JP2007130837A - Ink jet printer head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To grasp the temperature of a temperature detection article in a head holder more accurately by securing a temperature detection means easily under stably attached state to the temperature detecting section in the head holder of an ink jet recorder. <P>SOLUTION: A through hole 83 is formed in a circuit board 50 on a head holder 20 mounting a recording head 100 for recording on a recording medium, and the lead wire 81 of a thermistor 80 is inserted and secured in place. The lead wire 81 is bent in the direction perpendicular to the sidewall 30b1 of a plate 30 for radiating heat from the drive circuit 61 of the recording head 100, and a temperature sensitive portion 82 touches the sidewall 30b1 from the perpendicular direction due to elasticity of the lead wire 81. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ink jet printer head that performs recording by ejecting ink from a recording head onto a recording medium.

  In the industry, for example, in various products using thermal energy such as electrical appliances, a temperature sensor is attached to control the temperature of the influence of the thermal energy received by the object. For example, in Patent Document 1, in order to detect the temperature of the heating element provided on the mounting surface of the printed circuit board, the temperature sensing part of the temperature sensor is arranged in the vicinity of the heating element, and an elastically deformable lead wire of the temperature sensor is provided. , Passing through the notch that penetrates on the printed circuit board, the middle of the lead wire presses the non-mounting surface near the periphery of the notch, and the temperature sensing part is pressed in the direction to approach the heating element by its reaction It is attached with. Moreover, in patent document 2, two through-holes are formed in one side of the mounting plate fixed to the cooling unit of the refrigerator, and the main body portion of the thermistor for measuring the temperature in the refrigerator cabinet is attached. It is inserted into one through hole from the back side of the plate, and the lead wire of the thermistor is fixed in the other through hole. The body part of the thermistor is elastically deformed so that the tip part of the thermistor passes through a locking protrusion that protrudes inwardly of the notch formed on the mounting plate, and is brought into contact with the back surface of the mounting plate, thereby being stabilized by elastic force. It is in a worn state.

  As recording apparatuses such as printers, copying machines, and facsimiles, there is known an ink jet recording apparatus that performs recording on a recording medium by ejecting ink from a recording head as disclosed in Patent Document 3. In Patent Document 3, the recording head has a structure in which a plate-type actuator is stacked on a cavity unit having a plurality of nozzles for ejecting ink and a pressure chamber communicating with each of the nozzles, and a flexible wiring board is stacked. Yes. The cavity unit has an ink supply port on the upper surface thereof, and the ink is distributed to a plurality of pressure chambers through a manifold chamber extending from the ink supply port to reach the nozzles. By selectively driving the actuator, the volume of the pressure chamber is changed and ink is ejected from the nozzle. The recording head is attached to a substantially box-shaped head holder together with an ink tank (a damper device in Patent Document 3) for storing ink in order to supply ink to ink supply ports of the cavity unit according to ink color. The flexible wiring material of the recording head is provided with a driver IC having a drive circuit for ejecting ink, and is electrically connected to contact the heat radiating member for radiating heat generated by the driver IC. Furthermore, the tip of the flexible wiring material is connected to the circuit board on the head holder.

  Further, in Patent Document 4, when a thermistor is installed on a carriage and an ink jet head is mounted on the carriage, the base plate of the ink jet head is brought into contact with the thermistor, and the temperature of the base plate is estimated based on the temperature detected by the thermistor. Is described.

JP 2000-133908 A Japanese Patent Laid-Open No. 11-83307 Japanese Patent Laying-Open No. 2005-24679 (FIG. 3) JP-A-8-142318 (FIG. 3)

  In an ink jet recording apparatus, it is necessary to stabilize the ink discharge state and the discharge amount in order to obtain high print quality by ink discharge. In order to stabilize the ejection of ink, the influence of the ink temperature is particularly large.For example, if the temperature of the ejected ink is low, the viscosity of the ink increases and the ink cannot be ejected. Decreases, the discharge amount increases, and the discharge direction is bent. In the head holder, heat generated by a drive circuit for driving the actuator is transmitted to the recording head and the ink tank. Therefore, if the heat generated by the drive circuit increases in speed, the ink temperature rises as described above, affecting the print quality as well as the failure of the drive circuit itself and the components in the head holder. Could cause damage.

