JP2023151558A - recording device - Google Patents

Abstract

To suppress an amount of ink to be discharged to the outside of a recording head at the time of filling ink.SOLUTION: When a recording device performs an ink filling operation to a recording head from an ink tank, the recording device applies a pulse to a heat generator so as to heat the recording head to a target temperature and stops the filling operation when the applied pulse meets a predetermined condition.SELECTED DRAWING: Figure 7

Description

The present invention relates to a recording device.

Inkjet recording devices that record images on recording media by discharging ink are known to have a configuration in which ink discharged from a recording head is supplied from an ink tank provided in the device to the recording head through a tube or the like. .

When installing such a recording apparatus, it is necessary to fill an ink tank with ink through a tube to the head. Patent Document 1 discloses that the recording head is sealed with a cap that protects the recording head, and a negative pressure is generated in the tube by suction with a pump, and ink is sucked out from the ink tank and filled into the recording head. ing.

Japanese Patent Application Publication No. 2019-104185

However, with the method disclosed in Patent Document 1, it is not possible to determine whether or not the nozzles of the recording head are filled with ink. Therefore, if it is possible to fill the ink reliably, there is a possibility that more ink than necessary will be sucked out of the print head.

The present invention has been made in view of the above problems, and an object of the present invention is to suppress the amount of ink discharged to the outside of the recording head during ink filling.

The present invention provides: a recording means having an ink tank for storing ink, a nozzle for discharging ink, and a heating element for heating the vicinity of the nozzle; a temperature detection means for detecting the temperature of the recording means; filling means for filling ink from the ink tank into the recording means;
a drive control means for controlling the drive of the heating element, and when the filling means performs an operation of filling ink from the ink tank to the recording means, the drive control means controls the temperature detected by the temperature detection means. The heating element is characterized in that a pulse is applied to the heating element so that the temperature at which the heating element is heated reaches a target temperature, and when the pulse applied by the drive control means satisfies a predetermined condition, the filling means stops the filling operation.

According to the present invention, it is possible to suppress the amount of ink discharged to the outside of the recording head during ink filling.

FIG. 1 is an external perspective view showing an inkjet recording apparatus according to an embodiment. FIG. 1 is a schematic diagram showing an inkjet recording apparatus according to the present embodiment. FIG. 2 is a block diagram according to the present embodiment. FIG. 2 is a diagram of a chip structure within a recording head according to the present embodiment. It is a flowchart of temperature acquisition by the diode sensor 219 according to this embodiment. 7 is a flowchart during an initial ink filling operation according to the present embodiment. 5 is a timing chart during an initial ink filling operation according to the present embodiment.

<First embodiment>
(Configuration of inkjet recording device)
FIG. 1 is an external perspective view showing an overview of an inkjet printing apparatus (hereinafter also simply referred to as a printing apparatus) 701 in this embodiment. As shown in FIG. 1, a printing apparatus 701 includes a housing (exterior part) 702, an ink tank 101 that stores ink to be supplied to a printing head 107 (see FIG. 2), and a user can perform operations such as inputting commands. An operation panel 234 is provided. In this embodiment, the ink tank 101 is arranged on the front surface of the housing 702. Further, the operation panel 234 is arranged at the top of the housing 702.

FIG. 2 is a schematic diagram showing the internal mechanism of the recording device 701. The ink tank 101 is removably attached to an ink tank holder 102 provided in the main body of the apparatus. Ink tanks accommodating pigment inks of four colors, cyan ink, magenta ink, yellow ink, and black ink, are individually attached to the ink tank holder 102 . The ink tank 101 supplies ink of each color to a recording head 107 mounted on a carriage 108 via a supply tube 106. The carriage 108 removably mounts the recording head 107 thereon. The conveyance mechanism 109 conveys a recording sheet (recording medium) 111 supported by a platen in a conveyance direction A. The carriage 108 is configured to be able to reciprocate in a direction intersecting the transport direction A. The carriage 108 moves above the platen while the conveyance of the recording sheet 111 is stopped. The recording head 107 has an ejection port surface (nozzle surface) on which a plurality of ejection ports (nozzles) capable of ejecting ink of each color are arranged. The recording head 107 performs a recording operation of recording an image on the recording sheet 111 by discharging ink from the discharge ports while the carriage 108 is moving. When the recording operation for a predetermined area is completed, the recording sheet 111 is conveyed by a predetermined distance by the conveyance mechanism 109.

A recovery unit 110 is provided in an area outside the recording sheet 111 in the moving direction of the carriage 108 (outside the recording area). The carriage 108 moves to a position facing the recovery unit 110 when filling the recording head 107 with ink from the ink tank 101 (initial filling) or when recovering the ejection performance of the recording head 107 (during recovery operation). do. The recovery unit 110 includes a cap 112 that can cover the ejection port surface of the recording head 107, and a pump (suction pump) 113 connected to the cap 112 via a tube and disposed within the recovery unit 110. There is. When the carriage 108 moves to a position facing the recovery unit 110 , the recovery unit 110 raises the cap 112 and covers the ejection port surface of the recording head 107 with the cap 112 . The recovery unit 110 drives the pump 113 in a state where the cap 112 covers the ejection port surface of the print head 107 to create a negative pressure inside the cap 112 and perform a suction operation to suck ink from the print head 107. conduct.

FIG. 3 is a block diagram showing the configuration of the control section in the recording apparatus of this embodiment. The CPU 202 controls each part of the device and performs data processing via the main bus line 209. The CPU 202 executes printing operations, recovery operations including suction operations, etc. by controlling data processing, printing head driving, carriage driving, etc. via the following units in accordance with programs stored in the ROM 203. Further, the CPU 202 performs communication processing with a host device such as a PC or a smartphone via the interface 201. The RAM 204 is used as a work area for data processing by the CPU 202, and temporarily stores several lines of recorded data, parameters related to recovery operations, and the like. The image input unit 207 can temporarily hold an image input from the host device via the interface 201.

The print head 107 includes a plurality of heating elements 234 as print elements that generate energy for ejecting ink. It also includes a chip 218 that is driven by the head drive control circuit 216 and is provided with a driver circuit that energizes 234, a nozzle that ejects ink by foaming of the heating element 234, and an ink liquid chamber that supplies ink to the nozzle. ing. A recording element other than a heating element may be used, for example, a recording head 107 that ejects ink using a piezo element may be used.

A plurality of diode sensors 219 are provided on the chip 218 of the recording head 107 and detect the temperature of each part of the chip 218. The output of the diode sensor 219 outputs a voltage according to the detected temperature at a voltage level between GND and Vcc, and is input to the A/D port of the CPU 202. The CPU 202 converts the input analog value into a 10-bit digital value, and then converts it into a temperature by referring to a predetermined A/D value-temperature table stored in the ROM 203. Further, the temperature sensor 210 is a thermistor mounted on a printed circuit board inside the device, and is used to detect the ambient temperature inside the device. Similarly to the diode sensor 219, the temperature sensor 210 is configured such that a signal line to which a thermistor is connected indicates a voltage level between GND and Vcc in accordance with the temperature detected by a circuit within the printed circuit board. This signal line is similarly input to the A/D port of the CPU 202, converted to a digital value, and then converted to temperature by referring to the thermistor A/D value-temperature table stored in the ROM 203. .

The nonvolatile memory 205 stores information regarding the amount of ink of each color ejected onto the platen absorber, information regarding the elapsed time since the previous suction operation was performed, etc. acquired by the timer 208. The non-volatile memory 205 also stores information regarding the temperature inside the apparatus main body, which is acquired by the temperature sensor 210. The nonvolatile memory 205 can retain information even when the power of the main body of the apparatus is turned off. The recovery system control circuit 211 controls the operation of the wiper 213 (not shown in FIG. 2), the cap 112, and the pump 113 by controlling the drive of the recovery system motor 212 according to the recovery processing program stored in the RAM 204. control. The head drive control circuit 216 controls the drive for ink ejection by the print head 107, and causes the print head 107 to perform a preliminary ejection operation and ink ejection in a print operation. The carriage drive control circuit 230 controls the reciprocating movement of the carriage 108 according to print data processed by the image signal processing unit 206, and also controls the movement of the carriage 108 to a position facing a maintenance unit for performing a suction operation. Control. The conveyance control circuit 232 controls the conveyance operation of the recording sheet 111 by the conveyance mechanism 109. After the recording head 107 completes the recording operation for one line, the conveyance control circuit 232 intermittently conveys the recording sheet 111 by a predetermined amount in the conveyance direction A in order to record an image corresponding to the next line of recording data. Controls intermittent conveyance operation. The operation panel 234 includes an LCD, an LED, and a key SW, and inputs commands from the user and displays the status of the device to the user.

FIG. 4 shows a structural diagram of a chip of the recording head 107. Inside the chip 218, a nozzle row in which a plurality of nozzles are arranged in the Y direction for each color of ink is arranged in the X direction. In FIG. 4, nozzle rows of nozzles that eject four color inks, cyan ink, magenta ink, yellow ink, and black ink, are arranged. A plurality of nozzles are provided in each color row at a pitch of 600 dpi, and a plurality of heating element rows 234-1 to 234-4 are provided in the Z direction (backward side of the page) of each nozzle. Each heating element of the heating element 234 is selectively driven with electricity according to the image data to be printed, and as a result of foaming, ink of each color is ejected from the nozzle and printing is performed on the recording medium. Diode sensors 219-1 to 219-12 for temperature detection are arranged within the chip 218 as shown in the figure, and are capable of independently detecting temperatures at various locations within the chip 218. This makes it possible to separately detect temperatures near frequently used nozzles and infrequently used nozzles. The outputs of the diode sensors 219-1 to 219-12 are sequentially switched by a selector in the chip 218 and sequentially input to the CPU 202.

FIG. 5 shows a flowchart of temperature acquisition by the diode sensor 219 performed by the CPU 202.

As described above, the CPU 202 detects the temperature by inputting the output from the diode sensor 219 to the A/D conversion port of the CPU 202. The process in FIG. 5 is performed at the timing indicated by the arrow of head temperature acquisition timing 604 in FIG. 7, using an interrupt routine every 5 ms. When the interrupt occurs, the process shown in FIG. 5 is started, and in step S401, the diode sensor output A/D value is taken in. The acquired A/D value is stored in the RAM 204. The stored numerical values are stored independently for each of the plurality of diode sensors.

Next, in step S402, an average value is calculated by removing the maximum value and minimum value from the numerical values acquired seven times in the past. Then, the calculated average value is adopted as the output value of the diode sensor, and in step S403, the CPU 202 determines the output value of the diode sensor 219 by referring to the A/D value-temperature conversion table stored in advance in the ROM 203. Confirm the detected temperature.

Next, control of the initial ink filling operation will be explained using the flowchart of FIG. 6 and the timing chart of FIG. This process is performed by the CPU 202 operating according to a program stored in the ROM 203.

First, in step S501, it is determined whether or not ink exists in the ink tank 101. This determination is made by inspecting the continuity between two current-carrying pins (not shown) provided in the ink tanks 101 for each color. Since ink acts as a conductor, the presence of ink in the ink tank 101 can be confirmed by the presence or absence of current flowing between the pins. The determination result of the presence or absence of ink is sent to the CPU 202.

If it is determined in step S501 that there is no ink in the ink tank 101, the process advances to step S502 and corresponding error processing is performed. Here, the user is prompted to replenish ink by displaying "Please replenish ink in the ink tank" on the operation panel 234.

If it is determined in step S501 that there is ink in the ink tank 101, the process advances to step S503 and an ink filling operation 605 (see FIG. 7) is started (t0). In the ink filling operation 605, the carriage drive control circuit 230 drives the carriage 108 and moves the recording head 107 to the recovery position. Then, the recording head 107 is sealed with a cap 112, and by driving the pump 113 with the rotation of the recovery system motor 212, negative pressure is generated in the ink ejection nozzles of the sealed recording head 107. Due to the negative pressure, the ink in the ink tank 101 is drawn toward the recording head 107 through the tube 106, and the space between the tube 106 and the recording head 107 is filled with ink.

