JP2538205B2 - Ink jet recording device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an inkjet recording apparatus provided with a recovery device for preventing defective ink ejection due to clogging of an ejection port of a recording head, ink drying, and the like.

[Prior art]

An ink jet recording apparatus supplies ink into a recording head and drives elements (electrothermal transducers such as heating elements or electromechanical transducers such as piezo elements) corresponding to a plurality of ejection openings formed on the front surface of the recording head. ) Is driven based on the data signal to form flying ink droplets from the ejection port toward the sheet (recording medium such as paper or plastic thin plate), and the ink droplets are adhered for recording.

In this type of inkjet recording apparatus, in order to prevent the ejection port from being clogged due to ink thickening or ink drying due to evaporation of the ink solvent, dust adhesion, air bubble mixing, etc., capping of the ejection port and ejection from the ejection port are performed. A recovery device for sucking ink is provided.

Conventionally, this type of recovery device is configured to recover the malfunction of the recording head by operating the user by a manual operation such as lever operation when the malfunction of the recording head occurs due to defective ink ejection.

However, in such a conventional recovery device, an operation method instruction label or the like for allowing the user to perform the recovery operation is necessary, and there is a problem that the operating user feels complicated.

Also, if you do not follow the instructions,
Inconveniences such as wasteful suction and discharge of the recording ink may occur.

〔Purpose〕

The present invention has been made in view of the above prior art,
It is an object of the present invention to simplify the structure of a recovery device, reduce the size of the recovery device, and reduce the number of components, improve the reliability and reliability of the recovery operation, and input a signal by a switch operation. An object of the present invention is to provide an ink jet recording apparatus that can perform a series of recovery operations by itself.

〔Overview〕

The ink jet recording apparatus of the present invention includes a cap for covering an ejection port for ejecting ink, a suction pump for performing suction from the ejection port when the cap covers the ejection port, and a suction pump for sucking the ink. A vent valve for communicating the inside of the cap with the atmosphere while performing a cap, a cam groove for engaging with an engaging portion provided on the cap, and a circumferential cam portion for pressing the vent valve. And a worm wheel that is provided coaxially with the rotation axis of the plate-shaped rotation cam and that slides in the rotation axis direction while rotating the plate-shaped rotation cam, and the worm wheel. A worm that meshes with the worm, and a drive means for driving the worm to rotate. The cam groove regulates the engaging portion in accordance with the rotation of the plate-shaped rotary cam. The cap is moved forward or backward with respect to the discharge port, the peripheral cam portion presses the ventilation valve to open and close the ventilation valve, and the worm wheel causes the suction means to move in response to sliding of the worm wheel. The above object is achieved by adopting a configuration in which the suction means performs suction by pressing.

〔Example〕

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

FIG. 1 is a schematic perspective view showing a main configuration of an embodiment of an ink jet recording apparatus to which the present invention is applied.

In FIG. 1, a carriage 2 carrying a plurality of (four in the illustrated example) inkjet heads (recording heads) 1A, 1B, 1C, 1D is guided and supported by guide shafts 3, 3.

The driving force of the carriage motor 4 is transmitted to the carriage 2 via the timing belt 5, and the carriage 2 slides on the guide shafts 3 and 3 and moves along the platen 6. The carriage 2 scans reciprocally with the forward and reverse rotation of the motor 4.

In addition, a predetermined gap (for example, about 0.8 mm) is provided between the front surface of the recording heads 1A to 1D on the carriage 2 (the surface on which the ink ejection ports are formed) and the platen 6 (specifically, the sheet supported by the platen 6). ) Is provided.

During the scanning movement of the carriage 2, the recording signal is output to the recording heads 1A to 1D through the flexible wiring 7,
The recording heads 1A to 1D are driven at a timing related to the position to eject ink, and an image is recorded on a sheet (recording medium such as paper or a plastic thin plate) on the platen 6.

Recording head (inkjet head) 1A to 1D during recording
Ink ejection failure may occur due to dust or paper dust adhering to the vicinity of the ink ejection opening (for example, a dot forming unit consisting of 24 orifices), or air being caught from the ink ejection opening. is there.

Generally, an inkjet recording apparatus is provided with a recovery device RP for recovering this defective ink ejection.

In FIG. 1, when a recovery key (not shown) is operated to recover the defective ink ejection, the recording operation is interrupted and the carriage 2 moves toward the recovery device RP.

As the carriage 2 moves in the direction of the recovery device RP, the idle pulley 8, which supports the rotation of the timing belt 5 at one end, rotates. As the idle pulley 8 rotates, the deceleration planetary gear group 9 provided coaxially therewith also rotates.

When the carriage 2 moves to a predetermined position in the direction of the recovery device RP, the lever 10 engaged with the cam groove of the final stage gear (not shown) of the planetary gear group 9 moves in the direction of arrow A around the shaft 11 in the direction of arrow A. Rotate by the amount determined by.

When the lever 10 rotates in the direction of arrow A, the stay 12 engaged with the tip of the lever 10 slides in the direction of arrow B,
The plate 13 fixed to the stay 12 also moves in the direction of arrow B.

This plate 13 is engaged with the circumferential groove 15 of the ratchet gear 14, and the ratchet gear 14 is free to rotate but axially
It moves with 13.

Therefore, when the plate 13 moves in the direction of the arrow B, the ratchet gear 14 is switched from the state in which it meshes with the ratchet gear 16 to the state in which it meshes with the ratchet gear 17.

By this switching, the rotation of the sheet feeding motor (hereinafter referred to as LF motor) 18 is changed to the LF motor gear 19 and the idle gear 20.
Then, the state is transmitted to the ratchet gear 17 via the ratchet gear 14.

The ratchet gear 17 is integrally formed with a gear portion, and this gear portion meshes with the dowel gear 21.
This doweled gear 21 is the input gear of the recovery device RP, and therefore, by switching in the direction of arrow B, the LF motor
At 18, the recovery device RP is driven.

FIG. 2 is a rear view taken along the line II-II in FIG.
3 is a front view of the carriage 2 taken along the line III-III in FIG. 1, FIG. 4 is a schematic structural view of the recovery device RP in FIG. 1, and FIG. 6 is a plan view of the recovery device RP in the figure, FIG. 6 is a front view seen from the line VI-VI in FIG. 5, and FIG. 7 is a left side seen from the line VII-VII in FIG. FIG. 8 is a plan view, and FIG. 8 is a central longitudinal section of the recovery device of FIG.
9 and 10 are vertical cross-sectional views at different levels of FIG. 5, and FIG. 11 is a timing chart illustrating the operation sequence of the recovery device of the inkjet device according to the present invention.

In FIG. 1, the position of the carriage 2 is controlled with reference to the home position detected by a home position sensor (not shown) installed on the left side portion.

When the recovery key is operated as described above, the carriage 2 moves to a position where the inkjet heads (recording heads) 1A to 1D face the corresponding rubber caps 22A, 22B, 22C and 22D. In this position, the LF motor 18 has been switched to the recovery device RP drive side as described above, and thus the recovery operation is performed.

First, the wiping means for cleaning the ejection surface openings (surfaces on which the ejection openings are formed) of the recording heads 1A to 1D will be described.
The wiping means is configured to wipe off the ejection port surface by the cleaning blade 24.

When the LF (line feed) motor 18 rotates, the gear 21 with a dowel rotates, and the dowel 23 becomes a cleaning blade 24.
The cleaning blade 24 engages with the rear end portion 25 and projects toward the carriage 2 against a return spring (71 in FIG. 7) that biases toward the LF motor 18.

FIG. 2 shows an engaging portion between the dowel-equipped gear 21 and the cleaning blade 24.

From the initial state of FIG.
The LF motor 18 is stopped when the cleaning blade 23 rotates to a position where it presses the rear end portion 25 of the cleaning blade 24 to displace it.

The rotation of the LF motor 18 causes the rotation cam 26 (FIG. 4) of the recovery device RP that rotates at the final reduction ratio to rotate at the same time.

Therefore, the cap housing 27 supporting the rubber caps 22A to 22D tries to move in the direction of the inkjet heads 1A to 1D, but the gear 21 with dowel and the rotating gum (cam disk) 26 from the LF motor 18 does not work. Since the reduction gear ratios are greatly different, the movement of the cap housing 27 can be ignored, the gaps between the caps 22A to 22D and the recording heads 1A to 1D hardly change, and both do not come into contact with each other.

In FIG. 7, when the cleaning blade 24 constituting the wiping means is projected by the rotation of the dowel with gear 21, the claw 28 of the cleaning blade 24 pushes down the claw 30 of the holding lever 29 pivotally attached to the lower side thereof. It operates to get over the claw 30.

Therefore, the holding lever 29 is rotated counterclockwise around the lever shaft 31 against the return spring 72, and the holding lever 29 rotates clockwise after the pawl 28 of the cleaning blade 24 passes, Cleaning blade 24
The claw 28 is caught on the front side of the claw 30 of the holding lever 29, and the cleaning blade 24 is held in the protruding position.

With the cleaning blade 24 protruding, move the carriage 2 in the direction of the platen 6 (to the right in FIG. 1),
The blade 32 attached to the tip of the cleaning blade 24 wipes the ejection port surface of the inkjet heads 1A to 1D.

When the carriage 2 is moved from left to right in this way, the reset claw 33 (FIG. 3) of the carriage 2 becomes the tip claw of the holding lever 29.
34, the holding lever 29 is pushed down counterclockwise in FIG. 1, and the claw 28 of the cleaning blade 24 and the holding lever are engaged.
The engagement of 29 with the claw 30 is temporarily released.

Therefore, the cleaning blade 24 tries to retreat in the direction away from the inkjet heads 1A to 1D by the action of the return spring 71, but in that case, the cleaning blade 24
Since the backward movement is blocked by the doweled gear 21, the cleaning blade 24 is held in a protruding state even when the reset claw 33 of the carriage 2 passes.

While the carriage 2 moves further to the right, the ejection port surface of the inkjet heads 1A to 1D is wiped off (wiping).
Is done.

In that case, before the rotational force of the LF motor 18 is switched to the driving side of the platen 6 by the movement of the carriage 2, and the pawl 30 of the holding lever 29 is a pair of reset pawls 33, 35 of the carriage 2 (FIG. 3). During the period of being located between, the LF motor 18 is switched to the reverse rotation (reverse rotation) of the forward rotation (forward rotation) at the time of the recovery operation and is reversely rotated to the initial position. It is returned to the state shown in FIG.

LF in the ink suction operation (sequence) described later
Due to the reverse rotation of the motor 18, the dowel-equipped gear 21 rotates one or more revolutions in the reverse direction.
Passes through the clearance groove 49 (FIG. 2) of the rear end portion 25 of the cleaning blade 24, and gradually the cleaning blade 24
Is lifted in the direction of arrow C (Fig. 2) against the spring 50 (Fig. 2) and returned to its original position. Therefore, the cleaning blade 24 does not protrude to the ink ejection port side.

While the carriage 2 moves from left to right, the recording heads 1A to
When the cleaning of all the discharge port surfaces of 1D is completed, the reset claw 35 (FIG. 3) of the carriage 2 is engaged with the tip claw 34 of the holding lever 29. As a result, the locked state of the cleaning blade 24 is released, and the cleaning blade 24 is reset to the initial position (retracted position in FIG. 1) by the urging force of the return spring 71 (FIG. 7), and the discharge port surface The cleaning (wiping) operation ends.

The cleaning operation by the wiping unit as described above can be executed plural times by reciprocating the carriage 2.

By this cleaning operation (wiping operation), it is possible to reliably remove rubber, paper dust, thickened ink, etc. adhering to the ejection port surface.

Next, a recovery operation by suction of ink from the ejection port will be described.

FIG. 11 is a recovery device for the inkjet recording apparatus of FIG.
6 is a timing chart illustrating an operation sequence of an RP.

When the above-mentioned cleaning (cleaning or wiping) of the ejection port surface is completed, the carriage 2 moves from right to left to the position where the inkjet heads (recording heads) 1A to 1D face the respective caps 22A to 22D, and at that position. Stop.

After the carriage 2 is stopped, the LF motor 18 is rotated forward.

When this forward rotation continues, the rotational force of the dowel with gear 21 is transmitted to the shaft 36 (Fig. 5) of the dowel, which causes the pulley 37 (Fig. 5) that rotates integrally with the shaft to rotate, and the timing belt (not shown). The pulley 38 is rotated via the (illustrated), and the worm 39 (FIG. 4) rotating coaxially with the pulley 38 is rotated.

