JP2016203468A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device, in which when an image forming head is at high temperatures, a path is divided to perform image formation, and the image forming head can be effectively cooled and increase in power supply capacities of a power supply unit can be suppressed, by driving cooling means, utilizing excess electricity generated by dividing the path.SOLUTION: The image forming device comprises conveying means which conveys a medium 18 in a sub-scanning direction, an image forming head which performs printing on the medium 18 while moving in a main-scanning direction, cooling means which cools the image forming head, and a control device which controls operation of the conveying means, the image forming head and the cooling means.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image forming apparatus.

  2. Description of the Related Art Conventionally, in a printing apparatus, a conveying unit that conveys a medium such as printing paper in a certain direction (sub-scanning direction), a character or the like on a medium that is conveyed while moving in a direction orthogonal to the sub-scanning direction (main scanning direction) The image is formed by the print head that forms the image. However, if image formation is continued in a state where the image forming element provided in the print head is heated, the element may be burned out.

  For example, in the case of a serial dot impact printer that performs printing by the wire dot method, a print head including, for example, 24 wires arranged to form dots arranged in a column is provided. Then, by moving the print head in the main scanning direction and flying a predetermined wire (head impact) at a predetermined timing, an image such as a character composed of a plurality of ink dots is formed on the medium via the ink ribbon. Form. However, the print head includes an electromagnet for flying the wire, and a large amount of heat is generated when the electromagnet is driven.

  Therefore, in the conventional printing apparatus, the image forming method is changed according to the state of heat generation. That is, when the temperature of the print head is low, normal printing is performed in which an image of one pass is formed by one main scan, and when the temperature of the print head is high, in order to suppress heat generation, Pass division printing is performed in which an image of one pass is formed by a plurality of main scans.

  However, if pass-division printing is performed in which an image of one pass is formed by a number of main scans, the printing throughput is reduced. Therefore, a technique has been proposed in which a cooling fan is attached in the vicinity of the print head to perform forced cooling, and image formation is performed while suppressing a temperature rise so that the temperature of the print head does not become too high (see, for example, Patent Document 1). .) A technique for controlling the amount of heat exhausted by a cooling fan in accordance with the temperature in the printing apparatus has also been proposed (see, for example, Patent Document 2).

Japanese Patent Application Laid-Open No. 06-055577 Japanese Patent Application Laid-Open No. 08-095472

  However, in the conventional printing apparatus, a power supply unit having a large power supply capacity is required, which increases the size of the power supply unit and increases the cost. Since the cooling fan is a fan that rotates the blower blades attached to the rotor shaft of the motor to send the surrounding air to the object to be cooled for cooling, electric power for rotating the motor is required. Then, the power consumption of the motor necessary for the rotation of the cooling fan is assumed, and the power supply capacity necessary for the entire printing apparatus is determined. Therefore, a power supply unit having a large power supply capacity is inevitably required.

  The present invention solves the above-described conventional problems. When the image forming head is at a high temperature, the image is formed by dividing the path, and cooling is performed using surplus power generated by dividing the path. An object of the present invention is to provide an image forming apparatus capable of effectively cooling the image forming head by driving the means and suppressing an increase in the power supply capacity of the power supply unit.

  Therefore, in the image forming apparatus of the present invention, a conveying unit that conveys the medium in the sub-scanning direction, an image forming head that prints on the medium while moving in the main scanning direction, and a cooling unit that cools the image forming head And a control device that controls the operations of the conveying means, the image forming head, and the cooling means. The control device includes a head temperature measuring unit that detects the temperature of the image forming head, and the image forming head is at a high temperature. In this case, pass division printing is performed by the image forming head, and surplus power generated by causing the image forming head to perform pass division printing is used for the operation of the cooling unit.

  According to the present invention, in the image forming apparatus, when the image forming head is at a high temperature, the image is formed by dividing the path, and the cooling means is used by using surplus power generated by dividing the path. To drive. As a result, the image forming head can be cooled effectively, an increase in the power supply capacity of the power supply unit can be suppressed, and the power supply unit can be downsized.

1 is a schematic diagram illustrating a configuration of a main part of a printing apparatus according to a first embodiment of the present invention. FIG. 2 is a block diagram illustrating a control circuit configuration of a control device of the printing apparatus according to the first embodiment of the present invention. FIG. 2 is a block diagram illustrating a functional configuration of a control device of the printing apparatus according to the first embodiment of the present invention. It is a schematic diagram which shows the electric current waveform at the time of head impact in the 1st Embodiment of this invention. It is explanatory drawing of the maximum electric current amount when performing normal printing and pass division | segmentation printing in the 1st Embodiment of this invention. It is a figure which shows the control circuit of the fan motor of the cooling fan in the 1st Embodiment of this invention. It is a figure which shows the PWM control current waveform of the fan motor of the cooling fan in the 1st Embodiment of this invention. It is a flowchart which shows operation | movement of the head temperature measurement process in the 1st Embodiment of this invention. It is a flowchart which shows the operation | movement of the printing process in the 1st Embodiment of this invention. It is a flowchart which shows the operation | movement of the control process of the cooling fan in the 1st Embodiment of this invention. It is a block diagram which shows the function structure of the printing apparatus in the 2nd Embodiment of this invention. It is a flowchart which shows the operation | movement of the printing process in the 2nd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic diagram showing a main configuration of a printing apparatus according to a first embodiment of the present invention. In the figure, (a) is a top view and (b) is a side view.