In step S504, short pulse driving 603 is performed to raise the temperature of the recording head 107 to the target temperature 601. Here, heating is performed by short pulse driving 603 so that the temperature near the nozzle of the chip 218 of the print head 107 obtained by the diode sensor 219 becomes the target temperature 601. The target temperature 601 is set to a high temperature for ink that is considered to be equal to the internal temperature of the ink. The short pulse drive 603 applies voltage to the heating element 234 for ejecting ink in the chip 218 with a short pulse width that does not cause the ink to bubble. Since the heating element 234 is energized to generate heat when there is no ink, the energization is carried out for a short time so as not to damage the heating element 234 such as burning due to heat. Here, electricity is applied in short pulses, and since there is no ink to be ejected, the energy of the electricity is used to raise the temperature of the chip 218, and the temperature of the recording head 107 begins to rise.

Next, in step S505, the output value of the diode sensor 219 is checked at each timing to determine whether the target temperature 601 has been reached, as explained with reference to FIG. In this embodiment, the target temperature 601 is 40°C. If the target temperature 601 has been reached (t1), the heating control by the continuous short pulse drive 603 is stopped, and in step S506, the heating control is performed to maintain the target temperature 601. Heat retention control continues to check the temperature of the chip 218 using the diode sensor 219, and if the temperature falls below the specified value from the target temperature 601, the temperature of the chip 218 is kept constant by raising the temperature of the chip 218 again using the short pulse drive 603. to hold. In parallel with this heat-retaining operation, in step S507, a task of calculating and monitoring a driving time ratio is started to determine the ratio of how much short pulse driving 603 is performed per unit time. While this heat retention control and drive time ratio monitoring are being performed, the ink filling operation 605 continues, and ink eventually reaches the inside of the recording head 107 at timing t2 (ink 606 in the head becomes ink-filled). . When the ink reaches the target temperature 601, room-temperature ink flows into the nozzle of the chip 218, which is kept at the target temperature 601, and the heat capacity increases, so that the temperature of the chip 218 falls below the target temperature 601 (t3). When the decreased temperature is detected, short pulse drive 603 is performed again by heat retention control until the target temperature is reached (t4 to t5).

At this time, in step S508, the driving time ratio of the short pulse driving 603 increases more than the driving time ratio in the heat retention state due to the continuous short pulse driving 603 performed from t4 to t5 to return the temperature to the target temperature again. Wait until the ratio exceeds a predetermined ratio. Here, the CPU 202 determines that the ink has reached the chip 218 of the print head 107 based on the trigger in which the drive time ratio exceeds the specified ratio.

Then, the process advances to step S509, and the temperature acquisition control of the chip 218 and the monitoring of the drive time ratio by the diode sensor 219 are stopped. Next, the process advances to step S510, and a wait operation is performed for a predetermined time. Although it is determined in step S508 that the nozzles are filled with ink, the ink filling operation 605 is continued to some extent to ensure that all nozzles are filled with ink. After the wait time has elapsed, in step S511, the drive of the pump 113 by the rotation of the recovery system motor 212 is stopped, and the ink filling operation 605 is ended.

Further, in the embodiment described above, the temperature of the print head 107 is raised and the temperature is maintained by applying short pulse drive 603 to the heating element 234 for ink ejection, but implementation in other forms is also possible. be. For example, if a dedicated heating element for raising and keeping the print head temperature is provided in addition to the heating element 234 for ejecting ink, the temperature of the printing head 107 can be raised by driving and controlling the heating element. , it may be kept warm. It is also possible to use the driving of the heating element 234 for ejecting ink together with a heating element dedicated to raising the temperature of the recording head and keeping it warm.

Further, in the embodiment described above, as a predetermined condition for stopping the drive of the pump, the temperature change of the print head 107 is calculated by calculating the ratio per unit time of the head temperature increase and heat retention control by the short pulse drive 603. It was determined that the ink filling had been completed. However, the predetermined conditions may be different. For example, the ink reaching the nozzles of the recording head 107 and a drop in the head temperature may be used as a direct criterion for ink filling completion, and this temperature drop may be used as a trigger to determine the completion of ink filling. In this case, a threshold value is set several degrees Celsius below the target temperature for keeping the print head 107 warm, and when the temperature of the print head 107 falls below this threshold value during the heat keeping control, it is determined that ink filling is complete. The threshold value at this time is desirably set in consideration of a margin added to the lower limit of the temperature range indicated by the diode sensor 219 during the heat retention control.

Alternatively, ink filling may be determined to be completed when the time during which the temperature of the print head 107 has been lower than the target temperature for a predetermined time or more.

Since the temperature of the filled ink is close to the internal ambient temperature of the machine, changes in the drive time ratio and temperature changes of the recording head 107, which are the triggers for determining that ink filling is completed, are dependent on the conditions in which the device is installed and the heat retention. Conditions vary depending on the temperature difference of the recording head 107 in different states. Therefore, it is preferable that each threshold value can be changed depending on the temperature indicated by a temperature sensor that detects the ambient temperature inside the device. Further, it is also preferable to be able to change the heat retention setting temperature of the recording head 107 according to the internal temperature indicated by the temperature sensor 210.

Further, in the above-described embodiment, the ink filling operation was performed by suctioning the cap, but filling may be performed by other methods. For example, the recording head 107 may be filled by providing a pump in the tube and pressurizing the ink toward the recording head 107 side.

107 Recording head 219 Diode sensor 218 Chip

Claims (9)

an ink tank that stores ink;
a recording means having a nozzle for ejecting ink and a heating element for heating the vicinity of the nozzle;
temperature detection means for detecting the temperature of the recording means;
filling means for filling ink from the ink tank into the recording means;
a drive control means for controlling the drive of the heating element;
has
When the filling means performs an operation of filling ink from the ink tank to the recording means, the drive control means applies a pulse to the heating element so that the temperature detected by the temperature detection means becomes a target temperature. . A recording apparatus, wherein the filling means stops the filling operation when the pulse applied by the drive control means satisfies a predetermined condition. 2. The recording apparatus according to claim 1, wherein the predetermined condition is that the drive time per unit time of the pulse by the drive control means exceeds a predetermined time. an ink tank that stores ink;
a recording means having a nozzle for ejecting ink and a heating element for heating the vicinity of the nozzle;
temperature detection means for detecting the temperature of the recording means;
filling means for filling ink from the ink tank into the recording means;
a drive control means for controlling the drive of the heating element;
has
When the filling means performs an operation of filling ink from the ink tank to the recording means, the drive control means drives the heating element so that the temperature detected by the temperature detection means becomes the target temperature; A recording device characterized in that the filling means stops the filling operation when the temperature detected by the temperature detection means satisfies a predetermined condition. 4. The recording apparatus according to claim 3, wherein the predetermined condition is to detect that the temperature detected by the temperature detection means has fallen below a first temperature that is lower than the target temperature. 4. The recording apparatus according to claim 3, wherein the predetermined condition is that the time during which the temperature detected by the temperature detection means falls below the target temperature is longer than a predetermined time. 6. The recording apparatus according to claim 1, wherein the filling means stops the filling operation a predetermined time after the predetermined condition is satisfied. 7. The printing apparatus according to claim 1, wherein the heating element is a printing element that generates energy for ejecting ink from the nozzle. The pulse that the drive control means applies to the heating element when performing the filling operation has a pulse width shorter than the pulse that the drive control means applies to the heating element when ejecting ink from the nozzle, or 8. The recording device according to claim 7, wherein the applied voltage is low. 9. The recording apparatus according to claim 1, wherein the heating element and the temperature detection means are provided in the recording means.

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