In FIG. 4, the worm 39 is engaged with the worm wheel 40. A plurality of rectangular grooves 41 are formed on the shaft integral with the worm wheel 40, and as the worm wheel 40 rotates, the rotary cam 26 coaxial with the worm wheel 40 fits into the rectangular groove 41 and rotates at the same speed.

When the LF motor 18 continues to rotate, the embossment 42 (No. 9) of the cap housing 27 (FIG. 1) is inserted into the cam groove (not shown) of the rotary cam 26.
(Fig.) Is engaged, the cap housing 27 is moved in the direction of the inkjet heads 1A to 1D, and the rubber caps 22A to 22D are brought into close contact with the respective ejection port surfaces, and the capping state (capping closed) is achieved.

In FIG. 4, each rubber cap 22A to 22D has a conduit 4
3, 44 are connected, the conduit 43 is connected to the vent hole 45, and the conduit 44 is connected to the pump 46.

When in the capping state, as shown in the timing chart of the ink suction operation of FIG. 11, the ventilation valve 47 is in the opened state, the ventilation cam 45 is in the atmospheric state, and the rubber caps inside the rubber caps 22A to 22D are deformed. Even if the volume is compressed, the meniscus of the ejection port surfaces of the recording heads 1A to 1D does not recede.

In FIG. 4, when the forward rotation of the LF motor 18 continues, the circumferential protrusion 51 (FIG. 10) of the cam disk is rotated along with the rotation of the rotary cam 26.
Pushes the ventilation valve support 52 in the direction of arrow D (FIG. 4), and the ventilation valve 47 closes the ventilation hole 47 (closes the ventilation valve). This closing of the ventilation valve corresponds to the point S2 in FIG.

When the rotation of the worm wheel 40 (FIG. 4) is continued with the capping closed and the ventilation valve closed, a plurality of wheel cams 53 (FIG. 4) are formed at positions of different radial lengths in the radial direction of the worm wheel 40. The plurality of wheel cams 53 engage with cams having the same diameter on the housing side of the recovery device RP, and the worm wheel 40 moves downward.

At this time, since the shaft of the worm wheel 40 is fitted in the rotary cam (cam disc) 26 and the rectangular groove 41, the worm wheel 40 moves downward while rotating the rotary cam 26.

In FIG. 4, by moving the worm wheel 40,
The piston 55 of the pump 46 is pushed down via the steel ball 54. The steel balls 54 are for not transmitting the rotation of the worm wheel 40 to the piston 55.

When the piston 55 is pushed down, the inside of the cylinder 56 of the pump 46 becomes negative pressure, and the ink is sucked from the ejection port via the conduit 44.

The downward movement speed of the worm wheel 40 depends on the LF motor 18
The rotation speed can be controlled by the worm wheel 40
By considering the moving speed of the ink and the inflow amount of ink due to the negative pressure in the cylinder 56, it is possible to set the ink suction from the ejection port with a predetermined negative pressure and prevent the generation of dissolved air dissolved in the ink. You can

In FIGS. 4 and 11, when the worm wheel 40 has moved to the lowermost end (point S3 in FIG. 11) and continues to rotate in this lower end state, the circumferential projection 51 of the rotary cam (cam disc) 26 is rotated.
(FIG. 10) has passed the ventilation valve support 52 (FIGS. 4, 10) and the ventilation valve 47 (FIG. 4) allows the vent hole 45 to communicate with the atmosphere (vent valve open, FIG. 11). Corresponding to S4 point in).

By controlling the rotation speed of the worm wheel 40 in the lower end state, it is possible to control the time required for the air hole 45 to communicate with the atmosphere.

In FIG. 4, the inside of the cylinder 56 is in a negative pressure state and the vent hole is formed.
When 45 communicates with the atmosphere, the sucked ink in the rubber cap inside 48 flows into the cylinder 56 through the conduit 44 together with the air flowing in from the conduit 43, and the ink remaining amount in the rubber cap inside 48 decreases.

The degree of negative pressure inside the cylinder 56 when the vent hole 45 communicates with the atmosphere needs to be controlled by the rotation speed of the worm wheel 40 so that the meniscus of the discharge port does not recede.

The reason is that before the vent hole 45 communicates with the atmosphere, ink is being sucked from the ejection port and the sub-tank 58 at the rear of the ejection port
This is because the air layer 59 in FIG. 4 has a negative pressure, but when the vent hole 45 communicates with the atmosphere, the inside of the rubber cap 48 immediately becomes atmospheric pressure and the ink meniscus at the discharge port is retracted. In addition, it is necessary to control the rotation speed of the worm wheel 40.

In FIG. 4, when the ventilation valve 47 is opened and the worm wheel 40 continues to rotate, the worm wheel 40 follows the shape of the wheel cam 53, and the piston return spring 60 causes the worm wheel 40 to move to the lowermost end via the piston 55 and the steel ball 54. Returns to the top end (initial state). This time point corresponds to the point S5 in FIG.

In addition, when the piston 55 returns, the ink sucked into the cylinder 56 is discharged by the one-way valve 61 attached to the piston.
Exhausted through.

The rotational position of the worm wheel 40 is set to S5 and
At the time of coming during S6, the forward rotation of the worm wheel is switched to reverse rotation, and the ventilation valve 47 is opened (point S4 in FIG. 11).
By rotating until before and sucking air (empty suction) through the conduit 43, it is possible to reliably discharge the ink remaining in the rubber cap inside 48 during the above-described ink suction. If the number of times of the empty suction is repeated, a further effect can be obtained.

In the above description, the forward rotation worm wheel 40
When changing from the S3 state (moving to the bottom end) to the S4 state where the ventilation valve is open, it is necessary to control the rotation speed of the worm wheel 40 so that the meniscus of the discharge port does not retreat to a negative pressure. The control of this portion can also be performed by the following method.

That is, the rotation of the worm wheel 40 is stopped between the S3 state and the S4 state (see FIG. 11), and the air layer of the sub tank 58 is stopped.
If the 59 is reliably brought to the atmospheric pressure state and then proceeds to the next sequence, the retreat of the meniscus at the discharge port does not occur.

After the above-mentioned empty suction is completed, the worm wheel 40
The forward rotation continues from the point between point S6 and point S6, and the circumferential projection 51 (Fig. 10) of the rotary cam (cam disk) 26 similarly pushes the ventilation valve support 52 in the direction of arrow D to open the ventilation valve.
Close 47 (S7 point in Fig. 11).

At this time, since the vent hole 45 is closed by the flat part of the vent valve 47, the volume does not change at this part, and the meniscus of the discharge port does not recede even in the capping closed state.

After passing the ventilation valve 47 closed (S7 point in Fig. 11),
Vent valve 47 is opened from the rear end (S10 in FIG. 11) through the capping open (S9 in FIG. 11) from the rear end of capping (S8 in FIG. 11). (First
It moves to S11 point in Fig. 1), and after that, it ends (same as the initial state), that is, S12 point in Fig. 11 (same as S0 point).
Then, a series of operations is completed.

The printing failure can be prevented by executing the recovery operation described above, but as a more reliable recovery operation, the following sequence may be added between the points S7 and S12.

Hereinafter, the operation from the S7 point to the S12 point to be added will be described.

As described above, one cause of defective printing is the inclusion of air from the ejection port or the accumulation of air in the vicinity of the ejection port and the ink passage to the ejection port.

As described above, the removal of the air is almost completely recovered by the ink suction operation from the ejection port, but very rarely, the ink supply pipe 62 to the ejection port portion of the recording heads (inkjet heads) 1A to 1D. (Fig. 4) Or air adheres to the filter 63 in the ink supply pipe 62 in a bubble state,
Air may not be completely removed only by the above-described ink suction sequence, and ink droplets may cause splash or satellite at the time of recording.

In order to remove and recover this, first rotate the worm wheel 40 backward from the initial position S0 (or S12 point) of the recovery operation sequence between the ventilation valve 47 (S7 point) and the rear end of the capping closure (S8 point). , Switch from that position to forward rotation and return to the initial position S0 point (S12 point).

By repeating this operation multiple times, the rubber cap
When 22A to 22D put the discharge port in the capping state, the pressure inside the rubber cap 48, which is in the sealed state, increases, and air is forcedly sent from the discharge port. By sending the air in this way, the attached air in the valve state is removed.

After the above operation is completed, if the ink suction sequence at points S0 to S12 described above is performed, defective ink ejection can be more completely removed.

〔effect〕

As is clear from the above description, according to the inkjet recording apparatus of the present invention, a cap for covering the ejection port for ejecting ink, and suction from the ejection port when the cap covers the ejection port Suction pump, a ventilation valve for communicating the inside of the cap with the atmosphere when the suction pump is performing suction, a cam groove for engaging with an engaging portion provided in the cap, and the ventilation valve. A plate-shaped rotary cam provided with a circumferential cam portion for pressing against the plate-shaped rotary cam and a rotary shaft of the plate-shaped rotary cam, and the rotary shaft direction is rotated while rotating the plate-shaped rotary cam. A worm wheel that slides on the worm, a worm that meshes with the worm wheel, and drive means for rotationally driving the worm. The worm wheel regulates the engaging portion to move the cap forward or backward with respect to the discharge port, and the peripheral cam portion presses the ventilation valve to open or close the ventilation valve. According to the slide, the worm wheel presses the suction means so that suction is performed by the suction means. Therefore, the worm wheel for driving the suction pump is arranged coaxially with the rotating cam for controlling capping. Therefore, the structure of the recovery device can be simplified, the size can be reduced, and the number of parts can be reduced.
(EN) An inkjet recording apparatus which can improve the reliability and reliability of a recovery operation and can perform a series of recovery operations only by inputting a signal by a switch operation.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing a main configuration of an embodiment of an ink jet recording apparatus to which the present invention is applied, FIG. 2 is a rear view seen from a line II-II in FIG. 1, and FIG. Line II in Fig. 1
The front view of the carriage seen from I-III, FIG. 4 is a schematic structural view of the recovery device in FIG. 1, FIG. 5 is a plan view of the recovery device in FIG. 1, and FIG. 6 is FIG. The front view seen from the line VI-VI in the inside, FIG. 7 is the left side view seen from the line VII-VII in FIG. 5,
8 is a central longitudinal sectional view of the recovery device of FIG. 5, FIG. 9 is a horizontal sectional view of the recovery device of FIG. 5, and FIG. 10 is a cross section of the recovery device of FIG. 5 at a different level from that of FIG. FIG. 11 is a timing chart exemplifying the operation sequence of the recovery device for the inkjet recording apparatus according to the present invention. 1A to 1D ... Inkjet head (recording head), 2 ...
… Carriage, 6 …… Platen, 14,16,17 …… Ratchet gear, 18 …… Motor, 21 …… Dowel gear, 22A-22D
...... Cap, 24 …… Cleaning blade, 26 …… Rotating cam, 27 …… Cap housing, 28 …… Claw, 29 …… Holding lever, 30 …… Claw, 32 …… Blade, 33,35 …… Reset claw , 34 ... Tip claw, 39 ... Worm, 40 ... Worm wheel, 41 ... Rotating shaft, 42 ... Engaging part, 46 ... Suction pump, 47 ... Ventilation valve, 48 ... Inside cap, 51 …… Cam on the lap, RP …… Recovery device.

Claims (4)

(57) [Claims] 1. A cap for covering an ejection port for ejecting ink, a suction pump for performing suction from the ejection port when the cap covers the ejection port, and a suction pump for performing suction A vent valve for communicating the inside of the cap with the atmosphere while the cap is open, a cam groove that engages with an engaging portion provided on the cap, and a circumferential cam portion for pressing the vent valve. Plate-shaped rotary cam, a worm wheel that is provided coaxially with the rotary shaft of the plate-shaped rotary cam, and slides in the rotary shaft direction while rotating the plate-shaped rotary cam, and a worm that meshes with the worm wheel. And a drive means for rotationally driving the worm, wherein the cam groove restricts the engaging portion in response to the rotation of the plate-shaped rotary cam to face the discharge port. The cap is advanced or retracted, the peripheral cam portion presses the ventilation valve to open / close the ventilation valve, and the worm wheel presses the suction means in response to the slide of the worm wheel. As a result, suction is performed by the suction means. 2. The ink jet recording apparatus according to claim 1, further comprising a driving element for ejecting ink from the ejection port. 3. The ink jet recording apparatus according to claim 2, wherein the driving element is a heating element. 4. The ink jet recording apparatus according to claim 2, wherein the drive element is a piezo element.