JP2003291466A - Mechanism and method for judging failure of temperature sensor provided in print head of printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect an abnormal state resulting from the temperature sensor mechanism itself in the print head of a printer. <P>SOLUTION: While reciprocating a print head arranged with a plurality of recording elements and provided with a temperature sensor element in the main scanning direction, recording is performed by driving the recording elements and then printing is performed on a print sheet by carrying it in the subscanning direction. In such an operating method of a printer, temperature of the print head is determined based on the variation characteristics of the temperature sensor element under steady state of the print head and then it is stored. At the time of driving the print head, temperature of the print head is determined as the driving time temperature based on the variation characteristics of the temperature sensor element and the state of the temperature sensor element is judged based on the steady state temperature and the driving time temperature. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature sensor defect determination mechanism provided in a print head of a printer and a temperature sensor defect determination method.

[0002]

2. Description of the Related Art In an ink jet printer, a dot impact printer, etc. (hereinafter, these are collectively referred to simply as "printer"), a plurality of recording elements (nozzles) are arranged in a sub-scanning direction (vertical direction or width direction of printing paper). By driving the recording elements while reciprocating the arranged print heads in the main scanning direction (horizontal direction or width direction of the printing paper) on the printing paper, and by conveying the printing paper in the sub-scanning direction,
It realizes printing on printing paper. In the case of a color-compatible printer, a plurality of recording elements are arranged for each color in the print head.

Since the recording element of such a print head is electrically driven under the control of the control device provided inside the printer body, when the printer continuously prints for a long time, There is a possibility that the recording element becomes high temperature and deteriorates or breaks (burns). For this reason, the print head is provided with a temperature sensor element such as a thermistor, and when the control device detects an abnormally high temperature state by this temperature sensor element, the print head is temporarily stopped or the print head is stopped. The drive speed is slowed to protect the print head from the effects of heat.

[0004]

As described above, in general, a printer is equipped with a heat countermeasure mechanism so as to prevent the print head from reaching a high temperature state, and prevents damage due to an excessive temperature rise. However, if the temperature sensor element, which should have been installed in the print head, is disconnected for some reason, or if the temperature sensor element itself is defective or damaged, the control device determines that the print head is in an abnormally high temperature state. There is a problem that it cannot be detected and the print head cannot be effectively protected from heat.

Therefore, an object of the present invention is to provide a printer provided with a mechanism for detecting an abnormal state due to the temperature sensor mechanism itself of the print head.

[0006]

SUMMARY OF THE INVENTION The gist of the present invention is to reciprocally move a print head, in which a plurality of recording elements are arranged and a temperature sensor element is provided, on a printing paper in the main scanning direction. In a printer that realizes printing on the printing paper by driving and recording and conveying the printing paper in the sub-scanning direction, the printing is performed based on a change characteristic of the temperature sensor element when the print head is stationary. The temperature of the head is obtained and stored as a steady-state temperature, and when the print head is driven, the temperature of the print head is obtained as the drive-time temperature based on the change characteristics of the temperature sensor element. The purpose is to determine the state of the temperature sensor element based on the driving temperature.

That is, the present invention provides a printer that realizes printing on the printing paper by conveying the printing paper in the sub-scanning direction while reciprocating the printing head on the printing paper in the main scanning direction. A print head in which the recording elements are arranged, control means for controlling the drive of the recording elements of the print head with a predetermined drive power, a temperature sensor element provided in the print head, and connected to the temperature sensor element. A temperature calculation means for obtaining the temperature of the print head based on the change characteristic of the temperature sensor; a storage means for storing the temperature detected by the temperature calculation means; and a temperature stored in the storage means and the temperature calculation Determining means for determining the state of the temperature sensor element based on the temperature directly obtained by the means. Is another.

In the printer, the temperature calculated by the temperature calculating means when the print head is stationary and stored in the storage means, and the temperature calculated by the temperature calculating means when the print head is driven. It is characterized in that the state of the temperature sensor element is judged based on the above.

Further, the temperature calculating means is characterized in that the temperature is calculated with the initialization time immediately after the power is turned on as the steady state of the print head.