  In the figure, reference numeral 10 denotes a printer as an image forming apparatus in the present embodiment, that is, a printing apparatus, and may be an apparatus that performs printing by any method, such as an ink jet method, a thermal method, a thermal transfer method, or the like. Here, the printing apparatus is described as a dot impact printer that performs printing by the wire dot method.

  Reference numeral 11 denotes a print head as an image forming head of the printing apparatus 10, and a medium 18 such as a printing paper transported in the sub-scanning direction while moving in the main scanning direction (directions indicated by arrows A and B). To print. Therefore, the print head 11 is mounted on a space carriage 12 slidable in the main scanning direction along the space shaft 21. The space carriage 12 is connected to a power transmission belt 22 for transmitting the power of the space motor 40 and moves in the directions indicated by arrows A and B in FIG. 1A according to the rotation of the space motor 40. To do.

  A platen 13 of the printing apparatus 10 is a plate-like member extending in the main scanning direction, and includes a plurality of wires, i.e., dot pins, included in the print head 11 with an ink ribbon (not shown) interposed therebetween. The head impact is received and ink transfer from the ink ribbon to the medium 18 is promoted.

  Further, 20 is a ribbon protector made of a stainless steel thin metal plate attached to the space carriage 12, which is located between the ink ribbon and the medium 18, and the ink ribbon is rubbed against the medium 18 more than necessary. Is to prevent the occurrence of.

  Reference numeral 14 denotes a table of the printing apparatus 10 on which the medium 18 is set. Further, reference numeral 15 denotes a table sensor that detects that the medium 18 is set on the table 14 and detects the lower end of the medium 18.

  Reference numeral 16 denotes a paper guide which guides the medium 18 and feeds the paper in a stable state. When the medium 18 is thin thin paper, when the operator who scans the printing apparatus 10 sets the medium 18 on the table 14, the abutting feeling of the front end portion of the medium 18 against the feed roller 17 is weak. Depending on the force, the medium 18 may be set in a skewed state. In such a case, the operator slowly inserts the medium 18 along the paper guide 16.

  The printing apparatus 10 includes a feed roller 17 as a conveying unit that conveys the medium 18 in the sub-scanning direction. The feed roller 17 is a medium transport roller for drawing the medium 18 into the printing apparatus 10 and discharging the medium 18 out of the printing apparatus 10. The feed roller 17 disposed in front of the space carriage 12 is referred to as a front feed roller 17a, the feed roller 17 disposed behind the space carriage 12 is referred to as a rear feed roller 17b, and the front feed roller 17a and When the rear feed roller 17b is described in an integrated manner, it will be referred to as a feed roller 17. Each feed roller 17 includes roller rubbers 17a1 to 17a5 and 17b1 to 17b5 for applying a tension to the medium 18 to convey the medium 18.

  When the medium 18 is set on the table 14, the printing apparatus 10 detects that the medium 18 has been set by the table sensor 15 and operates the feed roller 17 to feed paper.

  Reference numeral 23 denotes a home position sensor for detecting the position of the print head 11 that moves together with the space carriage 12, and is used to generate a reference position for printing. Specifically, the home position sensor 23 is composed of a transmissive sensor. When the space carriage 12 moves toward the left end by the rotation of the space motor 40, the home position sensor 23 is located between the light emitting unit and the light receiving unit of the transmissive sensor. Further, the home position detection rib 24 attached to the space carriage 12 enters, and the print head 11 can be detected.

  Reference numeral 25 denotes a cooling fan as a cooling unit of the printing apparatus 10, which is attached to the print head 11 or the space carriage 12 to cool the print head 11.

  Further, the printing apparatus 10 includes a control device 60 (described later) that controls the operation of each unit.

  Next, the control circuit configuration of the control device 60 of the printing apparatus 10 will be described.

  FIG. 2 is a block diagram showing a control circuit configuration of the control device of the printing apparatus according to the first embodiment of the present invention.

  As shown in the figure, the control device 60 in this embodiment includes a microprocessor 30 as a main control device, a receiving circuit 31, an LED (Light Emitting Diode) / LCD (Liquid Crystal Display) display / switch input circuit. 32, sensor input circuit 33, I / O control circuit 34, CGROM 35, RAM (Random Access Memory) 36, ROM (Read Only Memory) 37, print head 11, print head control circuit 38, A space motor 40, a space motor control circuit 39, a line feed motor 42, a line feed motor control circuit 41, a cooling fan 25, a print head thermistor 43, and a power supply circuit 44 are connected to be able to communicate with the host PC 45. The

  The host PC 45 is a host computer as an image processing apparatus that functions as a host device of the printing apparatus 10 and is communicably connected to the receiving circuit 31 via a communication network (not shown), and print data is connected to the printing apparatus 10. Send. The host PC 45 is a personal computer, a server, or the like, and includes an input unit (not shown), a display unit, a control unit, a data transmission unit, and a storage unit.

  The microprocessor 30 receives print data from the host PC 45 via the receiving circuit 31, interprets the received print data command, inputs various switches input from the LED / LCD display / switch input circuit 32, and Printing including I / O control circuit 34, print head 11, space motor 40, line feed motor 42, etc., based on information related to output operation for LED / LCD display and various information input from sensor input circuit 33 Each operation including the printing operation of each unit of the apparatus 10 is integratedly controlled.

  The receiving circuit 31 receives data from the host PC 45. The LED / LCD display / switch input circuit 32 receives an operation by an operator and notifies the operator of the status of the printing apparatus 10 including an operation of a print stop switch (not shown). Further, the sensor input circuit 33 performs various types of printing apparatus 10 based on signals from various sensors including the table sensor 15, the home position sensor 23, and the print head thermistor 43 for measuring the temperature of the print head 11. Enter the state.

