JPH11115275A - Ink jet type recorder and method for controlling head cleaning for the recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the reliability of a recorder by effectively executing a cleaning operation of a recording head. SOLUTION: Cap members 8, 9 and a cleaning member 23 are disposed in a non-printing area of a recorder. In the case of executing the cleaning of recording heads 5, 6, the state of a platen gap PG is judged, and when the gap PG is not suitable for a cleaning operation of the head, the gap PG is regulated by a control means. As a result, at the time of cleaning the heads 5, 6, an effective negative pressure sucking operation of ink by the members 8, 9 is given, and a suitable wiping operation by the member 23 can be given as well.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus having a recording head which moves in the width direction of a recording sheet, and which prints an image by discharging ink droplets onto the recording sheet based on print data. More particularly, the present invention relates to an ink jet recording apparatus capable of controlling a platen gap to an optimum cleaning position when cleaning a recording head, and a head cleaning control method in the ink jet recording apparatus.

[0002]

2. Description of the Related Art With the development of personal computers, graphic processing has become relatively easy to execute. Therefore, there is a demand for a recording apparatus capable of outputting a hard copy of, for example, a color image displayed on a display with high quality.

[0003] In order to meet such a demand, a recording apparatus equipped with an ink jet recording head has been provided.
This ink jet recording apparatus is used for many printings including color printing because the noise at the time of printing is relatively small and small dots can be formed at a high density.

[0004] Such an ink jet recording apparatus is
An ink jet recording head that receives supply of ink from the ink storage unit, and a paper feeding unit that relatively moves the recording paper with respect to the recording head, wherein the ink is applied to the recording paper while moving the recording head according to a print signal. Recording is performed by ejecting droplets to form dots.

As described above, in order to prevent the clogging due to the filling of the recording head with the ink and the volatilization of the ink solvent, there is a process for forcibly sucking and discharging the ink from the recording head. Further, an operation is performed in which a drive signal irrelevant to print data is supplied to eject ink droplets from nozzle openings of a head.

[0006] Forcible ejection of ink for eliminating clogging of the recording head is usually called a cleaning operation, and is performed when printing is resumed after a long pause or when the user removes clogging of the recording head. When the cleaning switch is depressed to solve the problem, the recording head is sealed by capping means and negative pressure is applied to discharge ink droplets, followed by a wiping operation by a blade material made of an elastic plate such as rubber. Processing.

The operation of applying a drive signal to the recording head to eject ink droplets is usually called a flushing operation. During a cleaning operation, an irregular meniscus near the nozzle opening of the head is recovered by wiping or the like. This is an operation to be executed at regular intervals for the purpose of preventing clogging of a nozzle opening that discharges a small amount of ink droplets during printing.

On the other hand, when printing is performed on a recording sheet by a recording head, a platen (sheet guide plate) is provided in accordance with the thickness of the recording sheet in order to maintain an optimum distance between the recording head and the surface of the recording sheet. There is provided a platen gap adjusting means for adjusting an interval between the recording head and the recording head. In the platen gap adjusting means, generally, the distance between the recording head and the platen is adjusted by slightly moving the carriage side on which the recording head is mounted in the vertical direction.

[0009]

As described above, when cleaning the recording head, the recording head is sealed by capping means to discharge ink droplets, and a cleaning member made of an elastic plate such as rubber is used. As a result, processing such as wiping the ink layer adhered to the nozzle plate of the head is performed. However, the recording head is moved up and down by a platen gap adjusting means corresponding to the thickness of the recording paper, and its position is not constant.

Therefore, when the recording head is sealed by the capping means, the adhesion between the head and the cap tends to be unstable, and the effect of discharging ink droplets from the head becomes insufficient or the load on the carriage is reduced. Technical problems such as increase occur.

Further, the degree of contact (interference) between the head and the cleaning member changes, and the wiping characteristics of the nozzle plate surface of the head become poor. Technical problems such as contamination.

The present invention has been made in view of such circumstances, and when cleaning a head,
It is an object of the present invention to provide a recording apparatus capable of ensuring a good cleaning action by controlling a relative position between a head and a capping unit and a head and a cleaning member, and a head cleaning control method thereof.

