JP2748817B2 - Printing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing apparatus having a thermal head for performing printing by heating.

[0002]

2. Description of the Related Art In a printing apparatus having a thermal head for performing printing by heating, such as a thermal transfer type or a ribbon type, before starting printing, the temperature of the thermal head is measured to determine whether printing is possible. (Temperature measurement operation). This is because, for example, when printing is performed repeatedly so that the recording paper is painted black, and the temperature of the thermal head becomes higher than the allowable temperature, the portion where printing is not performed is printed black, so the temperature of the thermal head is set to the set temperature. This is for starting printing after confirming the following.

[0003]

Conventionally, this temperature measurement operation is performed either immediately before starting the conveyance of the recording paper from the recording paper cartridge to the thermal head, or immediately before the recording paper reaches the thermal head and starts printing. Crab was going.
If the temperature is measured immediately before the recording paper is conveyed to the thermal head, there is a problem that the temperature of the thermal head changes until the recording paper reaches the thermal head. On the other hand, if the temperature is measured immediately before starting printing, the recording paper once conveyed to the thermal head cannot be returned to the recording paper cartridge when it is determined that the temperature of the thermal head is high and printing cannot be performed. Therefore, the recording paper stays just before the thermal head to cause a kind of paper jam, and when such a situation occurs, the user needs to remove the recording paper. Even if the recording paper is automatically discharged when printing cannot be performed in order to prevent this paper jam, there is a problem that the recording paper is wasted.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and can measure the temperature of a thermal head immediately before printing, and can also be used to print a recording paper when the temperature of the thermal head is too high to perform printing. It is an object of the present invention to provide a printing apparatus that does not waste the printing.

[0005]

In order to achieve the above object, a printing apparatus according to the present invention comprises a print head for printing on a recording sheet by heating, and a recording sheet transport for transporting the recording sheet to the print head. Means, and a temperature measuring means for measuring whether the temperature of the print head is equal to or lower than a set value, wherein the temperature measuring means measures the temperature of the print head before the recording paper transport means starts transporting the recording paper. Measuring, and when the temperature is lower than a set value, the recording paper conveyance means starts conveyance, and the temperature measurement means measures the temperature of the print head again before starting printing of the recording paper by the print head. Is lower than the set value, the printing head starts printing on the conveyed recording paper.

[0006]

According to the printing apparatus of the present invention having the above-described configuration, before the recording paper transporting means starts transporting the recording paper, the temperature measuring means measures the temperature of the print head, and printing can be performed at a temperature lower than the set value. At times, conveyance is started, and when the temperature is higher than the set value and printing cannot be performed, the conveyance is suspended. Then, before the recording paper is conveyed to the print head and before the print head starts printing on the recording paper, the temperature measuring means measures the temperature of the print head again, and if the temperature is lower than the set value, the conveyed recording Start printing on paper. If printing cannot be performed because the temperature is higher than the set value, printing is suspended. In this way, before the recording paper conveyance unit starts conveyance of the recording paper, the temperature measurement unit measures the temperature of the print head, and when the temperature is higher than the set value and printing cannot be performed, the conveyance is stopped. It is possible to prevent a situation in which the recording paper is conveyed during the state in which the recording paper cannot be used and is wasted.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example in which a printing apparatus according to the present invention is applied to a facsimile apparatus will be described below with reference to the drawings.
FIG. 1 shows a facsimile apparatus 10 according to one embodiment of the present invention.
FIG. 3 is a block diagram showing the configuration of FIG. Facsimile machine 10
Is a network control unit (NCU) 12 for connecting to a public line, an analog signal transmitted via a telephone line is demodulated to a digital signal, and an analog signal for transmitting a digital signal of the own station via a telephone line. It has a modem 14 for modulating a signal and a CPU 16 for controlling communication and printing. The CPU 16 includes a jam sensor 18 for detecting a paper jam in the facsimile machine 10 and a thermal head 22 for printing on recording paper.
A strobe generating circuit 24 for applying a strobe to the thermal head 22, a P / S conversion circuit 26 for converting image information sent from the CPU 16 as a parallel signal into a serial signal and applying the serial signal to the thermal head 22, A temperature measuring device 20 for measuring the temperature of the recording medium 22, a motor driver 30 for driving a recording paper feed motor 28 for conveying the recording paper, and a ribbon peeling for pressing and peeling the printing ribbon and the recording paper. A motor driver 34 for driving the motor 32, a leading edge sensor 35 for detecting the position of the leading edge of the recording paper conveyed from a recording paper cartridge 55, which will be described later, and image information and the like sent from the facsimile machine of the other party are temporarily stored. RAM 36 for holding
A ROM 38 for holding control information and the like of the facsimile machine 10, an operation panel 40 provided with operation switches for the facsimile machine 10 and performing various displays by LEDs, and a transmission panel to the other party's facsimile machine. A CCD 44 for obtaining image information of the CCD, and converting image information of a serial signal from the CCD
An S / P conversion circuit 42 to be provided to the U 16 and a P / S conversion circuit 46 which converts a signal sent from the CPU 16 as a parallel signal to a serial signal and provides the serial signal to the CCD 44 are connected.