  The I / O control circuit 34 outputs a control signal to the print head control circuit 38, the space motor control circuit 39, the line feed motor control circuit 41, etc. based on the control signal from the microprocessor 30. The print head control circuit 38 controls the print head 11 having a plurality of dot pins to print a designated dot pattern. The space motor control circuit 39 controls the space motor 40 that moves the space carriage 12 on which the print head 11 is mounted in the main scanning direction. Further, the line feed motor control circuit 41 controls a line feed motor 42 that rotates the feed roller 17 that is a conveying unit that performs suction, line feed, discharge, and the like of the medium 18.

  The power supply circuit 44 functions as a power supply unit that supplies power to each unit of the printing apparatus 10. The CGROM 35 stores a built-in font (bitmap font) and is used for printing character data received from the host PC 45. The RAM 36 performs bit expansion of print data or is used as a management memory for the position of the medium 18. Further, the ROM 37 stores a control program for the microprocessor 30 and also stores a cooling fan control program to be described later.

  Next, the functional configuration of the control device 60 will be described.

  FIG. 3 is a block diagram showing a functional configuration of the control device of the printing apparatus according to the first embodiment of the present invention.

  As shown in the figure, the control device 60 according to the present embodiment includes a data receiving unit 50, a data analyzing unit 51, a bitmap developing unit 52, a head temperature measuring unit 53, and a thermal printing determination as functional units. Unit 54, pass printing control unit 55, cooling fan control unit 56, and printing unit 57.

  The data receiving unit 50 receives data from the host PC 45 in a predetermined transfer unit (for example, 1 byte unit). The data receiving unit 50 outputs the received data to the data analyzing unit 51. Then, the data analyzing unit 51 analyzes the data from the data receiving unit 50, performs processing for extracting print data, control codes, and the like, creates print data in block units or line units, and generates a bitmap developing unit 52. Output to. Then, the bitmap development unit 52 develops the print data from the data analysis unit 51 into bitmap data for one line that can be printed by unidirectional movement of the space carriage 12. Then, the bitmap development unit 52 outputs the developed bitmap data to the pass print control unit 55.

  The head temperature measuring unit 53 measures the temperature of the print head 11, that is, the head temperature based on the signal received from the print head thermistor 43, and performs A / D conversion on the head temperature (for example, −10 [° C. ] Is 00 [H] and 150 [° C.] is A / D converted so that it becomes FF [H]. Then, the thermal printing determination unit 54 reads a value obtained by A / D converting the head temperature from the head temperature measurement unit 53, and determines whether or not thermal printing is required due to the high temperature state of the head based on the current head temperature. To do. Here, for convenience of explanation, the printing operation in a high temperature state of the head is referred to as thermal printing. The thermal printing determination unit 54 reads the head temperature value every 15 seconds. This is because stable printing cannot be achieved if the temperature change varies in a short time.

  Here, an example of determining whether or not thermal printing is necessary is shown. For example, assuming that thermal printing is required when the temperature is 70 [° C.] or higher and the value obtained by A / D conversion of 70 [° C.] is 80 [H], the thermal print determination unit 54 determines the value obtained by A / D conversion. Is 80 [H] or more, it is determined that thermal printing is necessary, and when the A / D converted value is less than 80 [H], it is determined that thermal printing is unnecessary, that is, normal printing.

  When the thermal printing determination unit 54 determines that thermal printing is necessary, the thermal printing determination unit 54 outputs information indicating that thermal printing is to be performed to the pass printing control unit 55. Information indicating that normal printing is performed is output to the printing control unit 55. Then, the pass print control unit 55 receives the bitmap data from the bitmap development unit 52 and the information to the effect that thermal printing is performed or normal printing is performed from the thermal printing determination unit 54.

  Here, when information indicating that thermal printing is to be performed is received from the thermal printing determination unit 54, the pass printing control unit 55 is based on the bitmap data received from the bitmap development unit 52 in order to perform pass division printing. Thus, bitmap data adapted to pass division printing is generated and output to the printing unit 57. The pass print controller 55 outputs a request for high-speed rotation of the cooling fan 25 to the cooling fan controller 56.

  Note that bitmap data adapted to pass division printing is, for example, that one pass is divided into three passes to perform pass division printing, and the print head 11 is maximum at one head impact in normal printing. Assuming that the head is a 24-pin head that impacts 24 dot pins, the bitmap data received from the bitmap developing unit 52 so that printing is performed with a head impact of a maximum of 8 dot pins in one head impact. A mask is applied.

  On the other hand, when information indicating that normal printing is performed is received from the thermal printing determination unit 54, there is no need for pass division printing, so the pass printing control unit 55 uses the bitmap data received from the bitmap development unit 52 as it is. Output to the printing unit 57. The pass print controller 55 outputs a request for normal rotation of the cooling fan 25 to the cooling fan controller 56.

  When the rotation request of the cooling fan 25 is input from the pass print control unit 55, the cooling fan control unit 56 controls the cooling fan 25 by PWM (Pulse Width Modulation). Therefore, depending on whether the rotation of the cooling fan 25 is normal rotation or high-speed rotation, the motor that rotates the cooling fan 25, that is, the ON time for supplying current to the fan motor, and the current to the fan motor are supplied. The OFF time not to be set is set in advance, and the fan motor of the cooling fan 25 is turned ON / OFF in such a determined time.

  The printing unit 57 is an engine that performs printing. The printing unit 57 performs a printing operation or a feeding operation of the medium 18 based on the bitmap data output from the pass printing control unit 55, or directly prints according to a control code from the host PC 45. Control the engine core. Moreover, in order to interface with an operator, control of LED display, switch input, etc. which are not illustrated is also performed.

  Next, the operation of the printing apparatus 10 having the above configuration will be described. First, the surplus power and the operation of the cooling fan 25 will be described.

  FIG. 4 is a schematic diagram showing a current waveform at the time of head impact in the first embodiment of the present invention, and FIG. 5 is a maximum current amount when performing normal printing and pass division printing in the first embodiment of the present invention. It is explanatory drawing of.

  In the print head 11, in order to make the dot pin have a head impact, current is not always applied to the coil of the electromagnet corresponding to each dot pin, but it corresponds to the dot pin that should have a head impact according to the contents of printing. A current is allowed to flow through the coil of the electromagnet for a specified time each time at a predetermined timing. Therefore, as shown in FIG. 4, a pulsed current flows intermittently. In FIG. 4, the pin current is a current supplied to the coil of the electromagnet in order to make each dot pin have a head impact.

  The power supply circuit 44 as a power supply unit is also created in consideration of such pin current characteristics. For example, in the present embodiment, the maximum peak current for causing the dot pin to head impact is about 8 [A], but as described above, a current is constantly flowing through the coil of the electromagnet corresponding to each dot pin. Therefore, in the power supply circuit 44, the constant current generation circuit of 1 to 2 [A] and the capacitor having a relatively large capacity for dealing with the peak current are connected in parallel. When a large current (high power) is required to make the dot pin have a head impact, the power supply circuit 44 supplies the current to the coil of the electromagnet using the electric charge stored in the capacitor.

  Further, in the present embodiment, when the temperature of the print head 11 is high, that is, when the head is in a high temperature state, pass division printing is performed as thermal printing, in which an image of one pass is formed by many main scans. For example, as described above, when one pass is divided into three passes and pass division printing is performed, the maximum current (maximum power) required for printing per pass is when pass division printing is not performed. 1/3 of the maximum current. In this case, as shown in FIG. 5, there is a margin, that is, a surplus in the power capacity of the power circuit 44.

  In the present embodiment, such surplus current (surplus power) is used for the fan motor of the cooling fan 25.

  Next, a method of using surplus current for the fan motor of the cooling fan 25 will be described.

  FIG. 6 shows a control circuit for the fan motor of the cooling fan in the first embodiment of the present invention, and FIG. 7 shows a PWM control current waveform of the fan motor of the cooling fan in the first embodiment of the present invention. FIG.

  As shown in FIG. 6, the control circuit for the fan motor of the cooling fan 25 in the present embodiment uses a logic control circuit including a CPU, ROM, etc. as a low voltage circuit and a voltage of about +5 [V] from the power supply circuit 44. It includes two systems: a part that operates and a part that operates at about +40 [V] from the power supply circuit 44 using a circuit for driving the electromagnet of the print head 11 via the driver IC (head drive) as a high-voltage circuit. Yes. The fan motor of the cooling fan 25 is connected in series with the switching transistor of the fan motor, and is connected to a high voltage circuit for driving the electromagnet of the print head 11.

  As shown in FIG. 7, the cooling fan 25 can be rotated at an arbitrary number of rotations by PWM control of the fan motor. That is, the number of revolutions can be changed by changing the ratio (change in average current value) between the fan motor ON time and the fan motor OFF time within a certain period. Specifically, when the ON time is shortened, the rotation is slow, and when the ON time is lengthened, the rotation is high.

  For example, as described above, assuming that the print head 11 is a 24-pin head, if a current of 8 [A] is required when all 24 dot pins are subjected to a head impact in one head impact, the In the calculation, the current is 8 [A] /24=0.33 [A] per pin head. As described above, if the pass division printing is the three passes in which one pass is divided into three passes, a maximum of 8 dot pins are subjected to head impact. 0.33 [A] × 16 = 5.33 [A] corresponding to the current required for the head impact of the dot pins.

  On the other hand, in order to normally rotate the cooling fan 25 by PWM control of the fan motor, for example, it is assumed that an average current of 2 [A] is required at an ON time of 25 [%], and the cooling fan 25 is rotated at a high speed. Therefore, for example, if an average current of 4 [A] is required at an ON time of 50 [%], the current supplied to the fan motor is increased by 2 [A] in order to rotate the cooling fan 25 at a high speed. It is necessary to let Therefore, the cooling fan 25 can be rotated at a high speed by directing 2 [A] out of the surplus current of 5.33 [A] to the fan motor. Note that when the supplied current is doubled, the fan motor theoretically rotates at twice the rotational speed.

  Generally, the cooling capacity of the cooling fan 25 (the amount of heat released from the object to be cooled) is proportional to the amount of air blown by the cooling fan 25, that is, the rotational speed of the fan motor. Therefore, when the cooling fan 25 is rotated at a high speed twice as fast as normal rotation, the cooling capacity of the cooling fan 25 is doubled.

  Accordingly, since the cooling fan 25 can be rotated at high speed without increasing the power supply capacity of the power supply circuit 44, the cooling fan 25 can be cooled even in the high-temperature state where the cooling of the print head 11 is most necessary. It becomes possible to improve ability.

  Next, the operation of the cooling fan 25 in the normal printing state and the thermal printing state will be described.

  In the normal printing state, since the printing amount (head impact amount per unit time) is large, the maximum current required for the head impact is large and the surplus current is small, so the cooling fan 25 is normally rotated. Since the fan motor is PWM-controlled, the rotation speed of the cooling fan 25 can be reduced and rotated normally by shortening the ON time.

  Further, in the thermal printing state, since the pass division printing is performed, the printing amount is reduced, so that the maximum current required for the head impact is reduced, and surplus current is generated. Then, the surplus current is supplied to the fan motor to rotate the cooling fan 25 at a high speed. Since the fan motor is PWM-controlled, by increasing the ON time, the rotation speed of the cooling fan 25 can be increased and rotated at high speed.

  In the present embodiment, the cooling fan 25 is normally rotated during normal printing. This is because the temperature rise of the print head 11 is suppressed to a small extent so that the printing throughput does not decrease. . Of course, since the cooling fan 25 is rotating not a little, it is considered to increase the power supply capacity of the power supply circuit 44 accordingly.

  In the present embodiment, the cooling fan 25 can be stopped during normal printing, and the cooling fan 25 can be rotated only during thermal printing. In this case, the power supply capacity of the power supply circuit 44 can be reduced by the amount of current required to normally rotate the cooling fan 25.

  Next, operations of the head temperature measurement process, the printing process, and the control process of the cooling fan 25 of the printing apparatus 10 will be described. First, the operation of the head temperature measurement process for measuring the temperature of the print head 11 will be described.

  FIG. 8 is a flowchart showing the operation of the head temperature measurement process in the first embodiment of the invention.

  The control device 60 of the printing apparatus 10 performs head temperature measurement processing at regular intervals (for example, 100 [μs]) based on a timer (not shown) provided in the microprocessor 30.

  First, in step S1, the control device 60 determines whether 15 seconds have elapsed. Specifically, the head temperature measurement unit 53 performs the previous temperature measurement of the print head 11 performed based on a signal received from the print head thermistor 43 according to the count value of a 15-second time counter (not shown), that is, the head It is determined whether 15 seconds have elapsed from the temperature measurement. If 15 seconds have not elapsed since the previous head temperature measurement, the process is terminated, and if 15 seconds have elapsed since the previous head temperature measurement, the process proceeds to step S2.

  In step S2, the control device 60 measures the temperature of the head thermistor. Specifically, the head temperature measurement unit 53 measures the temperature of the print head 11 based on the signal received from the print head thermistor 43, that is, the head temperature measurement, and a value obtained by A / D converting the measured head temperature. Is output.

  Subsequently, in step S3, the control device 60 determines whether or not thermal printing is necessary. Specifically, the thermal printing determination unit 54 determines whether or not thermal printing is necessary based on the A / D converted value of the head temperature output from the head temperature measurement unit 53. If thermal printing is necessary, the process proceeds to step S4. If thermal printing is not necessary, the process proceeds to step S5.

  In step S4, the control device 60 sets thermal printing. Specifically, the thermal printing determination unit 54 sets information indicating that thermal printing is performed.

  In step S5, the control device 60 sets normal printing. Specifically, the thermal printing determination unit 54 sets information indicating that normal printing is performed.

  Note that information indicating that thermal printing is performed and information indicating that normal printing is performed may be set and held as flags. For example, the flag “1” may indicate that thermal printing is to be performed, and the flag “0” may indicate that normal printing is to be performed.

  Subsequently, in step S6, the control device 60 clears the 15-second time counter and ends the process. Specifically, the head temperature measurement unit 53 clears the 15-second time counter and ends the process so that the process can be started again after the next period of 15 seconds has elapsed.

Next, a flowchart will be described.
Step S1: It is determined whether 15 seconds have elapsed. If 15 seconds have not elapsed since the previous head temperature measurement, the process ends. If 15 seconds have elapsed since the previous head temperature measurement, the process proceeds to step S2.
Step S2: Measuring the temperature of the head thermistor.
Step S3: It is determined whether or not thermal printing is necessary. If thermal printing is necessary, the process proceeds to step S4, and if thermal printing is not necessary, the process proceeds to step S5.
Step S4: Thermal printing is set.
Step S5: Normal printing is set.
Step S6: The 15-second time counter is cleared and the process is terminated.

  Next, the operation of a printing process for performing thermal printing or normal printing will be described.

  FIG. 9 is a flowchart showing the operation of the printing process in the first embodiment of the present invention.

  First, in step S11, the control device 60 receives data. Specifically, the data receiving unit 50 receives data from the host PC 45, and the data analyzing unit 51 analyzes the data received by the data receiving unit 50.

  Subsequently, in step S12, the control device 60 determines whether or not reception of one line data has been completed. Specifically, the data analysis unit 51 determines whether or not the data reception unit 50 has received data corresponding to one line of print data. When the reception of one line data is completed, that is, when the data corresponding to the print data for one line has been received, the process proceeds to step S13. When the reception of one line data is not completed, that is, for one line. If the data corresponding to the print data has not been received, the process returns to step S11.

  In step S13, the control device 60 performs one line of expansion. Specifically, when the data analysis unit 51 analyzes the data received by the data reception unit 50 and creates and outputs one line of print data, the bitmap development unit 52 outputs the one line output by the data analysis unit 51. One minute of print data is expanded into one line of bitmap data.

  Subsequently, in step S14, the control device 60 determines whether or not the current printing operation is completed. Specifically, the pass printing control unit 55 determines whether the printing operation of the printing unit 57 is currently completed, that is, whether the printing operation is stopped. If the printing operation is completed, the process proceeds to step S15. If the printing operation is not completed, that is, if the printing unit 57 is currently printing, the next printing operation cannot be started, and the control device 60 returns to step S14, The determination whether or not the current printing operation is completed is repeated.

  In step S15, the control device 60 determines whether or not it is in a thermal printing state. Specifically, the pass printing control unit 55 performs thermal printing based on whether the information received from the thermal printing determination unit 54 is information indicating that thermal printing is performed or information indicating that normal printing is performed. Determine whether to do it. If it is not in the thermal printing state, that is, if normal printing is performed, the process proceeds to step S16. In the case of thermal printing, that is, when thermal printing is performed, the process proceeds to step S18.

  In step S16, the control device 60 sets the fan rotation request to normal rotation. Specifically, the pass print control unit 55 that has determined that normal printing is performed sets a normal rotation request for the cooling fan 25 and outputs the request to the cooling fan control unit 56.

  Subsequently, in step S17, the control device 60 starts printing and ends the process. Specifically, the pass print control unit 55 outputs the bitmap data received from the bitmap development unit 52 to the printing unit 57 as it is, and causes the printing unit 57 to start a printing operation for performing normal printing to perform processing. finish.

  In step S18, the control device 60 sets the fan rotation request to high speed rotation. Specifically, the pass printing control unit 55 that has determined to perform thermal printing sets a request for high-speed rotation of the cooling fan 25 and outputs the request to the cooling fan control unit 56.

  Subsequently, in step S19, the control device 60 performs pass printing activation. Specifically, the pass print control unit 55 generates bitmap data adapted to pass division printing based on the bitmap data received from the bitmap development unit 52 and outputs the bitmap data to the printing unit 57. Then, the pass printing control unit 55 causes the printing unit 57 to start a printing operation for performing pass division printing in which one pass is divided into a plurality of, for example, three passes.

  Subsequently, in step S20, the control device 60 determines whether or not all-pass printing has been completed. If completed, the process ends. If not, the process returns to step S19 to return to all passes. Repeat the determination of whether printing is complete. Specifically, the pass printing control unit 55 determines whether the printing unit 57 has completed printing for all of the divided passes, for example, all of the three passes, and all of the divided passes. If the printing is completed, the process ends. If not, the determination of whether or not the printing is completed is repeated until the printing is completed for all of the divided paths.

Next, a flowchart will be described.
Step S11: Data is received.
Step S12: It is determined whether the one-line data reception is completed. When the reception of one line data is completed, the process proceeds to step S13, and when the reception of one line data is not completed, the process returns to step S11.
Step S13: One line is expanded.
Step S14: It is determined whether or not the printing operation is currently completed. If the printing operation is completed, the process proceeds to step S15. If the printing operation is not completed, the determination is repeated.
Step S15: It is determined whether or not the thermal printing state is set. If it is not in the thermal printing state, the process proceeds to step S16, and if it is in the thermal printing state, the process proceeds to step S18.
Step S16: The fan rotation request is set to normal rotation.
Step S17: Printing is started and the process is terminated.
Step S18: The fan rotation request is set to high speed rotation.
Step S19: Pass printing is started.
Step S20: It is determined whether all pass printing has been completed. If all pass printing has been completed, the process ends. If all pass printing has not been completed, the process returns to step S19.

  Next, the operation of the cooling fan control process in the first embodiment of the present invention will be described.

  FIG. 10 is a flowchart showing the operation of the cooling fan control process in the first embodiment of the present invention.

  The control device 60 executes control processing for the cooling fan 25 at regular intervals (for example, 100 [μs]) based on a timer (not shown) provided in the microprocessor 30 as the main control device.

  First, in step S21, the control device 60 determines whether or not the fan ON time has elapsed. Specifically, the cooling fan control unit 56 determines whether or not the ON time for supplying current to the fan motor has passed a specified time. If the ON time has passed the specified time, the process proceeds to step S23. If the ON time has not passed the specified time, the process proceeds to step S22.

  In step S22, the control device 60 writes a fan ON command to the I / O port and ends the process. Specifically, the cooling fan control unit 56 writes a command to turn on the fan motor to an I / O port that turns on or off the fan motor of the cooling fan 25, and ends the process.

  In step S23, the control device 60 determines whether or not the fan OFF time has elapsed. Specifically, the cooling fan control unit 56 determines whether or not an OFF time during which no current is supplied to the fan motor has passed a specified time. If the OFF time has passed the specified time, the process proceeds to step S25. If the OFF time has not passed the specified time, the process proceeds to step S24.

  In step S24, the control device 60 writes a fan OFF command to the I / O port and ends the process. Specifically, the cooling fan control unit 56 writes a command to turn off the fan motor to an I / O port that turns on or off the fan motor of the cooling fan 25, and ends the process.

  In step S25, the control device 60 determines whether or not the fan rotation is a normal rotation request. Specifically, the cooling fan control unit 56 determines whether or not the pass print control unit 55 has output a normal rotation request for the cooling fan 25. If it is a normal rotation request, the process proceeds to step S26. If it is not a normal rotation request, that is, if it is a high-speed rotation request, the process proceeds to step S28.

  In step S26, the control device 60 sets the fan ON time for normal rotation. Specifically, the cooling fan control unit 56 sets the length of the ON time for supplying current to the fan motor so that the cooling fan 25 is normally rotated.

  Subsequently, in step S27, the control device 60 sets the fan OFF time for normal rotation and ends the process. Specifically, the cooling fan control unit 56 sets the length of the OFF time during which no current is supplied to the fan motor so that the cooling fan 25 is normally rotated, and ends the process.

  In step S28, the control device 60 sets a fan ON time for high-speed rotation. Specifically, the cooling fan control unit 56 sets the length of the ON time for supplying current to the fan motor so that the cooling fan 25 rotates at high speed.

  Subsequently, in step S29, the control device 60 sets the fan OFF time for high-speed rotation and ends the process. Specifically, the cooling fan control unit 56 sets the length of the OFF time during which no current is supplied to the fan motor so as to rotate the cooling fan 25 at a high speed, and ends the process.

Next, a flowchart will be described.
Step S21: It is determined whether the fan ON time has elapsed. If the fan ON time has passed the specified time, the process proceeds to step S23, and if the fan ON time has not passed the specified time, the process proceeds to step S22.
Step S22: Write a fan ON command to the I / O port and end the process.
Step S23: It is determined whether or not the fan OFF time has elapsed. If the fan OFF time has passed the specified time, the process proceeds to step S25, and if the fan OFF time has not passed the specified time, the process proceeds to step S24.
Step S24: Write a fan OFF command to the I / O port and end the process.
Step S25: It is determined whether the fan rotation is a normal rotation request. If the fan rotation is a normal rotation request, the process proceeds to step S26, and if the fan rotation is not a normal rotation request, the process proceeds to step S28.
Step S26 The fan ON time for normal rotation is set.
Step S27: The fan OFF time for normal rotation is set and the process is terminated.
Step S28 The fan ON time for high speed rotation is set.
Step S29: The fan OFF time for high speed rotation is set and the process is terminated.

  As described above, in the present embodiment, when the print head 11 becomes high temperature, the thermal print state is entered, and pass division printing is performed. Therefore, the maximum current required for the head impact is reduced and surplus power is generated, and the surplus power is generated. Is used to rotate the cooling fan 25 at a high speed. Thereby, the print head 11 can be cooled more effectively. The surplus power is the difference between the maximum current required for the print operation of the print head 11 when the pass division printing is not performed and the maximum current required for the print operation of the print head 11 when the pass division printing is performed. As described above, since the print head 11 that has reached a high temperature can be effectively cooled while suppressing the maximum amount of power consumed by the entire printing apparatus 10, there is no need to increase the power supply capacity of the power supply circuit 44. The power supply circuit 44 can be reduced in size and the cost can be reduced.

  Next, a second embodiment of the present invention will be described. In addition, about what has the same structure as 1st Embodiment, the description is abbreviate | omitted by providing the same code | symbol. The description of the same operation and the same effect as those of the first embodiment is also omitted.

  FIG. 11 is a block diagram showing a functional configuration of the printing apparatus according to the second embodiment of the present invention.

  As shown in the figure, the control device 60 of the printing apparatus 10 according to the present embodiment includes a data receiving unit 50, a data analyzing unit 51, a bitmap developing unit 52, and a cooling fan control unit 56 as functional units. The printing unit 57 and the printing duty (Duty) determination unit 58 are provided. The head temperature measurement unit 53, the thermal print determination unit 54, and the pass print control unit 55 are omitted.

  In the present embodiment, when the print duty of one line is low, it is noted that the power used for head impact is small, and the control device 60 determines the print duty of one line.

  Then, the bitmap development unit 52 develops the print data from the data analysis unit 51 into bitmap data for one line that can be printed by unidirectional movement of the space carriage 12, and the developed bitmap data is printed. Output to the unit 57 and the print duty determination unit 58.

  When the bitmap data for one line is input from the bitmap development unit 52, the print duty determination unit 58 calculates the print duty for one line and determines whether the duty is high.

  Whether the duty is high or not is determined based on the ratio of the number of dots to be printed with respect to the total number of dots including the unprinted portion in the printing of one line. That is, (print duty) = (number of print dots) / (number of all dots including unprinted portions). Thereby, it is possible to obtain the print duty in printing one line.

  The print duty determination unit 58 determines whether or not the print duty exceeds a predetermined threshold (threshold value) (for example, 0.25 (25 [%])). The print duty determining unit 58 determines that the duty is high if the print duty is equal to or greater than the threshold, and determines that the duty is low if the print duty is less than the threshold. Subsequently, the print duty determination unit 58 outputs the determination result to the cooling fan control unit 56.

  The cooling fan control unit 56 sets the rotation of the cooling fan 25 as a normal rotation if the duty is high, and determines the rotation of the cooling fan 25 as a normal rotation if the duty is high. The cooling fan 25 is rotated at a high speed. Depending on whether the rotation of the cooling fan 25 is normal rotation or high-speed rotation, the motor that rotates the cooling fan 25, that is, the ON time for supplying current to the fan motor, and OFF for not supplying current to the fan motor The time is set in advance, and the fan motor of the cooling fan 25 is turned ON / OFF in such a determined time.

  Since the configuration of other points is the same as that of the first embodiment, description thereof is omitted.

  Next, the operation of the printing apparatus 10 in the present embodiment will be described.

  FIG. 12 is a flowchart showing the operation of the printing process in the second embodiment of the present invention.

  Note that the operation up to the execution of one line, that is, the operation of START and steps S31 to S33 shown in FIG. 12, is the same as the operation of START and steps S11 to S13 shown in FIG. The description is omitted.

  In step S34, the control device 60 determines the print density. Specifically, when the bitmap data for one line is input from the bitmap developing unit 52, the print duty determination unit 58 calculates the print duty for one line and determines whether the duty is high or low. Judging.

  Subsequently, in step S35, the control device 60 determines whether or not the current printing operation is completed. Since this operation is the same as the operation in step S14 shown in FIG. 9, the description thereof is omitted.

  Subsequently, in step S36, the control device 60 determines whether or not the print duty is a high duty. Specifically, the cooling fan control unit 56 determines whether the print duty is a high duty or a low duty based on the determination result input from the print duty determination unit 58. When the print duty is high, the process proceeds to step S37, and when the print duty is not high, that is, the duty is low, the process proceeds to step S38.

  In step S37, the control device 60 sets the fan rotation to normal. Specifically, the cooling fan control unit 56 sets the cooling fan 25 so as to normally rotate.

  In step S38, the control device 60 sets the fan rotation at a high speed. Specifically, the cooling fan control unit 56 sets the cooling fan 25 to rotate at high speed.

  Subsequently, in step S39, the control device 60 starts printing and ends the process. Specifically, the bitmap developing unit 52 outputs the bitmap data to the printing unit 57, causes the printing unit 57 to start a printing operation for performing normal printing, and ends the process.

Next, a flowchart will be described.
Step S31: Data is received.
Step S32: It is determined whether the one-line data reception is completed. When the reception of one line data is completed, the process proceeds to step S33, and when the reception of one line data is not completed, the process returns to step S31.
Step S33: One line is expanded.
Step S34: The print density is determined.
Step S35: It is determined whether the printing operation is currently completed. If the printing operation is completed, the process proceeds to step S36. If the printing operation is not completed, the determination is repeated.
Step S36: It is determined whether the print duty is a high duty. If the print duty is high, the process proceeds to step S37, and if the print duty is not high, the process proceeds to step S38.
Step S37: The fan rotation is set to normal.
Step S38: The fan rotation is set at a high speed.
Step S39 Printing is started and the process is terminated.

  Note that the operation of the control process of the cooling fan 25 is the same as the operation of Step S21 to Step S29 shown in FIG. 10 described in the first embodiment, and thus the description thereof is omitted.

  As described above, in this embodiment, when the printing duty of one line is low, the maximum current required for the head impact is reduced and surplus power is generated. Therefore, the surplus power is used to rotate the cooling fan 25 at a high speed. It is supposed to let you. The surplus power is the difference between the maximum current required for the print operation of the print head 11 when the print duty is high and the maximum current required for the print operation of the print head 11 when the print duty is low. Thereby, the temperature rise of the print head 11 can be suppressed, and it can be used without surplus power.

  In the first and second embodiments, the case where the printing apparatus 10 is a dot impact printer has been described. However, this is for convenience of explanation, and the printing apparatus 10 is limited to a dot impact printer. It is not what is done.

  In the first embodiment, the case where the number of dot pins included in the print head 11 is 24 has been described. However, this is for convenience of description, and the number of dot pins is 24. It is not limited to.

  Further, in the first embodiment, an example has been described in which it is determined that thermal printing is necessary when the temperature of the print head 11 is 70 ° C. or higher. This is for convenience of explanation. The temperature threshold of the print head 11 for determining whether or not thermal printing is necessary is not limited to this.

  Furthermore, in the first embodiment, an example in which one pass is divided into three passes in the case of pass division printing has been described. However, this is for convenience of explanation, and the pass division is performed. The number is not limited to this.

  Further, in the first embodiment, the case where the control circuit for the fan motor of the cooling fan 25 is a circuit as shown in FIG. 6 is described. The fan motor control circuit of the fan 25 is not limited to this.

  Further, in the first embodiment, the example of the ON time and the OFF time in the case where the fan motor of the cooling fan 25 is PWM controlled has been described. The numerical values of the time and the OFF time are not limited to this, and are appropriately determined by experiments or the like in consideration of the characteristics of the cooling fan 25, the fan motor, and other members.

  Further, in the second embodiment, an example is described in which it is determined whether or not the cooling fan 25 is rotated at high speed based on whether or not the printing duty of one line is a high duty. However, the present invention is not limited to this. For example, when a single line includes a high-duty print block and a low-duty print block, the cooling fan 25 corresponds to each block. Can be changed between high-speed rotation and normal rotation.

  In addition, this invention is not limited to the said embodiment, It can change variously based on the meaning of this invention, and does not exclude them from the scope of the present invention.

  The present invention can be used in an image forming apparatus.

DESCRIPTION OF SYMBOLS 10 Printing apparatus 11 Print head 17a Front feed roller 17b Rear feed roller 18 Medium 25 Cooling fan 53 Head temperature measurement part 60 Control apparatus

Claims (5)

Conveying means for conveying the medium in the sub-scanning direction;
An image forming head for printing on the medium while moving in the main scanning direction;
Cooling means for cooling the image forming head;
A controller for controlling the operations of the conveying means, the image forming head, and the cooling means,
The control device includes a head temperature measuring unit that detects a temperature of the image forming head. When the image forming head is at a high temperature, the control device causes the image forming head to perform pass division printing, and causes the image forming head to perform pass division. An image forming apparatus, wherein surplus power generated by printing is used for the operation of the cooling unit.   The surplus power is a difference between the maximum power required for the printing operation of the image forming head when the pass division printing is not performed and the maximum power required for the printing operation of the image forming head when the pass division printing is performed. The image forming apparatus according to claim 1. Conveying means for conveying the medium in the sub-scanning direction;
An image forming head for printing on the medium while moving in the main scanning direction;
Cooling means for cooling the image forming head;
A controller for controlling the operations of the conveying means, the image forming head, and the cooling means,
The control apparatus uses surplus power generated by a low printing duty of the image forming head for the operation of the cooling unit.   The surplus power is a difference between a maximum power required for a printing operation of the image forming head when a printing duty is high and a maximum power required for the printing operation of the image forming head when a printing duty is low. The image forming apparatus according to 3.   The image forming apparatus according to claim 1, wherein the cooling power of the cooling unit is improved by using the surplus power for the operation of the cooling unit.

Images