[0013]

In order to achieve the above-mentioned object, an ink jet recording apparatus according to the present invention comprises: an ink jet recording head for discharging ink droplets corresponding to print data; Capping means for sealing and receiving a negative pressure from a suction pump, a cleaning member for wiping a nozzle opening surface of the recording head, and a recording head and a printing head according to a thickness of a printing medium printed by the recording head. Platen gap adjusting means capable of adjusting the interval with the medium,
When the recording head is located at the cleaning position, the control unit drives the platen gap adjusting unit such that the relative position between the recording head and the capping unit and / or the recording head and the cleaning member is constant. You.

In this case, in a preferred embodiment, the platen gap adjusting means is capable of rotating a pair of guide members for reciprocating a carriage on which the recording head is mounted via an eccentric portion with respect to the main body. The control means is configured to apply a rotational force to the guide member in conjunction with the movement of the carriage.

[0015] A head cleaning control method for an ink jet recording apparatus according to the present invention, which has been made to achieve the above object, comprises an ink jet recording head for ejecting ink droplets in accordance with print data; A head cleaning control method in an ink jet recording apparatus, comprising: capping means for sealing and receiving a negative pressure from a suction pump; and a cleaning member for wiping a nozzle opening surface of the recording head. Receiving the cleaning operation command, the gap determining step of determining the state of the platen gap, and controlling the platen gap to be the predetermined gap when the gap determining step determines that the gap is not the predetermined platen gap. Gap system A step, when the gap control step has been completed, is such as to perform the cleaning step of cleaning the recording head by said capping means and / or said cleaning member.

In this case, in a preferred embodiment, the gap judging step judges whether or not the platen gap is in the minimum state. In the step, the platen gap is controlled to be in the minimum state.

According to the ink jet type recording apparatus and the head cleaning control method as described above, when the cleaning operation command of the recording head is received, the state of the platen gap is determined, and when the platen gap is not suitable for the head cleaning action, The platen gap adjusting means is driven by the control means.

As a result, at the time of cleaning the recording head, the positive suction effect of the ink by the capping means can be surely enjoyed, and the proper wiping action by the cleaning member can be enjoyed.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an ink jet recording apparatus according to the present invention will be described based on an embodiment shown in the drawings.

FIG. 1 shows a state in which head cleaning is performed in an ink jet recording apparatus to which the present invention is applied. FIG. 2 shows a state in which ink is forcibly discharged from a head by capping means. It is shown.

Reference numeral 1 denotes a carriage. The carriage 1 is configured to be guided by a guide rod 2 and move in parallel to a platen (paper guide plate) 3. The carriage 1 is coupled to a part of a timing belt (not shown) and is configured to reciprocate along the guide rod 2 by driving the timing belt.

The two recording heads 5 are arranged so as to face a sheet 4 as a recording medium disposed on the upper surface of the platen 3.
6 is mounted on the carriage 1, ink is introduced into each of the recording heads 5 and 6, and printing can be performed by ejecting ink droplets onto the recording paper 4 on the platen 3 in accordance with the print data. It is configured as follows.

A capping device 7 as capping means is disposed in a non-printing area of the recording device, and includes a cap member 8 for sealing one recording head 5 and a cap member 9 for sealing the other recording head 6. Is the upper slider 10
A.

The upper slider 10A is mounted on the lower slider 10B mounted on the frame 11 via the lever 12 with an arc-shaped locus so as to be able to rise, so that the head can swing. The cap members 8 and 9 are configured to contact the recording heads 5 and 6 in parallel from below.

Then, as shown in FIG. 2, when the carriage 1 moves just above the capping device 7, the carriage 1
The lower slider 10B rises via the lever 12 and the cap member 8 mounted on the upper slider 10A when the engaging body 1a arranged on the upper slider 10B comes into contact with the engaging portion 10a attached to a part of the lower slider 10B. , 9 can seal the recording heads 5 and 6 arranged on the carriage 1.

As shown in detail in FIG. 3, the cap members 8 and 9 arranged in the capping device 7 are formed in a size that can seal the nozzle opening surfaces of the recording heads 5 and 6 with one space. The inner space surrounded by each of the cap members 8 and 9 has ink suction ports 13 and 14.
It is connected to the. A tube, which will be described later, is connected to the suction ports 13 and 14 to seal the nozzle openings of the recording heads 5 and 6 during non-printing. The recording heads 5 and 6 are adapted to be appropriately applied so that ink can be forcibly discharged from the recording heads 5 and 6.

The lower ends of the cap members 8 and 9 are connected to one ends of tubes 16 and 17, respectively. The other ends of the tubes 16 and 17 are connected to the atmosphere opening ports 19 and
20.

When the cap members 8 and 9 move to the positions where the recording heads 5 and 6 can be sealed, the area where the valve member 18 is located is constantly urged toward the valve member 18 by the spring 21 so that the valve member 18 can be closed. The valve body 22 which is in elastic contact with is disposed,
The atmosphere release ports V1 and V2 are formed by the atmosphere release ports 19 and 20 and the valve member 18.

Further, as shown in FIG. 1, on the print area side adjacent to the capping device 7, the nozzle opening surfaces of the recording heads 5, 6 mounted on the carriage 1 are wiped with the movement of the carriage 1, for example. The cleaning member 23 made of rubber is configured to be established.

The cleaning members 23 remove the dust and paper dust adhering to the nozzle plate before the ink is sucked from the recording heads 5 and 6, so that the adhesion between the cap members 8 and 9 can be improved. You. After the ink suction, the ink adhering to the nozzle plate is wiped off.

The cleaning member 23 is configured to be able to enter or retreat from the wiping position on the moving path of the recording heads 5 and 6 by the cleaner driving unit. FIG. 4 is an exploded perspective view showing the configuration of the pump unit 15 including the cleaner driving unit 50.

First, the pump unit 15 has a pump frame 15c having cylindrical portions 15a and 15b formed on both outer sides thereof.
In b, pump wheels 15d and 15e are arranged so as to be capable of normal rotation and reverse rotation by obtaining a driving force of a not-shown sheet feeding motor (hereinafter referred to as an ASF motor).

Each of the pump wheels 15d, 15e is provided with two shaft holes 15f, one end of which extends toward the center and the other end extends toward the outer periphery.
The rollers 15g supported by the shaft holes 15f can be shifted toward the center or toward the outer periphery in accordance with the rotation directions of the shafts d and 15e. The roller 15g presses the tube 15h between the cylindrical portions 15a and 15b to perform a squeezing action and a release action that does not pressurize the tube 15h.

One end of each of the tubes 15h is connected to each of the ink suction ports 13 and 14 of the capping device 7, and when a cleaning command is received, a negative pressure generated by driving the pump unit 15 reduces the cap. It is configured to be applied to the internal space surrounded by the members 8 and 9.

The cleaner driving unit 50 has a structure in which a cleaner cam 50b is loosely fitted to a rotating shaft of a pump wheel 15d via a clutch plate 50a, and the cleaner cam 50b is pressed against the clutch plate 50a by a compression spring 50c. ing.

A slide lever 50e having a cleaning member 23 formed thereon is mounted on the frame 50d so as to slide horizontally with respect to the frame 50d.
b is engaged.

The cleaner cam 50b is dragged in the same direction via the clutch plate 50a by one-way rotation of the pump wheel 15d, and acts to move the slide lever 50e in one horizontal direction. Further, the cleaner cam 50b is dragged in the other direction via the clutch plate 50a by the rotation of the pump wheel 15d in the other direction, and acts to move the slide lever 50e in the other horizontal direction.

Therefore, the cleaning member 23 mounted on the upper part of the slide lever 50e is moved forward and backward by the ASF motor for driving the pump unit 15 to the wiping position on the moving path of the recording heads 5, 6. The cleaning head 23 wipes the nozzle surfaces of the recording heads 5 and 6 when the cleaning member 23 enters the wiping position.

FIGS. 5 and 6 show the structure of the platen gap adjusting means 30. FIG. A guide rod 2 for guiding the carriage 1 includes two rods 2A,
2B, and these rods 2A and 2B
Eccentric pins 31 and 3 provided at both ends thereof, deflected in the same direction
2, and is rotatably attached to a guide frame (not shown). The carriage 1 is rotated in the same direction by a gap adjusting mechanism to be described later so that the supported carriage 1 can be separated or approached in parallel with the platen 3. In the drawing, reference numeral 33 denotes a paper feed roller.

The gap adjusting mechanism will be described below. The switching lever 35 is loosely fitted to a shaft 34 driven by a paper feed motor (hereinafter referred to as a PF motor) (not shown) so that the switching lever 35 can move in the axial direction. ing.
A sun gear 36 is arranged at the center of the switching lever 35, and the sun gear 36 is slidable in the direction of the shaft 34 and connected to the rotation direction, for example, the shaft 3
A part of 4 is formed on a square axis.

Two planetary gears 37, 38 always meshing with the sun gear 36 are rotatably mounted on the switching lever 35. When the switching lever 35 is pressed by the movement of the carriage 1, it moves in the direction of the shaft 34. Move,
According to the rotation direction of the PF motor, one of the planetary gears 37 and 38 meshes with an intermediate gear 39 described later.

The intermediate gear 39 has two planetary gears 3
7 and 38 are selectively engaged with each other, and are rotated by a fixed amount by a sector gear 41 (described later) and a modified Geneva gear unit 40 which is disengaged regardless of the rotation amounts of the planetary gears 37 and 38. , The sector gear 41 is configured to rotate by a fixed angle.

On the other hand, the sector gear 41 is fixed to the end of the shaft 32 so as to rotate integrally with one guide rod 2B. Further, a small sector gear 42 integral therewith meshes with a sector sector gear 43 disposed between the two guide rods 2A and 2B, and the end of the shaft 31 of the other guide rod 2A via this gear 43. It is configured to transmit rotation in the same direction to a small sector gear 44 fixed to the section.

In the platen gap adjusting means 30 constructed as described above, when printing on thick paper such as color-only paper or postcard, for example, when an operation button on a panel (not shown) is operated, a PF (not shown) is operated. The motor rotates the shaft 34 shown in FIG. 6 counterclockwise.

Accordingly, the switching lever 35 disposed at the shaft end rotates counterclockwise, and the intermediate gear 39 rotates in the direction of the arrow through the planetary gear 37 meshing with the sun gear 36. Further, the sector gear 41 meshing with the modified Geneva gear portion 40 of the intermediate gear 39 is rotated by a predetermined amount to a position where it contacts the stopper 41a, and one eccentric pin 32 integral with the sector gear 41 is rotated clockwise in the drawing.

At the same time, the sector-shaped sector gear 43 is rotated in the direction of the arrow through the small sector gear 42 integral with the sector gear 41, and the other small sector gear 44 meshing with the sector gear 43 is engaged.
The other eccentric pin 31 is rotated in the same direction via the.
As a result, the carriage 1 is pulled up by the guide rods 2A and 2B in parallel with the printing reference plane, that is, the platen 3.

It is needless to say that the platen gap PG can be narrowed by rotating the PF motor in the opposite direction to the state shown in FIG. .

A method of controlling head cleaning performed in the ink jet recording apparatus having the above-described configuration will be described with reference to the control flows shown in FIGS. Note that, in the flow described below, when the head cleaning is performed, the platen gap adjusting means shown in FIGS. 5 and 6 is controlled so that the platen gap PG is always minimized. Will be explained.

In FIG. 7, when a cleaning control signal is output by operating a cleaning command switch (not shown) or the like, a carriage lock (hereinafter referred to as CR lock) is released in step S11.

In step S11, the heads 5, 6 are capped (sealed) by the cap members 8, 9 during non-printing. Then, although not shown, a CR for locking the carriage is maintained so as to maintain the state.
A lock mechanism is provided. The CR lock mechanism is mounted on the paper feed roller shaft, and is configured to be released when the carriage is at the home position (HP) and the PF motor is rotated forward.

Subsequently, in step S12, it is determined whether or not the platen gap PG is small. This step S
In step 12, the state of the platen gap PG can be obtained from the status parameter held by the host, for example. If it is determined in step S12 that PG is not small (No), then in step S13, the carriage 1 is moved. Move to the print standby position. Then, in step S14, the PF motor is reversed to rotate the PG planetary gears 37 and 38.

Subsequently, in step S15, the carriage CR is moved to the PG switching position. As a result, the switching lever 35 is pressed by the carriage 1 along the shaft 34. Then, by rotating the PF motor forward in step S16, the planetary gear 38 is engaged with the intermediate gear 39.

In this state, the CR is moved to the print standby position as shown in step S17, and in step S18, the PF motor is rotated forward to reduce the PG. That is, in the platen gap adjusting means 30 shown in FIG. 5, by rotating each gear in a direction opposite to the direction of the arrow in FIG. 6, both guide rods 2A, 2B
As a result, the carriage 1 is pulled down in parallel to the printing reference plane, and the interval of the platen gap PG can be reduced.

In such a state, in step S19,
By reversely rotating the PF motor, the meshing state of the planetary gear 38 with the intermediate gear 39 can be released by an operation opposite to that in step S16.

Steps S13 to S13
Reference numeral 19 denotes an operation for operating the platen gap adjusting means 30 shown in FIGS. 5 and 6 to reduce the platen gap PG, and it is determined in step S12 that the platen gap is small (Yes). In this case, the process is bypassed to the next step S20 without going through these processes.

In step S20, a pump mode switching operation, that is, a power switching operation is performed. Although not shown, the ASF motor also serves to drive the pump unit 15 as described above, and switches to a pump drive mode for applying a negative pressure to the head during head cleaning. When the mode is switched to the pump mode in step S20, the process proceeds to step S21 to perform head cleaning.

The general sequence of the cleaning operation is as shown in FIG. That is, in step S211, the recording heads 5, 6 are moved to the non-printing area side and passed over the cleaning member 23 made of an elastic plate such as rubber disposed at the corresponding portion, thereby causing the recording heads 5, 6 to move. A wiping operation is performed to remove dust, paper dust, and the like attached to the nozzle plate.

In this case, the platen gap adjusting means 30 has already been operated to control the platen gap PG to be small, and therefore the cleaning member 23 has been controlled.
The degree of contact of the heads 5 and 6 with the nozzle plate, that is, the interference amount A is in an optimum state. The wiping operation in step S211 is performed to improve the adhesion of the recording head to the capping device in the process of forcibly sucking ink from the recording head by the subsequent capping device.

Next, in step S212, the carriage 1 is moved to the capping position to
6 starts a large amount of ink suction operation. That is, the recording heads 5 and 6 are sealed by the cap members 8 and 9, and the open-to-atmosphere valves V1 and V2 communicating with the cap members 8 and 9 are provided.
With the valve closed, the suction pump 15 is driven at a high speed for a predetermined time to accumulate a strong negative pressure in the cap members 8 and 9.

Accordingly, a relatively large amount of ink is discharged from the recording heads 5 and 6 to the cap members 8 and 9. Since the negative pressure remains in the recording heads 5 and 6 and the cap members 8 and 9 even after the suction pump 15 stops, when the atmosphere release valves V1 and V2 are opened here, air rapidly flows into the cap. Then, the meniscus of the head may be destroyed. Therefore, the negative pressure is released by leaving it for a predetermined time (step S213).

In the subsequent low-speed suction at step S214, the ink in the cap is sucked without bubbling with the atmosphere open valves V1 and V2 opened. And
Inject air and perform micro suction using the air as a damper. Thus, the valve V in step S215
By closing the valves 1 and V2, a minute amount of suction for quietly sucking the ink in the head is executed.

In the idle suction mode in step S216, the air release valves V1 and V2 are opened, the suction pump 15 is driven, and the ink stagnated in the cap members 8 and 9 becomes waste ink (not shown). Drained into tank.

Subsequently, in step S217, the carriage 1 is moved in the direction of the cleaning member 23, whereby the cap members 8, 9 are lowered, and the recording heads 5, 6 are moved.
Is performed to wipe off the ink adhering to the nozzle plate.

After such a cleaning operation is completed, FIG.
In step S22, the ASF mode switching operation is performed, and the sequence of all the cleaning operations ends.

Although the above description has been made based on the embodiment in which the PF motor is also used as the power for adjusting the platen gap, it goes without saying that the present invention can be applied without being limited to such a specific configuration.

In the above-described embodiment, the cap members 8 and 9 and the cleaning member 23 are controlled so that the platen gap PG is minimized.
Is performed, the same effect can be obtained even if the head is cleaned in an appropriate state other than the state where the platen gap PG is the minimum. Of course.

[0067]

As is apparent from the above description, in the ink jet recording apparatus and the head cleaning control method according to the present invention, when a cleaning operation command for the recording head is received, the state of the platen gap is determined and the platen gap is determined. If the gap is not suitable for the head cleaning operation, the control means drives the platen gap adjusting means.

As a result, at the time of cleaning the recording head, it is possible to enjoy the positive negative pressure suction action of the ink by the capping means and the appropriate wiping action by the cleaning member. Therefore, a good cleaning action can always be ensured for the recording head, and the reliability of this type of ink jet recording apparatus can be improved.

[Brief description of the drawings]

FIG. 1 is a front view showing a configuration of a capping unit in an ink jet recording apparatus to which the present invention is applied.

FIG. 2 is a front view showing a state in which a recording head is capped by a capping unit shown in FIG. 1;

FIG. 3 is a perspective view showing a more detailed configuration of the capping means shown in FIGS. 1 and 2;

FIG. 4 is an exploded perspective view showing a configuration of a pump unit and a cleaner driving unit provided in the recording apparatus shown in FIG.

FIG. 5 is a side view showing an example of a platen gap adjusting unit employed in the ink jet recording apparatus.

FIG. 6 is a side view showing a state where the gap is adjusted to be large in the platen gap adjusting means shown in FIG. 5;

FIG. 7 is a flowchart illustrating a head cleaning control method according to the present invention.

FIG. 8 is a flowchart showing details of cleaning operation steps in the flowchart shown in FIG. 7;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Carriage 2, 2A, 2B Guide rod 3 Platen 4 Recording paper 5, 6 Recording head 7 Capping device 8, 9 Cap member 10A Upper slider 10B Lower slider 15 Pump unit 15c Pump frame 15d, 15e Pump wheel 15h Tube 23 Cleaning member 30 Platen gap adjusting means 31, 32 Eccentric pin 33 Paper feed roller 34 Shaft 35 Switching lever 36 Sun gear 37, 38 Planetary gear 39 Intermediate gear 40 Geneva gear 41 Sector gear 42 Small sector gear 43 Sector gear 44 Small sector gear 50 Cleaner drive unit 50a Clutch plate 50b Cleaner cam 50e Slide lever

Claims (4)

[Claims] An ink jet recording head for ejecting ink droplets in accordance with print data; a capping means for sealing the recording head and receiving a negative pressure from a suction pump; and a nozzle opening surface of the recording head. A cleaning member for wiping, a platen gap adjusting means capable of adjusting an interval between the recording head and the printing medium according to a thickness of a printing medium printed by the recording head, and a position where the recording head is located at a cleaning position. And control means for driving the platen gap adjusting means such that the relative position between the recording head and the capping means and / or the recording head and the cleaning member is kept constant. Inkjet recording device. 2. The platen gap adjusting means comprises a pair of guide members for reciprocating a carriage on which a recording head is mounted, each of which is rotatably attached to a recording apparatus main body via an eccentric portion. 2. An ink jet recording apparatus according to claim 1, wherein said control means is configured to apply a rotational force to said guide member in conjunction with movement of a carriage. 3. An ink jet recording head that discharges ink droplets corresponding to print data, capping means for sealing the recording head and receiving a negative pressure from a suction pump, and a nozzle opening surface of the recording head. A head cleaning control method for an ink jet recording apparatus, comprising: a cleaning member for wiping the recording head; a gap determining step of determining a state of a platen gap in response to a cleaning operation command of the recording head; and the gap determining step. In the above, when it is determined that the gap is not the predetermined platen gap, a gap control step of controlling the platen gap to be a predetermined gap; and when the gap control step ends, the capping unit and / or the cleaning member By Performing a cleaning step of cleaning the recording head. 4. The gap determining step determines whether or not the platen gap is in a minimum state. If it is determined that the platen gap is not in a minimum state, the gap control step sets the platen gap to a minimum state. 4. The head cleaning control method for an ink jet recording apparatus according to claim 3, wherein the head cleaning control is performed such that: