JPS62261450A - Ink jet recorder - Google Patents

Abstract

PURPOSE:To stabilize the printing quality by automatically unclogging ink coagulation at fixed time intervals if an ink temperature lowers to lows a certain reference temperature T1 level. CONSTITUTION:A recording control 94 supplies individual signals PS1, PS2, PS3 to a controller 90 in response to the pressing of a power supply turn ON key, a printing start key and a pressure mode setting key. The controller 90 notifies the recording control to the effect that 'print mode ' is set by means of signal CS, judging, upon receipt of temperature information SS0, whether the temperature is lower than T1. If a lower temperature than T1 is detected, a timer to measure a fixed period of time is started. When the elapse of a fixed time is detected, 'circulation mode' and 'pressure mode' are set and again the print mode is set.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an inkjet recording device, and more particularly to an inkjet recording device that improves removal of clogging from head nozzles.

[Prior art]

As a conventional inkjet recording apparatus, there is one disclosed in Japanese Patent Application No. 58-244131 by the applicant. This includes a first tank as an ink supply source for a head for ejecting ink to perform recording, and a second tank as an ink supply source for the first tank. is equipped with three opening/closing means and a pump that can be operated in both forward and reverse directions.In addition to the print mode in which recording is performed by appropriately switching the opening/closing means and the pump's opening/closing states and operating states, the supply mode that supplies ink to the tank, pressurization mode that removes clogging from the nozzle of the head, circulation mode that removes air bubbles in the supply path, and stores ink. The ink supply device is configured so that it can also be set to storage mode.

When the temperature of the nozzle drops, the viscosity of the ink increases, making the nozzle more likely to become clogged. Since the standards for performing the removal operation are not constant, the print quality may become uneven.

〔the purpose〕

SUMMARY OF THE INVENTION An object of the present invention is to provide an inkjet recording apparatus that detects a drop in ink temperature and performs a clogging removal operation at regular intervals during printing, thereby eliminating variations in print quality.

[Summary of the invention]

An inkjet recording apparatus of the present invention includes an ink supply system having a head for discharging ink to perform recording, a tank for storing ink to be supplied to the head, an opening/closing means, and a pump. In an inkjet recording apparatus that can be set to a pressurizing mode in which the ink is pressurized by driving the opening/closing means and a circulation mode in which the ink is circulated by opening the opening/closing means and driving the pump, the ink jet recording apparatus has a means for detecting the liquid temperature of the ink. , in an inkjet recording apparatus that is set to a circulation mode or a pressurization mode at regular intervals depending on the liquid temperature.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an example of the configuration of the main parts of an inkjet recording apparatus to which the present invention can be applied. That is, in this embodiment, the present invention is applied to, for example, a four-color inkjet printer, which has a plurality of print heads in the width direction of recording paper, and prints on-demand. shall be carried out.

In FIG. 1, reference numeral 2 denotes a unit plate made of aluminum, for example, and seven hard disk elements 4 are provided on both the front and back sides of the unit plate 2, covering the entire width of the recording area of the recording paper.

Each head element 4 has 128 ink ejection nozzles in its width direction, facing the recording paper.

These head elements 4 are appropriately arranged on both sides of the unit plate 2, and a recording area is formed by the nozzle of the head element 4 arranged on the front side of the unit plate 2, and a recording area is formed by the nozzle of the head element 4 arranged on the back side. To enable recording of one line without overlapping a recording area in the width direction of recording paper. That is, when recording, first the head element 4 on the back side is driven to perform recording, and when the recorded area faces the head on the front side as the recording paper moves, the head element 4 on the front side is driven. By doing so, it is possible to record one line.

Reference numeral 6 denotes a distributor section, and for example, the one disclosed by the applicant in Japanese Patent Application No. 58-244138 can be used. This distributor 6 has a supply pipe 8
The head element 4 has an outgoing distributor 6A that supplies ink to the head element 4 via a supply pipe 8B, and a return distributor 6B that collects ink from the head element 4 via a supply pipe 8B. 7 is a joint (hereinafter referred to as D-T) that connects the distributor 6 and the supply pipe 8.
For example, the one disclosed in Japanese Patent Application No. 58-244132 by the applicant can be used. Each of these parts is a head unit 10 associated with one predetermined color of ink, and in this embodiment, four head units 1O are provided corresponding to the number of colors of ink.

20 is a motherboard, and 22 is a guide member that guides the unit plate 2 and attaches the head unit IO to the motherboard 20.

A first tank 30 stores ink and serves as an ink supply source for the head element 4, and is connected to the motherboard 2.
0 on the opposite side of the head unit 10. 4
0 is a second tank as an ink cartridge tank, and is guided by a guide member 24 disposed on the motherboard 20 so that it can be attached to the motherboard 20. The first tank 30 has a liquid level sensor, and when the liquid level sensor detects that the amount of ink in the first tank 30 has become less than a predetermined amount, the liquid is transferred from the second tank 40 to the first tank 30. Supply ink. 32 and 3
4 is an arm portion of the first tank 30, and arm portion 3
Opening/closing means 50 and 52 such as solenoid valves are attached to the arm portion 2, and opening/closing means 54 such as a solenoid valve and a pump 56 are attached to the arm portion 34. In addition, the opening/closing means 50, 52 and 54
In addition to electromagnetic valves, opening/closing throttles, gate valves, and the like can be used.

The solenoid valve 50 is connected to the first tank 3 formed in the arm portion 32.
A valve section 5 connects a conduit 60 leading to the ink storage part in the ink tank 0 and a joint 70 (hereinafter referred to as a DV joint) leading to the distributor 6A via the motherboard 20.
0A, and opens in response to the energization of the solenoid 50B to form an ink flow path. The solenoid valve 52 has a valve portion 52A that connects the air chamber in the first tank 30 and the outside air, and opens in response to the energization of the solenoid 52B, and the first
The air chamber inside the tank 30 is opened to the atmosphere. In addition, for example,
A dust filter 53 can also be provided on the atmosphere side of the valve portion 52A.

A solenoid valve 54 is formed in the arm portion 34 and is connected to the pump 56.
It has a valve part 54A that connects a joint part 72 connecting the pipe line 64 leading to the second tank 40 and the pipe 66 leading to the second tank 40, and a DV joint 74 that penetrates the motherboard and reaches the distributor 6B. This valve portion 54A opens in response to the energization of the solenoid 54B, and forms an ink flow path between the pump 56 and the distributor 6B. Note that 76 is a joint (hereinafter referred to as "r-c joint") that connects the pipe 66 and the second tank 40.

The pump 56 connects a pipe line 64 leading to the valve part 54 and the first tank 3.
0 to the second tank via a backflow prevention means such as a check valve, and the flow from the valve part 54A and the second tank 40 to the first tank is connected to the second tank through a backflow prevention means such as a check valve. Ink is supplied to the tank 30 and ink is sent to the valve portion 54A.

Each of these parts 30. 40. 50. 52. 54.
56 and the like are designated as ink supply stages for the head unit 10, and in this embodiment, four stages are provided depending on the color type of ink. In addition, in FIG. 1, only one stage is shown.

The ink supply stages connect them to the head unit IO via DV joints 70 and 74, as described above. This connection is Takemonsho 60-247504/,
You can use what is explained on the board.

Further, in FIG. 1, reference numeral 80 denotes a connector with a control section (not shown), which is attached to the motherboard 20.

82 is an interface port, and 84 is a flexible wiring board that transmits print control signals supplied from the control unit to the head element 4 and the like via the connector 80 and the interface port 82. 300 and 400 are
They are respectively provided on the unit plate 2, and are a heater for keeping the ink warm and a liquid temperature sensor for detecting the ink liquid temperature.

Further, reference numeral 500 denotes a cap portion that is positioned at the illustrated position to cap the nozzle portion when performing ejection recovery or the like of the nozzle portion. During recording, the cap portion 500 may be positioned, for example, at the bottom in the drawing, and when performing ejection recovery, it may be positioned along the guide rail as shown in the drawing, for example, by a drive means (not shown).

Next, a liquid level measuring device provided in the first tank 30 will be described.

FIGS. 2(A) and 2(B) are a perspective view and a sectional view taken along the line Ap; respectively, showing an example of the configuration of a first tank having a liquid level sensor. In this embodiment, the first tank 30 has a recess 36 and a protrusion 37 extending from the recess. A pair of sensors, for example, electrode plates 38, are disposed facing each other on the outer wall surface of the protrusion, and detect the electrostatic capacitance between the electrode plates to determine the height of the ink liquid level in the first tank 3o or Measure the presence or absence of ink. As this sensor, a photocoupler can also be used if the discharge section 37 is made of a transparent member.

In addition, the inside of the protrusion 137A, that is, the distance 1 of the sensor 38
3? A has a shape extending further downward from the location where the sensor 38 is disposed.

A tank 30 without such an extension of the gap fi 37A
' In the configuration shown in FIGS. 3(A) and 3(B), ink! As the liquid level decreases, the surface tension of the ink causes ink droplets to remain on the inner wall of the protrusion 37' where the sensor is disposed, resulting in erroneous detection by the sensor 38. On the other hand, according to the configuration shown in the second figure, the inside of the protrusion
No ink liquid remains on the sensor installation part of 37A,
With this, it is possible to accurately detect a decrease in the ink liquid level.

In addition, as shown in Fig. F2 (A), a recess 36 and a protrusion 37 are formed so that this sensor can be disposed near the center of the first tank 30, so that even if the tank 30 is slightly tilted, the correct liquid Preferably, the height of the surface can be detected.

FIG. 4 schematically shows an ink supply system consisting of a head unit and an ink supply stage. Here, 58 is the second tank 4
This is a check valve disposed at the T-C joint 76 that connects the second tank 40 and the conduit 66, and restricts the flow of ink only in the direction in which it flows out from the second tank 40.

Arrows F and R indicate the direction of ink flow in response to forward and reverse operation of pump 56, respectively. Further, ■ and A indicate an air chamber and an ink storage portion in the first tank 30, respectively.

By configuring the ink supply system in this way, the operating state of the pump 56 and the valve 50 . By appropriately switching the open/close states of 52 and 54 as shown in Table 1, the ink supply device can be set to each of the following modes. I will explain about it.

(1) Print mode Ink necessary for printing is supplied from the first tank 30 side to the head element 4. Note that this embodiment is applied to an on-demand type inkjet printer, so in this mode in which no pressure is applied to the ink during printing, and therefore the pump 56 is not driven, the ink is ejected from the head 4. is pipe 60, valve 50A, D-V joint 7
0. Via the distributor 6A and supply pipe 8A,
It is supplied to the head 4.

(2) Supply mode This is a mode in which ink is supplied from the cartridge tank 40 to the first tank 30, and this mode can be used when starting to use the inkjet printer and when the amount of ink in the first tank 30 decreases.

In this mode, valve 52A is open and valve 54A is closed;
Since the pump 56 is operated in the forward direction, ink flows from the second tank 40 in the F direction via the check valve, the pipe 64, the pump 56 and the pipe 68, and is supplied to the first tank 30. The liquid level in 30 rises.

(3) Circulation mode By circulating ink, when supplying ink to each head etc. during the initial use of the device, or when removing air bubbles in the heads or supply channels and refreshing the ink inside them at the same time. This is the mode used, and is set when the inkjet printer is used for a long time.

In this mode, all valves 50, 52, 54 are open and the pump 56 is run in reverse so that the ink is
In the direction, the first tank 30, the pipe 68, the pump 56, the pipe 64,
Valve 54A, D-V joint 72, distributor 6B, pipe 8B1 head 4, pipe 8A, D-V joint 7
0. It is returned to the first tank 30 via the valve 50A and the pipe 60. Air bubbles in the head 4 or supply path are removed from the first tank 30.
is collected and released into the atmosphere from the air chamber A through the valve 52A.

(4) Pressure mode In this mode, when the nozzles of the head 4 are dry or clogged, pressure is applied to the ink to push the ink out of the nozzles and remove it.

In this mode, valve 50A is closed, valves 52A and 54A are
is open and the pump 56 is operated in the opposite direction, so the ink flows from the first tank 30 in the R direction to the pipe 68, the pump 56, the pipe 64, the valve 54A, the D-V joint 72,
It is supplied to the head 4 via the distributor 6B1 pipe 8B.

(5) Preservation mode In addition to preventing ink evaporation and deterioration in the first tank 30,
This mode prevents ink leakage, and is used when the inkjet printer is not printing or during transportation.

In this mode, valves 50A, 52A, and 54A are closed and pump 56 is also stopped, so there is no ink flow into the supply path and no ink leaking from the device. Furthermore, since all the valves are closed, ink in the tank does not leak from the head portion due to ambient atmospheric conditions, such as temperature changes, and air, dust, etc. do not get mixed into the supply path.

Next, the manner in which the supply system is set to each of these modes will be described.

FIGS. 5A and 5B show the voltage V (volt) applied to the pump drive motor and the pump discharge flow m, respectively.
Q (c c / s e c 3 and in circulation mode, the pump discharge flow ffi Q (cc /
sec] and the value L/ of the leakage iL from the nozzle divided by Q.
It is a characteristic curve diagram showing the relationship with Q[:%]. Therefore, by setting the pump drive voltage V lower in the circulation mode than in the pressurization mode, ink leakage ff1L can be reduced.

Although FIG. 5 was obtained with the temperature constant, the slope of the curve changes using temperature-dependent viscosity as a parameter, so the output of the temperature sensor 400 is used to adjust the drive voltage V according to the temperature conditions. You can also set it appropriately. Furthermore, even in the pressurization mode, the amount of ink flowing out from the nozzle varies depending on the viscosity, which depends on the temperature conditions, so by controlling the drive voltage V, it is possible to prevent ink from flowing out more than necessary.

FIG. 6 shows an example of the configuration of a mode control section that performs mode setting. Here, 90 is a controller that performs mode control, and is a CPU in the form of a microprocessor.

In addition to the mode control procedure described later, it has a ROM etc. that stores tables related to the pump drive voltage V in the pressurization mode and the circulation mode depending on the temperature. Reference numeral 92 is an air bubble sensor, which detects the occurrence of air bubbles in the supply path and sends a signal SS.
l to the controller 90.

This bubble sensor 92 can be, for example, a pair of optical sensors provided on the outside of the supply pipe 8A made of a transparent member.

94 is a recording control unit, for example, a head drive control unit,
The printer may include an operation section including a power-on key, a print start command key, a pressure mode setting key, etc., and a display section. The recording control unit 94 supplies signals Psi, PS2, and PS3 to the controller 90 in response to pressing of a power-on key, a print start key, and a pressure mode setting key, respectively. Further, the controller 90
It is also possible to position the cap portion 500 at the position shown in the first diagram in response to the input of the signal PS3.

Signals DSO, DS2, and DS4 generated by controller 90 are drive signals for solenoids 50B, 52B, and 54B, respectively, and in response to the signals, valves 50A, 52A, and 54A, respectively, are opened.

The signal DS6 is a drive voltage signal for the pump 56, and the pump 56 is operated or stopped according to the set mode and temperature conditions. Signal C8 is an information signal sent to recording control section 94.

FIGS. 7 and 8 show an example of a mode control procedure. First, when the inkjet printer is powered on, it is set to supply mode in step Sl in response to the signal PSl. In the supply mode, as shown in FIG. 8A, first, in step 5A-1, the signal DSO is output.

The valves 50A and 52A are opened by DS2, the valve 54A is closed by the signal DS4, and the pump 56 is operated in the forward direction by the signal DS6. This operation can be performed by applying to the pump 56, for example, a voltage with a polarity opposite to that in the circulation mode or pressurization mode. Next, in step 5A=2, if it is determined by the signal SS2 that there is sufficient ink remaining in the first tank 30, the process returns to the procedure shown in FIG. 7, and if the remaining ink is insufficient, the second tank 30 is 4
Ink supply to the first tank 30 continues from 0. Here, if the liquid level sensor 38 does not detect an increase in ink in the first tank 30 even after a certain period of time has passed after this mode is set, it is assumed that there is no remaining ink in the second tank 40, and a signal is sent. Information to that effect may be sent to the recording control section 94 via line C8 and displayed.

In step S2, the circulation mode is set.

In this circulation mode, as shown in FIG. 8(B), first, in step 5B-1, the temperature information signal SSO generated by the temperature sensor 400 is used to develop the drive voltage V corresponding to the temperature in the ROM. Read from the table related to the mode. Then, in step 5B-2, the signals DSO, D
With S2 and DS4, valve 50A.

52A and 54A are all opened, and the pump 56 is reversed by the signal DS6. This operation can be performed, for example, by applying a drive voltage that corresponds to the temperature. Furthermore, in step 5B-3, if it is determined by the signal SSl that there are bubbles, the circulation is continued;
If no bubbles are detected, the process returns to the procedure shown in FIG.

In step S3, the storage mode is set.

In the storage mode, as shown in FIG. 8(D), all valves 50A, 52A, and 54A are closed by signals DSO, DS2, and DS4 in step 5D-1;
The pump 56 is stopped by the signal DS6, and the process returns to the procedure shown in FIG.

In step S4, the print start command signal PS
2, and if that signal is not supplied, the save mode is maintained.

In step S5, the remaining amount of ink in the first tank 30 is detected using the signal SS2, and if there is enough remaining ink, the process proceeds to step S6, and if there is not, the process proceeds to step S7, which is the supply mode (see FIG. 7). The process proceeds to step S6 via (A)).

In step S6, the occurrence of bubbles is detected using the signal S'S L, and if there are no bubbles, the process proceeds to step S8.
In some cases, the circulation mode in step S9 (Fig. 7(B)
) and then proceeds to step S8.

In step S8, the ink temperature is checked using the signal SSO, and if the temperature is higher than TI, the process proceeds to step SIO, and if the temperature is lower than TI, the process proceeds to the pressurization mode of step Sll. In the pressurization mode, as shown in FIG. 8(C), first, in step 5C-1, a table related to the pressurization mode is created in which the drive voltage corresponding to the temperature is developed in the ROM based on the temperature information SSO. Read from. Next, in step 5C-2, the valve 50A is closed by the signal DSO, and the signal DS2. Valve 52 by DS4
A, 54A is opened, the pump 56 is reversed by the signal DS6, ink is ejected from the nozzle of the head 4, and the nozzle is dried.

After removing the clogging, the process returns to step 510 in FIG. Note that this operation can be performed by applying a driving voltage corresponding to the temperature.

Step 10 is a step of recording a predetermined amount.

In step 10 printing, step 5F-1
Set to print mode. In the print mode, as shown in FIG. 8(E), the signal DSO.

The valves 50A and 52A are opened by DS2, the valve 54A is closed by the signal DS4, and the pump 56 is stopped by the signal DS6. Then, the controller 90 transmits the fact that the print mode has been set to the recording control section using the signal C8, and in step 5E-2, it is determined based on the humidity information SSO whether the temperature is lower than T1, and if the temperature is higher than Tl, In step 5F-3, it is determined based on the signal PSl from the recording control section 94 whether or not a predetermined amount of recording has been completed.

In step SF-2, when a temperature lower than 'rl is detected, a timer that measures a certain period of time is started in step 5F-4, and in step 5F-5 it is determined whether or not a certain period of time has elapsed. If the temperature is higher than Tl, the same judgment as in step 5F-3 is made in step 5F-6, and if the recording has not been completed, the same judgment as in step 5F-2 is made in step 5F-7. Go to 5F-2, if not,
Proceed to step 5F-5.

In step 5F-5, if the passage of a certain period of time is detected, the circulation mode is set in step 5F-8, the pressurization mode is set in step 5F-9, and step 5
At F-10, the print mode is set again and the process proceeds to step 5F-4.

When it is detected in step 5F-3 and step 5F-6 that the predetermined amount of recording has been completed, step SIO is completed, and the process moves to step 3 to prepare for the next (recording).

In the present invention, the determination as to whether or not to perform the clogging removal operation is made by detecting the liquid temperature of the ink and using the detected temperature to determine whether or not to perform the clogging removal operation.
Step 5F-1 and Step! in F diagram. SF 7
However, in addition to the ink temperature, the temperature to be detected may also be the temperature of the head unit or the temperature of the atmosphere around the head unit.

〔effect〕

As explained above, according to the present invention, when the ink temperature becomes lower than a certain reference temperature TI, the clogging removal operation is automatically performed at regular intervals, so that it is possible to realize a recording device with stable print quality. can.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an example of the configuration of an inkjet recording apparatus according to the present invention, and FIGS. 2(A) and (B) are perspective views each showing an example of the configuration of an ink storage device in the inkjet recording apparatus. 3(A) and (B) are sectional views showing a conventional ink storage device for comparison with the ink storage device shown in FIG. 2, and FIG. A fluid circuit diagram showing an example of the configuration of the supply system, FIG.
) and (B) are characteristic curve diagrams showing the relationship between the voltage applied to the motor that drives the pump and the discharge flow m of the pump, and the relationship between the discharge flow rate of the pump and the ink flow rate from the nozzle, respectively. The figure is a block diagram showing an example of the configuration of a mode control section that performs mode setting of the inkjet recording apparatus according to the present invention, and FIGS. 7, 8, and 9 are flowcharts showing examples of the mode control procedure. .

Claims (1)

[Claims] 1) An ink supply system including a head for discharging ink for recording, a tank for storing ink to be supplied to the head, an opening/closing means, and a pump, and by driving the pump with the opening/closing means closed, the ink can be removed. An inkjet recording apparatus that can be set to a pressurization mode in which the ink is pressurized and a circulation mode in which the ink is circulated by opening the opening/closing means and driving the pump, has a means for detecting the temperature of the ink, and has a means for detecting the temperature of the ink. An inkjet recording device characterized by setting a circulation mode and a pressurization mode at regular intervals.