JPS59207257A - Liquid jet recorder - Google Patents

Abstract

PURPOSE:To obtain a liquid jet recorder capable of exactly supplying recording liquid and also of preventing clogging by using a system in which the pressure when supplying the recording liquid to the recording liquid storage chamber of head unit is varied differently from the pressure when doing only recovery action of the meniscus of the jet head. CONSTITUTION:Pressure are two-stepwise generated by adjusting the position of a piston 41 in a pump 8 as a pressure generator, and the amounts of ink to be supplied to a subtank 31 from an ink tank are controlled. When the meniscus is only recovered, the negative pressure of the upper chamber of the pump 8 is made smaller to limit the supply of ink to the subtank 31. The mechanism for both actions of ink supply and meniscus recovery is used in common, and both actions can be performed exactly.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a liquid jet recording device such as a so-called inkjet recording device, which is capable of reliably supplying recording liquid and preventing clogging of a jet head. The problem is the means.

Conventional inkjet recording apparatuses have advantages such as direct recording, easy colorization, and negligible noise, and are attracting attention as a new recording technology. In particular, on-demand type inkjet recording devices are inexpensive and can be miniaturized, and are becoming central to the full-color printer technology that has been attracting attention recently.

However, conventionally, this type of recording device has a complicated ink supply system to the inkjet head, and the viscosity of the ink increases due to the evaporation of volatile substances in the ink at the tip of the head, resulting in poor ink ejection stability. The drawback was that it was difficult to hold.

First of all, regarding the ink supply system, various means have been proposed in the past, but the most representative one is a configuration in which the ink tank and the head are connected with a highly flexible tube, and the others are The ink tank is arranged on a head carriage and the ink tank and head are directly connected. However, in the former case, the tube is pulled as the head moves during recording, which causes problems with the durability of the tube itself, and also causes instability in carriage feeding due to load fluctuations caused by tube movement, i.e. (1 ) Misalignment of the recording point, (ii) Instability of ink ejection due to incomplete ink supply due to fluctuations in the flow path resistance of the air tube or incorporation of bubbles into the tube, and (iii) The relative position of the head and the ink tank. However, the more design constraints are required, the more difficult it becomes to optimally design equipment. On the other hand, the latter method increases the load on the printer to ensure sufficient ink for recording, which increases the size and cost of the entire device, and also causes the user's hands to be unable to maintain sufficient ink volume due to ink leakage when changing ink cartridges. It has the disadvantage of contaminating the equipment. These drawbacks become even more noticeable in an apparatus configured to hold a plurality of types of ink having different ink densities in order to improve image quality.

Next, as means for preventing clogging, capping means for preventing dryness at the tip of the public lens and means for discharging ink from the short end have been proposed and have been effective. However, in a configuration in which these operations are performed manually, there are disadvantages such as poor operability and ink ejection instability due to forgetting to cap, and the amount of ink ejected from the tip of the head. Since the residual ink in the ink tank decreases depending on the amount of ink remaining, it is necessary to provide special means to detect the remaining amount of ink.Furthermore, these means must be installed separately from the ink supply system, which reduces the size of the equipment. There are drawbacks that lead to increased formalism and increased costs.

Purpose of the Invention The present invention solves the above-mentioned drawbacks of conventional recording devices of this type, and provides a liquid jet recording device that can reliably supply recording liquid with a simple configuration and prevent clogging of the jet head. The purpose is to provide equipment.

More specifically, the present invention changes the pressure generated by the pressure generating means depending on whether the recording liquid is supplied to the recording liquid storage chamber of the head unit or when only the meniscus return operation of the ejection head is performed. It is an object of the present invention to provide a liquid jet recording device that can reliably supply recording liquid with a simple configuration and prevent clogging of a jet head by controlling the supply amount of recording liquid.

Structure of the Invention The present invention has a first recording liquid storage chamber with a large capacity (in a specific example described later, for example, the large capacity ink tank 16 in FIG. 1); and a second recording liquid storage chamber with a small capacity (also Sub-tank 31) in FIG. 2: Pressure generating means that generates at least two levels of pressure, and the amount of recording liquid supplied from the first recording liquid storage chamber to the second recording liquid storage chamber by the generated pressure. (pump 8 that changes the pressure on the head unit 2 depending on the position of the piston 41 in FIG. 3)
The invention is characterized by a liquid jet recording device comprising: and;

In the above, the citation of the specific examples described later does not limit the scope of the present invention in any way, and the embodiments of the present invention can be modified as appropriate within the scope of the above-mentioned backing claims.

