JP2013193373A - Inkjet recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inkjet recording apparatus which fixes ink to a recording medium by heating the recording medium and the ink by a heating means which is not in contact with the recording medium and is in a position opposite to an ink landing surface of the recording medium after the ink is discharged to the recording medium by a recording head, wherein the temperature can be accurately measured without the light receiving element of a temperature sensor being heated when the temperature sensor is installed in the vicinity of the heating means or when a hot wind is blown to the temperature sensor by air flow in the apparatus.SOLUTION: An inkjet recording apparatus includes a rigid case surrounding a temperature sensor for shielding infrared rays emitted from a heating means 13 and a surrounding member, and a heat insulating layer containing an air layer for moderately reducing the temperature change of the light receiving element in the inner part of the temperature sensor against the temperature change on the outside of the rigid case, between the temperature sensor and the rigid case.

Description

  The present invention relates to an ink jet recording apparatus that records an image on a recording medium by ejecting ink droplets with a recording head. In particular, the present invention relates to an ink jet recording apparatus that fixes ink onto a recording medium by discharging the ink onto the recording medium by a recording head and then heating the recording medium and the ink with a heating unit.

  A conventional inkjet recording apparatus is configured to form an image by ejecting ink droplets from a recording head at a desired timing and landing on the surface of a recording medium based on print data. In particular, when using an ink having a property of fixing to a recording medium by heating at a high temperature and drying, the recording medium and the ink are heated by a heating unit immediately after the ink is ejected to the recording medium by the recording head. The surface temperature of the surface of the recording medium on which the ink is landed is measured by a temperature sensor, and the heating temperature is controlled by feeding back the measured temperature. Among such configurations, when the heating means is in contact with the recording medium and heated, when the recording medium is bent or wrinkled, the heating means and the recording medium are in contact with each other. A noticeable temperature difference occurs between the parts that are not in contact with each other and problems such as color unevenness occur in the formed image. Generally, an irradiation-type heating device is installed. Further, since the temperature sensor that measures the surface temperature of the surface on which the ink of the recording medium lands is in contact with the recording medium, there is a concern that the formed image may be damaged, so the ink of the recording medium lands. In general, a radiation thermometer is installed at a position facing the surface and not in contact with the recording medium. In the ink jet recording apparatus having such a configuration, the infrared ray emitted from the heating unit is incident on the temperature sensor, the infrared ray emitted from the heating unit is reflected by a peripheral member other than the recording medium and is incident on the temperature sensor, in the vicinity of the heating unit There is a problem that the temperature cannot be measured accurately due to the fact that the light sensor inside the temperature sensor is heated by installing a temperature sensor in the device or by blowing hot air on the temperature sensor due to the air flow inside the device. It was.

  In order to solve such a problem, the infrared rays from the heating means are not incident on the temperature sensor directly or by reflection from the surrounding members, and the light reception inside the temperature sensor with respect to the temperature change of the air around the temperature sensor. It is sufficient that the temperature change of the element is gradual and the amount of change is small. For example, Patent Document 1 discloses a method of installing a temperature sensor at a position where infrared rays radiated from the heating unit do not reach, or a method of covering the heating unit with a parabolic reflector and shielding the infrared rays incident on the temperature sensor.

JP-A-2005-74627

  However, in the method of installing a temperature sensor at a position where infrared rays radiated from the heating means of Patent Document 1 do not reach, it is impossible to measure the surface temperature of the recording medium located directly under or near the heating means. In addition, the surface temperature of the recording medium immediately after the ink has landed cannot be controlled, and the infrared light reflected from the peripheral member may enter the temperature sensor. On the other hand, in the method of covering the heating means with a parabolic reflector and shielding the infrared rays incident on the temperature sensor, a temperature sensor is installed in the vicinity of the heating means, or hot air is blown onto the temperature sensor by the air flow in the device. There is a possibility that the light receiving element inside the thermometer is heated.

  Therefore, in the present invention, the infrared rays radiated from the heating means do not enter the temperature sensor directly or by reflection from peripheral members other than the recording medium, and the light-receiving element inside the temperature sensor responds to a temperature change around the temperature sensor. An object of the present invention is to provide an ink jet recording apparatus having a structure in which the temperature change is gradual and the change amount is small.

  The ink jet recording apparatus of the present invention is a recording head that discharges ink to a recording medium, and is located at a position facing the recording medium, and does not contact the recording medium and discharges the ink to the recording medium by the recording head. Immediately after that, the heating means for heating the recording medium and the ink, the 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 measured, and based on the measurement result In the ink jet recording apparatus comprising a temperature sensor for controlling the heating temperature of the heating means, the temperature sensor is a radiation thermometer, and includes a rigid case surrounding the temperature sensor, and the temperature sensor and the rigid case There is a heat insulating layer including an air layer between them, and the temperature of the light receiving element inside the temperature sensor against the temperature change outside the rigid case. Changes gradual, and the variation becomes small, is characterized in that not incident by reflection from other directly or the recording medium infrared rays emitted from said heating means to said light receiving element of the temperature sensor.

  According to the present invention, the temperature of the light receiving element inside the temperature sensor with respect to the temperature change around the temperature sensor is provided by providing the rigid case surrounding the temperature sensor and the heat insulating layer including the air layer between the temperature sensor and the rigid case. The change is gradual and the change amount is small, and the infrared rays emitted from the heating means do not enter the temperature sensor directly or by reflection from peripheral members other than the recording medium, and the ink ejected from the recording head is the recording medium. It is possible to accurately measure the surface temperature of the recording medium immediately after landing on the recording medium.

1 is a schematic configuration diagram illustrating a basic configuration of an ink jet recording apparatus according to an embodiment of the present invention and an installation structure of a temperature sensor. It is a schematic block diagram which shows another installation structure of the temperature sensor which concerns on embodiment of this invention. It is a front view which shows the structure of the rigid body case which concerns on embodiment of this invention. It is a front view which shows another structure of the rigid case which concerns on embodiment of this invention. It is a perspective view which shows another structure of the rigid case which concerns on embodiment of this invention.

Hereinafter, the ink jet recording apparatus of the present invention will be described in detail with reference to the drawings.
First, the overall configuration of the ink jet recording apparatus 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 recording apparatus and an installation structure of a temperature sensor according to an embodiment of the present invention. In FIG. 1, a recording medium 2 wound in a roll shape is installed on a recording medium installation base 1 having a rotation axis. 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, the ink immediately after landing on the recording medium 2 discharged 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 and the recording medium 2 on the platen 5 are heated to form ink. The moisture contained therein is evaporated, and then the portion of the recording medium 2 on which the ink has landed is transported to the front paper guide 19. The secondary heater 13 whose length in the main scanning direction is longer than that of the recording medium is used on the front paper guide 19. The recording medium 2 and the ink landed on the recording medium 2 are heated at a temperature higher than the temperature heated by the primary heater 8, whereby the resin contained in the ink is bonded to form a film. To settle. Further, in order to prevent adverse effects such as the temperature inside the ink jet recording apparatus 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 rear fan is provided on the outer wall of the ink jet recording apparatus. 15 is attached to take outside air into the ink jet recording apparatus. In addition, the primary heater 8 and the secondary heater 13 are infrared radiation heaters, and in order to increase the efficiency of infrared irradiation with respect to the object to be heated, the reflector 9a and the reflector formed of an Alster steel plate or stainless steel having a high infrared reflectance. 9 b is installed so as to cover the primary heater 8 and 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.

  Next, FIG. 2 is a block diagram showing another installation structure of the temperature sensor according to the embodiment of the present invention. An air intake duct is not provided between the blower fan 23a and the front cover 20, and between the blower fan 23b and the secondary heater cover 21, and the blower fan 23a and the blower fan 23b are provided on the front cover 20 and the secondary heater cover 21, respectively. A configuration may be adopted in which outside air is blown directly to each temperature sensor from the intake port.

  Next, the peripheral structure of the temperature sensor 10 will be described in detail with reference to FIG. FIG. 3 is a front view showing the structure of the rigid case according to the embodiment of the present invention. First, by covering the temperature sensor 10 with the cylindrical rigid body 26, infrared rays emitted from the primary heater 8 and the secondary heater 13 and infrared rays reflected on peripheral members other than the recording medium 2 are received by the light receiving lens of the sensor 10. The effect which prevents entering into 28 is acquired. Next, the surface of the rigid case 26 facing the light receiving lens 28 is formed of an infrared transmitting member 27 such as silicon or barium fluoride, and an intake hole 29 and a blower fan 23 are provided on the opposite surface, and further an infrared ray is provided. The exhaust hole 24 is provided on a surface different from the surface on which the transmissive member 27 and the blower fan 23 are installed. The exhaust holes 24 are arranged along the longitudinal direction of the sensor 10, and a plurality of exhaust holes 24 are provided in a slit shape. By making it long in the longitudinal direction, there is no place where hot air stays, it is difficult to stay, and heat is dissipated by passing air through the side of the rigid case 26. The diameter of the infrared transmitting member 27 is larger than the diameter of the light receiving lens 28. It may be the same. Further, the temperature sensor 10 is fixed to the rigid case 26 only by the support portion 30, and an air layer 31 is provided between the rigid case 26 other than the support portion 30 and the temperature sensor 10. With such a configuration, a cooling effect by sending the outside air into the rigid case 26 by the blower fan 23 and a heat insulating effect by the air layer 31 are obtained, and the temperature sensor 10 against the temperature change outside the rigid case 26. The temperature change of the light receiving element inside is gradual and the amount of change is small. At this time, in order to reduce the amount of heat transfer from the rigid case 26 to the temperature sensor 10, it is preferable to reduce the area where the support portion 30 and the temperature sensor 10 are in contact with each other as much as possible. The cable 25 including the power supply line and the signal line to the temperature sensor 10 is taken out from the wiring hole provided in the rigid case to the outside of the rigid case.

  Next, FIG. 4 is a front view showing a structure different from FIG. 3 of the rigid case according to the embodiment of the present invention. A configuration in which a light receiving hole 32 necessary for receiving infrared rays from the measurement object is provided on the surface of the rigid case 26 facing the light receiving lens 29 may be used. A light receiving hole 32 having a diameter approximately equal to the diameter of the light receiving lens 29 is disposed at a position inside from the tip of the rigid case 26. Since silicon and barium fluoride, which are infrared transmitting members, are expensive, the cost can be reduced by using a simple configuration in which the light receiving holes 32 are provided.

  Next, FIG. 5 is a perspective view showing still another structure of the rigid case according to the embodiment of the present invention. In this configuration, the blower fan 23 and the infrared transmitting member 27 are omitted, and the temperature of the temperature sensor 10 is kept constant only by the heat insulating effect of the air layer 31 between the rigid case 26 and the temperature sensor 10. In this configuration, the effect of keeping the temperature of the temperature sensor 10 as constant as the configuration introduced in FIGS. 3 and 4 cannot be expected, but this is the simplest configuration and the temperature change around the rigid case 26 is relatively small. It is effective for. The rigid case 26 is provided with a fixing portion 33, and the fixing portion 33 and the primary heater support member or the temperature sensor support member are connected and fixed by screws.

  The present invention can be used for an ink jet printer.

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 9a, 9b Reflector 10, 10a, 10b Temperature sensor 11 Primary intake duct 12 Primary heater support member 13 Secondary Heater 14 Pinch roller 15 Rear fan 16 Secondary intake duct 17 Temperature sensor support member 18 Hole 19 Front paper guide 20 Front cover 21 Secondary heater cover 22 Print heads 23, 23 a, 23 b Air blow fan 24 Exhaust hole 25 Cable 26 Rigid case 27 Infrared transmitting member 28 Light receiving lens 29 Air intake hole 30 Supporting portion 31 Air layer 32 Light receiving hole 33 Fixing portion

Claims (5)

  A recording head that discharges ink to the recording medium; and the recording medium and the ink that are in a position facing the recording medium and that do not contact the recording medium and immediately after the ink is discharged to the recording medium by the recording head Heating means for heating the recording medium, and a position facing the ink landing surface of the recording medium and not in contact with the recording medium, measuring the surface temperature of the recording medium, and determining the heating temperature of the heating means based on the measurement result In an inkjet recording apparatus including a temperature sensor for controlling, the temperature sensor is a radiation thermometer, and includes a rigid case surrounding the temperature sensor, and a heat insulation including an air layer between the temperature sensor and the rigid case. A temperature change of the light receiving element inside the temperature sensor with respect to the temperature change outside the rigid case, and the change amount is small. Becomes, the ink jet recording apparatus characterized by infrared rays emitted from the heating means is not incident by reflection from other directly or the recording medium to the light receiving element of the temperature sensor.   The rigid case is provided with a light receiving hole that is the same size or larger than the lens for receiving the infrared light at a position facing the surface of the temperature sensor having the lens that receives the infrared light. The inkjet recording apparatus according to claim 1.   The rigid case is provided with a light receiving hole that is the same size or larger than the lens for receiving the infrared light at a position facing the surface of the temperature sensor having the lens that receives the infrared light. The ink jet recording apparatus according to claim 1, wherein the light receiving hole is closed with an infrared transmitting member.   The said rigid body case has a ventilation fan in the position which does not oppose the surface which has the lens which receives the infrared rays of the said temperature sensor of the said temperature sensor, and the exhaust hole which exhausts the air in the said rigid body case. The inkjet recording apparatus according to any one of 3.   The inkjet recording apparatus according to claim 4, further comprising a communication unit that communicates the inside of the rigid case and the outside of the inkjet recording apparatus via the blower fan.

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