JP2015178261A - Inkjet printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inkjet printer that is configured to fix ink to a recording medium by heating the recording medium and the ink with heating means which is positioned to oppose to an ink-impact surface of the recording medium and does not contact the recording medium, which can accurately measure a temperature by reducing a measurement error for each recording medium by a temperature sensor for measuring a temperature of the recording medium.SOLUTION: A contact type temperature sensor is provided in a platen that supports a recording medium; a calibration value is calculated from a measurement result by the contact type temperature sensor and a measurement result by a non-contact type temperature sensor before a temperature of a heater is controlled using only the non-contact type temperature sensor; and the temperature of the heater is controlled in consideration of the calibration value when controlling the temperature of the heater using only the non-contact type temperature sensor.

Description

  The present invention relates to an inkjet printer.

  2. Related Art Ink jet printers that record images by ejecting ink onto recording media such as recording paper and resin films are widely known. There are various types of inks used in ink jet printers. For example, there are inks that have the property of being fixed on a recording medium and dried by heating at a high temperature. When using this ink, it is necessary to heat immediately after ejecting the ink landed on the recording medium. At this time, it is necessary to control the heating by the heating means so that the recording medium and the ink have an appropriate temperature. For example, the recording apparatus described in Japanese Patent Application Laid-Open No. 2013-193373 employs a configuration in which the surface temperature of the surface of the recording medium on which ink is landed is measured by a temperature sensor, and the heating temperature is controlled by feeding back the measured temperature. Has been. A heating device of an infrared irradiation method is installed at a position facing the surface on which the ink of the recording medium lands without contacting the recording medium, and a temperature sensor for measuring the surface temperature of the surface of the recording medium on which the ink lands, It is arranged without contacting the position facing the recording medium. Moreover, in order to suppress the influence on the temperature sensor by a heating means, the structure which heat-insulates the heat | fever transmitted to a temperature sensor is taken.

JP 2013-193373 A

However, since the conventional technology uses a temperature sensor that detects infrared rays, the measured value differs depending on the surface condition such as the color and material of the recording medium. Inkjet printers have a variety of materials for recording media printed by users. For this reason, if printing is performed without calibration, temperature control is not constant for each recording medium, and a difference occurs in the image quality of the output result to the recording medium.
Therefore, an ink jet printer capable of controlling the temperature control for each recording medium to be constant has been desired.

  The inkjet printer of the present invention is a recording head that discharges ink to a recording medium, a platen that supports the recording medium, and a position facing the recording medium, and does not contact the recording medium, and the recording head Immediately after ejecting the ink to the recording medium, the recording medium, heating means for heating the ink, and a position facing the ink landing surface of the recording medium and not in contact with the recording medium, the surface temperature of the recording medium is set. A correction for correcting a measurement value of the non-contact temperature sensor in an inkjet printer comprising: a non-contact temperature sensor to measure; and a control unit that controls a heating temperature of the heating unit based on a measurement result of the non-contact temperature sensor Correction value storage means for storing a value, and a contact temperature sensor that contacts the platen and measures the temperature of the platen And measuring the surface temperature of the recording medium supported on the platen by the non-contact temperature sensor before controlling the heating means using only the measurement result of the non-contact temperature sensor, The temperature of the platen is measured by a contact sensor, and the correction value for correcting the measurement value measured by the non-contact sensor is calculated from the measurement value measured by the contact sensor and the measurement value measured by the non-contact sensor. The correction value is stored in the correction value storage means, and when the heating means is controlled using only the measurement result of the non-contact temperature sensor, the measurement value measured by the non-contact temperature sensor and the correction value storage are stored. The heating means is controlled based on a correction value stored in the means.

  According to the ink jet printer of the present invention, it is possible to provide an ink jet printer capable of suppressing the error of the measured value of the surface temperature and making the temperature control for each recording medium constant even if the recording medium is different.

FIG. 1 is a diagram illustrating the configuration of an inkjet printer. FIG. 2 is a block diagram of the ink jet printer. FIG. 3 is a diagram for explaining the temperature measurement of the recording medium. FIG. 4 is a flowchart for explaining the operation. FIG. 5 is an external view of the ink jet printer.

Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram illustrating the configuration of an inkjet printer. Hereinafter, the ink jet printer of the present invention will be described in detail with reference to the drawings. First, the overall configuration of the ink jet printer according to the present embodiment will be described with reference to FIG. FIG. 1 is a configuration diagram showing a basic configuration of an ink jet printer and a temperature sensor installation structure. A recording medium 2 wound in a roll shape is installed on a recording medium installation base 1 having a rotating shaft. The recording medium 2 is conveyed by a conveying roller 4 and a pinch roller 14 provided between the rear paper guide 3 and the platen 5, passes over the rear paper guide 3, the platen 5, and the front paper guide 19 and is discharged. A carriage 6 is supported on a rail 7 so as to be able to reciprocate in the main scanning direction perpendicular to the conveyance direction of the recording medium 2 above the platen 5. One or more print heads 22 are mounted on the carriage 6 and eject ink droplets onto the medium 2 on the platen 5. First, by heating the recording medium 2 on the platen 5 and the ink that has been ejected from the print head 22 by the primary heater 8 whose length in the main scanning direction is longer than that of the recording medium 2 and landed on the recording medium 2, The water contained in the ink is evaporated and the ink is hardened and fixed to the recording medium 2. Next, the recording medium 2 on which ink has landed is conveyed onto the front paper guide 19, and the recording medium 2 on the front paper guide 19 is landed on the recording medium 2 by the secondary heater 13 whose length in the main scanning direction is longer than that of the recording medium. The ink is heated at a temperature higher than the temperature heated by the primary heater 8 to further evaporate the moisture and bond the resins contained in the ink to form a film and fix it on the recording medium 2. . Further, in order to prevent adverse effects such as the temperature inside the ink jet printer being raised by the primary heater 8 and the secondary heater 13 and the nozzle plate (not shown) of the print head 22 being dried, a back fan 15 is provided on the outer wall of the ink jet printer. It is installed so that outside air can be taken into the inkjet printer.

  Further, the primary heater 8 and the secondary heater 13 are infrared radiation heaters, and are not in contact with the object to be heated. In addition, the primary heater 8 and the secondary heater 13 are provided with a reflector 9a and a reflector 9b made of an Alster steel plate or stainless steel having a high infrared reflectance to increase the efficiency of infrared irradiation with respect to the object to be heated. It is installed so as to cover the secondary heater 13. The temperature heated by the primary heater 8 and the secondary heater 13 is measured by measuring the surface temperature of the recording medium 2 at the portion heated by the primary heater 8 and the secondary heater 13 by the primary temperature sensor 10a and the secondary temperature sensor 10b, respectively. In addition, by controlling the power supplied to the primary heater 8 and the secondary heater 13, the measurement location is controlled to be maintained at a predetermined temperature. For example, ON / OFF control or supply power increase / decrease control is performed for the supply power control. The primary temperature sensor 10a is fixed to the primary heater support member 12, and the secondary temperature sensor 10b is fixed to the temperature sensor support member 17. Further, the primary temperature sensor 10a is opposite to the surface facing the recording medium. The blower fan 23b is provided on the same surface of the blower fan 23a and the secondary temperature sensor 10b. Further, a primary intake duct 11 that communicates the front cover 20 having the intake holes and the blower fan 23a, and a secondary intake duct 16 that communicates the secondary heater cover 21 that has the intake holes and the blower fan 23b are provided. The outside air is sent to the primary temperature sensor 10a and the secondary temperature sensor 10b through these intake ducts. A hole 18 is provided in the secondary heater cover 21 between the secondary temperature sensor 10 b and the recording medium 2, and the secondary temperature sensor 10 b measures the surface temperature of the recording medium 2 through the hole 18. The primary temperature sensor 10a and the secondary temperature sensor 10b, and the blower fan 23a and the blower fan 23b have the same specifications.

  A contact temperature sensor 24 is disposed on the back surface of the platen 5. The contact temperature sensor 24 measures the temperature of the platen 5. Preferably, the temperature is fixed to the back surface of the platen 5 in the detection range of the primary temperature sensor 10a so that the temperature at the same location can be measured. However, since the platen 5 is made of aluminum or the like and has a high thermal conductivity, the platen 5 has almost the same temperature even if it is a little away.

  Further, since the primary heater 8 of this ink jet printer has a structure that heats the direction of the platen 5 from the upper part of the platen 5, the recording medium 2 on the platen 5 is heated almost uniformly over the entire width. There is an advantage that can be.

  In addition, since a non-contact sensor is used, the temperature at the time of measurement can be measured without considering heat transfer and time until a steady state is reached, and it is possible to deal with recording media of various materials and thicknesses.

  A preliminary contact temperature sensor 41 is disposed on the carriage 6. For example, when a recording medium with poor thermal conductivity, such as paper or plastic film, or a recording medium with a thickness of about 2.0 mm or more is used, the non-contact sensors 10a and 10b are calibrated.

  FIG. 2 is a block diagram of the ink jet printer. The control circuit 25 is a control circuit that controls the entire inkjet printer. The recording unit 27 includes a recording head 22, a carriage 6 on which the recording head 22 is mounted, and a mechanism that reciprocates the recording head 22 in the width direction of the recording medium 2, and is a unit that records an image on the recording medium 2. The recording means 27 is controlled by the control circuit 25. The carriage 6 is moved along the rail 7 in the width direction of the recording medium 2 by the carriage moving means 28. The carriage moving unit 28 is controlled by the control circuit 25.

  The transport unit 29 includes a transport roller 4 and transports the recording medium 2. The conveying means 29 is controlled by the control circuit 25. The linear encoder 26 detects a linear scale (not shown) disposed along the rail 7 and detects the positions of the carriage 6 and the recording head 22. The detection result is output to the control circuit 25, and the control circuit 25 calculates the positions of the carriage 6 and the recording head 22. The linear encoder 26 is controlled by the control circuit 25. A desired image can be recorded by ejecting ink from the recording means 27 in accordance with the detected position.

  The ROM 31 is a non-volatile memory, and stores a program for controlling the ink jet printer, initial setting values, and the like. The control circuit 25 operates according to this program. The RAM 30 is a memory used for work memory of the control circuit 25, temporary storage of data, and the like.

  The heater control means 32 can control the power supply to the primary heater 8 and the secondary heater 13 to increase or decrease the temperature. The heater control means 32 operates under the control of the control circuit 25.

  The non-contact temperature sensor 33 includes a primary temperature sensor 10a and a secondary temperature sensor 10b. The non-contact temperature sensor 33 operates under the control of the control circuit 25 and outputs the measured temperature to the control circuit 25. The primary temperature sensor 10 a measures the temperature of the recording medium 2 on the platen 5, and the secondary temperature sensor 10 b measures the temperature of the recording medium 2 on the front paper guide 19 and outputs it to the control circuit 25. . The control circuit 25 controls the heater control means 32 based on the acquired temperature to control power supply to the primary heater 8 and the secondary heater 13. That is, if the temperature is lower than the target temperature, the supplied power is increased. If the temperature is higher than the target temperature, the supplied power is decreased.

  The contact temperature sensor 24 measures the temperature of the platen 5. The contact temperature sensor 24 operates under the control of the control circuit 25 and outputs the measured temperature to the control circuit 25. Based on the temperature acquired by the contact temperature sensor 24, the set value of the primary temperature sensor 10a is changed. By changing the set value, it is possible to acquire measurement values that do not depend on external factors.

  The preliminary contact temperature sensor 41 is used when the recording medium has poor thermal conductivity and when there is a thickness and the heat is not sufficiently transmitted to the platen 5. Switching between the contact temperature sensor 24 and the preliminary contact temperature sensor 41 is switched by the user before the temperature rise, or when the temperature of the contact sensor 24 does not rise even after a certain time has elapsed after the temperature rise starts, the heater output is temporarily cut off. Switch. The preliminary contact temperature sensor 41 is disposed on the carriage 6. The preliminary contact temperature sensor 41 includes lifting means, and is usually lifted to a position where it does not contact the recording medium. When measuring the temperature, the temperature is lowered so as to come into contact with the object to be measured. In the calibration, the temperature measured by the preliminary contact temperature sensor 41 is regarded as the correct temperature, and a correction value for the temperature measured by the non-contact temperature sensor 33 is obtained. The correction value is set so that a value obtained by adding the correction value to the temperature measured by the non-contact temperature sensor 33 becomes a value regarded as a correct temperature.

  The suction unit control means 34 is a means for controlling a fan (not shown) that sucks the recording medium 2 provided on the platen 5. The recording medium 2 is sucked from the infinite number of suction holes provided in the platen 5 on the flat plate by sucking air under the platen by turning the fan to make negative pressure and sucking the recording medium through the suction holes to thereby change the ink landing surface. Keep it flat. Further, the suction unit control means 34 can also control the rear fan 15 to adjust the amount of outside air supplied into the housing. Thereby, temperature control in a housing | casing can also be performed.

  FIG. 3 is a diagram for explaining the temperature measurement of the recording medium. The recording medium 2 is conveyed on the platen 5 and heated by the primary heater 8. The temperature of the surface of the recording medium 2 is detected by the primary temperature sensor 10a. A temperature detection range 35 indicated by a dotted line indicates a range detected by the primary temperature sensor 10a. The contact temperature sensor 33 is disposed on the back surface of the platen 5. It is fixed to the back surface of the temperature detection range 35 and detects the temperature of that portion. Although this location is preferable, the temperature of the platen 5 is substantially the same at the position of the contact temperature sensor 36 indicated by the dotted line at the end of the platen 5, and the temperature can be measured. Since the platen 5 has a high thermal conductivity and is heated by the primary heater 8 from above, the temperature becomes substantially uniform. Preferably, it is installed on the back surface of the conveyance range of the recording medium 2.

  FIG. 4 is a flowchart for explaining the operation. In order to appropriately control the primary heater 8, it is necessary to calibrate the primary heater 8. This is because it is necessary to accurately measure the temperature of the recording medium 2 heated by the primary heater. The non-contact temperature sensor calculates a temperature based on infrared rays from the object. If the emissivity of infrared rays from the object is not accurate, the calculated result will not be accurate. This is because the emissivity varies depending on the state of the surface of the measurement object. In order to accurately measure the temperature, it is necessary to set the emissivity for each measurement target. It is necessary to execute this setting, that is, calibration processing.

  First, in step S1, the primary heater 8 is heated to a target temperature. The measurement at this time is performed using the primary temperature sensor 10a and using a preset initial value. Therefore, there is a possibility that an error is included. The target temperature is a temperature at which the recording medium 2 is fixed.

  In step S2, it is determined whether the calibration by the preliminary contact temperature sensor 41 has been selected before the temperature rise. If not selected, the process proceeds to step S3. If selected, the process proceeds to step S6.

  In step S3, the temperature of the contact temperature sensor 24 is measured. That temperature is the original temperature of the recording medium. In step S7, the emissivity of the primary temperature sensor 10a is set so that the temperature acquired from the contact temperature sensor 24 and the temperature detected by the primary temperature sensor 10a are the same. Thereafter, the temperature is measured using the set emissivity. At this time, it is possible to store the emissivity in association with the type of the recording medium 2 used, and to set the emissivity shown in the related diagram when it is desired to use this type of recording medium 2, in terms of work efficiency. To preferred. If the detected temperature of the contact temperature sensor 24 has not reached the target temperature, the process proceeds to step S4.

In step S4, it is determined whether a predetermined temperature detection time is exceeded. If not, the process returns to step S3, and if exceeded, the process proceeds to step S5.
Step S5 is a flow that passes when the contact temperature sensor 24 cannot detect an appropriate temperature due to the nature of the recording medium 2. Here, in order to directly detect the temperature on the recording medium 2, the temperature on the recording medium 2 is detected using the preliminary contact sensor 41 mounted on the carriage 6, and the emissivity of the primary temperature sensor 10a is based on this temperature. Set. Next, the process proceeds to step S7.

  If it is selected in advance in step S2 that the preliminary contact temperature sensor 41 is used, the temperature is raised for a predetermined time stored in the ROM in advance, and then the process in step S5 is performed. The reason why the calibration operation is performed after the elapse of a predetermined time is that the emissivity of the non-contact sensor 10a is not appropriate and the emissivity is greatly deviated, for example, there is a possibility of heating for a long time. An appropriate time is obtained in advance by experiments or the like, and the temperature is raised for this time.

  Further, when performing this calibration, it is preferable to stop the rear fan 15 by controlling the suction unit control means 34. Since a disturbance of detection is caused by taking in outside air, it is preferable to detect the temperature in a state in which the disturbance is suppressed. Further, it is preferable to detect the recording medium 2 in a state where the recording medium 2 is adsorbed to the platen 5 by controlling the adsorption unit control means 34. This is because the temperature difference can be detected as much as possible by bringing the recording medium 2 and the platen 5 into close contact with each other. In this case, it is more preferable that the suction mechanism of the platen 5 is divided into a plurality of blocks, and detection is performed in a state where only the platen 5 portion of the block where the contact temperature sensor 24 is disposed is sucked. This is because the disturbance due to the air flow from the suction hole is eliminated, and the recording medium 2 and the platen 5 are brought into close contact with each other, so that the temperature difference can be detected in the least possible state.