Sometimes it's called ink.

With reference to the drawings, a specific example of the liquid jet recording apparatus according to the present invention will be described below, with the overall configuration, the capping device, and the configuration of the liquid jet head unit.

The configuration of the pump, the configuration of the control system, and the order of their actions will be explained in detail.

Overall Configuration of Liquid Jet Recording Apparatus (FIG. 1) In FIG. 1, reference numeral 1 indicates a platen that is interlocked with a paper feeding mechanism (not shown).

2 is a liquid ejecting head unit, the details of which will be described later. A carriage 3 is driven by a carriage motor 4 along a screw 5 and a guide 6 in the direction of the arrow. These control mechanisms are well known and are not related to the gist of the invention of this application, so detailed explanations will be omitted.

7 is a capping device, and 8 is a pump, the details of which will be described later in connection with FIGS. 2 and 3, respectively. 9 is a pulse motor for driving the pump, 10 is a worm gear, and 11 is an electromagnetic clutch. The worm gear 10 is interlocked with the motor 9 via the electromagnetic clutch 11 and drives the cam 15. 12 is a motor for driving the capping device, 13 is a worm gear, and 14 is a capping device 7.
The worm gear 13 is interlocked with the motor 12 and meshes with the wheel 14 to drive the capping device 7. 16 is a large-capacity recording liquid tank (hereinafter referred to as ink tank); 17 is a suction tube that connects the pump 8 and the capping device 7; 18 is a supply tube that connects the ink tank 16 and the capping device 7; and 19 is an injection tube. Recovery tube, 20, for discharging ink from the tip (same < 32a) of the head (32 in Figure 2)
is a waste liquid tube that connects the pump 8 and the waste liquid tank 2, SWI is a detection switch that detects the initial position of the carriage 3, and PA is a recording paper.

Capping device and liquid injection head unit configuration (
(Figure 2) Figure 2 shows a sub-tank that stores the capping device 7 and the liquid ejection edge, 32 is a known injection rad, 32a is its tip, 33 is an ink supply port, and 34 is a suction port.The pressure inside the sub-tank 31 is In addition to controlling and discharging ink, it has a level pointer 34a, and functions to keep the initial amount of ink supplied to the sub tank 31 constant. 35 indicates ink stored in the subtank 31.

Reference numeral 36 denotes a main body of the capping device 70, which is fixed to the main body of the recording device (not shown). 37 is a cap made of a material such as rubber; 38 is a movable member to which the cap 37 is fixed; the movable member 38 is fitted with the main body 36 by a guide (not shown), and the wheel 14 is fixed; It is driven by the motor 12 in the direction of the arrow. 39 is a spring movable member 38
is urged toward the head unit 2. Note that 1 in the figure
7.18 and 19 indicate the suction tube, supply tube and recovery tube, respectively, as in FIG.

Pump configuration (Figure 3) FIG. 3 is a sectional view showing details of the pump 8.

In the figure, 41 is a piston that fits into the cylinder 42, and 0
It is sealed by rings 41a, 41b, 41c and 4-1d, and is urged upward by a spring 43. 44 and 45 are located below the piston 41. A valve 46 is made of an elastic member, and a portion thereof is fixed to the piston 41. 4.7il-1: Waste liquid discharge port.

Configuration of Control System (Fig. 4) Fig. 4 shows a block diagram of the control system, in which 100 is a recording device control circuit, in addition to the usual digital control section, CNT counters 100a, n, counter 1QOb, n2 counter 100c. , 'W register 100d.

It includes a timer 100e. The functions of the CNT counter 100a to timer 100e will be described later.

Reference numeral 101 denotes a recording device drive circuit, which transfers an end signal to the control circuit 10 ( ) in response to the end of recording;
The recording start signal is maintained from 0. A signal output circuit 102 transfers a high level signal to the control circuit 100 when the initial position detection switch SW1 of the carriage 3 is activated.
A signal output circuit 3 transfers a high level signal to the n2 counter 100c in the control circuit 100 when the recovery switch SW2 is activated.

104, 109, 111 and 112 are carriage motors 4. Pump drive pulse motor9. This is a driver for the electromagnetic clutch 11 and the capping device driving motor 12, and is controlled by the control circuit 100.

113 is a remaining ink level warning indicator for the large-capacity ink tank 16 (FIG. 1), and 114 is its driver 0115
1 is a potentiometer that detects the position of the piston 41 (Fig. 3), and 116 is a level detector. Depending on the output level of the potentiometer 115, the piston 41 is located at the bottom dead center, intermediate center, or top dead center. determine whether it is in
The signal S1 is set to high level when the center is at the bottom dead center, the signal S is set to high level when the center is at the middle point, and the signal S3 is set to high level when the center is at the top dead center, and these signals are input to the control circuit 100. 117 is a detector p that detects the position of the capping device 7 (Figs. 1 and 2); 118 is a signal output circuit that outputs a high level signal υ when the recording start switch SW3 is pressed; The signal is transferred to timer 1000 or the like. Note that in place of the remaining ink amount warning display 113 in the above, a display device that displays the remaining amount itself may be provided.

Effects of a specific example of the liquid jet recording device according to the present invention (first
(Figures 1 to 5) Next, the operation of the apparatus shown in Figures 1 to 4 will be explained with reference also to the flowchart in Figure 5.

(1.) Recording liquid supply and meniscus return operation When the recording of a predetermined number of sheets is completed, the CNT counter 100a outputs a signal indicating this and is reset itself (Fig. 5 a3). 2
120 and below, the drawing number is omitted and only the step number is displayed) 0 This signal causes the n1 counter to 100.
b counts up ``1'', and the carriage motor driver 104 drives the carriage motor 4 to return the carriage 3 to the initial position (steps 221 to 222).

The return of the carriage 3 is confirmed by the initial position detection switch SWI, and the capping motor driver 112 drives the capping device drive motor 12 by the high level output of the signal output circuit 102, thereby causing the movable member 38 of the capping device 7 to move. The mesh of the worm gear 13 and the wheel 14 causes the worm to move to the tip of the head unit 2.

Due to the movement of the movable member 38, the suction tube 17 and the suction port 34. Supply tube 18 and ink supply port 33. and 9 recovery tube 19 and the tip 32a of the liquid ejecting head.
□Engage each other. In this state, the capping position detector 117 operates to confirm that the capping position is located, and the capping motor driver 112 is turned off. Even if the capping motor driver 112 is turned off, the cap 37 is pressed toward the tip of the head unit 2 by the spring 39, and the above-mentioned attachment is not released (steps 223 to 226).

Next, the pump motor driver 109 and the clutch driver 111 are operated to drive the pump driving pulse motor 9 and the electromagnetic latch 11, and the gear 10. Therefore, the cam 15 is rotated (step 227). As the cam 15 rotates, the piston 41 of the pump 8 begins to descend, and the upper chamber of the pump 8 becomes under negative pressure. This negative pressure becomes maximum when the piston 41 reaches the bottom dead center.

In this process, the suction port 34
1 becomes negative pressure, and accordingly, ink is supplied from the ink tank 16 to the sub tank 31 via the supply port 33 and the supply tube 18. At the same time, ink is suctioned from the tip 32a of the ejecting head via the recovery tube 19 to restore the meniscus of the head.

The pressure in the upper chamber of the pump 8 is restored by the sucked air and ink, and the pressure in the sub-tank 31 is also restored by the supply of ink. Here, the level pointer 34a is
It is set so that a predetermined pressure is restored when the ink level reaches the same pointer. Depending on the recording state, excess ink may remain in the sub tank 31 and the level pointer 34 may
Even if it exceeds a, it is the discharge port 34 and the suction tube 17.
The ink is discharged as excess ink to the pump 8 via the ink. Therefore, the air in the sub-tank 31 is reliably maintained at a certain amount or more, and by setting the level pointer 34a at a position lower than the head tip 32a, pressurized printing will not occur. Pressure fluctuations can be suppressed by the damper effect of air, and since the meniscus at the head tip 32a has also recovered, good recording can be performed.

On the other hand, air and discharged ink from the head unit 2 are sent to the upper chamber of the pump 8 via the suction tube 17 and the second connection hole 45. While the piston 41 is descending, the pressure in the lower chamber increases and the drain valve 46 is closed, so the previously discharged ink accumulated in the first chamber is discharged from the discharge port 47 and the waste liquid tube 2.
o is discharged to the waste liquid drain 721 at AZ'. When the piston 41 reaches the bottom dead center, the signal Sl becomes high level, so after confirming this, the pump motor driver 109. Clutch driver 111 is turned off and motor 9 stops.

The piston 41 is then held in its position by the holding force of a worm gear (not shown) (steps 228 to 229).

During this holding period, the above operation is completed and the pressure in the upper chamber is restored. After confirming that the predetermined time required for these has elapsed, the motor 9 is reversed and the piston 41 is raised (
There is no backflow to steps 230-2. The piston 41 is
It is held by the barb 43 which reaches the top dead center. Next, the capping motor driver 112 operates again, the capping device driving motor 12 reverses, and the movable member 38 returns to its initial position, thereby releasing the capping of the head unit 2, making it possible to record, and performing a series of operations. Complete (step 232.(c),..., ■,...
song, steps 204-208).

The liquid jet recording device described above has a large capacity ink tank 16.
and a small-capacity subtank 31 in the head unit 2, and a pump 8, which is a single pressure generating means, supplies ink from the ink tank 16 to the subtank 31, and discharges ink from the tip 32a of the ejection head 32. Since the meniscus recovery is performed at the same time, the ink supply can be performed accurately with a simple configuration. Also, since the meniscus recovery is performed at the same time, stable recording can be performed. Furthermore, the ink supply can be performed with a single pressure generating means. Since the structure is such that supply and meniscus recovery are performed simultaneously, it is possible to downsize the device and reduce manufacturing costs.

Furthermore, in the above recording apparatus, the single capping device 7 is provided with an ink supply system (supply tube 18) and an ink suction system (recovery tube 19) for meniscus recovery.
Since it is configured to engage with and disengage from the ink supply port 33 and the ejection head 32 in the inner part, in combination with the above-mentioned configuration, a fluid path for ink supply and meniscus return can be configured with a simple mechanism. This is possible, and the above-mentioned operations can be performed reliably, and reliability can be improved. Furthermore, since there is no extra load on the carriage motor 4 during recording, such as an ink supply tube, the inertia can be reduced, the precision of carriage feeding can be improved, and the motor can be made smaller. This greatly contributes to reducing production costs. Furthermore, the degree of freedom in arranging the ink tank 16 is increased, and operability can be further improved.

Furthermore, since the above-mentioned recording device is configured to intentionally supply ink to the sub-tank 31 after recording a predetermined number of sheets, the ink tank is divided into a large-capacity main tank 16 and a small-capacity sub-tank 31. Even with this configuration, ink can be supplied accurately, and thereby the above-mentioned effects such as miniaturization of the device and improvement of operability can be achieved.

(2) When the operation recovery switch SW2 for only meniscus recovery is operated, the signal output circuit 103 transfers a high level signal to the counter 100c, and the %2 counter 100c counts up 1. Subsequently, the pump motor driver 109 operates to drive the pump driving pulse motor 9 and move the piston 41 from the position A to the position B in FIG. 3. Movement of the piston 41 is confirmed by the signal s2 becoming high level, and then the carriage motor driver 104 operates to drive the carriage motor 4 and return the carriage 3. switch S
The return of the carriage 3 is confirmed by the operation of Wl, and the capping morph driver 112 operates to rotate the capping device drive motor 12 in the forward direction, thereby engaging the capping device 7 with the head unit 2 (steps 241 to 24).
6). Check that you have reached the capping position below (
Step 247), the operations after step 226 in FIG. 5 are performed, but in this case, since the piston 41 has already descended to the position B in FIG. Since the negative pressure in the upper chamber 8 is small, the ink supply to the subtank 31 is restricted to perform the meniscus recovery operation.

The above-mentioned liquid jet recording device has a piston 410 and 16. Since it is configured to generate two levels of pressure by adjustment and thereby control the amount of ink supplied from the ink tank 16 to the sub tank 31, the generated pressure can be switched between the ink supply operation and the operation that only returns the meniscus. As a result, a considerable part of the mechanism for both operations can be shared and both operations can be performed reliably, thereby avoiding the complication of the ink supply and meniscus recovery mechanisms and deterioration of operability in conventional recording devices. be able to.

(3) Automatic capping operation When recording of one sheet is completed, the timer 100e starts operating in response to an end signal from the recording device drive circuit 101. The timer 100e is reset by a signal output from the signal output circuit 118 by operating the recording start switch SW3. Therefore, if recording of information to be recorded is started within the set time of the timer 100e, the camping operation is not performed and normal recording is performed. -Force setting~205. ■
). However, although the pump 8 returns after the meniscus returns (step 231), the capping device 7 does not retract, but is retracted only when the recording start switch SW3 is operated (steps 204 to 208). As a result, the tip 32a of the ejecting head 32 is uncapped for the first time at the start of recording, thereby preventing it from drying out. This point also applies to the other operations described above.

(4) Ink remaining amount detection operation In the above-mentioned printing apparatus, the supply amount W at one time of ink supply,
The ink supply amount W during the meniscus return operation is always constant, and the initial capacity W in the ink tank 16 is also constant. Let 1, nI, and n2 be the number of ink supplies and the number of times only the meniscus return operation is performed, respectively. , W' is the remaining amount of ink, then W' = W - (n, W1+ n, W, ) -
-The relationship (1) holds true. Therefore n1 counter 1
00b and n2 counters] and OOc by calculating equation (1), and the remaining amount of ink can be determined from the result.

Specifically, for the previous count value bi, n, counter 1
00b or n2 Every time the counter IQOc counts up, the memory contents of the W register 100d W "' Wl,
(n, w, 10?Z2 W@), compare it with the reference value ■, and if W<v, the remaining amount warning driver 1
14 to cause the remaining amount warning display 113 to display a warning. As described above, instead of the warning display 113, a display device that displays the remaining amount itself may be used.

If a warning is displayed, the ink tank 16 is refilled with ink and the W register 100d is reset (step 251).
~255).

According to the above configuration, it is possible to easily know whether or not the ink tank 16 requires ink replenishment, and instead of being able to prevent recording of all four children due to running out of ink, a special system is used to detect the remaining amount of ink. Since no equipment is required, the amount of remaining ink can be easily detected even in devices that use many types and large amounts of ink, such as multicolor recording devices.
It is possible to reduce the size of equipment and improve operability.

In the apparatus shown in FIGS. 1 to 4, a pump 8 serving as a pressure generating means generates two levels of pressure, and the amount of ink supplied from the ink tank 16 to the sub tank 3J is controlled by this generated pressure. However, the generated pressure can be set in three or more stages, and a plurality of pressure generating means can be provided.

Effects of the Invention As described in detail above, according to the present invention, a first recording liquid storage chamber with a large capacity and a second recording liquid storage chamber with a small capacity are provided to generate at least two levels of pressure. Since the pressure generating means controls the amount of recording liquid supplied from the first recording liquid storage chamber to the second recording liquid storage chamber, the generated pressure can be increased by, for example, the recording liquid supply operation and the operation that only returns the meniscus. By switching, a considerable portion of the mechanism for one-car operation can be shared, and both operations can be performed reliably. Therefore, separate mechanisms are required for recording liquid supply and meniscus return, and the structure is simpler than that of conventional devices, which do not require separate mechanisms to increase the size of the device and reduce reliability and operability. ar+; In fact, various operations necessary for liquid jet recording can be executed, and reliability and operability can be improved and manufacturing costs can be reduced.

[Brief explanation of the drawing]

The drawings show a specific example of the liquid jet recording device according to the present invention, and FIG. 1 is a perspective view showing the overall configuration of the liquid jet recording device, and FIG. 2 is a diagram showing the head unit and camping device in the device shown in FIG. A sectional view showing the details, Figure 3 is a sectional view showing the details of the pump, and Figure 4 is a block diagram of the control system.
5(4) and 5(B) are a set of flowcharts explaining the operation of the apparatus of FIGS. 1 to 4, and FIG.
It is a figure which shows the arrangement of FIG. 5(A) and FIG. 5(B). In the figure, 2 is a liquid jet head unit, 3 is a carriage, and 4 is a liquid ejecting head unit.
1 is a carriage motor, 7 is a capping device, 8 is a pump, 9 is a pulse motor for driving the pump, 10 is a worm gear, 12 is a motor for driving the capping device, 15 is a cam, 16 is a large capacity ink tank, 17 is a suction tube, 1
8 is a supply tube, 19 is a recovery tube, 31 subtanks, 32 is an ejection head, 32a is its tip, 33 is an ink supply port, 34 is a suction port, 37 is a cap, 38 is a movable member, 39 is a spring, 41 is a Piston, 43 is spring, 4
6 is a valve, 113 is a remaining amount warning indicator, and SWI is a detection switch for detecting the initial position of the carriage 3.

Claims (1)

[Scope of Claims] A large-capacity first recording liquid storage chamber. and a second recording liquid storage chamber with a small capacity. Pressure generating means for generating at least two levels of pressure, and controlling the amount of recording liquid supplied from the first recording liquid storage chamber to the second recording liquid storage chamber based on the generated pressure. A liquid jet recording device comprising: