JP3224110B2 - Print head temperature control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling the temperature of a print head of a printer, which is an output device of information equipment.

[0002]

2. Description of the Related Art Generally, the temperature of a print head rises when a printer continuously performs a printing operation. If the temperature exceeds the heat-resistant temperature of the coil or the like, the coil may be damaged.
For this reason, a temperature detecting element is conventionally incorporated in the print head, and when the temperature exceeds a set temperature, control such as printing stop is performed to prevent breakage.

[0003]

However, when the temperature exceeds the set temperature, if printing is immediately stopped, it takes time for heat transfer between the coil and the temperature detecting element. Therefore, the temperature of the temperature detecting element may decrease, and it may take several tens of seconds before printing is started again.If this time is long, the user often distrusts other malfunctions. .

[0004] The amount of printing per unit time may vary from a low printing density of characters or the like to a high printing density of graphics or the like. Has reached the set value, the temperature of the coil has already become considerably higher than the set temperature, and there is also a possibility of burning. Therefore, lowering the set temperature of the temperature detecting element unit in accordance with a high printing density causes a decrease in throughput.

Therefore, in order to improve this, as shown in FIGS. 5 and 6, a two-stage temperature alarm of a low setting alarm temperature TA1 and a high setting alarm temperature TA2 is provided. Instead of stopping printing when TA1 is exceeded, limit printing is performed by two-pulse printing or a method such as reducing the printing speed, and the temperature rise is suppressed.
Even so, the temperature rises and the alarm temperature TA2 is set high
A method has also been proposed in which printing is stopped when the number exceeds the limit.

Although the above-mentioned problems have been alleviated to some extent by this, printing is stopped when the printing density is high as shown in FIG. 5, and the intermediate area is sometimes skipped by the method of controlling one line at a time. The effect is not obtained unless the two-stage temperature difference is set large. Further, when the printing density is low, as shown in FIG. 6, the temperature is stabilized at a low temperature, and the throughput may be reduced.

Further, when two electronic components such as a sensor, for example, other than a coil are mounted, the upper limit (limit temperature) of the temperature becomes strict. However, control that does not exceed the upper limit and is stable near the upper limit is desired.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to make it possible to perform stable control in the vicinity of an upper limit and to mount an electronic component having a strict upper limit. It is an object of the present invention to provide a print head temperature control method which can be performed.

[0009]

[MEANS FOR SOLVING THE PROBLEMS] To achieve the above object
The method of controlling the temperature of the print head of the present invention,
Printing modes are provided in multiple stages.
The first temperature range for shifting the print mode in the direction of decreasing temperature
The print mode in a direction that increases the print frequency
A second temperature region is provided. And every predetermined time
The print head temperature is detected and the detected print head
The print mode is shifted in accordance with the temperature region of. That is,
The print head temperature is in the first temperature range or the second temperature range;
If it is in the temperature range,
The print mode is shifted.

[0010]

According to this, the printing mode is automatically changed to a printing mode of a printing frequency at which the printing head can continue printing stably, and after the printing is stabilized, printing is continued almost without stopping at almost the same printing mode. Can be.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings. 1 to 3 show an embodiment of the present invention. FIG. 1 is a flowchart showing a print head temperature control procedure, FIG. 2 is a view showing a print mode, FIG. 3 and FIG.
FIG. 4 is a diagram showing a temperature region and a result of control according to the present invention.

First, referring to FIGS. 3 and 4,
3 and 4, the vertical axis represents temperature, and the horizontal axis represents time. The temperature alarm is set in two stages, an alarm temperature T1 of a low setting and an alarm temperature T2 of a high setting, and the temperature is set such that the detector temperature Td on the vertical axis is higher than the alarm temperature T2, that is, Td> T2. The temperature range is TH, and the detection unit temperature Td is higher than the alarm temperature T1 and lower than the alarm temperature T2, that is, T1 <Td <T.
The temperature region of No. 2 is TM (first temperature region) , and the temperature T of the detecting portion is
d is lower than the alarm temperature T1, that is, Td <T1
Is divided into three temperature regions, where TL (second temperature region) is indicated, and the detection portion temperature Td is indicated by a solid line, and the coil temperature Tc is indicated by a dotted line. The detection unit
The temperature Td is detected by a detecting unit (temperature detecting means) not shown.
It is assumed that the print head temperature is known.

The print mode (MD) shown in FIGS. 3 and 4 corresponds to the contents of the print mode MD shown in FIG. That is, in the print mode MD shown in FIG. 2, the print frequency when printing at the maximum speed is set to 100%, and this is set as the print mode MD = 1, so that the print frequency decreases as the print mode increases by one. It is adjusted by combining printing conditions such as printing speed, multi-pass printing, printing direction (both directions, one-way printing), and short intervals, and the printing frequency of print mode MD = 2 is 60.
%, The print frequency of the print mode MD = 3 is 36%, the print frequency of the print mode MD = 4 is 22%, the print frequency of the print mode MD = 5 is 13%, and the print frequency of the print mode MD = 6 is 0.
%, The printing is stopped when the printing mode MD = 6.

Next, the control procedure of the print head will be described with reference to the flowchart shown in FIG. When the temperature control subroutine of step S1 is started from the main control of the printer, first, in step S2, the temperature of the print head (detection section temperature Td) is detected by a detection section (not shown).

Next, in step S3, the detection unit temperature Td is compared with the alarm temperature T2. Here, the detection unit temperature T
If d is higher than the alarm temperature T2 (Td> T2) and it is determined that the temperature d is within the temperature range TH, the printing mode MD is set to 6 (stop printing) in step S4, and the process proceeds to step S13 and ends.

On the other hand, when it is determined in step S3 that the detecting portion temperature Td is lower than the alarm temperature T2, the process proceeds to step S5, and in this step S5, it is determined whether a predetermined time or more has elapsed from the previous processing. . If the predetermined time has not elapsed, the process shifts to step S13 and ends, and if it has elapsed, the process shifts to step S6.

When the process proceeds to step S6, the detection unit temperature Td and the alarm temperature T1 are compared in step S6. Here, when it is determined that the detection unit temperature Td is higher than the alarm temperature T1 (Td> T1) and is within the temperature region TM, the print mode MD is increased by one in step S7 (MD = MD + 1), Move to step S8.

Next, in step S8, the print mode MD
Is determined to be 5 or more, that is, MD> 5. If MD> 5, the process proceeds to step S9 to reset the print mode MD to 5, that is, MD = 5, and proceeds to step S13 to end. If not 5, go from step S8 to step S
13 and ends.

On the other hand, in this step S6, the detection unit temperature Td
Is lower than the alarm temperature T1 (Td <T1) and is determined to be within the temperature range TL, the print mode MD is reduced by one in step S10, and the process proceeds to step S11 as (MD = MD-1).

Next, in step S11, the print mode M
It is determined whether D is 1 or less, that is, whether MD <1, and if MD <1, the process proceeds to step S12 to set the print mode MD to 1,
That is, MD = 1 is reset, and the process proceeds to step S13 and ends. If MD <1, step S11
Then, the process directly proceeds to step S13 and ends. And
When printing is performed by the main control, printing is performed under printing conditions according to the printing mode set here.

Next, when this control method is applied to the operation examples shown in FIGS. 3 and 4, FIG. 3 shows an example in a case where the printing density is high. The print mode MD changes from 1 to 2, and the temperature range is TM at the next opportunity and at the next opportunity. Therefore, the print mode MD increases from 2 to 3, and from 3 to 4, respectively.
Thereafter, when the detection unit temperature Td becomes lower than the alarm temperature T1 and returns to the temperature region of TL again, the print mode MD decreases from 4 to 3. Thereafter, the detection unit temperature Td only slightly fluctuates up and down around the alarm temperature T1, and the print mode MD also repeats steps 2 and 3 and becomes stable. In addition, the coil temperature does not differ from the temperature of the detecting portion except for the initial stage, and is considerably stabilized as compared with the conventional case shown in FIG. This initial temperature difference from the coil shortens the processing period (in this case, the print mode MD
May become large and become unstable), or by using another method such as a method of pseudo-calculating the temperature of the coil and controlling with the pseudo-calculated value.

On the other hand, FIG. 4 shows an example in the case where the printing density is low. In this case, as in the case of FIG.
Only slightly fluctuates up and down around the alarm temperature T1, and the print mode MD is also in a state where 1 and 2 are repeated, and is stable.

Therefore, according to this control method, the detection unit temperature Td is obtained regardless of whether the printing density is high or low.
Is stabilized only by slightly changing up and down around the alarm temperature T1. For this reason, since the temperature difference between the alarm temperature T1 and the alarm temperature T2 can be reduced, the alarm temperature T1 is reduced to the conventional alarm temperature TA1 shown in FIGS.
It can be set higher. In addition, if there is no temperature difference from the initial coil described above, the alarm temperature T2 can be set higher.

In order to carry out the present invention, a temperature detecting means for detecting a print head temperature alarm in two or more stages is required. The temperature detecting means includes a temperature detecting element such as a thermistor in the print head. Is built-in, and the resistance change of the thermistor is changed to voltage, and it is generated by comparing with two or more sets of comparison voltages corresponding to the detected temperature by the comparator,
This can be realized by reading with an A / D converter. Further, since control of various printing conditions for realizing each printing mode shown in FIG. 2 is a combination of those conventionally performed, it can be realized by having a control table corresponding to each printing mode.

If the number of print modes is normally set so as not to cause a temperature alarm in character printing, the maximum print density of graphics is 5 or 6 times. 1
/ 5, 1/6. On the other hand, the ratio between successive print modes (low print frequency ÷ high print frequency)
In order to make a stable transition, around 60% is appropriate,
From the calculation, it is the fourth in FIG. 2, that is, 22% in the print mode MD4.
Type is required. However, when simplifying the control table, the control table may not be constant from 40% to 90%, and the number of print modes may be increased.

The cycle of switching the printing mode is preferably set to a time close to that, since heat transfer is from several tens of seconds to several minutes, but the effect is not necessarily constant but can provide a sufficient effect. is there.

Further, in the above embodiment, the temperature region is set to T
H, TM, and TL. In order to further suppress the fluctuation, an intermediate temperature region TC (third temperature region) is provided between the temperature region TM and the temperature region TL. If the print mode is not changed if it is in the temperature area TC, the print mode M corresponding to the print pattern at that time is not changed.
D is stable, and it is possible to reduce the disturbance of the print alignment and the difference in print density, which are likely to occur due to the shift of the print mode MD.

[0028]

As described above, according to the method for controlling the temperature of the print head according to the present invention, the print head automatically changes to the print mode of the print frequency at which the print head can continue printing stably. Can continue printing in almost the same printing mode with almost no stop. Also, except when the initial rise or when the printing density changes suddenly, the printing mode that matches the printing pattern is naturally selected and stabilized, so that the difference between the temperature of the detector and the temperature of the coil can be minimized. Thus, the case where the print density changes suddenly at the initial rise or when it is suddenly improved is improved. When incorporated in this, overshoot of the coil portion temperature is eliminated, and other electric elements can be mounted with confidence. Further, the temperature at the time of saturation is constant irrespective of the printing pattern, and its value can be set higher than in the conventional case, so that the throughput can be improved.

[Brief description of the drawings]

FIG. 1 is a flowchart illustrating an example of a control method according to the present invention.

FIG. 2 is a diagram illustrating a print mode.

FIG. 3 is a diagram showing a temperature region and a result of control according to the present invention.

FIG. 4 is a diagram showing a temperature region and a result of control according to the present invention.

FIG. 5 is a diagram showing a result of control by a conventional control method.

FIG. 6 is a diagram showing a result of control by a conventional control method.

[Explanation of symbols]

T1 alarm temperature T2 alarm temperature TH temperature range TM temperature range (first temperature range) TL temperature range (second temperature range) Tc coil temperature Td detector temperature TC temperature range (third temperature range)

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor: Tadashi Ishikawa, 1-7-12 Toranomon, Minato-ku, Tokyo Oki Electric Industry Co., Ltd. (56) References JP-A-2-117844 (JP, A (58) Fields investigated (Int. Cl. ⁷ , DB name) B41J 2/30 B41J 2/35-2/38

Claims (3)

(57) [Claims] A temperature detecting means for detecting a temperature of a print head.
If you have multiple printing modes with different printing frequency
First, the printing mode is shifted in the direction in which the printing frequency decreases.
The print mode is shifted in the direction of the temperature range and the print frequency
And a second temperature area for printing, and the print head is detected by the temperature detecting means at predetermined time intervals.
A print head temperature control method, wherein the print mode is shifted in accordance with the detected temperature range of the print head. 2. The first temperature region and the second temperature region.
Between the band, a third temperature territory without shifting the printing mode
The print head temperature control method according to claim 1, wherein an area is provided. 3. The print head temperature control method according to claim 1, wherein a ratio (low print frequency / high print frequency) between the successive print modes is changed from 40% to 90%.