JP2017007189A - Inkjet recording device, and method for controlling temperature of ink used therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the time required to reach a set ink temperature in order to favorably keep the preparation of ink particles responded to the environmental temperature to quickly provide a stable printing quality.SOLUTION: An inkjet recording device comprises a main body part 1 storing a control part and a circulation part, a printing head part 5 generating ink particles, and a cable connecting the printing head part 5 to the main body part 1. The printing head part 5 has a nozzle body 13 generating the ink particles to eject, a heater unit 12 for heating the ink to be fed to the nozzle, and an ink circulation pipe 23 circulating the ink from the nozzle body 13. The main body part 1 composes an ink circulation path comprising an ink circulation valve 22 communicated and connected by the pipe 23 via the cable, an ink circulation pump 21 and a main ink vessel 6. The control part is composed to flow the heated ink into the circulation path when heating the ink by the heater unit 12 and to control a flow rate.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an industrial inkjet recording apparatus, and more particularly to control of ink temperature suitable for generating ink particles at ambient temperature.

  In general, an ink jet recording apparatus that converts continuously ejected ink into particles, charges and deflects particles necessary for character creation, and collects particles that are not used for printing without charging and deflection. The uniformity of the ink particles ejected from the nozzle body is greatly affected by the print quality. In order to stabilize the print quality, a configuration in which an ink heating device for heating ink is provided on the front side of the nozzle is disclosed in, for example, Japanese Patent Laid-Open No. 11-58770 (Patent Document 1). .

Japanese Patent Laid-Open No. 11-58770

  The above-mentioned Patent Document 1 discloses that the ink temperature is controlled in order to optimally maintain the production of good ink particles that affect the print quality. We do not consider warm time. In addition, the nozzle body is made of metal, and there is a problem that it takes time to heat the nozzle body easily.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an ink jet recording apparatus and a method for controlling the ink temperature used in the ink jet recording apparatus that heats the ink in a short time from the ejection of ink to the target ink temperature with a simple configuration.

  In order to solve the above problems, for example, the configuration described in the claims is adopted. The present application includes a plurality of means for solving the above-described problems. To give an example, a main body that houses a control unit and a circulation unit, a print head that generates ink particles, a main body, and a print head are provided. An ink jet recording apparatus having a cable to be connected, wherein the print head includes a nozzle body that generates and ejects ink particles, a heater unit for heating ink supplied to the nozzle, and an ink circulation that circulates ink from the nozzle body The main body portion constitutes an ink circulation path including an ink circulation valve, an ink circulation pump, and a main ink container that are connected to each other by an ink circulation tube via a cable as a circulation portion. Is configured to control the flow rate by flowing the heated ink through the ink circulation path when the heater unit heats the ink.

  Ink jet recording apparatus capable of supplying ink temperature at an ink viscosity necessary for atomizing ink in a short time even when the environmental temperature changes, and capable of good printing, and control of ink temperature used therefor Can provide a method.

1 is an overall schematic diagram of an ink jet recording apparatus according to Embodiment 1. FIG. 1 is a path configuration diagram of an ink jet recording apparatus in Embodiment 1. FIG. FIG. 4 is a diagram illustrating an opening / closing time of an ink circulation valve in Example 1. FIG. 5 is a diagram illustrating an example of an ink temperature increase characteristic depending on an opening / closing time of an ink circulation valve in Embodiment 1. 6 is a flowchart of ink heating control in Embodiment 1. FIG. FIG. 6 is a diagram comparing the switching target temperature and the arrival time of the target ink temperature when the ink circulation valve is intermittently opened and closed in the first embodiment. 6 is a path configuration diagram of an ink jet recording apparatus in Embodiment 2. FIG.

  Embodiments of the present invention will be described below with reference to the drawings.