Next, the configuration of the temperature measuring device 20 of the facsimile machine 10 will be described with reference to FIGS. The temperature measuring device 20 of the present embodiment includes a timer IC 21
And a time constant circuit 23. The timer IC 21 has an input terminal 21a for receiving a temperature measurement command from the CPU 16, an input terminal 21c for receiving a trigger pulse of 32 μs, and an output for outputting the counted pulse number (corresponding to the measured temperature) to the CPU 16 side. Terminal 21
b, and a terminal 21 d connected to the time constant circuit 23. The time constant circuit 23 is connected to resistors R1 and R2 connected in series, a thermistor S connected in parallel to the resistor R1 and having a resistance value that changes according to temperature, a grounded capacitor C, and a predetermined voltage. A terminal E and a time constant determined by the total resistance of the resistors R1 and R2 and the thermistor S and the capacitance of the capacitor C.

When measuring the temperature of the thermal head 22 (measuring temperature), the CPU 16 issues a temperature measurement command to the timer IC 21 and applies a predetermined voltage to the terminal E of the time constant circuit 23. FIG. 3A shows a CR charging waveform in the time constant circuit 23 at this time. The timer IC 21 is configured to generate a constant reference voltage. The timer IC 21 compares the charging voltage of the time constant circuit 23 with the reference voltage. T until the reference voltage becomes equal to the reference voltage [FIG. 3 (b)].
Is measured by counting the number of trigger pulses of 32 μs. That is, when the temperature of the thermal head 22 is high, the charging voltage of the time constant circuit 23 becomes equal to the reference voltage in a short time, and when the temperature is low, the charging voltage of the time constant circuit 23 becomes low. It takes a long time to reach the reference voltage. This time T is calculated by the timer IC 21
A trigger pulse of 32 μs, that is, a measurement with a resolution of 32 μs, and this measured value is sent from the output terminal 21 b to the CPU 16.
Send to the side. The CPU 16 senses the temperature of the thermal head 22 based on the number of pulses, and normally prints by comparing the number of pulses with a value set as a print temperature allowed for the thermal head 22 as described later. That is, it is determined whether a high temperature error has occurred.

Next, the printing operation of the facsimile machine 10 of the present embodiment will be described with reference to FIG. 4 which is a flowchart showing this operation and FIG. 5 which shows the recording paper conveyance state. First, prior to the description of the flowchart of FIG. 4, the recording paper transport mechanism of the facsimile apparatus 10 of the present embodiment will be described with reference to FIG. The recording paper cartridge 55 stores the recording paper 51.
A platen 53 is placed on top of the recording paper cartridge 55, and a thermal head 22 for performing linear printing in the main scanning direction at a position opposed to the platen 53, and a position for detecting the leading end position of the recording paper 51. A tip sensor 35 is provided. FIG. 5A shows a state before the recording paper 51 is fed. When the printing operation is started, the recording paper 51
Is a recording paper cartridge 55 by a paper feed roller (not shown).
It is taken out from the inside and transported to the thermal head 22 by the platen 53. FIG. 5B shows a state in which the recording paper 51 has been sent to the thermal head 22. When the printing is completed, the recording paper 51 is discharged as shown in FIG.

In the facsimile apparatus 10 shown in FIG. 1, when the image information transmitted from the other facsimile apparatus is received by the NCU 12, it is demodulated into a digital signal by the modem 14 and added to the CPU 16. C
The PU 16 decodes the transmitted image information that has been compressed, creates print data based on the decoded image information, and starts a printing process based on the print data. This printing process is shown in FIG.
This will be described with reference to the flowchart of FIG. When the print data is completed (judgment step 1 is Yes), in step 2 the state before the conveyance of the recording paper 51 stored in the recording paper cartridge 55 is started [FIG. Measure the temperature (temperature measurement).
That is, the CPU 16 sends a temperature measurement command to the temperature measuring device 20 to measure the temperature of the thermal head 22. And
When the CPU 16 receives a pulse (number of pulses) corresponding to the measured temperature from the temperature measuring device 20,
Compared with the temperature threshold value (first set value) before the transfer of
It is determined whether a high-temperature error has occurred, that is, whether the temperature of the thermal head 22 is high and printing cannot be performed normally (determination step 3).