  For this reason, in order to manage the ink temperature and the temperature of the recording head, temperature detecting means such as a thermistor is mounted as in Patent Document 4, and the recording head, ink, etc. are detected from the detected temperature based on the temperature calculation formula. The temperature of the target object is calculated and estimated, and control is performed so that the target temperature falls within a suitable range based on the result.

  In order to effectively control the recording head in a suitable temperature range, the temperature of the object such as the recording head and ink should be as close as possible to the actual measurement, such as the recording head in the head holder, the ink tank, etc. It has been demanded to measure the temperature near the object. Furthermore, temperature detection means such as a thermistor has been required to maintain a stable mounting state so as not to be separated from the object as much as possible in order to correctly detect the temperature of the object.

  In the case where the inkjet head is attached to and detached from the carriage as in Patent Document 4, the print quality is affected unless the inkjet head is accurately positioned on the carriage. On the other hand, if the thermistor does not come into contact with the base plate of the inkjet head in a certain relationship, temperature detection will vary. For this reason, not only the accuracy of the ink jet head mounting portion on the carriage but also the thermistor corresponding thereto requires high positional accuracy. The thermistor mounting structures of Patent Documents 1 and 2 cannot solve this problem.

  The present invention has been made to solve the above-described problems, and a temperature detecting means is simply fixed in a stable mounting state to a temperature detection portion in a head holder of an inkjet printer head, and the inside of the head holder is An object of the present invention is to provide an ink jet printer head capable of more accurately grasping the temperature of the temperature detection part.

  According to a first aspect of the present invention, there is provided a recording head for recording on a recording medium, a head holder for mounting a circuit board, temperature detecting means provided on the circuit board on the head holder, and the recording head. In the ink jet printer head having a drive circuit for driving, the temperature detecting means includes a temperature sensing part for detecting temperature, and a lead wire protruding from the temperature sensing part and having a length capable of elastic deformation, The tip of the lead wire is attached to the circuit board, and the temperature sensing portion of the temperature detecting means is pressed against the temperature detection portion by the spring force of the lead wire generated by the elastic deformation. And

  According to a second aspect of the present invention, in the ink jet printer head according to the first aspect, the temperature detecting means is a thermistor.

  According to a third aspect of the present invention, in the ink jet printer head according to the first aspect, the temperature detection unit is a heat radiating plate that is in contact with the drive circuit so as to conduct heat.

  According to a fourth aspect of the present invention, in the ink jet printer head according to the third aspect, the heat radiating plate and the circuit board are placed on the head holder in such a manner that their extended surface directions intersect each other. It is characterized by.

  According to a fifth aspect of the present invention, in the ink jet printer head according to the third aspect, the temperature detection unit moves the temperature detection unit in a direction parallel to a surface against which the temperature detection unit of the temperature detection unit is pressed. It has the latching | locking part latched impossible.

  According to a sixth aspect of the present invention, in the ink jet printer head according to the fifth aspect, the locking portion is a hole formed on the temperature detection portion.

  According to a seventh aspect of the present invention, in the ink jet printer head according to the fifth aspect, the locking portion has a protruding portion that protrudes from the temperature detection portion so as to surround the temperature sensing portion. Features.

  According to the first aspect of the present invention, the lead wire of the temperature detecting means is attached to the circuit board and has a length that can be elastically deformed. Since the temperature sensing part is pressed, the elasticity of the lead wire absorbs the error when fixing the circuit board when assembling the head holder, so the temperature sensing part has no variation with respect to the temperature sensing part. It can be contacted in a stable state and an accurate temperature can be measured.