  Alternatively, the secondary temperature sensor 10b may be the same as the primary temperature sensor 10a, and the emissivity may be set to be the same as that of the primary temperature sensor 10a. Further, a contact temperature sensor may be arranged on the back surface of the front paper guide 19 and the same calibration as that of the primary temperature sensor 10a may be performed.

  FIG. 5 is an external view of the ink jet printer. It is an external view of an inkjet printer. The ink jet printer 40 supports the casing 39 with the legs 37. The leg portions 37 are fixed to both ends of the lower surface of the housing 39. Along the front paper guide 19, the recording medium 2 is discharged in the direction indicated by the arrow 38 from the gap between the front paper guide 19 and the secondary heater cover 21. The front paper guide shown in FIG. 5 is longer than the front paper guide shown in FIG. 1, and guides the recording medium 2 downward.

  The present invention can be used in an ink jet printer. In particular, the present invention can be used for a large ink jet printer that records on a wide recording medium.

DESCRIPTION OF SYMBOLS 1 Recording medium installation stand 2 Recording medium 3 Rear paper guide 4 Carrying roller 5 Platen 6 Carriage 7 Rail 8 Primary heater 13 Secondary heater 10a Primary temperature sensor 10b Secondary temperature sensor 24 Contact temperature sensor

Claims (7)

A recording head for ejecting ink onto a recording medium;
A platen that supports the recording medium;
Heating means that heats the recording medium and the ink immediately after the ink is ejected to the recording medium by the recording head without being in contact with the recording medium at a position facing the recording medium;
A non-contact temperature sensor for measuring the surface temperature of the recording medium, located at a position facing the ink landing surface of the recording medium and not in contact with the recording medium;
Control means for controlling the heating temperature of the heating means based on the measurement result of the non-contact temperature sensor;
In an inkjet printer comprising:
Correction value storage means for storing a correction value for correcting the measurement value of the non-contact temperature sensor;
A contact temperature sensor that contacts the platen and measures the temperature of the platen;
Before controlling the heating means using only the measurement result of the non-contact temperature sensor, the surface temperature of the recording medium supported by the platen is measured by the non-contact temperature sensor, and the contact sensor detects the surface temperature. The temperature of the platen is measured, the correction value for correcting the measurement value measured by the non-contact sensor is calculated from the measurement value measured by the contact sensor and the measurement value measured by the non-contact sensor, and the correction value Is stored in the correction value storage means,
When the heating unit is controlled using only the measurement result of the non-contact temperature sensor, the heating unit is based on the measured value measured by the non-contact temperature sensor and the correction value stored in the correction value storage unit. Inkjet printer characterized by controlling the above.   The heating means is a heater that is disposed at a position facing the recording medium side of the platen over a length equal to or longer than the length of the platen in a non-contact manner with respect to an object to be heated. The inkjet printer according to claim 1.   The ink jet printer according to claim 1, wherein the temperature sensor is a radiation thermometer. The platen is provided with a plurality of suction holes, and has a suction chamber communicating with the suction holes on the back side of the platen, and a suction fan for discharging air from the suction chamber to the outside,
When recording on the recording medium by the recording head, the suction fan is operated, and the suction fan is stopped during temperature measurement of the non-contact temperature sensor and the contact sensor in order to calculate the correction value. The inkjet printer according to any one of claims 1 to 3, wherein the inkjet printer is characterized.   The inkjet printer according to any one of claims 1 to 4, wherein the calculation of the correction value is a calculation for changing an emissivity of the non-contact temperature sensor.   6. The fan according to claim 1, further comprising a fan for cooling the inside of the housing, wherein when the temperature measurement for calculating the correction value is performed, the fan is stopped. 2. An ink jet printer according to item 1.   The recording head is mounted on a carriage, and the carriage is further provided with a second contact temperature sensor having a lifting function, and instead of the measurement value measured by the contact sensor arranged on the platen, 2. The correction value for correcting the measured value measured by the non-contact sensor is calculated based on a temperature measured by bringing a second contact temperature sensor into contact with the surface of the recording medium. The inkjet printer according to claim 5.

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