Furthermore, the control means is characterized in that the print head is driven with a second drive power that is less than or equal to a first drive power required for a printing operation by a printing element of the print head.

Further, the control means drives the print head with the second drive power after the steady-state temperature of the print head is obtained during the initialization processing. There is.

Further, the judgment means obtains a difference value between the temperature stored in the storage means and the temperature obtained by the temperature calculation means, and when the difference value is within a predetermined allowable value, It is characterized in that the temperature sensor element is judged to be in an error state.

The invention of the product as the printer is also realized as a method invention. Specifically, the present invention performs recording by driving the print element while reciprocally moving a print head in which a plurality of print elements are arranged and a temperature sensor element is provided on a printing paper in the main scanning direction. In a method of operating a printer that realizes printing on the printing paper by transporting the printing paper in a sub-scanning direction, the temperature of the printing head is changed based on a change characteristic of the temperature sensor element when the printing head is in a steady state. And storing as a steady-state temperature, a step of obtaining the temperature of the print head as a driving temperature based on a change characteristic of the temperature sensor element when the print head is driven, and a steady-state temperature. A step of judging the state of the temperature sensor element based on the driving temperature, and an operating method of the printer.

The above invention is also realized as a program or a recording medium recording the program.

In the present specification, the term "means" does not simply mean physical means, but also includes the case where the functions of the means are realized by software. Further, the function of one means may be realized by two or more physical means, or the functions of two or more means may be realized by one physical means.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic side sectional view of a printer 1 according to this embodiment, and the printing mechanism of the printer 1 will be mainly described.

The printing paper P is rotatably set while being inserted in the shaft portion 101, and the pair of front and rear driven rollers 10 are used.
2 and the drive roller 103. The drive roller 103 is driven by the printing paper motor 104. When the printing paper motor 104 is driven in the normal direction, a rotational force is transmitted from the driving roller 103 to the printing paper P, and the printing paper P rotates in the feeding direction (counterclockwise direction in the drawing). On the other hand, when the printing paper motor 104 is driven in the reverse direction, a rotational force is transmitted from the driving roller 103 to the printing paper P, and the printing paper P rotates in the winding direction (clockwise direction in the drawing).

A paper feed driven roller 105 and a paper feed drive roller 106 are provided on the conveyance path of the printing paper P sent out.
Is provided. The printing paper P is the paper feed driven roller 10
5 and the sheet feeding drive 106, and the sheet is sandwiched and sent out. A transport roller 107 and a paper discharge roller 108 are further arranged on the transport path fed from the rollers 106 and 107. These rollers 107, 108
Each of them has a driving roller located on the lower side and a driven roller located on the upper side, and holds the printing paper P therebetween. Between the transport roller 107 and the paper discharge roller 108,
The platen 109 is arranged.

The carriage 110 has a carriage shaft 111.
It is slidably supported by. Then, a carriage motor (not shown) is driven to move the carriage 110 along the carriage shaft 111 in the axial direction (main scanning direction).
Move back and forth. A print head 112 is attached to the lower surface of the carriage 110. The print head 112 is
Ink is supplied from an ink cartridge (not shown), ink droplets are ejected from recording elements (nozzles) of the print head 112 to be fixed on the printing paper P, and printing recording is performed. The print head 112 is provided with a thermistor (not shown) as a temperature sensor element, and the printer 1 detects the temperature of the print head 112 based on a signal from the thermistor.

Further, the carriage 110 is provided with a cutter device 113. This cutter device 113
Is to cut at a predetermined position of the printing paper P so that the printing paper P that has been printed and sent out is a cut sheet of a predetermined size. The cutting device 113 is configured such that the movable blade is engaged with the fixed blade so that the fixed blade can be cut.
The printing paper P is cut by moving in the axial direction together with 0. The printing paper P cut by the cutter device 113 is discharged to the outside by the auxiliary drive roller 114. A paper detection sensor 115 is provided between the cutter device 113 and the print head 112, and the presence or absence of the print paper P on the downstream side of the print head 112 is determined based on the detection signal output from the paper detection sensor 116. To be done.

FIG. 2 is a block diagram for explaining a schematic functional configuration of the printer 1. As shown in FIG. 1, functional description of the printer 1 shown in FIG.
It can be divided into a control device 21 that controls the operation of the entire printer 1 and a print engine 22 that performs image formation processing by fixing ink on the conveyed printing paper under the control of the control device 21. The print engine 22 is shown as a typical one of the members constituting the printing mechanism described in FIG.

The control device 21 controls the print engine 22 in order to execute the print processing on the print paper P based on the print job data transmitted from the external host computer. The control device 21 is composed of an interface circuit 23, a system section 24, and a drive circuit section 25.

The interface 23 provides a function for communicating with a host computer connected via a cable. The printer 1 receives print job data from the host computer via the interface 23. The connection with the host computer is
It may be network connection, serial or parallel connection, and can be selectively used as appropriate.

The system section 24 includes processors 241, R
It is composed of an OM 242 and a RAM 243. A rewritable non-volatile memory may be provided as appropriate.
The processor 241 is a RAM that functions as a main storage device.
While using 243, various control programs stored in the ROM 242 are executed, and the printer 1 is comprehensively controlled. In other words, various control programs are executed by the processor 141 to cooperate with other hardware and cause the printer 1 to realize a predetermined function. Typically, the system unit 24 realizes a job interpretation function, a print control function, a cutter device control function, and the like. The job interpretation function is a function of interpreting print job data received via the interface 23 and generating image data. The generated image data is R
Written to an image buffer memory configured as part of AM 243. Further, the print control function controls the drive circuit unit 25 based on the image data written in the image buffer memory, and indirectly the print engine 2
This is a function of controlling the number 2.

The drive circuit section 25 includes the print engine 22.
For mechanically controlling the mechanical members of the print engine 22, and is appropriately configured according to the configuration of the print engine 22. The drive circuit unit 25 drives and controls the print engine 22 under the control of the system unit 24.

The system section 24 can control the print head 112 to operate in at least two drive modes via the drive circuit section 25. The first drive mode (normal drive mode) is a mode in which the recording elements of the print head 112 are driven to perform actual print recording as normal print processing. The second drive mode (dummy drive mode) is a mode in which the print elements of the print head 112 are driven, but actual print recording is not performed. That is, in the second drive mode, the print head 1
The 12 recording elements are driven with a drive power that is equal to or lower than the drive power required to actually perform print recording.

FIG. 3 is a sequence diagram for explaining these drive modes. As shown in the figure, in the second drive mode, since the application time and the applied voltage are smaller than those in the first drive mode, drive power is supplied to the print head 112, but the print element is driven. However, the ink is not ejected. In this example,
In the second drive mode, the voltage is lowered and the frequency is raised (the cycle is shortened) to obtain electric power equal to or lower than the necessary drive electric power. For example, even if the voltage is kept constant, only the frequency is raised. , And vice versa.

Returning to FIG. 2, the temperature measuring circuit 26 calculates the temperature of the print head 112 based on the temperature change characteristic of the thermistor 27 attached to the print head 112 under the control of the system unit 24, and the print head 112 The temperature state of 112 is determined. When the temperature measuring circuit 26 determines that the print head 112 is in a high temperature state, it sends a temporary stop signal to the system unit 24, and the thermistor 27 attached to the print head 112 is defective. When making a determination, an error signal is sent to the system unit 24.

FIG. 4 shows a temperature measuring circuit 2 according to this embodiment.
6 is a block diagram illustrating a configuration of No. 6. Under the control of the system unit 24, the temperature calculation unit 41 applies a reference voltage to the thermistor 27, and obtains the temperature by obtaining the electrical characteristic (resistance value) of the thermistor from the measured voltage. Under the control of the system unit 24, when the temperature is obtained in the steady state, the temperature calculation unit 41 stores the temperature in the storage unit 42 as the steady state temperature. The stationary state means a state in which the printer 1 is not driving the print head 112 and most of the heat generated by the past driving is radiated. Therefore, the steady-state temperature is
It can be said that the temperature is almost equal to the temperature of the environment in which the printer 1 is installed. Typically, it is immediately after the power is turned on after the power is turned off for a while.

Under the control of the system section 24, the high-temperature state determining section 44 drives the recording elements of the print head 112 to perform actual print recording as normal print processing.
It is determined whether or not the temperature calculated by the temperature calculation unit 41 exceeds a predetermined set value, and if it is determined that the temperature exceeds the predetermined set value, a temporary stop signal is sent to the system unit 24. That is, it is driven by the print head 11
2 is notified to the system unit 24 that the temperature has become high. When receiving the temporary stop signal, the system unit 24 temporarily stops the print processing that is being executed or slows down the drive speed of the print head 112 to reduce heat generation to the print head 112. Feedback control so that As a result, the printer 1 can effectively prevent the print head 112 from being in an abnormally high temperature state.

The error state determination unit 44 is the system unit 24.
Under the control of the above, while the recording element of the print head 112 is being driven or after being driven, the steady-state temperature stored in the storage unit 42 and the temperature obtained by the temperature calculation unit 41 are compared and If it is determined whether the difference value is within a predetermined allowable value, and if it is determined that the difference value is not within the predetermined allowable value, an error signal is sent to the system unit 24. That is,
This is to determine whether or not the temperature of the print head 112 has changed due to driving, and if there is no temperature change, notify the system unit 24 that a failure has occurred in the temperature sensor mechanism such as the thermistor 27. .

FIG. 5 is a flow chart for explaining the checking process of the temperature sensor mechanism in the printer 1 according to this embodiment. This process is performed by the printer 1, for example.
When the power is turned on, it is executed as one of various initialization processes, and thereafter, it is executed at an appropriate timing until the power is turned off.

As shown in FIG. 1, when the printer 1 is turned on, the temperature calculation unit 2 is controlled by the system unit 24.
6 measures and calculates the current temperature of the print head 112 and stores it as the steady-state temperature (STEP 50).
1). Next, the system unit 24 drives the print head 112 in the second drive mode (STEP 502). The second drive mode is a mode in which the recording elements of the print head 112 are driven so that actual print recording is not performed, as described above. The temperature calculation unit 26 measures and calculates the temperature immediately after the print head 112 is driven in the second drive mode (STEP 503). Then, the temperature calculation unit 26
Compares the previously calculated and stored steady-state temperature with the temperature just calculated, and determines whether or not the difference value is within a predetermined allowable value (STEP 504). When the temperature calculation unit 26 determines that the difference value is not within the predetermined allowable value, the thermistor 27 and the like determine that the temperature is normal and do nothing and end. On the other hand, when it is determined that the temperature is within the predetermined allowable value, the temperature calculation unit 26 determines that there is an abnormality in the thermistor 27 or the like because there is no temperature increase due to the drive, which is supposed to occur. An error signal is output to the system unit 24 (STEP 505). When the system unit 24 receives the error signal from the temperature calculation unit 26, the system unit 24 performs a predetermined error process (STEP50.
6).

As described above, according to this embodiment, the temperature state of the driven print head 112 is monitored and controlled so as not to reach an abnormally high temperature, while some trouble occurs in the temperature sensor mechanism such as the thermistor 27. It is possible to monitor whether or not the temperature condition has occurred and the temperature condition cannot be monitored. Therefore, the control device 21 can immediately recognize that the thermistor 27, which should be attached to the print head 112, has come off due to some cause, or that the thermistor 27 itself is defective or damaged, and the error handling can be performed. Will be able to do.

The above embodiment is an example for explaining the present invention, and is not intended to limit the present invention only to this embodiment. The present invention can be implemented in various forms without departing from the gist thereof. For example, the operation of the function realizing means has been described in a sequential manner, but the operation is not particularly limited to this. Therefore, as long as there is no contradiction in the operation, the order of processing may be changed or the operations may be performed in parallel.

In the above embodiment, the ink jet printer is described as an example, but the present invention can be applied to a printer that drives a print head, for example, a dot impact printer.

[0038]

According to the present invention, it becomes possible to monitor whether or not the temperature state cannot be monitored due to some trouble in the temperature sensor mechanism. Therefore, it is possible to avoid a situation in which the abnormal temperature state of the print head cannot be detected and the print head cannot be protected from heat because the temperature sensor mechanism is not normal.

[Brief description of drawings]

FIG. 1 is a schematic side sectional view of a printer according to an embodiment of the present invention.

FIG. 2 is a block diagram for explaining a schematic functional configuration of a printer according to an embodiment of the invention.

FIG. 3 is a sequence diagram for explaining drive modes of the printer according to the embodiment of the present invention.

FIG. 4 is a block diagram illustrating a configuration of a temperature measurement circuit according to an embodiment of the present invention.

FIG. 5 is a flowchart for explaining a temperature sensor check process in the printer according to the embodiment of the present invention.

[Explanation of symbols]

1 ... Printer 21 ... Control device 22 ... Print engine 23 ... Interface circuit 24 ... System Department 25 ... Drive control circuit 26 ... Temperature calculation unit 27 ... Temperature sensor element

Claims (11)

[Claims] 1. A printer that realizes printing on the printing paper by transporting the printing paper in the sub-scanning direction while reciprocating the printing head in the main scanning direction on the printing paper, wherein a plurality of recording elements are provided. An array of print heads, a control unit that controls the drive of the recording elements of the print heads with a predetermined drive power, a temperature sensor element provided in the print head, and a temperature sensor connected to the temperature sensor element. Temperature calculating means for obtaining the temperature of the print head based on the change characteristics of the print head, storage means for storing the temperature detected by the temperature calculating means, temperature stored in the storing means and the temperature calculating means. And a determination unit that determines the state of the temperature sensor element based on the temperature. 2. The temperature calculated by the temperature calculating means when the print head is stationary and stored in the storage means, and the temperature calculated by the temperature calculating means when the print head is driven. The printer according to claim 1, wherein the state of the temperature sensor element is determined. 3. The printer according to claim 2, wherein the temperature calculation means determines the temperature by regarding an initialization process immediately after the power is turned on as a stationary time of the print head. 4. The first control unit, which is required for a recording operation by a recording element of the print head,
4. The printer according to claim 2, wherein the print head is driven with a second drive power that is equal to or lower than the drive power of. 5. The control means drives the print head with the second drive power after the steady-state temperature of the print head is obtained during the initialization processing. The printer according to claim 4, wherein 6. The determination means obtains a difference value between the temperature stored in the storage means and the temperature obtained by the temperature calculation means, and when the difference value is within a predetermined allowable value, 6. The printer according to claim 1, wherein the temperature sensor element is determined to be in an error state. 7. A printing head, wherein a plurality of printing elements are arranged and a print head provided with a temperature sensor element is reciprocally moved in the main scanning direction on the printing paper to drive the printing elements to perform printing, and the printing paper is printed. In a method of operating a printer that realizes printing on the print sheet by transporting the print head in the sub-scanning direction, the temperature of the print head is determined based on the change characteristics of the temperature sensor element when the print head is in a steady state. Always storing as temperature, when driving the print head, obtaining the temperature of the print head as the driving temperature based on the change characteristic of the temperature sensor element, the steady-state temperature and the driving temperature And a step of determining the state of the temperature sensor element based on the above. 8. The method of operating a printer according to claim 7, wherein the temperature is determined with the initialization time immediately after the power is turned on as the steady state of the print head. 9. The step of obtaining the driving temperature includes a first step required for a recording operation by a recording element of the print head.
9. The method of operating a printer according to claim 7, wherein the print head is driven with a second drive power that is equal to or lower than the drive power of. 10. A difference value between the steady-state temperature and the driving temperature temperature is obtained, and when the difference value is within a predetermined allowable value, it is determined that the temperature sensor element is in an error state. 10. The method of operating a printer according to claim 7, wherein the method is the same as that of claim 1. 11. A printing head, wherein a plurality of printing elements are arrayed and a print head provided with a temperature sensor element is reciprocally moved in the main scanning direction on the printing paper to drive the printing elements to perform printing, and the printing paper is printed. Is a program for controlling a printer that realizes printing on the printing paper by transporting the print head in the sub-scanning direction, the program being based on a change characteristic of the temperature sensor element when the print head is stationary. A function of obtaining the temperature of the head and storing it as a steady-state temperature; a function of obtaining the temperature of the print head as a drive temperature based on a change characteristic of the temperature sensor element when the print head is driven; And a function for determining the state of the temperature sensor element based on the driving temperature, the program being realized. .