In the decision step 3, a high temperature error,
That is, when the temperature of the thermal head 22 is high and printing cannot be performed normally, the judgment step 3 becomes Yes, the process returns to the judgment step 1, and the temperature is measured again in the step 2. By repeating this operation, the process waits until the thermal head 22 cools and printing can be performed normally. On the other hand, when no high-temperature error has occurred, the determination in step 3 is No, and the process proceeds to step 4.

In step 4, the recording paper 51 is fed to the position of the thermal head 22. That is, as shown in FIG. 5B, the CPU 16 takes out the recording paper 51 in the recording paper cartridge 55 by a paper feed roller (not shown), sends a command to the motor driver 30 shown in FIG. , The platen 53 is rotated to convey the recording paper 51. When the recording paper 51 passes in front of the leading edge sensor 35, the leading edge sensor 35
6, a driving signal of the recording paper feed motor 28 is interrupted to stop the recording paper 51 in a state where the platen 53 has conveyed the recording paper 51 to the position of the thermal head 22.

In this state, the process proceeds to step 5, where the temperature of the thermal head 22 is measured again. That is,
The CPU 16 sends a temperature measurement command to the temperature measurement device 20 to cause the temperature of the thermal head 22 to be measured. And CPU
16 receives a pulse corresponding to the measured temperature from the temperature measuring device 20, compares the pulse with a temperature threshold value (second set value) before printing the recording paper 51, and determines whether a high-temperature error has occurred. It is determined whether printing can be performed normally (determination step 6).

If a high-temperature error has not occurred in the determination step 6 (No in the determination step 6), the flow proceeds to the processing in step 7 and printing is performed. That is, a command is sent to the motor driver 30 again, and the recording paper feed motor 28 is driven to rotate the platen 53 so that the recording paper 51 is conveyed. In synchronization with this, the strobe generation circuit 2
A signal is sent to the recording paper 51 to print on the recording paper 51 by the thermal head 22 that prints in a line in the scanning direction. Here, the printing energy supplied to the thermal head 22 is:
The print quality is set according to the temperature of the thermal head 22, and the printing quality accompanying the temperature change of the thermal head 22 is guaranteed. In the printing operation in the step 7, the thermal head 2 measured in the step 5 is used.
2, printing is performed on the recording paper 51 with the optimum printing energy based on the temperature. When the printing is completed, proceed to Step 8,
The CPU 16 ejects the recording paper 51 from the facsimile machine 10 as shown in FIG. On the other hand, if it is determined in the above-described determination step 6 that a high-temperature error occurs, that is, if the temperature of the thermal head 22 is high and printing cannot be performed normally, the determination in the determination step 6 becomes Yes, the process proceeds to the step 9, and the CPU 16 , Printing paper 51 on which printing is not performed
From the facsimile machine 10. Then, the process returns to the process of step 1 to restart the process for printing.

As described above, the facsimile apparatus 10 according to the present embodiment determines whether or not printing can be performed normally before the recording paper 51 is conveyed (determination step 3).
Printing cannot be performed normally due to high temperature (judgment step 3 is Y
es) indicates that the conveyed recording paper 51
Is prevented from being discharged without being printed.
Further, since the temperature measurement operation (step 5) for confirming the temperature of the thermal head 22 is performed immediately before printing, a situation in which the temperature of the thermal head 22 during printing differs from the temperature during measurement is prevented.

Here, as described above, the facsimile apparatus 10 of the present embodiment sets the recording paper 5
Two types of set values, a temperature threshold value before conveyance (1) (first set value) and a temperature threshold value before printing of the recording paper 51 (second set value) in the determination step 6 are used. The reason will be described in detail. In this embodiment, in order to prevent a situation in which printing on the conveyed recording paper 51 cannot be performed, a high-temperature error judgment is performed before the conveyance of the recording paper 51 (judgment step 3). Is checked (judgment step 6). If the same value is used as the reference value for the two determinations, when the temperature of the thermal head 22 is close to the temperature set as the reference, one side is determined as a high temperature error, On the other hand, there is a case where a high temperature error is not determined. That is, in the determination before the conveyance of the recording paper 51 in the determination step 3, the conveyance of the recording paper 51 is started assuming that no high-temperature error has occurred, and in the determination before the printing of the recording paper 51 in the next determination step 6, Thermal head 2
Despite the fact that 2 is the same temperature, it is determined that a high temperature error has occurred, and the determination step 6 becomes Yes,
It is expected that the recording paper 51 will be discharged as it is without printing.

In particular, in this embodiment, as described above with reference to FIGS. 2 and 3, the temperature of the thermal head 22 is set to 32 μs.
, The number of counted pulses may differ even when the same temperature is measured. For this reason, as a value (threshold) equal to the criteria for determining the high temperature error,
For example, when 30 pulses are set, when the same temperature is measured in step 2, 31 pulses are obtained. In determination step 3, it is determined that no high-temperature error has occurred. 30 pulses are obtained, and it may be determined in the determination step 6 that a high temperature error has occurred.

Further, the facsimile apparatus 10 of the present embodiment
When a power failure occurs, the image information transmitted from the other facsimile machine stored in the RAM 36 is lost. Therefore, in the event of a power failure, a management report indicating the fact of the power failure is restored to the power failure state. It is configured to launch immediately after doing. The printing of this management report is repeated as many times as it is actually performed. Accordingly, as described above, when the same value is used as the set value for the determination of the high temperature error twice, the determination in the determination step 3 and the determination in the next determination step 6 are different, and the printing is performed without printing. In some cases, the recording paper 51 that is not printed is discharged by the thermal head 22.
Will be repeated until cooled.

For this reason, in the facsimile apparatus of this embodiment, as described above, the recording paper 51 in the judgment step 3 is used.
Is a stricter value than the temperature threshold (second set value) before the printing of the recording paper 51 in the determination step 6, for example, the second set value. The value is set to 104% of the value. This reliably prevents the recording paper 51 conveyed to the thermal head 22 from being discharged without being printed. Also,
In this embodiment, since the printing energy supplied to the thermal head 22 is determined based on the measured temperature of the recording paper 51 before printing, the printing energy is higher than that based on the measured temperature of the recording paper 51 before conveyance. Printing quality is guaranteed with accuracy.

In the above-described embodiment, the printing operation of the facsimile apparatus has been described as an example. However, the present invention is not limited to this. Can be used.

[0022]

As is apparent from the above description,
According to the printing apparatus of the present invention, since the temperature is measured before the recording paper is transported, it is possible to prevent a situation in which printing is not performed on the transported recording paper and the recording paper is directly discharged. Further, since the temperature of the thermal head is checked immediately before printing, a situation in which the temperature of the thermal head during printing differs from the temperature during measurement is prevented.

[Brief description of the drawings]

FIG. 1 is a block diagram of a facsimile apparatus according to one embodiment of the present invention.

FIG. 2 is a configuration diagram of a temperature measuring device of the facsimile apparatus shown in FIG.

FIG. 3 is a waveform diagram of the temperature measuring device shown in FIG.

4 is a flowchart showing a printing operation of the facsimile machine shown in FIG.

FIG. 5 is a schematic diagram for explaining a recording paper conveying operation by the facsimile apparatus shown in FIG. 1;

[Description of Signs] 10 Facsimile machine 16 CPU 20 Temperature measuring device 22 Thermal head 24 Strobe generation circuit 28 Recording paper feed motor 51 Recording paper 53 Platen

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI H04N 1/23 102 B41J 29/00 U

Claims (2)

(57) [Claims] A print head configured to print on the recording paper by heating; a recording paper transport unit configured to transport the recording paper to the print head; and a measurement unit configured to measure whether a temperature of the print head is equal to or less than a set value. A temperature measuring unit that measures a temperature of a print head before the recording paper transport unit starts transporting the recording paper, and the temperature of the recording paper is lower than a set value if the temperature is lower than a set value. The transport means starts transporting,
The temperature measurement unit measures the temperature of the print head again before the print head starts printing the recording paper, and starts printing on the conveyed recording paper when the temperature is lower than a set value. Characteristic printing device. 2. The method according to claim 1, wherein a value before the start of recording paper conveyance by the recording paper conveyance unit is set to be lower than a value before the recording head starts printing the recording paper by the print head. The printing device according to claim 1, wherein: