JP2002192759A - Recording head control method for recording apparatus and recording apparatus - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To prevent a recording operation of a recording head from frequently stopping. SOLUTION: A recording head 18 is mounted on a carriage traveling along a platen 21. The recording head has a head body 40 provided with a plurality of recording wires 35, and a thermistor 52 for detecting the temperature of the head body. A control substrate unit that causes a recording wire to protrude to cause a recording head to perform a recording operation, thereby recording an image on a sheet S conveyed between a platen and the recording head. The substrate unit detects a recording pattern of an image to be recorded on a sheet by the recording head in advance, and changes a temperature threshold value for stopping the recording operation of the recording head based on the detected temperature detected by the thermistor according to the recording pattern. It is configured to be set by setting.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording head control method and a recording apparatus for a recording apparatus for controlling the recording operation of a recording head having a plurality of recording wires based on a temperature detected by a temperature detector in the recording head. Related to the device.

[0002]

2. Description of the Related Art In a recording apparatus, a plurality of recording wires of the recording head are struck onto a sheet located on a front peripheral surface of the platen via an ink ribbon while the recording head travels in an axial direction of a platen. There is a dot impact printer that performs recording and writing on this sheet. In a recording head of such a printer, a radiator is provided on an outer peripheral portion of a head body having a driving coil (electromagnet coil) for driving a recording wire as a heating element. A temperature detecting element (thermistor) for detecting the temperature of the head main body is disposed on the outer peripheral portion. The thermistor detects the temperature of the head main body, the temperature of which rises as the recording operation of the recording head is performed.

As shown in FIG. 8, a control device for such a recording apparatus has a temperature detected by a thermistor at a threshold m (10 m).
(0 ° C.), the recording operation of the recording head is stopped. The reason will be described below.

That is, when ordinary characters (letter quality, draft, etc.) are recorded on a sheet, the temperature detected by the thermistor and the heat generation temperature of the drive coil in the head body are indicated by broken line a and solid line in FIG. When the thermistor detects the threshold value m (100 ° C.), the heating temperature of the drive coil becomes about 130 ° C. On the other hand, when all solid images, which are images of a recording pattern with a duty of 100%, are printed on a sheet, the temperature detected by the thermistor and the heat generation temperature of the drive coil in the head main body are represented by the broken line c and the solid line d in FIG. When the thermistor detects the threshold value m (100 ° C.), the heating temperature of the drive coil becomes about 170 ° C. Here, the duty refers to the ratio of the number of dots by the recording wire 35 per recording unit, for example, per character on average.

When the temperature of the drive coil exceeds about 170 ° C., the drive coil is burned, and the lubricant for lubricating the recording wire is deteriorated. For this reason, even when the image of the recording pattern with the highest heat generation amount of the drive coil and the duty of 100%, that is, when the entire solid is recorded, the image is recorded on the sheet so that the drive coil does not burn out. When the temperature detected by the thermistor reaches the threshold value m (100 ° C.) for the recording pattern of, the recording operation of the recording head is stopped.

[0006]

When ordinary characters (letter quality, draft, etc.) are recorded on a sheet, when the thermistor detects a threshold value m (100 ° C.), the temperature of the drive coil is still about 130 ° C. In addition, there is a sufficient margin before the drive coil is burned.

However, even in the case of recording ordinary characters, the recording operation of the recording head is stopped whenever the thermistor detects the threshold value m (100 ° C.). May occur frequently.

SUMMARY OF THE INVENTION An object of the present invention is to provide a recording head control method and a recording apparatus for a recording apparatus which can prevent the recording operation of the recording head from frequently stopping. It is in.

[0009]

According to a first aspect of the present invention, a recording head includes a head body having a plurality of recording wires, and a temperature detector for detecting a temperature of the head body. In a recording head control method for a recording apparatus that controls recording of an image on a sheet by projecting a recording wire and causing the recording head to perform a recording operation, a recording pattern of an image to be recorded on a sheet by the recording head is determined in advance. The temperature threshold for detecting and stopping the recording operation of the recording head based on the detected temperature detected by the temperature detector is changed and set according to the recording pattern.

According to a second aspect of the present invention, in the first aspect of the present invention, a temperature threshold value for stopping the recording operation of the recording head based on the temperature detected by the temperature detector is recorded on the sheet. This is based on the case where the duty of a recording pattern of an image is high, and is set higher than the reference value in other cases.

According to a third aspect of the present invention, in the second aspect, the case where the duty of the recording pattern of the image recorded on the sheet is high means that the recording pattern of the image recorded on the sheet has a high duty. It is characterized by including 100%.

According to a fourth aspect of the present invention, in the second aspect, the case where the duty of the recording pattern of the image recorded on the sheet is high means that the recording pattern of the image recorded on the sheet is a graphic pattern. It is characterized by being a character or bit image.

[0013] The invention according to claim 5 is the invention according to claims 1 to 4.
In the invention according to any one of the above, the change of the temperature threshold value for stopping the recording operation of the recording head based on the detected temperature detected by the temperature detector is performed stepwise.

According to a sixth aspect of the present invention, a recording head is mounted on a carriage that travels along a platen, and the recording head includes a head body having a plurality of recording wires;
A temperature detector for detecting the temperature of the head main body, and the control device causes the recording head to execute a recording operation by projecting the recording wire, thereby allowing a recording operation to be performed between the platen and the recording head. In a recording apparatus that records an image on a sheet conveyed to the control device, the control device detects a recording pattern of an image to be recorded on the sheet by the recording head in advance, and performs the detection based on a detected temperature detected by the temperature detector. The temperature threshold for stopping the recording operation of the recording head is changed and set according to the recording pattern.

According to a seventh aspect of the present invention, in the invention of the sixth aspect, the control device sets a temperature threshold value for stopping the recording operation of the recording head based on the temperature detected by the temperature detector. The present invention is characterized in that the reference value is set to be higher than the reference value when the duty of the print pattern of the image to be printed on the sheet is high, and in other cases, it is set higher than the reference value.

According to an eighth aspect of the present invention, when the duty of the recording pattern of the image recorded on the sheet is high, the recording pattern of the image recorded on the sheet is high. It is characterized by including 100%.

According to a ninth aspect of the present invention, in the invention according to the seventh aspect, the case where the duty of the recording pattern of the image recorded on the sheet is high means that the recording pattern of the image recorded on the sheet is graphic. It is characterized by being a character or bit image.

According to a tenth aspect of the present invention, in the invention according to any one of the sixth to ninth aspects, the control device comprises:
The temperature threshold for stopping the recording operation of the recording head based on the temperature detected by the temperature detector is changed in a stepwise manner.

The first to tenth aspects of the present invention have the following effects.

Generally, the duty of a recording pattern of an image recorded on a sheet is high (for example, duty 1).
The temperature of the drive coil in the head body that drives the recording wire rises as the total solid, graphic character, or bit image of 00% increases, and therefore, the temperature detected by the temperature detector that detects the temperature of the head body increases. On the other hand, the lower the duty of the recording pattern (for example, a normal character such as letter quality or draft with a duty of about 15%), the lower the temperature of the drive coil, and therefore the lower the temperature detected by the temperature detector. For this reason, the temperature threshold for stopping the recording operation of the recording head based on the temperature detected by the temperature detector is changed and set according to the recording pattern of the image recorded on the sheet, for example, when the duty of the recording pattern is high. , And set high when the duty of the recording pattern is low. As a result, it is possible to prevent the recording operation of the recording head from frequently stopping when recording normal characters having a low duty of the recording pattern.

[0021]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing a printer main body of a dot impact printer to which an embodiment of a recording apparatus according to the present invention is applied. FIG. 2 is a side sectional view showing the printer main body of FIG.

The printer 10 as a recording apparatus shown in these figures records a large number of recording wires (not shown) of a recording head on a sheet S via an ink ribbon 31 (FIG. 2) to record dots. , A dot impact printer that prints images containing characters. Here, the sheet S is not only plain paper such as cut sheet paper or continuous paper, but also OHP
(Overhead Project) Sheets, coated paper, films, etc.

The printer 10 is configured as shown in FIG.
A printer main body 11 as a recording apparatus main body, a push tractor unit 12 and a discharge unit 13 detachably mounted on the printer main body 11, and a sheet supply guide 34 also detachably mounted on the printer main body 11.
(FIG. 2) and an upper case and a lower case (not shown) that cover the upper and lower parts of the printer main body 11, respectively.

The printer body 11 includes a base frame 14 as a body frame, a sheet guide frame 15
(FIG. 2), a left side frame 16 and a right side frame 17, a printing mechanism unit 20 including a recording head 18 and a carriage 19, and a sheet transport including a platen 21, a sheet guide 22, and a pinch roller 25 (FIG. 2). Mechanism 23
And is configured.

The base frame 14 and the seat guide frame 15 are arranged substantially in parallel as shown in FIG. 2, and the left side frame 16 and the right side frame 17 are provided at both ends of the base frame 14 and the sheet guide frame 15, respectively.
Are respectively erected and fixed. As shown in FIG. 1, between the left side frame 16 and the right side frame 17, a carriage guide shaft 24 is hung and pivotally supported, and a platen 21 is hung and rotatably disposed. Have been. The seat guide 22 is provided on the left side frame 16.
And the right side frame 17, and is fitted and fixed to the seat guide frame 15. Also, the rear portions of the left side frame 16 and the right side frame 17,
The push tractor unit 1 is provided on each upper part.
2. A tractor unit mounting portion and a discharging unit mounting portion (not shown) to which the discharging unit 13 can be mounted are provided.

The push tractor unit 12 shown in FIG.
Sends out the continuous paper as the sheet S to the sheet transport mechanism 23, and the sheet supply guide 34 supplies the cut sheet as the sheet S to the sheet transport mechanism 23 one by one. The discharge unit 13 pulls out continuous paper or cut sheet from the sheet transport mechanism 23 to the outside of the printer 10.

That is, as shown in FIG. 2, the rotation of the tractor belt 26 of the push tractor unit 12 causes
By the action of the pins 27 of the tractor belt 26, the continuous paper is guided by the sheet guide 22 of the sheet transport mechanism 23, and passes through a sheet transport path 28 formed between the sheet guide 22 and the platen 21. And is fed in the direction of arrow α. When the push tractor unit 12 is not operating, cut sheets can be supplied one by one from the sheet supply guide 34 to the front of the platen 21 via the sheet conveyance path 28. Also, discharge unit 1
3, the continuous paper or cut sheet on which characters or the like are recorded by the recording head 18 is moved from the platen 21 of the sheet conveying mechanism 23 by an arrow β as described later.
Pulled out in the direction. Thereby, the continuous paper or cut sheet is conveyed in the sub-scanning direction orthogonal to the main scanning direction of the carriage 19 described later.

The carriage 19 shown in FIG. 1 is slidably inserted through a carriage guide shaft 24 and has a recording head 18 mounted thereon. Since the carriage guide shaft 24 is arranged in parallel with the platen 21, the carriage 19
Are the platen 21 and the carriage guide shaft 24
Are provided so as to be able to move (run) in the main scanning direction which coincides with the axial direction.

The carriage 19 is guided by a carriage guide shaft 24 via a timing belt 30 (FIG. 2) by forward or reverse rotation of a carriage drive motor (not shown), and travels leftward or rightward in FIG. 1 in the main scanning direction. You.

The recording head 18 has a large number of recording wires 3
5 (only one recording wire 35 is shown in FIG. 3), and the ink ribbon 31 is located forward of the recording wires 35 in the protruding direction. The recording head 18 is the carriage 1
9, the recording wire 35 is caused to protrude to strike the ink ribbon 31 while traveling in the main scanning direction, and the ink of the ink ribbon 31 is applied to the platen 21 and the ink ribbon 31.
And an image including characters is recorded on the sheet S (continuous paper or cut sheet) conveyed between the sheet S and the sheet S.

In the recording operation by the recording head 18, one line of recording is performed by the recording wire 35 of the recording head 18 while the carriage 19 travels leftward or rightward in the main scanning direction, and the recording of one line is performed. Each time the sheet S is a continuous sheet, the platen 21 and the push tractor unit 12 of the sheet conveying mechanism 23 shown in FIG.
When the sheet S is a cut sheet, the platen 21, the pinch roller 25, and the discharge unit 13 of the sheet conveying mechanism 23 respectively convey the sheet S by a predetermined amount (usually between lines). The operation is performed by repeating these operations.

Reference numeral 32 shown in FIG. 2 is formed between the base frame 14 and the sheet guide frame 15 so as to open therefrom.
A bottom sheet supply port for supplying the sheet S into the inside.

The drive control of the platen 21, the push tractor unit 12 and the discharge unit 13, the running control of the carriage 19, and the recording wire 3 of the recording head 18
The control of the recording operation by 5 is performed by a control board unit 33 (FIG. 2) as a control device. This control board unit 33
Is disposed below the sheet guide frame 15 behind the printer main body 11, for example.

As shown in FIG. 3, the recording head 18 has a nose portion 41 connected to a head body 40 and a radiator 42 disposed outside the head body 40.

In the head main body 40, a core 44 around which an electromagnet coil 43 as a driving coil is wound is integrally formed with a plurality of frames 45 at predetermined intervals in a circumferential direction, and the core 44 is attracted to the core 44 by energizing the electromagnet coil 43. A driven wire lever 46, and this wire lever 46
A return spring 48 that urges the pin 47 in a direction away from the core 44 in a direction away from the core 44; and a recording spring that is connected to the tip of the wire lever 46 and projects from the nose portion 41 when the wire lever 46 is attracted to the core 44. And a wire 35.

The head bodies 40 are stacked in two stages in the direction in which the recording wire 35 advances and retreats, and are arranged as a combined head body. However, in FIG.
Only 0 is shown.

The nose portion 41 guides the reciprocating operation including the projecting operation of the recording wire 35, and includes a plurality of intermediate guides 49 disposed therein and one distal guide 50 disposed at the distal end. Is provided. The plurality of recording wires 35 penetrate through the intermediate guide 49 and the distal end guide 50 to guide the reciprocating operation. FIG. 3 shows a case where one recording wire 35 penetrates the intermediate guide 49 and the tip guide 50, and the other recording wires 35 are omitted.

The radiator 42 is formed in a substantially cylindrical shape as shown in FIGS. 3, 4 and 5, and a plurality of fins 51 are integrally provided on the outside. The radiator 42 is arranged on the outer peripheral portion of each head body 40 in the above-mentioned combined head body and covers each head body 40. This radiator 42
When the electromagnet coil 43 of each head body 40 is energized, the electromagnet coil 43 becomes a heating element and generates heat.
1 to dissipate heat to cool these head bodies 40.

As shown in FIGS. 3 to 5, a temperature detector (temperature detection) for detecting the temperature of the frame 45 of the head main body 40 is provided on the outer peripheral portion of the frame 45 in one head main body 40 of the head main body combined body. A thermistor 52 as an element is provided. The thermistor 52 has a groove 54 formed on the inner peripheral surface 53 of the radiator 42 in a state where the radiator 42 is installed on the head body 40 of the head body combined body.
Housed within.

The temperature of the frame 45 of the head main body 40 detected by the thermistor 52 is controlled by the control board 33.
(FIG. 2). The control board unit 33 detects a recording pattern of an image to be recorded on the sheet S by the recording wire 35 before the recording wire 35 is projected to cause the recording head 18 to perform a recording operation.

By the way, as the recording operation of the recording head 18 is performed, the temperature of the electromagnet coil 43 in the head body 40 rises. In order to prevent the electromagnet coil 43 from burning and the lubricant for lubricating the recording wire 35 from deteriorating, the control board unit 33 controls the recording head when the temperature detected by the thermistor 52 reaches a predetermined temperature threshold. 18
Is stopped to stop the recording operation.

The control board section 33 is provided with a thermistor 5
Recording head 18 based on the temperature detected by
The predetermined temperature threshold value for stopping the recording operation is changed and set according to the recording pattern of the image detected as described above.

That is, the control board unit 33 includes the thermistor 5
Recording head 1 based on the temperature detection value detected by
The temperature threshold value for stopping the printing operation of No. 8 is set based on the case where the duty of the printing pattern of the image printed on the sheet S is high, and in other cases, the temperature threshold value is increased stepwise from the reference value. I have. Here, the duty means a recording wire 35 per recording unit, for example, an average per character.
Means the ratio of the number of dots.

For example, as shown in FIG. 6, the control board unit 33 sets the temperature threshold for stopping the recording operation of the recording head 18 based on the temperature detected by the thermistor 52 to the sheet S.
The duty of the recording pattern of the image recorded in
When the duty is 100%, the temperature is set to 100 ° C., this 100 ° C. is set as a reference value, and when the duty of the recording pattern is 45 to 70%, it is set to 105 ° C. lower than the reference value, and the duty of the recording pattern is set to 25 to 45%. At 110 ° C., and 120 ° C. when the duty of the recording pattern is 15 to 25%, and the duty of the recording pattern is 5%.
When the duty of the recording pattern is 0 to 5%, the temperature is set to 130 ° C, and when the duty of the recording pattern is 0 to 5%, the temperature is set to 140 ° C.

More specifically, as shown in FIG. 7, when all solid images, which are images of a recording pattern with a duty of 100%, are printed on the sheet S, the temperature detected by the thermistor 52 changes as shown by a broken line C. Electromagnetic coil 4 in 40
The heat generation temperature of No. 3 changes as shown by the solid line D. At this time, the temperature threshold M for stopping the recording operation of the recording head 18 based on the temperature detected by the thermistor 52 is set to 100 ° C. (FIG. 6).
When detecting (100 ° C.), the control board unit 33 stops the recording operation of the recording head 18.

In this case, the thermistor 52 has a temperature threshold M
When (100 ° C.) is detected, the heating temperature of the electromagnet coil 43 becomes about 170 ° C. At this point, the recording head 1
8 is stopped, so that the electromagnetic coil 43
The temperature does not exceed ℃. As a result, burning of the electromagnet coil 43 and deterioration of the lubricant for lubricating the recording wire 35 are prevented.

When ordinary characters such as letter quality and draft, which are images of a recording pattern with a duty of 5 to 15%, are recorded on the sheet S, the temperature detected by the thermistor 52 is as shown by a broken line A in FIG. The heating temperature of the electromagnet coil 43 in the head main body 40 varies as shown in FIG.
As shown by the solid line B in FIG. At this time, the temperature threshold value N at which the recording operation of the recording head 18 is stopped is set to 130 ° C. (FIG. 6) based on the temperature detected by the thermistor 52. Therefore, the thermistor 52 detects this temperature threshold value N (130 ° C.). At this time, the control board unit 33 stops the recording operation of the recording head 18.

However, the thermistor 52 operates at the temperature threshold N (1
It takes a long time from the start of the recording operation of the recording head 18 until the temperature of 30 ° C. is detected. As a result, when the recording head 18 records normal characters which are images of a recording pattern with a duty of 5 to 15%, the recording operation of the recording head 18 is prevented from frequently stopping.

As described above, a plurality of rows are recorded on the sheet S, but the control board unit 33 records the plurality of rows on the sheet S during the conveyance of the sheet S in the sub-scanning direction before recording each row. The recording pattern of the image to be recorded is detected as described above, and a temperature threshold value (temperature threshold value M, N, etc.) for stopping the recording operation of the recording head 18 is determined based on the detection result. The control board unit 33 causes the thermistor 52 to detect the temperature of the head main body 40 both during the conveyance of the sheet S and during the recording operation on the sheet S.

As described above, according to the present embodiment, the following effects can be obtained.

The heating temperature of the electromagnet coil 43 in the head body 40 for driving the recording wire 35 increases as the duty of the recording pattern of the image to be recorded on the sheet S by the recording head 18 increases (for example, 100% duty). And
Therefore, the thermistor 5 for detecting the temperature of the head body 40
The temperature detected by 2 is high. On the other hand, the lower the duty of the image recording pattern (for example, the duty
% Of ordinary characters such as letter quality and draft), the electromagnet coil 43 has a low heat generation temperature, and therefore the temperature detected by the thermistor 52 is also low. For this reason, the temperature threshold for stopping the recording operation of the recording head 18 based on the temperature detected by the thermistor 52 is changed and set according to the recording pattern of the image recorded on the sheet S. Is high (70-
100% duty) and set high when the duty of the recording pattern of the image is low (for example, 0 to 15% duty). Thereby, the recording head 18
In the case of recording normal characters such as letter quality and draft, the duty of the recording pattern of the image to be recorded on the sheet S is low, it is possible to prevent the recording operation of the recording head 18 from frequently stopping.

As described above, the present invention has been described based on the above embodiment, but the present invention is not limited to this.

For example, the control board unit 33 includes the thermistor 5
Recording head 1 based on the temperature detection value detected by
The temperature threshold value at which the recording operation of Step 8 is stopped is based on the case where the recording pattern of the image recorded on the sheet S is a graphic character or a bit image. In other cases, the temperature threshold value is more gradual or curved than the reference value. You may set it up.

The control board section 33 includes a thermistor 52.
Recording head 18 based on the temperature detection value detected by
The temperature threshold value for stopping the recording operation is based on the case where the duty of the recording pattern of the image recorded on the sheet S is 100%, and in other cases, the temperature threshold value increases stepwise or in a curve from the reference value. May be set.

[0056]

As described above, according to the recording head control method of the recording apparatus according to the first aspect of the present invention, the recording head includes a head main body having a plurality of recording wires, and a temperature of the head main body. And a temperature detector for detecting the temperature of the recording medium. The recording head controls the recording head so that an image is recorded on a sheet by causing the recording wire to protrude to perform a recording operation. The head detects a recording pattern of an image to be recorded on a sheet in advance, and sets a temperature threshold value for stopping the recording operation of the recording head based on the detected temperature detected by the temperature detector,
Since it is changed and set according to the above recording pattern,
Frequent stoppage of the recording operation of the recording head can be prevented.

According to the recording apparatus of the present invention, a recording head is mounted on a carriage that travels along a platen, and the recording head includes a head body having a plurality of recording wires, and a recording head. A temperature detector for detecting a temperature of the main body, wherein the control device causes the recording head to perform a recording operation by projecting the recording wire, thereby conveying the recording wire between the platen and the recording head. In the recording apparatus for recording an image on a sheet to be recorded, the control device detects a recording pattern of an image to be recorded on the sheet by the recording head in advance, and based on the detected temperature detected by the temperature detector, Since the temperature threshold value for stopping the recording operation is changed and set according to the recording pattern, the recording operation of the recording head is frequently performed. It can be prevented from being stopped.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a printer main body of a dot impact printer to which an embodiment of a recording apparatus according to the present invention is applied.

FIG. 2 is a side sectional view showing the printer main body of FIG.

FIG. 3 is a sectional view showing the recording head of FIG.

FIG. 4 is an exploded perspective view showing the recording head of FIG.

FIG. 5 is an exploded perspective view of the disassembled recording head of FIG. 4 viewed from another angle.

6 is a graph showing a relationship between a temperature threshold value at which the recording operation of the recording head of FIG. 1 is stopped and a duty of a recording pattern of an image recorded on a sheet.

7 is a graph showing a relationship between a heating temperature of a drive coil in a head main body of the recording head of FIG. 1 and a temperature detected by a thermistor of FIG. 3;

FIG. 8 is a graph showing a relationship between a heating temperature of a drive coil in a head body of a recording head and a temperature detected by a thermistor in a conventional recording apparatus.

[Explanation of symbols]

 Reference Signs List 10 printer (recording device) 18 recording head 19 carriage 21 platen 33 control board unit (control device) 35 recording wire 40 head body 52 thermistor (temperature detector) S sheet M, N temperature threshold

Claims (10)

[Claims] A recording head includes a head body having a plurality of recording wires, and a temperature detector for detecting a temperature of the head body. A recording operation is performed on the recording head by projecting the recording wires. A recording head control method for a recording apparatus that controls to record an image on a sheet by causing the recording head to detect a recording pattern of an image recorded on a sheet by the recording head in advance, and to detect a detected temperature detected by the temperature detector. A printhead control method for a printing apparatus, wherein a temperature threshold value for stopping a print operation of the printhead is changed and set in accordance with the print pattern based on the above. 2. A temperature threshold for stopping a recording operation of a recording head based on a temperature detected by the temperature detector, based on a case where the duty of a recording pattern of an image recorded on a sheet is high, and 2. The method according to claim 1, wherein the value is set to be higher than the reference value.
6. A recording head control method for a recording apparatus according to claim 1. 3. The image forming apparatus according to claim 2, wherein the duty of the recording pattern of the image recorded on the sheet is high when the recording pattern of the image recorded on the sheet includes a duty of 100%. 6. A recording head control method for a recording apparatus according to claim 1. 4. The recording medium according to claim 2, wherein the duty of the recording pattern of the image recorded on the sheet is high when the recording pattern of the image recorded on the sheet is a graphic character or a bit image. 6. A recording head control method for a recording apparatus according to claim 1. 5. The method according to claim 1, wherein the step of changing the temperature threshold value for stopping the recording operation of the recording head based on the temperature detected by the temperature detector is performed stepwise. 6. A recording head control method for a recording apparatus according to claim 1. 6. A recording head mounted on a carriage traveling along a platen, the recording head having a head body having a plurality of recording wires and a temperature detector for detecting a temperature of the head body. A recording device that records an image on a sheet conveyed between the platen and the recording head by causing the recording device to perform a recording operation by projecting the recording wire. The control device detects in advance a recording pattern of an image to be recorded on a sheet by the recording head, and sets a temperature threshold value for stopping the recording operation of the recording head based on the detected temperature detected by the temperature detector, to the recording pattern. A recording device configured to change and set according to the conditions. 7. The control device according to claim 1, wherein the control unit sets a temperature threshold value for stopping a recording operation of the recording head based on a temperature detected by the temperature detector based on a case where the duty of a recording pattern of an image recorded on a sheet is high. 7. The recording apparatus according to claim 6, wherein, in other cases, the recording apparatus is set to be higher than the reference value. 8. The method according to claim 7, wherein the case where the duty of the recording pattern of the image recorded on the sheet is high is a case where the recording pattern of the image recorded on the sheet includes the duty of 100%. The recording device according to any one of the preceding claims. 9. The recording medium according to claim 7, wherein the duty of the recording pattern of the image recorded on the sheet is high when the recording pattern of the image recorded on the sheet is a graphic character or a bit image. The recording device according to claim 1. 10. The control device according to claim 1, wherein the control device changes the temperature threshold value for stopping the recording operation of the recording head in a stepwise manner based on the temperature detected by the temperature detector. The recording device according to claim 6.