  First, an overall overview of the ink jet recording apparatus will be described with reference to FIG. FIG. 1 is an overall schematic diagram of an ink jet recording apparatus according to the present embodiment. In FIG. 1, an ink jet recording apparatus includes a main body 1 in which a control unit 2 and a circulation unit 3 are housed, a print head unit 5 that generates ink particles 16 necessary for printing, a main body unit 1 and a print head. It consists of a cable 4 that connects the parts 5.

  Hereinafter, the path configuration in the ink jet recording apparatus will be described with reference to FIG. FIG. 2 is a path configuration diagram of the ink jet recording apparatus according to the present exemplary embodiment, and is a diagram illustrating a path configuration mainly including the circulation unit 3 built in the main body unit 1. In FIG. 2, the main ink container 6 is filled with ink 7a. The main ink container 6, the ink supply valve 8, the ink supply pump 9, the ink filter 10, the ink pressure adjusting valve 11 that adjusts the ink pressure, the heater unit 12, and the nozzle body 13 are connected in communication by an ink supply pipe 14. The gutter 18 for collecting the particles 15, the ink collection pump 19, and the main ink container 6 are connected in communication by an ink collection pipe 20. In order to circulate the ink 7 a from the nozzle body 13, the ink circulation pump 21, the ink circulation valve 22, and the main ink container 6 are connected in communication by an ink circulation pipe 23 to form an ink circulation path.

  In addition, the sub ink container 24 is filled with the ink 7 b, and the ink supply valve 25 and the ink supply pump 9 are connected to each other through an ink supply pipe 26. The intensifying fluid container 27 is filled with intensifying fluid 28, and the intensifying fluid 28, the intensifying pump 29, and the intensifying fluid replenishing valve 30 are connected in communication by a intensifying fluid replenishing pipe 31.

  Next, the operation will be described. The ink 7 a filled in the main ink container 6 is supplied by the supply pump 9 through the ink supply pipe 14. The ink pressure adjusting valve 11 adjusts the supplied pressurized ink 7 a to a predetermined pressure, and the pressure-adjusted ink is supplied to the nozzle body 13 through the heater unit 12.

  The pressurized ink 7a supplied to the nozzle body 13 is ejected from the tip of the nozzle body 13 and becomes ink particles 15 due to the surface tension of the ink. The ink particles 15 are charged to a charge amount according to the character information by the charging electrode 16, deflected by the deflection electrodes 17 a and b (a: plus electrode, b: minus electrode), and printed on a printing object (not shown). . Ink particles 15 that are not used for printing are captured by the gutter 18, collected in the main ink container 6 by the ink recovery pump 19 through the ink recovery pipe 20, and the ink 7 a circulated from the nozzle body 13 passes through the ink circulation pipe 23. The ink is returned to the main ink container 6 for reuse by the viscometer (not shown), the ink circulation valve 22 and the ink circulation pump 21.

  FIG. 3 is a diagram showing the opening / closing time of the ink circulation valve in the present embodiment. In FIG. 3, the horizontal axis indicates time, and the vertical axis indicates opening / closing of the ink circulation valve 22. In this embodiment, in order to heat the ink in the nozzle in a short time, the ink flow rate passing through the nozzle must be adjusted, and the time 34 for opening the ink circulation valve 22 and the time 35 for closing the ink circulation valve 22 The flow rate is controlled by the period 36 of the opening / closing time. That is, when ink is heated, the ink is flowed to the ink circulation path to control the flow rate. The ratio of the open time 34 to the period 36 is called a duty ratio. Here, until the target ink temperature is reached by heating by the heater unit, the ink circulation valve 22 is intermittently opened and closed repeatedly at a cycle 36, ink circulation is performed by the ink circulation path, and printing is waited. When the target temperature is reached, the intermittent operation of the ink circulation valve 22 is stopped, the ink circulation is stopped, and the print mode is switched.

  Further, the period 36 is set to a period that does not synchronize with the frequency of the ink circulation pump 21, so that fluctuations in the ink flow rate can be suppressed. For example, if the frequency of the ink circulation pump 21 is 4 Hz, it is preferable to set the cycle to a frequency that cannot be divided by 4, for example, 7 Hz, or an integer multiple thereof.

  FIG. 4 is a diagram illustrating an example of the ink temperature increase characteristic depending on the opening / closing time of the ink circulation valve. In FIG. 4, each curve shows an increase curve of the ink temperature when the opening / closing time of the ink circulation valve is changed. That is, the ink temperature rise curve is 37 when the ink circulation valve 22 is always closed and the ink circulation path is not used. On the other hand, when the opening time of the ink circulation valve 22 is long and the closing time is short, for example, when the duty ratio of the opening time is 10%, the ink temperature rise curve is 38. In the case of the curve 38, since the flow rate of the ink circulation path is larger than that in the case of the curve 37, the amount of ink passing through the heater unit is increased and the amount of ink to be heated is increased. The amount of ink circulated increases, the temperature rises faster due to the warming effect of the warm ink, and the ink temperature in the nozzle increases in a short time. On the other hand, the ink temperature at the time of saturation is low because it flows before it warms up due to the large flow rate. In addition, when the opening time is shortened and the closing time is extended, for example, when the duty ratio of the opening time is 5%, the ink temperature rise curve is 39. In this case, the flow rate is higher than that of the closed curve 37. Since the temperature rises quickly, the flow rate is smaller than in the case of the curve 38, so that the temperature at the time of saturation tends to be deprived of heat by the nozzle, and the temperature at the time of saturation becomes lower. Further, when the opening time and the closing time are set to a time that is intermediate between the curve 38 and the curve 39, for example, when the duty ratio of the opening time is 7%, the ink temperature rise curve is 40, and the ink temperature in the nozzle Is higher than the curve 37 in the closed state, and the ink temperature at saturation approaches the curve 37 in the closed state.

  FIG. 5 shows a flowchart of the ink heating control in this embodiment. In FIG. 5, when the ink jet recording apparatus is activated (step S01), an ambient temperature is detected at any time by a temperature detector (not shown) built in the apparatus body (S02). When ink is ejected based on the detected ambient temperature, the heater unit 12 is operated if the temperature is lower than the temperature set according to each condition (S03), and if it is equal to or higher than the set temperature, the printer is ready for printing (S10). . When the operating ambient temperature is lower than the set temperature and the heater unit 12 is operated, first, the heater built in the heater unit 12 is operated with high power (S03). Next, as shown in FIG. 3, the ink circulation valve 22 is intermittently opened / closed by the flow rate control based on the opening time 34, the closing time 35, and the opening / closing time 36 (cycle), thereby circulating the warmed ink. (S04, S05). Thereafter, it is determined whether the warmed ink has reached the ink temperature for switching from the warmed state by the high applied voltage to the target ink temperature control (S06), and when the temperature has been reached, the ink circulation valve 22 is closed (S06). S07). Thereafter, printing is waited until the target ink temperature is reached by the heater unit (S08, S09), and when the target temperature is reached, a printable state is entered (S10).

  At any time, the ambient temperature is measured (S11) to determine whether the temperature has changed (S12). When the temperature changes, the target ink temperature is controlled by the heater unit (S13). If there is no temperature change, printing is possible. State (S10).

  FIG. 6 is a diagram comparing the switching target temperature and the arrival time of the target ink temperature when the ink circulation valve 22 is intermittently opened and closed. In FIG. 6, as described in FIG. 4, by optimizing the duty ratio of the opening time 34 using the ink circulation path, the ink circulation valve 22 is closed and the ink circulation path is not used. It is possible to shorten the arrival time of the switching target temperature and the target ink temperature. Here, the switching target temperature is a state in which the heater unit is operated with high power and heated to control the flow rate by intermittently opening and closing the ink circulation valve 22, and the ink circulation valve 22 is stopped from being intermittently opened and closed. This is a target temperature for switching to a state where the temperature is controlled to the target ink temperature by controlling the temperature of the heater unit without using the circulation path. Here, a temperature higher than the final target ink temperature is set as the switching target temperature.

  As described above, the flow rate control method based on the opening time 34, the closing time 35, and the opening / closing time period 36 of the ink circulation valve 22 is more effective than the case where the ink circulation valve 22 is closed and the ink circulation path is not used. There is an effect that the time for heating can be shortened.

  As described above, the present embodiment is an ink jet recording apparatus having a main body that houses a control unit and a circulation unit, a print head that generates ink particles, and a cable that connects the main body and the print head. The print head has a nozzle body that generates and ejects ink particles, a heater unit for heating ink supplied to the nozzle, and an ink circulation pipe that circulates ink from the nozzle body. The ink circulation path is composed of an ink circulation valve, an ink circulation pump, and a main ink container that are connected to each other by an ink circulation pipe via a cable as a unit. The flow rate is controlled by flowing the heated ink through the circulation path.

  A method of controlling ink temperature of an ink jet recording apparatus that performs printing by generating ink particles and ejecting the ink particles from a print head so as to control the flow rate of ink heated by the heating device. Configure.

  As a result, even if the environmental temperature changes, an ink jet recording apparatus capable of supplying ink temperature at an ink viscosity necessary for atomizing ink in a short period of time and capable of good printing with an inexpensive configuration, and ink used therefor A temperature control method can be provided. In addition, it has a great effect on a small-diameter orifice with a small ejection amount and a high ink viscosity.

  FIG. 7 is a diagram illustrating a path configuration of the ink jet recording apparatus according to the present embodiment. 7 is different from FIG. 2 in that an ink heating circulation valve 32 and an ink heating circulation pipe 33 are provided, and the heater unit 12, the nozzle body 13, the ink circulation pump 21, and the ink heating circulation valve 32 are provided with an ink heating circulation valve 32. The ink heating circulation path is configured by being connected by the warm circulation pipe 33, and the ink is circulated.

  Accordingly, as a means for shortening the time for warming the ink, the ink circulation valve 22 is closed, and the ink is circulated through a short pipe in the ink heating circulation pipe 33, so that the heat radiation amount can be reduced and is necessary for ink heating. Time can be shortened. In this case, the time required for ink heating can be shortened by intermittently opening and closing the ink heating circulation valve 32 as described in the first embodiment.

  As described above, the present embodiment is an ink jet recording apparatus having a main body that houses a control unit and a circulation unit, a print head that generates ink particles, and a cable that connects the main body and the print head. The print head has a nozzle body that generates and ejects ink particles, a heater unit for heating ink supplied to the nozzle, and an ink circulation pipe that circulates ink from the nozzle body. An ink circulation pump and an ink heating circulation valve connected to each other by an ink circulation pipe via a cable as a part constitute an ink heating circulation path connected to a heater unit by an ink heating circulation pipe. At the time of heating the ink by the heater unit, the heated ink is supplied to the ink heating circulation path to control the flow rate.

In the above-described embodiment, the ink circulation valve 22 and the ink heating circulation valve 32 are provided with a throttle member in place of, or together with, a valve that performs intermittent opening / closing control for flow rate adjustment. Therefore, an electromagnetic valve that can control intermittent opening and closing is unnecessary, or the load of the electromagnetic valve can be reduced.
Further, in order to print stable characters, it is necessary to reduce the change in the ink ejection speed with respect to the change in the ink temperature. This is because it is necessary to create ink particles suitable for printing a stable character, and the particle formation constant affects the creation of these particles. This particle constant is a function of the ink ejection speed. The ink ejection speed is small when the viscosity of the ink is low, and is large when the viscosity is high. By controlling the ink viscosity to be substantially constant with respect to changes in the ink temperature, the ink ejection speed becomes substantially constant, and it becomes possible to print characters that are stable over a wide range of operating temperatures.

  The present invention is not limited to the above-described embodiments, and includes various modifications. The above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

DESCRIPTION OF SYMBOLS 1 ... Main-body part (inkjet recording device), 2 ... Control part, 3 ... Circulation part, 4 ... Cable, 5 ... Print head part, 6 ... Main ink container, 7a, b ... Ink, 8 ... Ink supply valve, 9 ... Ink supply pump, 10 ... ink filter, 11 ... ink pressure regulating valve, 12 ... heater unit, 13 ... nozzle body, 14 ... ink supply pipe, 15 ... ink particles, 16 ... charging electrode, 17a, b ... deflection electrode, 18 ... Gutter, 19 ... Ink collection pump, 20 ... Ink collection pipe, 21 ... Ink circulation pump, 22 ... Ink circulation valve, 23 ... Ink circulation pipe, 24 ... Sub-ink container, 25 ... Ink supply valve, 26 ... Ink supply pipe, 27 DESCRIPTION OF SYMBOLS ... Reinforcement liquid container, 28 ... Reinforcement liquid, 29 ... Reinforcement pump, 30 ... Reinforcement liquid supply valve, 31 ... Reinforcement liquid supply pipe, 32 ... Ink heating circulation valve, 33 ... Ink heating circulation pipe, 34 ... circulation 35 ... Circulation valve closing time, 36 ... Opening / closing time (cycle), 37 ... Temperature rise curve when the circulation valve is closed, 38 ... Circulation valve opening time: Long, Closing time: Short 39 ... Circulation valve open time: short, close time: long temperature rise curve, 40 ... Circulation valve open time: medium, close time: temperature rise curve

Claims (7)

An ink jet recording apparatus having a main body that houses a control unit and a circulation unit, a print head that generates ink particles, and a cable that connects the main body and the print head.
The print head includes a nozzle body that generates and ejects ink particles, a heater unit for heating ink supplied to the nozzle, and an ink circulation pipe that circulates ink from the nozzle body.
The main body portion constitutes an ink circulation path including an ink circulation valve, an ink circulation pump, and a main ink container that are connected to each other by the ink circulation pipe via the cable as the circulation portion.
The ink jet recording apparatus, wherein the controller controls the flow rate by flowing the heated ink through the ink circulation path when the heater unit heats the ink. The inkjet recording apparatus according to claim 1,
The ink jet recording apparatus according to claim 1, wherein the controller controls the flow rate of the ink in the ink circulation path by repeatedly opening and closing the ink circulation valve when the heater unit heats the ink. The inkjet recording apparatus according to claim 2,
The ink jet recording apparatus according to claim 1, wherein the opening and closing of the ink circulation valve controls the length of the opening time and the length of the closing time. The inkjet recording apparatus according to claim 2,
A temperature detector for measuring the ink temperature inside the nozzle body;
An ink jet recording apparatus, wherein the ink circulation valve is repeatedly opened and closed until the measured ink temperature reaches a predetermined temperature, and the ink circulation valve is closed when the ink reaches the predetermined temperature. The inkjet recording apparatus according to claim 1,
The ink jet recording apparatus, wherein the controller is configured to provide a throttle member to control the ink flow rate in the ink circulation path when heating the ink by the heater unit. An ink jet recording apparatus having a main body that houses a control unit and a circulation unit, a print head that generates ink particles, and a cable that connects the main body and the print head.
The print head includes a nozzle body that generates and ejects ink particles, a heater unit for heating ink supplied to the nozzle, and an ink circulation pipe that circulates ink from the nozzle body.
The main body has an ink circulation pump and an ink heating circulation valve that are connected to each other by the ink circulation pipe via the cable as the circulation part, and is connected to the heater unit by an ink heating circulation pipe. Comprising
The ink jet recording apparatus, wherein the controller controls the flow rate by flowing the heated ink through the ink heating circulation path when the heater unit heats the ink. A method for controlling the ink temperature of an ink jet recording apparatus that performs printing by generating ink particles and ejecting the ink particles from a print head,
An ink temperature control method for an ink jet recording apparatus, comprising: controlling a flow rate of ink heated by a heating apparatus.

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