  Further, the temperature detecting means is composed of a temperature sensing part and a lead wire protruding from the temperature sensing part, the tip of the lead wire is attached to the circuit board, and the temperature sensing part is located away from the circuit board by the lead wire. Therefore, it is possible to install a temperature sensing unit in the vicinity of an object whose temperature is to be detected, such as a recording head or ink. Therefore, it is possible to measure the temperature of the target object that is closer to the actual measurement than in the past.

  According to the invention described in claim 2, since the temperature detecting means is a thermistor, the invention described in claim 1 can be easily configured.

  According to the third aspect of the present invention, since the temperature-detected portion is a heat radiating plate in which the heat generated from the drive circuit is in conductive contact, the temperature of the heat generated by the drive circuit can be measured with a value closer to the actual measurement. In addition, the drive circuit can be controlled more accurately by temperature.

  According to the invention described in claim 4, since the heat sink and the circuit board are arranged on the head holder in such a manner that the extended surface directions intersect with each other, the temperature sensitivity protruded from the circuit board by the lead wire. The temperature sensor can be brought into contact with the temperature sensing part by effectively utilizing the elasticity of the lead wire, and the contact state between the temperature sensing part and the temperature sensing part can be stably maintained to accurately detect the temperature. Can be done.

  According to the invention described in claim 5, since the temperature detection part has a locking part that locks the temperature sensing part so as not to move in a direction parallel to the surface to which the temperature sensing part of the temperature detection unit is pressed. When assembling the head holder, the temperature sensing part can be stably attached to a predetermined position of the temperature detection part, and a more accurate temperature can be measured.

  According to the invention described in claim 6, since the locking portion is a hole formed on the temperature detection portion, the invention described in claim 5 can be easily configured.

  According to the seventh aspect of the present invention, since the locking portion has the protruding portion that protrudes from the temperature detection portion and surrounds the periphery of the temperature sensitive portion, the invention according to the fifth aspect can be easily configured. Can do. In addition, for example, when it is difficult to process the hole as in claim 6 in the non-temperature detection unit, such as when an engagement part is provided in an ink tank or the like in the head holder, the stable operation is achieved without performing the hole processing. A wearing state can be achieved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Although not shown, the ink jet recording apparatus is supplied from an ink cartridge of a plurality of colors to the ink tank 5 that stores each ink in the ink jet printer head 1 via each ink supply tube, and the ink is supplied to the recording head 100. Is done. The recording head 100 is configured to perform recording by ejecting ink from the nozzles of the recording head 100 by selectively driving the actuator 7b while scanning and moving in parallel with the recording medium.

  As shown in FIG. 1, the ink jet printer head 1 generally includes a recording head 100, a reinforcing frame 40 that is formed in a substantially rectangular flat plate shape in plan view and has an exposed opening 40 a, and a substantially box shape made of a resin material. The head holder 20 includes a heat radiating plate 30 that radiates heat from a drive circuit 61 on a flexible wiring board 60 described later, an ink tank 5 that stores ink, and a circuit board 50. The head holder 20 also has a function as a carriage.

  As shown in FIG. 1, the head holder 20 includes a pair of side walls 20 a and 20 b facing each other, and a bottom wall 20 c that vertically partitions an internal space formed by being surrounded by the side walls. In the space below the head holder 20, the recording head 100 is supported via the reinforcing frame 40, and the ink tank 5 and the heat transfer plate 30 are accommodated in the upper space, and further the upper surface side of the head holder 20. The circuit board 50 is supported.

  The recording head 100 includes a cavity unit 7a in which a plurality of plates are stacked and a plate-type actuator unit 7b, similar to the known one described in Japanese Patent Application Laid-Open No. 2005-24679. The flexible wiring board 60 having flexibility is laminated. The cavity unit 7 a has a plurality of ink nozzles formed in a row on the lower surface, and has an ink supply port 17 for each ink color on the upper surface, and a manifold extending from each ink supply port 17. Ink is distributed to a plurality of pressure chambers via flow paths (not shown), and each pressure chamber reaches a corresponding nozzle. The direction substantially orthogonal to the direction of each nozzle row is the moving direction of the inkjet printer head 1 relative to the recording medium.

  The actuator unit 7b has a plurality of actuators corresponding to the respective pressure chambers, that is, piezoelectric deformation portions. The piezoelectric deformation portions are deformed by selectively applying a voltage, and pressure is applied to the ink in the pressure chamber. Then, ink is selectively ejected from the nozzles to perform recording on the recording medium. The flexible wiring board 60 has a driving IC chip that houses the driving circuit 61 mounted in a direction perpendicular to the arrangement direction of the nozzle rows, and one end of the flexible wiring board 60 is stacked on the upper surface of the actuator unit 7b. Electrically connected. The other end is inserted from below into a through-hole 20c1 formed in the bottom wall 20c of the head holder 20, and extends upward between a side wall 30b1 of the heat sink 30 described later and a side wall 20a of the head holder 20, and a circuit board described later 50 connectors 51 are connected. The drive circuit 61 converts print information and voltage transmitted from the ink jet recording apparatus main body side via the circuit board 50 into a drive voltage signal for each actuator of the actuator unit 7b and supplies the drive voltage signal to the actuator. The flexible wiring board 60 has a wiring pattern for the same as a known flexible printed cable.

  The reinforcing frame 40 is fixed to the lower surface side of the bottom wall 20 c of the head holder 20 with an adhesive, and the recording head 100 is fixed to the lower surface side of the reinforcing frame 40. The actuator unit 7b is disposed so as to be exposed to the bottom wall 20c side from the exposure port 40a opened in the reinforcing frame 40. An ink supply path 40b for each ink provided through the reinforcing frame 40 is connected to an ink supply pipe 5a of the ink tank 5 and an ink supply port 17b of the recording head 100, which will be described later, thereby supplying ink to the recording head 100. To supply.

  The ink tank 5 is divided into a plurality of ink tanks (not shown) for each ink color, and these ink tanks are supplied to the ink supply pipe 5a for each ink. And extends toward the recording head 100. Each of these ink supply pipes 5 a is connected to the ink supply path 40 b of the reinforcing frame 40 and the ink supply port 17 b of the recording head 100.

  The heat radiating plate 30 is for radiating the heat generated by the drive circuit 61 mounted on the flexible wiring board 60 to the outside, and is formed of a material having good conductivity (for example, a metal material such as aluminum). In the first embodiment, the shape is a seat surface portion 30a formed with a flat surface, and as shown in FIG. 3, the shape rises at a right angle from the seat surface portion 30a so as to form a substantially L shape in a side view, and the vertical direction. And a second side wall 30b2 bent at a right angle from the side wall 30b1 so as to form a substantially L shape in plan view. The heat radiating plate 30 is mounted in the head holder 20 by fixing the two mounting holes 30a1 formed in the seat surface portion 30a to the mounting boss 20c2 projecting from the bottom wall 20c of the head holder 20, and the side wall 30b1. And 30b2 are located along two sides of the ink tank 5. The drive circuit 61 is pressed by the rubber-like elastic member 19 fixed to the bottom wall 20c of the head holder 20 so as to be in contact with the lower surface of the seat surface portion 30a of the heat radiating plate 30 so as to allow heat conduction.

    The circuit board 50 is fixed to the upper end opening of the head holder 20 across the side walls 20b, 20b, and the extending surface directions of the circuit board 50 and the side wall 30b1 of the heat sink 30 intersect each other at substantially right angles. Be placed. The circuit board 50 is connected to a main control circuit (not shown) stationary on the recording apparatus main body side via a flexible wiring member 52 in order to transmit voltage and print information from the ink jet recording apparatus main body to the recording head. Has been. A connector 51 on the circuit board 50 is connected to a flexible wiring board 60 extending from the recording head 100. On the circuit board 50, a through hole 83 penetrates in the vertical direction, and a lead wire 81 of a thermistor 80 described later is inserted into the through hole 83 from below the circuit board 50, and a conductive brazing material (solder) is applied. Molten and connected. The through-hole 83 is disposed in a space between the ink tank 5 and the side wall 30b1 of the heat sink 30 with the lead wire 81 of the thermistor 80, and the temperature sensing portion 82 is pressed against a locking portion 70 (to be described later) of the heat sink 30. Thus, it is formed on the circuit board 50. The temperature detected by the thermistor 80 is transmitted as a voltage signal to the main control circuit on the recording apparatus main body side via the flexible wiring member 52, and a signal for controlling the recording head 100 is generated via the drive circuit 61. .

  Here, the thermistor 80 will be described. As shown in FIGS. 1 to 3, the thermistor 80 is composed of two lead wires 81 and a temperature sensing part 82 in which a temperature detecting element is glass-coated. One end of the lead wire 81 is connected to the temperature sensing part 82, and the like. The end is inserted into the through hole 83 of the circuit board 50 from below and is fixed with a conductive wax material (solder). The two lead wires 81 extend downward from the circuit board 50 substantially in parallel with the side wall 30b1 of the heat dissipation plate 30, and are bent at a lower end thereof in a direction perpendicular to the side wall 31b1. When the lead wire 81 is in a natural state (a state before the circuit board 50 is fixed to the head holder 20), the distance from the through hole 83 to the tip of the temperature sensing part 82 in plan view is such that the circuit board 50 is the head. The distance from the through hole 83 in a state fixed to the holder 20 to the temperature-detected portion (side wall 31b1) is larger than the distance in plan view. Therefore, when the circuit board 50 is fixed to the head holder 20, the temperature sensing part 82 is pressed substantially perpendicularly to the side wall 31b1 by the elasticity of the lead wire 81, and comes into contact with the heat radiating plate 30 so as to conduct heat. Preferably, the temperature sensing part 82 is fitted to a locking part 70 described later formed on the side wall 31b1. The two lead wires 81 are covered with a non-conductive resin or a coating material so as not to contact each other or to contact a component in the head holder to cause a short circuit. In addition, a coating material is applied to the connection portion between the temperature sensing portion 82 and the two lead wires 81 for waterproofing and fixing.

  The installation position of the thermistor 80 is preferably a position at which heat generated by the operation of the drive circuit 61 can be detected as accurately as possible. The temperature sensing portion 82 may be brought into contact with the seat surface portion 30a of the heat sink near the drive circuit 61. Although the heat dissipation plate 30 has good thermal conductivity, the side wall 30b1 can be sufficiently detected. The temperature sensor 82 may be brought into contact with the side surface of the ink tank 5 to detect the ink temperature. The thermistor 80 may not be one, and a plurality of thermistors 80 may be installed. In that case, it is necessary to appropriately calculate and use temperatures detected by a plurality of thermistors 80, for example. Further, although the thermistor 80 is used as the temperature detecting means in this embodiment, a platinum resistance thermometer or a thermocouple can also be used.

  The locking portion 70 is a recessed portion that is recessed or penetrated in the side wall 30b1 in FIG. 3, and positions the temperature sensing portion 82 at a predetermined position along the surface direction of the side wall 30b1. Further, the locking portion 70 may be a protruding portion that projects around the temperature sensing portion 82.

  FIG. 4 shows a second embodiment of the present invention, in which the seating surface portion 30a of the heat radiating plate 30 is substantially rectangular in plan view (a plane parallel to the bottom wall 5b of the ink tank 5), and one end thereof is flexible. While being in contact with the drive circuit 61 on the wiring board 60, it is fixed to the bottom wall 5 b of the ink tank 5 so as to extend in a direction parallel to the arrangement direction of the nozzle rows. The seat surface portion 30a may be in contact with the bottom wall 5b of the ink tank 5, and the circuit board 50 and the seat surface portion 30a of the heat radiating plate 30 are arranged in a horizontal relationship with each other.

  As in the first embodiment, one end of the two lead wires 81 of the thermistor 80 penetrates and is connected to the through hole 83 on the circuit board 50, and the other end is connected to the temperature sensing unit 82. The two lead wires 81 are bent in a zigzag shape that is continuously bent as shown in FIG. The thermistor 80 is moved downward from the through hole 83 so that the temperature sensing part 82 is pressed almost perpendicularly to the engaging part 70 on the seat surface part 30a in the space between the ink tank 5 and the side wall 20a of the head holder. It arrange | positions and is in contact with the heat sink 30 so that heat conduction is possible. Further, the heat radiating plate 30 rises from the bottom wall portion 30a of the second embodiment at a right angle and extends in the vertical direction from the side wall 30b1 (see the first embodiment), or from the side wall 30b1 so as to form a substantially L shape in plan view. A second side wall 30b2 bent at a right angle may be provided.

With this configuration, even if there is an assembly error or the like between the temperature detection unit (heat radiating plate or ink tank) and the circuit board, the temperature sensing portion of the thermistor is the temperature detection unit (heat radiating plate or ink tank). However, it is possible to perform temperature detection with little variation among products by making contact with the elastic state of the lead wire in a stable state. In addition, since the temperature-sensitive portion is locked to the locking portion, the position of the temperature-sensitive portion with respect to the temperature-sensitive portion temperature detection portion is not shifted by scanning of the head holder 20 accompanying printing of the ink jet recording apparatus. , More accurate temperature detection can be performed.

It is a disassembled perspective view of the head holder of the inkjet recording device which implemented this invention. It is AA sectional drawing of the head holder 20 of the 1st Example of this invention. It is BB sectional drawing of the head holder 20 of the 1st Example of this invention. It is BB sectional drawing of the head holder 20 of the 2nd Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 5 Ink tank 20 Head holder 30 Heat sink 30b1 Side wall 50 Circuit board 60 Flexible wiring board 61 Drive circuit 70 Locking part 80 Thermistor 81 Lead wire 82 Temperature sensing part 83 Through-hole 100 Recording head

Claims (7)

A recording head for recording on a recording medium and a head holder for mounting a circuit board;
Temperature detecting means provided on the circuit board on the head holder;
In an inkjet printer head having a drive circuit for driving the recording head,
The temperature detecting means includes
A temperature sensing part for detecting the temperature, and a lead wire protruding from the temperature sensing part and having a length that can be elastically deformed, and a tip part of the lead wire is attached to the circuit board,
An ink jet printer head, wherein the temperature sensing part of the temperature detecting means is pressed against the temperature sensing part by the spring force of the lead wire generated by the elastic deformation.   2. The ink jet printer head according to claim 1, wherein the temperature detecting means is a thermistor.   2. The ink jet printer head according to claim 1, wherein the temperature detection unit is a heat radiating plate in contact with the drive circuit so as to be capable of conducting heat.   4. The ink jet printer head according to claim 3, wherein the heat radiating plate and the circuit board are placed on the head holder in such a manner that their extended surface directions intersect each other. 5.   The said temperature detection part has the latching | locking part which latches the temperature sensing part so that it cannot move in the direction parallel to the surface where the temperature sensing part of the said temperature detection means is pressed. Inkjet printer head.   6. The ink jet printer head according to claim 5, wherein the locking portion is a hole formed on the temperature detection portion. 6. The ink jet printer head according to claim 5, wherein the locking portion has a protruding portion that protrudes from the temperature detection portion so as to surround the temperature sensing portion.

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