terminal portion is provided. A coil 16c is wound around a bobbin 16b provided, and both ends of the winding are connected to the terminal portion of the bobbin 16b. As shown in FIG. 5, on a disk-shaped base plate 18 using iron or the like. 24 are equally arranged along the circumferential direction.

On the base plate 18, a first yoke 19 having a magnetic field response, a permanent magnet 20, a second yoke 21 having a magnetic field response, and a spacer 22 using iron or the like are laminated. Are cylindrical shapes with the same outer diameter, and the shape after lamination is cylindrical.
The spacers 22 support 24 plate springs 24 as long plate-like spring members at regular intervals in the circumferential direction, and the free ends of the plate springs 24 extend toward the center of the print head 6 respectively. ing. Further, a long plate-shaped armature 25 having a magnetic field response is attached between approximately the middle and the tip of the leaf spring 24, and a thin wire pin 6a formed of iron or the like is attached to the tip of the armature 25. Are installed respectively.

  Such a leaf spring 24 is arranged in a state where it is supported by the spacer 22 and bent toward the core 16 a by the magnetic force of the permanent magnet 20. A cylindrical armature yoke 27 having magnetic field responsiveness is installed on the leaf spring 24, and a guide frame 28 made of resin or the like is installed on the armature yoke 27. Is provided with a guide portion 29 for positioning the wire pin 6a at the center portion of the print head 6 and guiding the direction of protrusion and withdrawal thereof.

A space sheet 31 formed of resin or the like is disposed under the base plate 18, and terminals of the bobbin 16 b to which both ends of the coil 16 c are connected pass through the space sheet 31 and are formed on the printed circuit board 32. It is electrically connected to the pattern. A temperature sensor 9 that detects the head temperature T of the print head 6 is mounted on the printer board 32.
Further, both ends of the coil 16 c are electrically connected to the drive circuit 5 through the printed circuit board 32, and the temperature detected by the temperature sensor 9 (head temperature T) is output to the control unit 1 through the printed circuit board 32. Further, a heat sink 33 as a heat radiating member is attached to the lower side of the printed circuit board 32 so as to surround the component parts, and the guide frame 28 and the heat sink 33 are coupled by a clamper 34 formed of a spring material. 6 are assembled together.

First, a printing operation by the printer 100 of this embodiment will be described.
When the character generator 4 generates the excitation timing of each drive element D for one row based on the print data stored in the storage unit 3, the control unit 1 sends a command signal for driving the print head 6 to the drive circuit. As shown in FIG. 6, the drive circuit 5 drives the print head drive motor 7 in accordance with the received command signal to move the print head 6 to a predetermined position, and the wire pin 6a of the print head 6 protrudes. And print characters.

At the time of printing, when the coil 16c of the print head 6 is excited for a predetermined time by the drive circuit 5, the magnetic force of the core 16a is canceled, and the leaf spring 24 installed in the bent state is released and the armature 25 is released. The wire pin 6a installed on the paper protrudes, pushes out an ink ribbon (not shown) containing ink, and strikes the paper P conveyed between the print head 6 and the platen 14 with the wire pin 6a simultaneously protruded to generate characters, etc. Is printed.
The command signal includes a command for performing a line feed after printing of the line. At the time of the line break, the medium transport motor 8 is driven via the drive circuit 5 to rotate the platen 14 to cause the paper P Is carried for a certain length to make a line feed.
In this way, while the paper P is conveyed between the print head 6 and the platen 14, printing of one line on the page of the print data is performed.

As described above, the printer 100 according to the present embodiment is a printer including the print head 6 having the plurality of wire pins 6a and the plurality of drive elements D that drive the wire pins 6a by electromagnetic force. This is a dot impact printer in which the wire pin 6a is selectively driven by the driving element D to protrude, and printing is performed on the paper P via the ink ribbon.
In the control unit 1 of this embodiment described above, the count value calculation for calculating the respective count values N1 to N24 related to the drive history of the 24 drive elements D1 to D24 (see FIG. 5) based on a predetermined condition. Means 1a is provided (see FIG. 1), and the calculated count values N1 to N24 are stored for each drive element D in counters C1 to C24 provided in the storage unit 3.

Here, the temperature threshold value, the count threshold value, the start setting value, and the subtraction value Ng used in the update process and the print process of the count value N of the printer 100 of the present embodiment executed by the flowcharts shown in FIGS. 7 and 8 will be described.
Note that these threshold values and set values are set by an experiment or the like in which the drive element D is actually driven by the printer 100 of this embodiment, and are stored in the storage unit 3 in advance.
The temperature threshold (used in the printing process of FIG. 8) predicts the temperature of the drive element D from the head temperature T, which is the internal temperature of the print head 6 detected by the temperature sensor 9, and the temperature of the drive element D is the drive element D. The threshold value is set to perform a protective operation before reaching a dangerous temperature (180 ° C. in the present embodiment) that induces burning, etc., and in this embodiment, in the case of character printing of ordinary kanji / kana mixed text Only the temperature threshold value is set by an experiment or the like before the dangerous temperature is reached.

  That is, in the case of character printing of ordinary kanji-kana mixed sentences, all the driving elements D1 to D24 are used, and the number of times of driving (= the number of times of excitation) is also compared to the case where only one driving element D1 is continuously driven. Even the temperature of the drive element D that is very few and most frequently used is close to the detected temperature of the temperature sensor 9 at that time, and therefore, for example, the drive element D that is most frequently used in character printing of kanji-kana mixed sentences. When the temperature detected by the temperature sensor 9 is 30 ° C. lower than the temperature, the temperature threshold is set to a temperature 30 ° C. lower than the dangerous temperature (see FIG. 12).

  In this way, it becomes possible to set the temperature threshold value to a relatively high temperature in accordance with the actual situation, and to a protective operation that regulates the printing speed or the like of the print head 6 in character printing of ordinary kanji-kana mixed text. The number of characters can be reduced and the number of characters printed within the same time can be increased to improve printing efficiency.However, printing of characters is not limited to ordinary kanji-kana mixed sentences. In the embodiment, a count threshold described later is provided to prevent the drive element D from being burned out.

  When determining the count threshold value, the start setting value, and the subtraction value Ng, if the driving element of interest is the driving element D1, the driving element D1 is the central element, and the driving element D2 and the driving element located on both sides of the driving element D1. D3, time elapse when drive element D4 and drive element D5 (see FIG. 5, hereinafter referred to as five drive elements D1 to D5 having drive element D1 as a central element) adjacent thereto are continuously driven simultaneously As a result, the temperature rise of the drive element D1 located in the center, the temperature decrease of the drive element D1 after the continuous drive is stopped, the state of rise and fall of the head temperature T, the count threshold value and the start set value, the subtraction The state of increase and decrease of the count value N1 adjusted for the value Ng was combined and set based on the experimental result shown in FIG.

The count threshold value (used in the printing process of FIG. 8) is determined from the number of times the drive elements D1 to D5 are driven when the temperature of the drive element D1 located in the center reaches a dangerous temperature in the experiment of FIG. The count value N1 calculated in the flowcharts of FIG. 7 and FIG. 8 using the elapsed time is set as the count threshold (see the circles in FIG. 9).
In this embodiment, the count threshold is set in this way because the temperature threshold is set assuming the case of character printing of a mixed kana-kana sentence as described above. In the case of continuous printing such as printing Chinese characters or filling ○ △ ◇ □, hyphens, wavy lines, dots, etc., it is assumed that only a specific drive element D and its peripheral elements are driven continuously. This is also for predicting the reached temperature at the end of one-line printing of the specific drive element D based on the number of times the drive element D is driven to prevent the specific drive element D from reaching the dangerous temperature.

  As shown in FIG. 10, the start set value (used in the update process in FIG. 7) is a set value set for each temperature range of the head temperature T, which is the detected temperature of the temperature sensor 9, and is printed at a high temperature place or printed. When the drive element D1 when the drive elements D1 to D5 are continuously driven reaches a dangerous temperature when the head temperature T has risen due to any reason or the like and is at the upper limit temperature in the temperature range of the head temperature T A value that fills the difference between the count value N1 and the count threshold is set as the start set value in the temperature range (for example, the start set value 3 in the temperature range of the head temperature T2 or more and less than T3 is shown in FIG. □ is set).

  That is, as shown in FIG. 11, the start set value is a print in which five drive elements D1 to D5 having the drive element D1 as a central element are simultaneously started from a low start set value set at room temperature. The drive element D1 when the above-described continuous drive printing is performed from a high start set value set at a high temperature with respect to the time for the count value N1 of the drive element D1 to reach the count threshold when it is performed. The set value is set to shorten the time for the count value N1 to reach the count threshold, and the temperature of the drive element D1 is a dangerous temperature even when the head temperature T of the print head 6 is continuously driven from the high temperature. It is a set value set to prevent reaching.

  The subtraction value Ng (used in the update process of FIG. 7) means a temperature decrease of the drive element D in the time interval between the periodic update processes described with reference to FIG. 7. In the experiment in FIG. After the elapse of time, when the count value N1 of the drive element D1 becomes the count threshold value (circle mark shown in FIG. 9), the drive of the five drive elements D1 to D5 is stopped, and the temperature of the drive element D1 located at the center is The subtraction value Ng is periodically subtracted by the update process of the count value N1 with respect to the time (t1 shown in FIG. 9) until it decreases with time and becomes equal to the temperature detected by the temperature sensor 9 (head temperature T). As a result, the count value N1 of the drive element D1 that has reached the count threshold value is decreased, and the temperature is set at the time when the temperature of the drive element D1 becomes equal to the detected temperature (head temperature T) of the temperature sensor 9. Said opening Set value becomes time (t2 shown in FIG. 9) is set to be the same or more.

That is, the time until the temperature of the driving element D1 located in the center after driving stops becomes equal to the head temperature T is measured, and the decrease in temperature in the time interval between periodic update processes is measured based on this measurement time. Is a set value set in terms of the count value N1.
In addition, the subtraction value Ng and the count threshold are set so that the head temperature T reaches the temperature threshold at least before the count value N reaches the count threshold in the case of normal Kanji / Kana mixed character printing. Has been.

Hereinafter, the update process of the count value N periodically performed during the operation after starting in the printer of the present embodiment will be described according to the step indicated by S using the flowchart shown in FIG.
In the following description, i is a number (i = 1 to 24) for distinguishing each of the 24 drive elements D. For example, when i = 1, the drive element Di represents the drive element D1, The counter Ci indicates the counter C1, and the count value Ni indicates the count value N1.

When the control unit 1 of the printer 100 is turned on and the processing operation is started by the program stored in the storage unit 3, the count value N is periodically (every 20 ms in this embodiment) by the clock function. The update process timing is monitored, and when it is recognized that the update process timing is reached, the process proceeds to step S1. If it is not the timing of the update process, the monitoring is continued.
S1: The control unit 1 that has recognized that it is the timing of the update process acquires the head temperature T that is the internal temperature of the print head 6 based on the output from the temperature sensor 9.

S2: The control unit 1 that has acquired the head temperature T acquires the count values N1 to N24 stored in the counters C1 to C24 of the storage unit 3.
S3: The controller 1 that has acquired the head temperature T and the count values N1 to N24 sets the number i to “1” in order to calculate the count value Ni during the update process of the drive element Di.
S4: The control unit 1 calculates a new count value Ni by subtracting the subtraction value Ng from the count value Ni (currently i = 1) by the count value calculation means 1a.

S5: The control unit 1 that has calculated the new count value Ni, based on the head temperature T acquired in step S1, the start set value of the temperature range to which the head temperature T acquired from the storage unit 3 belongs (see FIG. 10). Is compared with the calculated count value Ni. If the count value Ni is less than the read start set value, the process proceeds to step S6. If the count value Ni is greater than or equal to the start set value, the count value Ni is updated. It determines with unnecessary and transfers to step S7.
S6: The control unit 1 that has determined that the calculated count value Ni is less than the start set value rewrites the calculated count value Ni with the start set value, and proceeds to step S7. Thus, when the calculated count value Ni is less than the start set value, the count value Ni is rewritten to the start set value in order to protect the print head 6 on the safest side.

S7: The control unit 1 that has rewritten the count side Ni to the start set value or determined that the count value Ni does not need to be updated moves to step S8 when the current number i is less than 24, and the current number i is In the case of 24 or more, it is determined that the calculation of the count value N in the update process of all the drive elements D is finished, and the process proceeds to step S9.
S8: The controller 1 that has determined that the current number i is less than 24 increments the number i by adding “1” to the current number i (i = 2 at the current stage), and returns to step S4 to return to the drive element Di. The calculation of the count value Ni is repeated.

S9: The control unit 1 that has determined that the calculation of the count value N in the update process of all the drive elements D has been completed, writes the count values N1 to N24 in the counters C1 to C24 of the storage unit 3, and the current count value N The update process is terminated.
The processing operation for updating the count value N is continued until the printer 100 is powered off.
When the print data is received from the personal computer 2 during the periodic execution of the update process of the count value N described above, the control unit 1 starts the print process by the program stored in the storage unit 3.

Hereinafter, the printing process by the printer of this embodiment will be described according to the steps indicated by SA using the flowchart shown in FIG.
In the following description, j is a line number. For example, j = 1 indicates the first line.
SA1: When printing processing is started, the control unit 1 temporarily stores the received print data in the storage unit 3, and sets the line number j to “1” in order to execute printing of the first line.
SA2: When reading the print data of the jth row (j = 1 at the present stage) from the storage unit 3, the control unit 1 proceeds to step SA3 if the print data of the jth row exists. If there is no print data for that line, the current print process is terminated, and the process waits for the reception of print data from the personal computer 2 while executing the above update process.

SA3: Recognizing that the print data of the j-th row exists, the control unit 1 reads the print data of the row from the storage unit 3, and the character generator 4 causes the number of times of excitation of each drive element D in the row (= drive). Number) and the excitation timing of which position on the paper P each excitation is generated, and the generated number of excitations of the drive element D is acquired.
SA4: The control unit 1 that has acquired the number of times of excitation of each drive element D reads and acquires the count values N1 to N24 stored in the counters C1 to C24 of the storage unit 3. The count values N1 to N24 acquired in this case are the count values N stored in the storage unit 3 in step S9 of the update process of the count value N.

SA5: The controller 1 that has acquired the number of times of excitation of each drive element D and the count values N1 to N24 sets the number i to “1” in order to calculate the count value Ni of the drive element Di at the end of printing of the row. To do.
SA6: The control unit 1 calculates the row count value ΔNi, which is the count value Ni for one row in the printing of the row of the drive element Di, by the count value calculating unit 1a, and proceeds to step SA7. The calculation method of the row count value ΔNi in this case is performed as follows.

That is, since i = 1 at this stage, when the row count value ΔN1 is calculated for the drive element D1,
Row count value ΔN1 = Number of excitations of drive element D1 + Influence coefficient 1 × (Number of excitations of drive element D2 + Number of excitations of drive element D3) + Influence coefficient 2 × (Number of excitations of drive element D4 + Number of excitations of drive element D5) (1)
Calculate with

That is, when the calculation target is the drive element D1, as shown in FIG. 5, the influence of the drive element D2 and the drive element D3 located on both sides of the drive element D1, and the drive element D4 and the drive element located next to them. The row count value ΔN1 is calculated in consideration of the influence of D5.
As shown in FIG. 12, the influence coefficient 1 and the influence coefficient 2 in this case are the temperature rise of the drive element D1 when only the drive element D1 is continuously driven in the experiment, and the drive element D2 and the drive adjacent to the drive element D1. When the three drive elements D1 to D3 including the element D3 are continuously driven, the temperature of the drive element D1 rises. Further, the five drive elements D1 to D5 including the drive element D4 and the drive element D5 adjacent thereto are continuously driven. In this case, the temperature rise of the driving element D1 is measured, and the influence on the driving element D1 of the driving element D2 and the driving element D3 on both sides, and the influence on the driving element D1 of the driving element D4 and the driving element D5 on the side. Is a coefficient obtained to take into account.

  For example, when the temperature rise of the driving element D1 when the five driving elements D1 to D5 are continuously driven reaches 180 ° C., only the driving element D1 is used with the same printing time (about 25 seconds in the example of FIG. 12). Assuming that the temperature rise of the drive element D1 when continuously driven is 75 ° C., and the temperature rise of the drive element D1 when continuously driving the three drive elements D1 to D3 is 150 ° C., the drive element D2 and the drive element D3 The influence coefficient 1 for the drive element D1 is about 0.5 to fill the difference of 75 ° C. due to the addition of the drive element D1, and the drive elements D1 to D3 are set to the row count value ΔN1 when only the drive element D1 is driven. The row count value ΔN1 of the drive element D1 when continuously driven at the same time is set to be approximately doubled by the influence coefficient 1.

  The influence coefficient 2 of the drive element D4 and the drive element D5 with respect to the drive element D1 is about 0.2 that fills the difference 30 ° C. due to the addition of them, and the row count value ΔN1 when only the drive element D1 is driven. On the other hand, the row count value ΔN1 of the drive element D1 when the drive elements D1 to D5 are continuously driven simultaneously is set to be about 2.4 times by the influence coefficient 1 and the influence coefficient 2.

  As described above, the influence coefficient of the present embodiment is such that the influence of the drive element D2 and the drive element D3 that are close to each other is close to the drive element D1 (center element) to be calculated. The influence coefficient 2 is set so that the influence of the driving element D4 and the driving element D5 that are set apart from the driving element D1 and the driving element D1 located adjacent to the driving element D2 is smaller than the influence coefficient 1 is set. Is set.

SA7: The control unit 1 that has calculated the row count value ΔNi in printing of the row of the drive element Di newly adds the calculated row count value ΔNi to the count value Ni read in step SA4 by the count value calculation unit 1a. A simple count value Ni is calculated.
SA8: The control unit 1 that has calculated the new count value Ni moves to step SA9 when the current number i is less than 24, and counts all the drive elements D when the current number i is 24 or more. It is determined that N has been calculated, and the process proceeds to step SA10.

SA9: The controller 1 that has determined that the current number i is less than 24 increments the number i by adding “1” to the current number i (i = 2 at the present stage), and returns to Step SA6 to return to the drive element Di. The calculation of the count value Ni is repeated.
SA10: The control unit 1 that has determined that calculation of the count values N of all the drive elements D has been completed writes the count values N1 to N24 in the counters C1 to C24 of the storage unit 3, and proceeds to step SA11.
SA11: The controller 1 that has written the calculated count values N1 to N24 in the counters C1 to C24 obtains the head temperature T, which is the internal temperature of the print head 6, based on the output from the temperature sensor 9.

SA12: The control unit 1 that has acquired the head temperature T reads the count threshold described above from the storage unit 3, and all the count values N1 to N24 written to the counters C1 to C24 in step SA10 are less than the count threshold. In this case, it is determined that the protection operation of the print head 6 is unnecessary, and the process proceeds to step SA15. If any of the count values N1 to N24 is equal to or greater than the count threshold value, the protection operation for restricting the print operation of the print head 6 is performed. Is determined to be necessary, and the process proceeds to step SA13.
SA13: The control unit 1 that determines that the protection operation of the print head 6 is necessary because any one of the count values N1 to N24 has reached the count threshold value causes the print processing by the print head 6 to be temporarily stopped. Set the processing mode to pause mode.

SA14: The control unit 1 that has set the processing mode to the sleep mode waits for the elapse of the pause time in the pause mode by the clock function, and when the pause time has elapsed, the control unit 1 proceeds to Step SA15.
SA15: The control unit 1 that has determined that the protection operation of the print head 6 is unnecessary because all of the count values N1 to N24 are less than the count threshold or that has finished the pause in the pause mode has been described above from the storage unit 3 When the head temperature T is less than the read temperature threshold, the print head 6 is determined not to require a protection operation, and the process proceeds to step SA17. If the temperature is equal to or higher than the temperature threshold, it is determined that a protection operation for restricting the printing operation of the print head 6 is necessary, and the process proceeds to step SA16.

  SA16: The control unit 1 that has determined that the protection operation of the print head 6 is necessary when the head temperature T is equal to or higher than the temperature threshold value performs a printing process in order to reduce the printing speed of the print head 6 from the normal case. The mode is set to the print speed reduction mode, and the print head 6 is driven at the excitation timing of each drive element D generated by the print head drive motor 7 and the character generator 4 necessary for printing in the print speed reduction mode. The command signal for transmitting is transmitted to the drive circuit 5, and the process proceeds to step SA18.

  SA17: When the head temperature T is less than the temperature threshold value, the control operation of the printing unit 6 that has determined that printing is performed as usual since the protection operation of the print head 6 is unnecessary is set to the normal printing speed mode. A command signal for driving the print head 6 at the excitation timing of each drive element D generated by the print head drive motor 7 and the character generator 4 necessary for setting and printing at the normal print speed is provided in the drive circuit 5. To step SA18.

SA18: The control unit 1 drives the print head drive motor 7 and the print head 6 by the drive circuit 5 according to the command signal transmitted to the drive circuit 5 from either of the above steps SA16 and SA17, and performs predetermined printing of the row. When the printing of the line is completed, a line feed is performed for printing the next line, and the process proceeds to step SA19.
SA19: The control unit 1, which has finished the line feed to the next line, adds “1” to the current line number j, increments the line number j (j = 2 at this stage), and prints the next line. Returning to step SA2, printing of a new line is repeated.
In this way, the printing process by the printer 100 of this embodiment is executed.

In this embodiment, when the control unit 1 determines in step SA15 or SA16 that the protective operation of the print head 6 is necessary because the head temperature T is equal to or higher than the temperature threshold, the processing mode of the printing process is performed. Has been described as shifting to the printing speed reduction mode, but may be shifted to the pause mode.
In the present embodiment, when the control unit 1 determines in step SA12, SA13, SA14 that the protection operation of the print head 6 is necessary because any of the count values N1 to N24 has reached the count threshold. In the above description, the processing mode of the printing process is shifted to the pause mode. However, the printing mode may be shifted to the printing speed reduction mode.

  As described above, according to this embodiment, the counters C1 to C24 for writing the count values N1 to N24 are provided for the drive elements D1 to D24, and the protection operation is necessary based on the count values N1 to N24. A counter threshold C1 is provided using an influence coefficient 1 and an influence coefficient 2 that are reduced each time the position of the target drive element D and the drive element D that is continuously driven at the same time are separated. The count values N1 to N24 respectively stored in .about.C24 are added every time one line is printed, and when any of the count values N1 to N24 reaches the count threshold, the mode is shifted to the pause mode or the printing speed reduction mode. Therefore, even when the print data having a high frequency of use of only the target drive element D and its peripheral drive element D is repeatedly printed, Before the driving element D to become a dangerous temperature, the processing mode of the printing process is shifted to the pause mode or the printing speed reduction mode, and the protection operation for restricting the printing operation of the print head 6 can be performed. Burnout of the element D can be prevented.

  In addition, in the case of character printing of ordinary kanji-kana mixed text, a temperature threshold is set for determining whether or not a protective operation is necessary based on the head temperature T before the dangerous temperature is reached, so that normal kanji-kana mixed text is set. In the case of character printing, since the head temperature T reaches the temperature threshold and shifts to the printing speed reduction mode or the pause mode at least before the count values N1 to N24 reach the count threshold, FIG. As shown in FIG. 4, the temperature of the target drive element D and the temperature sensor 9 detected when the target drive element D and its peripheral drive elements D are continuously driven as in the conventional temperature threshold setting method are detected. Considering the temperature difference from the head temperature T, the setting of the temperature threshold value of this embodiment is compared with the case where the temperature threshold value is set so as to decrease the printing speed before the target drive element D reaches the dangerous temperature. Like the way In the case of character printing of a normal kanji-kana mixed sentence, the temperature threshold value can be set by using the fact that the temperature difference between the temperature of the target drive element D and the head temperature T detected by the temperature sensor 9 becomes small. As shown in FIG. 14, the number of characters to be printed within the same time can be increased, and the printing efficiency in the printing process of the printer 100 can be improved.

  Further, since the start set value is provided for each temperature range of the head temperature T, for example, after the printing is finished, the power is turned off once, and the print head 6 is turned on before the temperature returns to the normal temperature. Even when repeated, the processing mode can be shifted to the pause mode or the printing speed reduction mode before the dangerous temperature is reached, and burning of the driving element D when the head temperature T is high can be prevented.

  As described above, in the present embodiment, the printer has a print head having a plurality of drive elements D and the count value N related to the drive history of each drive element D while the print head performs predetermined printing. A count value calculating means for calculating by adding the number of times of driving of the drive element D to be calculated and the number of times of driving the peripheral elements of the drive element D to be calculated and a predetermined influence coefficient; A storage unit that stores the count value N calculated by the calculation unit; and a determination unit that determines whether any of the count values N of the drive elements D stored in the storage unit is equal to or greater than a predetermined count threshold value. When the determination means determines that the count threshold value is exceeded, the operation shifts to a protection operation that restricts the print operation of the print head, so that only the drive element D to be calculated and its peripheral elements are used frequently. Even when the printing data is repeatedly printed, the printing operation of the print head can be shifted to the protective operation before the temperature of the target driving element D reaches the dangerous temperature. Burnout can be prevented.

Hereinafter, the printer of this embodiment will be described with reference to FIGS. Note that parts similar to those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.
As shown in FIGS. 15 and 16, the printer 100 of this embodiment is provided with a gap lever 41 for changing the gap between the print head 6 and the platen 14, and the gap lever 41 is connected to the rail 12. The gap between the tip of the print head 6 and the platen 14 can be changed by operating the gap lever 41.

Reference numeral 42 denotes a gap sensor as a gap detection means, which detects the position of the gap lever 41 and has a function of outputting the gap between the print head 6 and the platen 14 to the control unit 1.
43 is a scale plate as a gap display device (see FIG. 16), and is a plate-like member on which a gap scale consisting of scales and numerals is written so as to follow the operation direction of the gap lever 41. The gap between the print head 6 and the platen 14 corresponds to the position where the lever 41 is operated and stopped.

  The gap scale of the present embodiment is set in five stages for each paper type of the paper P so that the gap between the print head 6 and the platen 14 becomes wider as the gap scale number increases (the following). In the description, when the number of the gap scale is “1”, it is expressed as gap scale 1. The same applies to the excitation time and the gap correction coefficient described later.) In the case of the thin paper P, the gap scale 1 is used, and the two or five sheets of paper that are thickened according to the number of sheets to be stacked, such as a copy paper in which the paper P is stacked two to five sheets. In this case, the gap scale 2 to the gap scale 5 are set to be used, and if the user operates the gap lever 41 at the position of the gap scale corresponding to the paper type, the gap between the print head 6 and the platen 14 is set. It is configured to be an appropriate clearance.

  Further, when the gap between the print head 6 and the platen 14 becomes wide, it is necessary to increase the excitation time per one time (= number of driving times) of the coil 16c of the driving element D in accordance with the increase in the gap. Therefore, the control unit 1 according to the present embodiment sets the excitation time per excitation frequency of the drive element D according to the position of the gap scale recognized from the output from the gap sensor 42 to the print head corresponding to the position of the gap scale. 6 is set to an appropriate excitation time corresponding to the gap between the platen 14 and the platen 14, and the printing process is executed.

  In this case, when the print head 6 is driven with the excitation time 1 per excitation frequency of the drive element D when the gap scale is 1, and when the drive element D is excitation time per time when the gap scale is 5, When the print head 6 is driven at time 5, the excitation time 5 is longer, and when the print head 6 is driven at excitation time 5, the temperature rises than when the print head 6 is used at excitation time 1. In other words, if the excitation time per one excitation is increased, the amount of heat generated is increased and the temperature rise of the drive element D is increased. In this embodiment, the temperature rise is caused by the difference in excitation time. In order to correct the difference, a gap correction coefficient corresponding to each gap scale is provided according to the position of the gap scale shown in FIG. 17, and the gap scale corresponding to these paper types is provided. Its excitation time and the gap correction coefficient and the like are stored in the storage unit 3 is set in advance for.

  Such a gap correction coefficient is obtained by continuously driving the five drive elements D1 to D5 having the drive element D1 as the central element at the same time for each gap correction coefficient using the printer 100 according to the present embodiment. The temperature increase with time of the driving element D1 located in the center at this time is set based on the experimental results. Specifically, as in the case of the first embodiment, the gap scale 1 For example, the temperature rise of the drive element D1 located in the center when the experiment is performed with the gap scale 5 (excitation time 5) is compared with the temperature rise of the drive element D1 located in the center when the experiment is performed with the (excitation time 1). If it is 1.5 times, the gap correction coefficient 1 is set to “1”, the gap correction coefficient 5 is set to “1.5”, and the gap scale 5 is set. Remote count value N is set to reach 1.5 times faster count threshold (see FIG. 18). That is, with respect to the time at which the count value N1 of the drive element D1 located at the center reaches the count threshold when the five drive elements D1 to D5 having the drive element D1 as the central element are continuously driven at the gap scale 1 at the same time. In the gap scale 5, when the same five drive elements D1 to D5 are continuously driven at the same time, the time for the count value N1 of the drive element D1 located at the center to reach the count threshold is larger than the gap correction coefficient 5 / gap. The correction coefficient is 1 time faster. The other gap correction coefficients 2 to 4 are set in the same manner.

Hereinafter, the printing process by the printer of this embodiment will be described with reference to the flowchart shown in FIG.
The processing operation of the update process of the count value N in the present embodiment is the same as the processing operation of the update process of the count value N described in the first embodiment with reference to FIG.
Since the processing operations of steps SB1 to SB4 of the present embodiment are the same as the processing operations of SA1 to SA4 of the first embodiment, description thereof is omitted.

SB5: The control unit 1 that has acquired the number of times of excitation of each drive element D and the count values N1 to N24 recognizes the gap scale of the gap lever 41 based on the output from the gap sensor 42, and from the storage unit 3 to the gap scale. The corresponding gap correction coefficient and excitation time are read and acquired. In this description, it is assumed that the recognized gap scale is the gap scale 5 and the gap correction coefficient 5 and the excitation time 5 are read from the storage unit 3.
SB6: The control unit 1 that has acquired the gap correction coefficient 5 and the excitation time 5 corresponding to the gap scale 5 sets the number i to “1” in order to calculate the count value Ni of the drive element Di at the end of printing of the row. Set.

SB7: The control unit 1 calculates the row count value ΔNi that is the count value Ni for one row in the printing of the row of the driving element Di by the count value calculating unit 1a, and proceeds to step SB8. The calculation method of the row count value ΔNi in this embodiment is performed as follows.
That is, since i = 1 at this stage, when the row count value ΔN1 is calculated for the drive element D1,
Row count value ΔN1 = [Number of excitation of drive element D1 + Influence coefficient 1 × (Number of excitation of drive element D2 + Number of excitation of drive element D3) + Influence coefficient 2 × (Number of excitation of drive element D4 + Excitation of drive element D5) Times)] x gap correction factor 5 (2)
Calculate with That is, the row count value ΔN1 of the present embodiment is calculated by multiplying the row count value ΔN1 calculated in step SA6 of the first embodiment by the gap correction coefficient 5.

Subsequent processing operations in Steps SB8 to SB20 are the same as the processing operations in SA7 to SA19 in the first embodiment, and a description thereof will be omitted.
In this case, in step SB17 (corresponding to step SA16 in the first embodiment), the command signal transmitted to the drive circuit 5 is the print head drive motor 7 and the character generator necessary for printing in the print speed reduction mode. A command signal for driving the print head 6 at the excitation timing and the excitation time 5 of each drive element D generated in 4 is transmitted.

In step SB18 (corresponding to step SA17 in the first embodiment), the command signal transmitted to the drive circuit 5 is generated by the print head drive motor 7 and the character generator 4 necessary for printing at the normal printing speed. A command signal for driving the print head 6 is transmitted at the excitation timing and excitation time 5 of each drive element D.
In this way, the printing process is executed by the printer 100 that can change the gap between the print head 6 and the platen 14 in accordance with the medium type of this embodiment.

In this embodiment, in step SB16 and SB17, when the control unit 1 determines that the protection operation of the print head 6 is necessary because the head temperature T is equal to or higher than the temperature threshold, the processing mode of the printing process Has been described as shifting to the printing speed reduction mode, but may be shifted to the pause mode.
Further, in this embodiment, when the control unit 1 determines in step SB13, SB14, SB15 that the protection operation of the print head 6 is necessary because one of the count values N1 to N24 has reached the count threshold value. In the above description, the processing mode of the printing process is shifted to the pause mode. However, the printing mode may be shifted to the printing speed reduction mode.

  As described above, when printing of frequently used print data of only the target drive element D and its peripheral drive elements D is repeatedly performed, the same print data is used when the medium type is one sheet. When printing is performed with a gap between the print head 6 corresponding to the gap scale 1 and the platen 14 and the medium type is a five-sheet overlap sheet, when printing is performed with a gap corresponding to the gap scale 5, the medium type is a single sheet ( In the case of the gap corresponding to the gap scale 1, any of the count values N1 to N24 reaches the count threshold before the temperature of the target drive element D reaches the dangerous temperature, and the protective operation can be performed. When the medium type is a five-sheet overlap sheet (gap corresponding to the gap scale 5), the excitation time becomes long. Therefore, before any of the count values N1 to N24 of the target drive element D reaches the count threshold, Rises up to the temperature critical temperature of the driving element D, there is a risk of burning the driving element D.

  On the other hand, in this embodiment, when calculating the count values N1 to N24 for each row, a gap correction coefficient for correcting the row count value ΔNi according to the gap scale is provided. Even if the print data is the same as that of the gap scale 1 using the gap correction coefficient 5, any one of the count values N1 to N24 increases earlier than when printing is performed on the gap scale 1. Any of the count values N1 to N24 reaches the count threshold before the temperature of the driving element D to be reached reaches the dangerous temperature, and a protective operation for restricting the printing operation of the print head 6 can be performed. Burnout can be prevented.

  As described above, in the present embodiment, the printer has a print head having a plurality of drive elements D and the count value N related to the drive history of each drive element D while the print head performs predetermined printing. The change in the gap between the print head and the platen is added to the sum of the number of times of driving the driving element D to be calculated and the number of times of driving the peripheral elements of the driving element D to be calculated multiplied by a predetermined influence coefficient. Count value calculating means for multiplying by a correction coefficient for correcting the excitation time change of the drive element D due to the above, a storage section for storing the count value N calculated by the count value calculating means, and a drive stored in the storage section A determination unit configured to determine whether any one of the count values N of the element D is equal to or greater than a predetermined count threshold; and when the determination unit determines that the count is equal to or greater than the count threshold, the printing operation of the print head is regulated. Since the shift to the protective operation is performed, the temperature of the target drive element D is obtained even when the print data frequently used only for the drive element D and its peripheral elements is repeatedly printed. Before the temperature reaches the dangerous temperature, the printing operation of the print head can be shifted to the protection operation, and the drive element D can be prevented from being burned out.

In each of the above-described embodiments, the case where the number of wire pins is 24 print heads has been described. However, in the case where the number of wire pins is 9 print heads, the count values N1 to N9 calculated in the same manner as described above in the counters C1 to C9. If N9 is stored, the same effect as described above can be obtained.
In each of the above embodiments, the influence coefficient 1 and the influence coefficient 2 are set in consideration of the five drive elements D including the drive element D to be calculated and the surrounding drive elements D. The row count value ΔN may be calculated by considering the seven or more drive elements D and providing a similar influence coefficient for each of them. In this case, each influence coefficient is preferably set so as to decrease as the distance from the drive element D to be calculated increases as a result of experiments.

  Furthermore, in each of the above-described embodiments, a description has been given assuming that a plurality of start set values are provided for the temperature range of the head temperature T. However, a plurality of count threshold values are provided for the temperature range of the head temperature T, and the head temperature T is As the value increases, the same effect as described above can be obtained even if the count threshold value is decreased.

DESCRIPTION OF SYMBOLS 1 Control part 1a Count value calculation means 2 Personal computer 3 Memory | storage part 4 Character generator 5 Drive circuit 6 Print head 6a Wire pin 7 Print head drive motor 8 Medium conveyance motor 9 Temperature sensor 11 Carriage 12 Rail 13 Drive belt 14 Platen 16a Core 16b Bobbin 16c coil 18 base plate 19 first yoke 20 permanent magnet 21 second yoke 22 spacer 24 leaf spring 25 armature 27 armature yoke 28 guide frame 29 guide portion 31 space sheet 32 printed circuit board 33 heat sink 41 gap lever 42 gap sensor 43 scale plate 100 printer

Claims (8)

A printing apparatus that includes a print head having a plurality of wire pins and a plurality of drive elements that drive the wire pins by electromagnetic force, and that selectively projects the wire pins by the drive elements and performs printing on a medium via an ink ribbon In
Protection operation means for restricting the printing operation of the print head in order to protect the drive elements;
A determination unit that calculates a count value related to the drive history of each of the drive elements by a predetermined method, compares the calculated count value with a predetermined threshold value, and determines whether or not the protection operation unit needs to be executed; A printing apparatus comprising: The printing apparatus according to claim 1,
The count value calculated by the predetermined method is a predetermined value for the number of times of driving of the drive element to be calculated and the number of times of driving peripheral elements of the drive element to be calculated while the print head performs predetermined printing. A printing apparatus having a count value obtained by adding a drive count multiplied by an influence coefficient. The printing apparatus according to claim 1,
The count value calculated by the predetermined method is a predetermined value for the number of times of driving of the drive element to be calculated and the number of times of driving peripheral elements of the drive element to be calculated while the print head performs predetermined printing. A printing apparatus, characterized in that a count value is obtained by multiplying the sum of the number of driving times multiplied by an influence coefficient and a correction coefficient for correcting a change in excitation time of the drive element due to a change in the gap between the print head and the platen. The printing apparatus according to claim 2 or 3,
The printing apparatus according to claim 1, wherein the influence coefficient is set so as to decrease as a distance between the drive element to be calculated and the peripheral element increases. The printing apparatus according to any one of claims 1 to 4,
Temperature detecting means for detecting the internal temperature of the print head;
And a means for setting a start set value of the counter value of each driving element in accordance with the internal temperature detected by the temperature detecting means. The printing apparatus according to any one of claims 1 to 5,
Storage means for storing the calculated count value;
The count value stored in the storage means is a count value obtained by adding the calculated count value to the count value periodically calculated based on the head temperature of the print head already stored in the storage means. Characteristic printing device. The printing apparatus according to any one of claims 1 to 6,
The printing apparatus according to claim 1, wherein the protection operation unit pauses the printing operation or reduces a printing speed of the printing operation. In a control method of a print head, which has a plurality of wire pins and a plurality of drive elements that drive the wire pins by electromagnetic force, and prints on a medium by selectively projecting the wire pins by the drive elements,
Protection that regulates a printing operation to protect each of the drive elements by calculating a count value related to the drive history of each of the drive elements by a predetermined method and comparing the calculated count value with a predetermined threshold value A method for controlling a print head, comprising: determining whether or not an operation needs to be performed.

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