JP2012176572A - Heating source control method, heating source control device, and inkjet recording apparatus with the device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heating source control method capable of suppressing the maximum power amount even if the number of heating sources increases, a heating source control device, and an inkjet recording apparatus having the device.SOLUTION: A heating source control method is performed so that a plurality of heating sources are caused to sequentially start driving, from the first to m-th (m is an integer), by a pulse width modulation control, and that each heating source becomes a target temperature by changing a duty ratio based on proportion, integration, and differential action. In the method, when an n-th (1≤n<m, n is an integer) heating source started driving earlier reaches a threshold temperature near the target temperature or reaches a threshold duty ratio, an n+1 th heating source starts driving, and the n+1 th heating source is controlled, within a driving period, by a duty ratio determined so that the sum total of the duty ratio of the n+1 th heating source and that of the heating source started driving earlier is less than 100%, and by a driving pulse whose phase is set to be shifted with respect to a driving pulse of the heating source started driving earlier.

Description

  The present invention relates to a heating source control method for controlling the temperature of a plurality of heating sources by PWM control (Pulse Width Modulation), a heating source control device, and an ink jet recording apparatus including the same.

Conventionally, as a method for controlling this type of heating source, a method is known in which the duty ratio is adjusted by PWM control so that a plurality of heaters have a target temperature (see Patent Document 1).
In this control method, first, the temperature of each heater is detected, and the duty ratio of PWM control is set based on the detected temperature. Then, each heater is heated based on the set duty ratio. By repeating this process, the plurality of heaters are maintained at the target temperature.

JP 2009-86963 A

  However, in the conventional control method described above, PWM control functions effectively when each heater reaches the vicinity of the target temperature. However, when starting up a plurality of heaters, all the heaters are controlled with a duty ratio of 100%. Therefore, the technical significance of PWM control is weak. In this case, a plurality of heaters must be turned on at the same time, and power supply capacity corresponding to the number of heaters is required. For this reason, the running cost can be kept low, but there is a problem that the initial cost increases.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a heating source control method, a heating source control device, and an ink jet recording apparatus including the same, which can suppress the maximum power amount even when the number of heating sources increases.

  The heating source control method of the present invention starts driving a plurality of heating sources from the first to m (m is an integer) in order by pulse width modulation control, and is proportional so that each becomes a target temperature. A heating source control method for controlling the duty ratio while changing the duty ratio based on the integral / differential operation, and the nth heating (1 ≦ n <m: n is an integer) that has started driving in advance. When the source reaches the threshold temperature or threshold duty ratio of the target temperature, the driving of the (n + 1) th heating source is started, and the (n + 1) th heating source is set to the duty ratio with the preceding heating source within the driving cycle. Control is performed with a duty ratio determined so that the sum total is 100% or less and with a drive pulse set with a phase shifted from the drive pulse of the preceding heating source.

  The control apparatus for a heating source according to the present invention starts driving a plurality of heating sources from the first to m (m is an integer) in order by pulse width modulation control, and is proportional so that each becomes a target temperature. A control device for a heating source that controls the duty ratio while changing the duty ratio based on the integral / differential operation, and a temperature detecting means for detecting the temperature of each heating source, and each heating source based on the detected temperature. Duty ratio determining means for determining the duty ratio of the driving pulse to be applied, pulse setting means for setting the pulse width of the driving pulse to be applied to each heating source based on the determined duty ratio, temperature detecting means, and duty ratio determination Control means for controlling the means and the pulse setting means, wherein the control means is the nth (1 ≦ n <m: n is an integer) th drive source that has started driving in advance. When the threshold temperature or threshold duty ratio is reached, the driving of the (n + 1) th heating source is started, and the sum of the duty ratios of the (n + 1) th heating source and the preceding heating source in the driving cycle is 100%. Control is performed with a duty ratio determined as follows and with a drive pulse set with a phase shifted with respect to the drive pulse of the preceding heating source.

  According to these configurations, after the nth heating source reaches the threshold temperature or threshold duty ratio of the target temperature, the driving of the (n + 1) th heating source is started. Since the n-th heating source is controlled based on the proportional / integral / derivative operation, the duty ratio decreases as the threshold temperature (or threshold duty ratio) is approached. Therefore, by driving the (n + 1) th heating source so that the driving pulses do not overlap during the control period, the duty ratio of the (n + 1) th heating source can be made relatively large and driving can be started. Thereby, the nth heating source and the (n + 1) th heating source can be efficiently heated without increasing the maximum power amount. That is, the duty ratio of the preceding drive including the nth heat source and the duty ratio determined so that the sum of the duty ratios of the (n + 1) th heat source is 100% or less and the nth heat source is Since the driving pulse of the heating source of the preceding drive and the (n + 1) th driving pulse are not overlapped, the maintenance heating of the nth heating source or the like affects the initial heating of the (n + 1) th heating source. There is no. That is, it is possible to quickly reach the target temperature with the electric power of one heating source and maintain the target temperature, and it is possible to significantly suppress the maximum amount of power.

  In this case, the threshold temperature is preferably the target temperature.

  According to this configuration, since the power required to maintain the temperature of the heating source that has once reached the target temperature can be very small, the necessary power supply capacity can be obtained by causing the heating source to reach the target temperature in order. Can be reduced.

  In this case, the threshold temperature is preferably a temperature that has reached 90% of the target temperature.

  In this case, the threshold duty ratio is preferably 5%.

  According to these configurations, it is possible to smoothly perform the maintenance heating of the nth heating source and the initial heating of the (n + 1) th heating source.

  In this case, the plurality of heating sources are two heating sources, and one heating source is controlled by a driving pulse set based on an increment counter obtained by dividing the driving cycle, and the other heating source has a driving cycle. It is preferable to control by a driving pulse set based on the divided decrement counter.

  In this case, the plurality of heating sources are two heating sources, and the control means is configured such that one heating source is controlled by a driving pulse set based on an increment counter obtained by dividing the driving cycle, and the other heating source is It is preferably controlled by a drive pulse set based on a decrement counter obtained by dividing the drive cycle.

  According to these configurations, the phases of the drive pulses can be easily shifted by adjusting the timing of the drive pulses by each counter.

  In this case, it is preferable that each heating source heats the ink jet head and the ink supply channel connected to the ink jet head.

  In this case, it is preferable that each heating source heats the ink jet head and the ink supply channel connected to the ink jet head.

  According to these configurations, the ink to be ejected can be efficiently heated by the heating source via the inkjet head and the ink supply channel. As a result, the viscosity of the ink is lowered and appropriate ink ejection is enabled.

  An ink jet recording apparatus of the present invention is an ink jet recording apparatus that performs recording on a recording medium by scanning an ink jet head relative to the recording medium, and includes the above-described heating source control device. To do.

  According to this configuration, drawing can be performed without degrading the drawing quality, and the initial cost for heating can be reduced.

(A) of an inkjet recording device is a top view, (b) is a side view. It is a block diagram of a control apparatus. It is a circuit diagram of a control device when paying attention to around the heater. It is a control block diagram concerning the control method of a heater. It is explanatory drawing (1) for demonstrating the control method of a heater. It is explanatory drawing (2) for demonstrating the control method of a heater.

  Hereinafter, an inkjet recording apparatus to which a heating source control device and a control method of the present invention are applied will be described with reference to the accompanying drawings. This ink jet recording apparatus prints a desired image or the like by ejecting an ultraviolet curable ink by an ink jet head onto a thin film recording medium to be discharged in a so-called reel-to-reel format. is there. Moreover, since the ultraviolet curable ink to be used has a high viscosity at normal temperature, it is discharged from an inkjet head in the state which heated and made the viscosity low. In the following description, the recording medium conveyance direction is defined as the X-axis direction, and the direction orthogonal to the X-axis direction is defined as the Y-axis direction.

  As shown in FIG. 1, an inkjet recording apparatus 1 includes a machine base 2, a feeding device 3 that feeds out a long recording medium W wound in a roll shape, and a winding device that winds up a printed recording medium W. 4 and a work stage 5 disposed on the machine base 2 for sucking and setting the supplied recording medium W, and extending in the X-axis direction, and passing the recording medium W in the X-axis direction via the work stage 5 The X-axis table 6 that is intermittently fed, the Y-axis table 7 spanned in the Y-axis direction so as to straddle the X-axis table 6, the carriage 8 that is movably mounted on the Y-axis table 7, and the carriage 8 And a plurality of inkjet heads 9 for drawing on the recording medium W by discharging ultraviolet curable ink, and an ultraviolet irradiation device mounted on the carriage 8 and irradiating the recording medium W after drawing with ultraviolet rays to cure the ultraviolet curable ink. 10 and To have.

  The ink jet recording apparatus 1 includes an ink supply device 11 that supplies ultraviolet curable ink to a plurality of ink jet heads 9 for each ink color, a maintenance device 12 that performs maintenance and recovery of the functions of the ink jet head 9, and the ink jet recording device 1. And a control device 13 (control means) for overall control.

  In the ink jet recording apparatus 1, the recording medium W fed out by the feeding apparatus 3 is sucked and set by the work stage 5, and then the recording medium W is intermittently fed in the X-axis direction via the work stage 5 by the X-axis table 6 (sub-direction). Scanning), and drawing is performed by ejecting ultraviolet curable ink from the inkjet head 9 while reciprocating (main scanning) the carriage 8 with respect to the drawable area of the recording medium W set by suction. The recording medium W is not limited to a roll that can be continuously supplied, and a single-sheet recording medium W may be used.

  A feed roller 21 and a feed roller 22 are attached to an upstream end and a downstream end of the work stage 5 in the conveyance (X-axis) direction, respectively. The feeding roller 21 and the feeding roller 22 are free-rotating nip rollers provided so as to be movable up and down, and sandwich the recording medium W so that the recording medium W faces the upper surface of the work stage 5. The work stage 5 is intermittently fed in the X-axis direction (from the upstream side to the downstream side) by the X-axis table 6 with the recording medium W being sucked and set.

  The X-axis table 6 is disposed on the machine base 2 and has a pair of X-axis guide rails 23 extending in the X-axis direction, and an X-axis for slidably moving the work stage 5 along the X-axis guide rails 23. And a moving mechanism 24. The X-axis table 6 moves the recording medium W in the X-axis direction (sub-scanning direction) by the drawing width (line feed distance) while the carriage 8 shifts from the forward movement (reverse movement) to the backward movement (forward movement). Sends to the downstream side (feed feed).

  The Y-axis table 7 includes a Y-axis guide rail 25 that spans the machine base 2 so as to straddle the Y-axis direction, and a Y-axis movement mechanism 26 that moves the carriage 8 slidably along the Y-axis guide rail 25. ,have. The Y-axis table 7 reciprocates the inkjet head 9 and the ultraviolet irradiation device 10 in the Y-axis direction (main scanning direction) via the carriage 8. In synchronism with the reciprocation of the carriage 8, ultraviolet curable ink is ejected from the inkjet head 9 and drawing is performed. At the same time, the ultraviolet curable ink immediately after drawing is cured by ultraviolet irradiation by the ultraviolet irradiation device 10.

  The ink supply device 11 includes a plurality of main tanks 51 for each ink color provided in the maintenance device 12, a plurality of sub tanks 53 for each ink color mounted on the carriage 8, and a plurality of ink colors for connecting the main tank 51 and the sub tank 53. And a plurality of head-side ink channels 54 (ink supply channels) for each ink color connecting the sub-tank 53 and the inkjet head 9 (in FIG. 1, 1). Only the set is shown. In the present embodiment, two types of ultraviolet curable inks (6 types) of clear (CL), yellow (Y), cyan (C), magenta (M), and black (K) in total are used. For this reason, six sets of the main tank 51, the sub tank 53, the tank side ink flow path 52, and the head side ink flow path 54 are provided for each ink color.

  The carriage 8 is attached to a slider (not shown) of the Y-axis moving mechanism 26 and reciprocates in the Y-axis direction by the Y-axis moving mechanism 26. The carriage 8 includes a plurality of sub tanks 53 for each ink color, a plurality of head-side ink flow paths 54 for each ink color, a plurality of ink jet heads 9 for each ink color, and an ultraviolet irradiation device 10. Has been. The ultraviolet irradiation device 10 has a pair of light irradiation lamps 34 and 34 mounted on the carriage 8 so as to sandwich the plurality of inkjet heads 9. Although details will be described later, the carriage 8 includes a plurality of (six) sheet-like heaters 55 (heating sources) that collectively heat the sub-tanks 53, the head-side ink flow paths 54, and the inkjet heads 9. And a plurality (six) of temperature sensors 56 (temperature detecting means) for detecting the temperature of each heater 55 are mounted. That is, the number of heaters 55 and temperature sensors 56 corresponding to the ink color (number of channels: 6) are mounted on the carriage 8.

  Each inkjet head 9 has a nozzle row 33 composed of a plurality of ejection nozzles 31 on the nozzle surface 32, and ejects different types (colors) of ultraviolet curable ink for each inkjet head 9. Yes. Since the ultraviolet curable ink used in the embodiment has a high viscosity at room temperature, it is discharged from each inkjet head 9 in a state where the viscosity is lowered by heating with the heater 55 described above.

  As shown in FIGS. 2 and 3, the control device 13 includes a memory unit 61 that stores a control program and data, an image memory unit 62 that stores predetermined drawing data, a memory unit 61, and an image memory. The controller unit 63 that controls the unit 62, and the driver unit 64 that drives each device constituting the inkjet recording apparatus 1 according to a command from the controller unit 63. The controller unit 63 includes a print control unit 65 that controls the inkjet head 9 and the ultraviolet irradiation device 10, and a system controller 66 that controls the X-axis table 6, the Y-axis table 7, the heater 55, and the like. The temperature sensor 56 is connected to the system controller 66.

  In the drawing operation, the print controller 65 and the system controller 66 cooperate to intermittently feed (sub-scan) the recording medium W in the X-axis direction by the X-axis table 6 and reciprocate the carriage 8 based on the drawing data. The inkjet head 9 is driven while operating (main scanning), and ultraviolet curable ink is selectively ejected to perform drawing (see FIG. 2). In the temperature control, the system controller 66 controls the heater 55 based on the detection result of the temperature sensor 56, and heats the sub tank 53, the head side ink flow path 54, and the inkjet head 9 to a desired temperature.

  As shown in FIG. 3, focusing on the two-channel heater 55 controlled simultaneously, the control device 13 is connected to the CPU 71, the two AD conversion circuits 72 connected to the temperature sensors 56, and the heaters 55. And two interfaces (I / O) 73 for transmitting a control signal to each heater 55 based on a command from the CPU 71. The control device 13 AD-converts the detection result of the temperature sensor 56 and transmits an ON / OFF switching control signal to each heater 55. In response to this control signal, the heater 55 is driven via the switching transistor 74 connected to the heater power source (heater driver).

  Next, a method for controlling the heater 55 by the system controller (the control device 13 for the heater 55) 66 will be described with reference to FIGS. The thing of this embodiment has the inkjet head 9 of six (6 channels) according to a color, and the heater 55 is six lines. In the control of the heater 55, two of the six systems (two channels) are set as one set, and the same temperature control is performed on the three sets of heaters 55. Therefore, in the following description, the two heaters 55 constituting the set are referred to as a first heater 79 and a second heater 57, respectively, and a control method thereof will be described.

  This control method starts driving the two heaters 55 in order by pulse width modulation control (PWM control), and based on proportional / integral / differential operation (PID operation) so that each becomes a target temperature, Control while changing the duty ratio. That is, each heater 55 is feedback-controlled by a PID operation, and the two heaters 55 are controlled in association with each other based on a common control cycle.

  As shown in FIG. 4, the CPU 71 determines the duty ratio of the drive pulse applied to the heater 55 based on the detected temperature of the heater 55, and the drive pulse applied to the heater 55 based on the determined duty ratio. The pulse width is set. Since the duty ratio is set based on the PID operation, the duty ratio decreases as it approaches the target temperature from the start of driving (duty ratio 100%), and becomes 0% when the target temperature is reached (see FIG. 5). In the embodiment, based on each counter obtained by dividing the drive cycle, a drive pulse taking into account the duty ratio is applied to each heater 55 (57) at a set timing (phase) (see FIG. 6). .

  Specifically, first, heating of the first heater 79 is started at a duty ratio of 100% (starting of the heater 55). Next, the temperature of the first heater 79 is detected by the first temperature sensor 77, and the duty ratio is determined by the PID operation based on the detection result (duty ratio determining means). And based on the determined duty ratio, the pulse width of the drive pulse applied to the heater 55 is set (pulse setting means). At this time, the first heater 79 is controlled by a drive pulse set based on an increment counter obtained by dividing the drive cycle. Thus, the duty ratio is initially controlled at 100%, and when the temperature of the first heater 79 approaches the target temperature, the duty ratio is gradually decreased to reach the target temperature. For example, the temperature is increased from 20 ° C., which is room temperature, to 40 ° C., at which the viscosity of the ultraviolet curable ink is lowered. The first heater 79 that has reached the target temperature is hardly required to be heated, and may be heated at a duty ratio of about 5% when the detected temperature becomes equal to or lower than the target temperature.

  When the first heater 79 reaches the target temperature, heating of the second heater 57 is started. The second heater 57 is also controlled based on the PID operation while changing the duty ratio. Specifically, the duty ratio is set so that the sum of the duty ratio of the first heater 79 and the duty ratio of the second heater 57 is 100% or less within the driving cycle. That is, the amount obtained by subtracting the duty ratio of the first heater 79 from 100 percent is set as the maximum duty ratio of the second heater 57. Then, the temperature of the second heater 57 is detected by the second temperature sensor 78, and the duty ratio by the PID operation based on the detection result is compared with the maximum duty ratio to determine the duty ratio. At this time, the second heater 57 is controlled by a drive pulse set by shifting the phase with respect to the drive pulse of the first heater 79 by a drive pulse set based on a decrement counter obtained by dividing the drive cycle. That is, the drive pulse of the first heater 79 and the drive pulse of the second heater 57 do not overlap, and the second heater 57 can be initially heated by using up the duty ratio 100%.

  Even after the first heater 79 and the second heater 57 have reached the target temperature, both the heaters 55 and 57 have a duty ratio at a set timing (phase) based on each counter obtained by dividing the PID operation and the driving cycle. Is applied to each heater 55 (57) for control.

  According to the above configuration, after the first heater 79 reaches the target temperature, the second heater 57 is driven, and the second heater 57 is driven so that the drive pulses do not overlap during the control cycle. Thus, the first heater 79 and the second heater 57 can be efficiently heated without increasing the maximum power amount. That is, the plurality of heaters 55 can quickly reach the target temperature with the power of one heater 55 to maintain the target temperature, and the maximum amount of power can be significantly suppressed.

  The driving of the second heater 57 may be started when the first heater 79 reaches 90% of the target temperature. Alternatively, the second heater 57 may be driven when the threshold duty ratio of the first heater 79 reaches 5%. Thereby, the maintenance heating of the 1st heater 79 and the initial heating of the 2nd heater 57 can be performed smoothly.

  In this embodiment, the temperature of each heater 55 is detected, but the temperature of the inkjet head 9 or the head-side ink flow path 54 may be detected and feedback controlled.

  DESCRIPTION OF SYMBOLS 9 ... Inkjet head 54 ... Head side ink flow path 55, 57 ... Heater W ... Recording medium

Claims (10)

The pulse width modulation control starts to drive a plurality of heating sources from the first to m (m is an integer) in order, and based on proportional / integral / differential operations, the duty is set so that each becomes a target temperature. A heating source control method for controlling while changing the ratio,
When the nth (1 ≦ n <m: n is an integer) th heating source that has started driving in advance reaches the threshold temperature or threshold duty ratio of the target temperature,
Start driving the (n + 1) th heating source,
The (n + 1) th heating source is set with a duty ratio determined so that the sum of the duty ratios with the preceding heating source is 100% or less within the driving cycle, and with a phase shifted from the driving pulse of the preceding heating source. A control method of a heating source, characterized by controlling with a drive pulse.   The method of controlling a heating source according to claim 1, wherein the threshold temperature is a target temperature.   The method of claim 1, wherein the threshold temperature is a temperature that reaches 90% of a target temperature.   The method of controlling a heating source according to claim 1, wherein the threshold duty ratio is 5%. The plurality of heating sources are two heating sources,
One of the heating sources is controlled by a driving pulse set based on an increment counter obtained by dividing the driving cycle, and the other heating source is a driving pulse set based on a decrement counter obtained by dividing the driving cycle. The method of controlling a heating source according to any one of claims 1 to 4, wherein the method is controlled by the following.   6. The heating source control method according to claim 1, wherein each of the heating sources heats an ink jet head and an ink supply channel connected to the ink jet head. The pulse width modulation control starts to drive a plurality of heating sources from the first to m (m is an integer) in order, and based on proportional / integral / differential operations, the duty is set so that each becomes a target temperature. A control device for a heating source that controls the ratio while changing the ratio,
Temperature detecting means for detecting the temperature of each heating source;
A duty ratio determining means for determining a duty ratio of a driving pulse applied to each heating source based on the detected temperature;
Based on the determined duty ratio, pulse setting means for setting the pulse width of the drive pulse applied to each heating source,
Control means for controlling the temperature detection means, duty ratio determination means and pulse setting means,
The control means includes
When the first heating source that has started driving 1 ≦ n <m: n is an integer) reaches the threshold temperature or the threshold duty ratio of the target temperature,
Start driving the n + 1th heating source,
The n + 1th heating source is phased with respect to the driving pulse of the preceding heating source at a duty ratio determined such that the sum of the duty ratios with the preceding heating source is 100% or less within the driving cycle. A control device for a heating source, characterized in that the control is performed with drive pulses set by shifting. The plurality of heating sources are two heating sources,
The control means includes
One of the heating sources is controlled by a driving pulse set based on an increment counter obtained by dividing the driving cycle, and the other heating source is a driving pulse set based on a decrement counter obtained by dividing the driving cycle. The heating source control device according to claim 7, wherein the heating source control device is controlled by:   The heating source control device according to claim 7 or 8, wherein each of the heating sources heats an ink jet head and an ink supply channel connected to the ink jet head. An inkjet recording apparatus that performs recording on the recording medium by scanning an inkjet head relative to the recording medium,
An ink jet recording apparatus comprising the heating source control apparatus according to claim 9.

Images