JPH04282257A - Ink jet recording device - Google Patents

Abstract

PURPOSE:To enable a pumping action for ink transport to be performed normally at an ink jet recording device. CONSTITUTION:The piston action of a pump for ink transport is initiated at a cam phase of 190 deg., that is, a state where a piston is pressed down. In other words, the piston action begins with a state where the piston is drawn back.

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, and more particularly to control of a pump in an ejection recovery mechanism.

0002

2. Description of the Related Art In an ink jet recording apparatus, for example, ink is supplied from an ink cartridge filled with recording ink to a recording head, and ink droplets are produced as recording droplets from ejection ports provided in the recording head. is discharged.

Incidentally, in such an inkjet recording apparatus, dust or air bubbles may get mixed into the ink tank or the ink supply system from the ink tank to the recording head. Furthermore, bubbles may be generated in the ink within the ink path as the ink is ejected. The ejection ports provided in the print head or the ink paths that communicate with them generally have a narrow inner diameter of a few microns, so if these dust and air bubbles stay in the ink paths of the print head, they will obstruct the flow of ink that accompanies ejection. However, the ink ejection efficiency and ejection responsiveness to recording signals are reduced. Also,
In severe cases, it may become clogged, making it impossible to eject ink.

[0004] Furthermore, if the inkjet recording device is filled with ink and no ink is ejected for a long time,
The moisture in the ink may evaporate, causing the ink to thicken or solidify, which may also cause ink ejection abnormalities.

In order to prevent this, it is desirable to restore the ink ejection state of the recording head to a good state, and recovery methods for this purpose include a pressure recovery method and a suction recovery method. Among these, the suction recovery method closes the area around the ink discharge port with a cap and uses a suction pump etc. to suction it to remove obstacles such as stuck ink, air bubbles, dust, etc. that remain in the ink path. It is something to do. Further, such a suction recovery mechanism is also used to fill an ink path from an ink cartridge to a recording head with ink at the time of initializing the apparatus, such as when filling ink.

FIG. 15 schematically shows the conventional structure of such a suction recovery system. The suction recovery system includes a pump section 27 that generates negative pressure, a cap section 17 that creates a sealed space for the recording head 1, and controls the amount of ink suction and prevents an increase in the pressure acting on the recording head during capping. It consists of an atmosphere communication section 100 for In the figure, this is the area surrounded by a dashed line.

[0007] Also, what is surrounded by a broken line is a carriage portion in a serial printer type device, and the recording head 1 and sub tank 76 are mounted on this carriage.

The other parts are called an ink supply system, and include an ink cartridge 90 and a needle 171, which are removable from the main body of the apparatus.
, pressure sensor type ink level sensor (ink sensor)
72 etc., which are connected by tubes 175, 176 and 177.

The ink cartridge 90 is composed of an ink pack 92 containing ink and a waste ink absorber 93. The ink pack 92 is made of an aluminum laminate bag and is filled with liquid ink. The waste ink absorber 93 is connected to the waste ink tube 1 from the pump 27.
It is provided to absorb waste ink discharged through the ink 76. When the ink in the ink pack 92 runs out, the entire ink cartridge will be replaced.

The needle 171 is provided at a portion facing the ink pack 92, and has a tubular shape made of, for example, SUS material, and has a pointed end at one end to facilitate insertion into the ink pack 92. This pointed end has several small holes for ink communication formed at its tip. And this needle 1
71 is fixed to the main body of the printer by a suitable fixing member.

The ink sensor 72 is also attached to the printer body, and is installed in the middle of the supply tube 175 to measure the pressure inside the supply tube 175 (the ink pack 92
(corresponding to the pressure of ) is detected. That is, when the ink in the ink pack 92 decreases, the ink in the supply tube 75 (
As the pressure inside the ink pack 92 decreases, the ink sensor 72 is turned off.

0012

By the way, in the above-mentioned suction recovery system, the piston reciprocates inside the cylinder of the pump 27 to create a negative pressure inside the cap 17 and the tube 178 communicating therewith, thereby removing the ink from the ink path, etc. Performs ink suction. In this case, in the conventional suction recovery system, the forward movement of the piston was performed by pushing the piston via a rod connected to the piston, and the backward movement was performed by pulling the piston.

On the other hand, if there is a condition that causes relatively large resistance to the movement of the piston, such as when ink adhered to the cylinder wall or around the piston has solidified, The resistance force generated between the piston and the cylinder wall is greater than normal. Therefore, if an attempt is made to move the piston against such resistance, negative pressure, for example 2 to 3 times greater than normal pressure, will be applied to the piston and the rods connected to the piston to operate it. It will take a while. Moreover, such a resistance force acts unevenly or unevenly on the movement of the piston.

[0014] When an abnormal condition that causes a large resistance to the piston movement as described above occurs, if the forward movement of the piston in the suction recovery operation of the pump is performed while pushing the piston as described above, the piston will be affected. Due to this pushing force and the above-mentioned non-uniform resistance force, the piston constitutes a statically unstable system. Therefore, if the pushing force of the piston continues to be applied in this state, the piston tends to rotate within the cylinder, further increasing the resistance force generated between it and the cylinder wall. As a result, the piston, rod, etc. may be damaged, or the piston may not operate normally.

The present invention has been made to solve the above-mentioned conventional problems, and its purpose is to:
By starting the piston operation of the pump for suctioning and discharging ink in an inkjet recording device by pulling the piston, the piston operation can be performed normally, and there is no risk of damage to the piston etc. The purpose is to provide a recording device.

[0016]

[Means for Solving the Problems] To solve the problems, the present invention provides a pump used to perform an ink transport operation in an inkjet recording device that performs recording by ejecting ink onto a recording medium. , a pump that generates the transfer force in the ink transfer operation by reciprocating the piston inside the cylinder of the pump; The present invention is characterized by comprising a transfer operation control means for starting from a state.

[0017]

[Operation] According to the above configuration, the forces that act on the piston when it is pulled are the above-mentioned pulling force and the resistance force from the cylinder, and the piston on which these act on constitutes a statically stable system. .

[0018] As a result, even if the above-mentioned resistance force acts relatively large and non-uniformly on the piston due to ink sticking to the cylinder wall, and the piston attempts to rotate within the cylinder, the above-mentioned resistance force will prevent the rotation. Since it acts as a restraint, the resistance force does not increase further when the piston is pulled.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings.

FIG. 1 is a perspective view showing the main parts of an inkjet recording apparatus according to the present invention.

In FIG. 1, a recording head 1 includes energy generating means (piezoelectric element, resistance heating element, etc.) built therein.
By selectively driving the energy generating means according to recording information, ink is ejected from the ejection openings corresponding to each of the energy generating means. The carriage 2 can carry the recording head 1 and move in the main scanning direction, and at this time, the movement of the carriage 2 is guided by a carriage shaft 3 that slidably supports the carriage 2. A recording medium 4 such as recording paper is conveyed by a feed roller 5 depending on the recording situation.

The pulse motor 6 serves as a drive source for the feed roller 5 and automatic paper feeding. 7 is cap 17
This is a pump carriage that supports a cap unit consisting of a cap unit, etc., and is movable in parallel to a carriage shaft 3, and the movement of this pump carriage 7 is guided by a guide shaft 8. Further, the pump carriage 7 is urged rightward in the figure by a return spring 9. Further, the pump carriage 7 is provided with an arm 7a, and the tip of the arm 7a is attached to the carriage 2.
A hole 7b into which the protrusion 2a provided on the right side surface can be fitted is provided. A protrusion 2a provided on the carriage 2 fits into this hole 7b when the carriage 2 moves to the left. Thereby, when the cap 17 is placed over the ejection surface of the recording head 1, the carriage 2 can be prevented from rotating in the vertical direction.

As shown in FIG. 2, one end of a leaf spring 10 is fixed to the rear end of the pump carriage 7, which is elastically deformed in the traveling direction of the pump carriage 7. Further, the other end of the leaf spring 10 is held so that both sides thereof are sandwiched between a slide gear support base 12 that supports the slide gear 11. Further, the slide gear support stand 12 is provided so as to be movable along the slide shaft 13 in parallel to the traveling direction of the pump carriage 7. Thereby, the slide gear 11 can be operated by the elastic force of the leaf spring 10 that acts in accordance with the movement of the pump carriage 7. As a result, the carriage 2 moves and the protrusion 2 of the carriage 2
a engages with the hole 7b of the arm portion 7a of the pump carriage 7, and the carriage 2 and the pump carriage 7 move together, so that the slide gear 11 moves parallel to the running direction of the pump carriage 7.

As a result of this movement, the slide gear 11 is arranged parallel to the running direction of the pump carriage 7, as shown in FIG.
4, 15, or 16. In FIG. 3, 14 is a feed gear that transmits driving force to a paper feeding gear, 15 is an ASF gear that transmits driving force for paper feeding in an automatic sheet feeder (ASF), and 16 is a driving force that is transmitted to a suction recovery device. It is a pump gear.

The pump gear 16 is made up of two gears, and as shown in FIG. 1 again, the left gear 16b meshes with the idler gear 70 of the suction recovery device. In this way, the pump carriage 7 and the leaf spring 10
Depending on the stop position of the carriage 2, which is transmitted via
The slide gear 11 meshes with any of the gears 14, 15, and 16, and the driving force of the pulse motor 6 can be selectively transmitted to each device.

FIG. 4 is a sectional view showing details of the capping unit.

The cap 17 is made of an elastic member such as rubber in order to come into pressure contact with the outer edge of the ejection surface of the recording head 1 with elastic force, and is made of an elastic member such as rubber.
7b. Further, the cap 17 is supported by a cap holder 18, and this cap holder 18 is further held by a holder 19. On the back side of the cap holder 18, there is a rod-shaped tip with a holder 19.
A projection 18a is provided that penetrates the rear wall.
A coil spring 20 is externally fitted between the cap holder 18 and the rear wall of the holder 19. In addition, the protrusion 18a
An E-ring 21 is attached to the tip of the cap holder 18 to restrict movement of the cap holder 18 in the direction of the recording head 1. Note that the cap holder 18 is movable in the left-right direction of the figure by a guide (not shown) provided on the holder 19 with respect to the holder 19, and the holder 19 is movable in the left-right direction of the figure with respect to the pump carriage 7. It is movable in the left and right directions in the figure by a guide (not shown).

A groove 19a is provided at the rear of the holder 19, and a rail 22 is inserted into this groove 19a. The rail 22 is divided into two in the vertical direction (in this case, the rails 22a and 22b only need to move independently, and even if they are independent of each other, one rail may be divided into two in the middle). The lower rail 22b is used to move the holder 19 forward and backward relative to the recording head 1, and the upper rail 22a is used to open and close the atmosphere release valve 23. A rail arm 22c is provided on the back of this rail 22, and a rail dowel 22c is provided at the tip of the rail arm 22c.
d is provided. Note that the rail 22 is fixed to a pump base 25 as shown in FIG.

Further, as shown in FIG. 4, the holder 19 is provided with an atmosphere release valve 23, which is biased toward the left side in the figure by a spring 24. As shown in FIG. Therefore, the atmosphere release valve 2
3 is movable in the left-right direction in FIG. 4 in response to contact with the rail 22a.

The atmosphere release valve 23 is installed by inserting it into the holder 19 from above and fixing it. Further, the atmosphere release valve 23 is located at a position corresponding to the front of the vent 17a provided in the cap 17, and by closing this vent 17a with the atmosphere release valve 23, the space 17b can be sealed. Furthermore, an ink absorber 69 is disposed at the bottom of the cap 17, and when ink is sucked, it can absorb and hold a part of the sucked ink, and when capping, the evaporation of this ink creates a high humidity inside the cap 17. This prevents the ink near the ejection ports of the recording head 1 from drying.

[0031] The rail 22 is made of an elastic material,
When viewed from the top of the printer, it has a shape that protrudes toward the recording head 1 toward the left in the figure, as shown in FIG. 7 and the like.

When the carriage 2 and the recording head 1 mounted thereon are in the recording range as shown in FIG. 1, the pump carriage 7 is urged by the return spring 9, It is in contact with the side surface of the base 25. In this state, the recording head 1 is not present in the area facing the cap 17, and the atmosphere release valve 23 does not close the vent port 17a.

Next, when the carriage 2 moves to the left beyond the recording range and its protrusion 2a comes into contact with the arm portion 7a, the pump carriage 7 also moves together, and when it moves further to the left, as shown in FIG. The atmosphere release valve 23 of the holder 19 is
It moves while contacting the rails 22a and 22b. Then, when the carriage 2 moves to the position shown in FIG.
The cap 17 gradually moves toward the recording head 1 according to the slope of the rail 22b and comes into pressure contact with the ejection surface. Note that the pressing force at this time is about 300 g due to the spring 20. At this time, as shown in FIG. 8, the holder 19 and the atmosphere release valve 23 are offset by a distance l in the longitudinal direction of the rail 22a(b). Therefore, even if the angles at which the rails 22a and 22b are bent and the positions thereof are the same, the atmosphere release valve 23 reaches the bent position with a delay. Therefore, at the beginning when the cap 17 caps the ejection surface of the recording head 1, the ventilation port 17a is not closed, and the space 17b between the cap 17 and the recording head 1 is closed.
is in communication with the atmosphere. As a result, the recording head 1 is not pressurized by capping, so that ejection failure due to receding of the meniscus at the ejection port is prevented.

Furthermore, when the carriage 2 moves to the left and the atmosphere release valve 23 reaches the bending point of the rail 22a, the atmosphere release valve 23 closes the vent 17a of the cap 17, and the space 17b becomes sealed. When the carriage 2 further moves to the left from this state and comes to the position shown in FIG. 9, the slide gear 11 meshes with the pump gear 16 and the suction recovery device is activated. At this time, as shown in FIGS. 4 to 6, the suction tube 26 is connected to the cap 17, and the other end is connected to the cylinder 27S of the pump 27 as shown in FIG. The generated negative pressure is guided to the space 17b via the suction tube 26.

By positioning the carriage 2 in the position shown in FIG. 9, the slide gear 11 and the pump gear 16 mesh as described above, and the rotational force of the pulse motor 6 is transmitted to the pump gear 16 via the slide gear 11. Furthermore, as shown in FIG.
0b, and is sequentially transmitted to the gear portion of the pump cam 28. The idler gear 70 has a gear portion 7 that meshes with the pump cam 28.
0b and a cam 70c for driving the rubbing member 37 are integrally formed. The pump cams 28 and 29 are integrated with a positioning dowel (not shown), and the pump cam shaft 30
It is rotatably supported on the shaft. On the mutually opposing surfaces of the pump cams 28 and 29, there is provided a parallel pin 32 integrally connected to the piston 31, as shown in FIG.
An elliptical groove is provided so that each of both ends can be slid. This allows the piston 3 to move according to the rotation of the cam.
1 can move up and down.

Furthermore, as shown in FIG. 5, the pump cam 29
has a protrusion 3 for pushing down one end of the pump flag 33.
4, and this pump flag 33 is supported by a guide shaft 8 so as to be rotatable about the guide shaft 8. Further, a light shielding plate 33a is provided at the other end of the pump flag 33. When the carriage 2 moves to a predetermined position corresponding to the light shielding plate 33, this light shielding plate 3
3a, the protrusion 34 of the cam 29 rotates and moves upward while in contact with one end of the pump flag 33, and as shown in FIG.
can be engaged with. As a result, the transmission type sensor 3
The light beam sent from the light emitting part 5 to the light receiving part is blocked,
By managing the number of pulses of the pulse motor 6 from this point of interruption, it becomes possible to control the position of the suction recovery device.

When the protrusion 34 further rotates from this state and comes off one end of the pump flag 33, the pump flag 33 rotates about the guide shaft 8 in the opposite direction as described above due to its own weight or the elastic force of the spring, and the pump The engagement between the light shielding plate 33a of the flag 33 and the transmission type sensor 35 is released. Note that the rotation of the pump flag 33 is stopped by a stopper (not shown) provided on the pump base 25. An arm 28b provided on the rail 22a is provided on the right side surface of the pump cam 28. As a result, the arm 22C is pulled in accordance with the rotation of the cam 28, the air release valve 23 is released from contact with the vent 17a using the rail 22a, and the space 17b of the cap 17 can be opened to the atmosphere.

The rubbing member 37 is held by a rubbing lever 36 as shown in FIG. 11, and a dowel 36a provided on the rubbing lever 36 is connected to a cam portion 70c of the idler gear.

Therefore, the motor 6 is driven by the pump gear 16.
b to the idler gear 70, and as the cam 70c integrally formed with the idler gear 70 rotates, the cam 70
The dowel 36a moves along the groove (not shown) provided in c.
The rubbing lever 36 receives a rotational moment about the rotation center 36b, and moves forward and backward relative to the movement area of the recording head 1.
You will have to retreat.

As a result, the rubbing member 37 (made of, for example, ether polyurethane continuous pore material) can be advanced to a position where it overlaps the recording head 1. In this way, the rubbing member 3
7 in the direction of the moving area of the recording head 1,
By moving the carriage 2 from the left to the right of the apparatus in front of the rubbing member 37, the rubbing member 37 performs a sweeping operation on the ejection surface of the recording head 1. As a result, ink droplets, impurities, etc. attached to the ejection surface are removed, and ejection stability of the recording head 1 is ensured. The pressing force of the rubbing member 37 against the recording head 1 can be managed by a spring 71 shown in FIG. 11 (the pressing force is, for example, 100
g). Further, in FIG. 11, 72 is a holder that holds the rubbing member 37.

[0041] Here, it is important that the gear ratio between the gear portion 28a of the pump cam and the gear portion 70b of the idler gear 70, which mesh with each other, is an integer. This is because, as described above, the pump cam 29 and the gear portion 28b operate as one unit, and the protrusion 34 provided on the pump cam 29 drives the pump flag 33, and the light shielding plate 33 drives the transmission type sensor 5 provided on the carriage 2. This is because by blocking light transmission, the position of the suction recovery device is controlled by managing the number of pulses of the pulse motor 6 from the time of this blocking. In other words, when the idler gear 70 rotates an integral number of times for one rotation (rotating 360 degrees with respect to the shaft 30) of the gear portion 28a of the pump cam 28, the cam portion 70c also rotates the same integral number of times. The rubbing member 37 also moves forward or backward the same integral number of times. Therefore, the pump cam 2 before the pump cam 28 rotates.
The relative phase relationship between the pump cam 8 and the rubbing member 37 is maintained even at the end of one revolution of the pump cam.

Additionally, by controlling the rotational position of the pump cam 28, the forward and backward movement of the rubbing member 37 can be managed. In this embodiment, the gear portion 28a of the pump cam has 50 teeth, and the gear portion 70 of the idler gear 70 has 50 teeth.
The number of teeth of b was 25, and the gear ratio was 2:1. As a result, for one rotation of the pump cam 28, the idler gear 70 rotates twice.
As it rotates, the rubbing member 37 also moves forward and backward twice. And pump cam 2 before the pump cam rotates
8 and the rubbing member 37 is maintained even at the end of one revolution of the pump cam.

Further, in order to ensure the ejection stability of the recording head 1, a wiper 38 is provided on the right side plate of the pump base 25. This wiper 38 has a wall thickness of 0.3, for example.
A silicone rubber plate or the like having a diameter of 1.0 mm can be used, and is fixed to the right side plate so as to always overlap the recording head 1 (the amount of overlap is, for example, 1.0 mm). As a result, when the recording head 1 passes in front of the wiper 38, the ejection surface is always wiped.
Paper powder, dust, ink scum, etc. attached to the ejection surface are removed.

FIG. 12 is a timing chart of the suction recovery operation. In FIG. 12, the "flag" is the light shielding plate 33
When the sensor 35 blocks the light beam of the transmission type sensor 35 provided at the bottom of the carriage, it is indicated as "ON", and otherwise it is indicated as "OFF". The "pump" indicates a state in which the piston 31 is pulled up by the cams 28 and 29 as "OFF", and a state in which it is pushed down is "ON", and the "communication valve" indicates that the rail 22a is pulled down by the rotation of the cam 28. The state in which the inside of the cap 17 is open to the atmosphere as shown in FIG.
A closed state is defined as "closed", "urethane" indicates a state in which the urethane rubbing member 37 moves forward in accordance with the rotation of the idler gear 70 as "ON", and a retracted state as "OFF".

FIG. 13 shows the piston 31 in the pump 27.
FIG. 14 is a sectional view showing a state in which the piston 31 is operated in a pulling state and pulled up to the top of the process, and FIG. 14 is a sectional view showing a state in which the piston 31 is operated in a pushing state and pushed down to the bottom of the process.

In these figures, an O-ring 80 seals between the rod 31R connected to the piston 31 and the cylinder 27S. Further, the pump ring 81 is made of rubber, has play, is disposed in a groove provided in the piston 31, and seals between the cylinder 27S and the piston 31. When pump cams 28 and 29 (only cam 29 is shown) rotate, the grooves 2 formed in these cams
9d and 28d (not shown) are engaged with the parallel pin 32 provided on the rod 31R, so that the piston 3
1 reciprocates within the cylinder 27S. By this reciprocating movement, the space 17b of the cap 17 is inserted through the tube 26.
A negative pressure is generated in the recording head 1, and the ink sucked from the ejection port of the recording head 1 is sucked into the cylinder via the tube 26 or the like.
It can then be discharged out of the cylinder.

13 and 14 do not show the valve mechanism for suction through the tube 26, the valve mechanism and discharge path for discharging ink, but these mechanisms are known ones. It can be done.

The suction recovery operation using the pump 27 will be explained with reference to the timing chart of FIG.

First, phase 1 of the pump cam shown in FIG.
Suction operation starts from 90°. At this time, the piston 31 is in the state shown in FIG. Thereafter, by rotating the motor 6 in the normal direction (in the direction in which the phase of the pump cam increases) to a cam phase of 45°, the light shielding plate 33a is operated, and it is detected that the flag is "ON". That is, it is confirmed that the recording head 1 is at a position facing the recovery device, and the cam position is initialized. In this normal rotation, the piston 31 changes from the depressed state shown in FIG. 14 to the state shown in FIG. 13 by being pulled.

Next, the piston 31 is pushed down by normal rotation of the cam phase of 130° to 180°, and then the communication valve is opened. Next, a waiting time is provided at a cam phase of 240°, for example, 300 milliseconds, and ink is sucked. piston 31
At this time, the state is shown in FIG. 14. Next, cam phase 3
The piston 31 is rotated forward to 60° to bring it into the state shown in FIG. 13, and then the cam phase is reversed to 190°. At this time, the communication valve is "open", so when the piston 31 is pushed down, the ink accumulated in the cap is sucked, but the ink is not sucked from the recording head, and only the inside of the cap can be cleaned. .

The recovery operation is performed through the steps described above. In this operation, the phase is 90° to 130° as necessary.
Stop the pump cam between
By performing a reciprocating operation with respect to 7, the ejection surface of the recording head can be cleaned.

The state in which the recovery operation starts will now be described with reference to FIGS. 13 and 14. here,
A case will be explained in which the cam 29 (28) rotates in a counterclockwise direction.

The starting position of the conventional piston is shown in FIG.
This is the state shown in . In this case, if the sliding resistance generated between the O-ring 80 and pump ring 81 and the cylinder 27 is uneven due to adhesion of solidified ink, etc., the force acting on the piston 31 will constitute a statically unstable system. In addition to being pushed down in the -y direction by the pump cam 29, it also falls down in the x direction, and this fall increases as the pump cam 29 is pushed down. If the above-mentioned sliding resistance is large, if you continue to push down in such a state, not only will normal suction operation not be possible, but in the worst case, the piston 31
Otherwise, damage may occur.

On the other hand, when the present invention is applied and the starting position of the piston 31 is as shown in FIG.
The forces acting on 1 constitute a statically stable system. Therefore, even if the sliding resistance is uneven, the piston 3
A resultant force will always act on 1 to prevent it from collapsing. Therefore, the sliding resistance does not increase as the piston 31 is pulled up, and this operation can be performed normally.

[0055] The pump operation shown in the above embodiment is as follows:
Although the invention relates to ink suction from a recording head, it goes without saying that the application of the present invention is not limited thereto. That is, the present invention can be applied to any type of ink transport using a pump operation in an inkjet recording apparatus. (Others) In particular, the present invention is an inkjet recording method that includes a means (for example, an electrothermal converter, a laser beam, etc.) for generating thermal energy as energy used for ejecting ink, This provides excellent effects in recording heads and recording apparatuses that use energy to cause changes in the state of ink. This is because such a system can achieve higher recording density and higher definition.

For its typical configuration and principle, see, for example, US Pat. Nos. 4,723,129 and 4,740.
Preferably, it is carried out using the basic principles disclosed in the '796 specification. This method is the so-called on-demand type.
It is applicable to both continuous types, but in particular, in the case of on-demand type, it is applicable to the electrothermal converter placed corresponding to the sheet holding the liquid (ink) or the liquid path. , by applying at least one drive signal that corresponds to recorded information and provides a rapid temperature rise exceeding nucleate boiling, the electrothermal transducer generates thermal energy to produce film boiling on the thermally active surface of the recording head. liquid (ink) that corresponds one-to-one to this drive signal.
This is effective because it can form air bubbles inside. The growth and contraction of the bubble causes liquid (ink) to be ejected through the ejection opening to form at least one droplet. It is more preferable to use this drive signal in a pulse form, since the growth and contraction of bubbles can be carried out immediately and appropriately, making it possible to eject liquid (ink) with particularly excellent responsiveness. This pulse-shaped drive signal is described in US Pat. No. 4,463,359 and US Pat.
345262 are suitable. Furthermore, if the conditions described in US Pat. No. 4,313,124 concerning the invention regarding the temperature increase rate of the heat acting surface are adopted, even more excellent recording can be performed.

[0057] In addition to the configuration of the recording head that is a combination of ejection ports, liquid paths, and electrothermal converters (straight liquid flow path or right-angled liquid flow path) as disclosed in the above-mentioned specifications, U.S. Pat. No. 4,558,333 and U.S. Pat. No. 44 disclose a configuration in which a heat acting part is arranged in a bending region.
A configuration using the specification of No. 59600 is also included in the present invention. In addition, JP-A-59-123670 discloses a configuration in which a common slit is used as a discharge part for a plurality of electrothermal converters, and a hole that absorbs pressure waves of thermal energy is disclosed. The effects of the present invention are also effective even with a configuration based on Japanese Patent Application Laid-open No. 138461/1985 which discloses a configuration corresponding to the discharge section. That is, regardless of the form of the recording head, according to the present invention, recording can be performed reliably and efficiently.

Furthermore, the present invention can be effectively applied to a full-line type recording head having a length corresponding to the maximum width of a recording medium that can be recorded by the recording apparatus. Such a recording head may have either a configuration in which the length is satisfied by a combination of a plurality of recording heads, or a configuration as a single recording head formed integrally.

In addition, even in the case of a serial type as in the above example, the recording head is fixed to the main body of the apparatus, or by being attached to the main body of the apparatus, electrical connection with the main body of the apparatus and ink flow from the main body of the apparatus are possible. The present invention is also effective when using a replaceable chip-type recording head that can be supplied with ink or a cartridge-type recording head in which an ink tank is integrally provided in the recording head itself.

Further, it is preferable to add ejection recovery means for the recording head, preliminary auxiliary means, etc. to the configuration of the recording apparatus of the present invention, since this further stabilizes the effects of the present invention. Specifically, these include heating the recording head using a capping means, a cleaning means, a pressure or suction means, an electrothermal transducer, a separate heating element, or a combination thereof. For example, there may be mentioned a pre-heating means for performing the ejection, and a pre-ejection means for ejecting other than recording.

Regarding the type and number of recording heads to be mounted, for example, in addition to a single head that corresponds to a single color ink, there are also systems that correspond to a plurality of inks of different recording colors and densities. A plurality of them may be provided. That is, for example, the recording mode of the recording apparatus is not limited to a recording mode for only a mainstream color such as black, but may also be a recording mode in which the recording head is configured integrally or in a combination of multiple colors, Alternatively, the present invention is extremely effective for an apparatus equipped with at least one of the full-color recording modes using color mixing.

In addition, in the embodiments of the present invention described above, the ink is described as a liquid, but an ink that solidifies at room temperature or lower, and that softens or liquefies at room temperature, may also be used. Generally speaking, in inkjet systems, the temperature of the ink itself is adjusted within the range of 30°C or higher and 70°C or lower to keep the viscosity of the ink within a stable ejection range. Sometimes, ink in liquid form may be used. In addition, in order to actively prevent temperature rise due to thermal energy by using the energy to change the state of the ink from a solid state to a liquid state, or to prevent ink from evaporating, it is possible to solidify and heat the ink when left standing. An ink that is liquefied by water may also be used. In any case, by applying thermal energy in accordance with the recording signal, the ink is liquefied and the liquid ink is ejected, or the ink has already begun to solidify by the time it reaches the recording medium. The present invention is also applicable when using ink that is liquefied for the first time. Ink in such cases is disclosed in Japanese Patent Application Laid-open No. 54-56847 or Japanese Patent Application Laid-open No. 60-71.
In a state where it is held as a liquid or solid in the porous sheet recesses or through holes, as described in Japanese Patent No. 260,
It may also be configured to face the electrothermal converter. In the present invention, the most effective method for each of the above-mentioned inks is to implement the above-mentioned film boiling method.

In addition, the inkjet recording apparatus of the present invention may be used as an image output terminal for information processing equipment such as a computer, a copying machine combined with a reader, or a facsimile machine having a transmitting/receiving function. It may also take a form.

[0064]

As is clear from the above explanation, according to the present invention, the forces that act on the piston when it is pulled are the above-mentioned pulling force and the resistance force from the cylinder. constitutes a statically stable system.

[0065] As a result, even if the above-mentioned resistance force acts relatively large and unevenly on the piston due to ink sticking to the cylinder wall, and the piston attempts to rotate within the cylinder, the above-mentioned resistance force will prevent the rotation. Since it acts as a restraint, the resistance force does not increase further when the piston is pulled.

As a result, if the pump is not operated for a long period of time and residual ink sticks to the cylinder wall etc.,
When the piston begins to move when the resistance to the piston is uneven and large, if the piston moves against such resistance, the movement may not work properly or the piston may be damaged. can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of an inkjet recording apparatus according to the present invention.

FIG. 2 is a perspective view of a gear mechanism for explaining switching between paper feed drive and cap drive in the recording apparatus.

FIG. 3 is a perspective view of a gear mechanism for explaining switching between paper feed drive and cap drive in the recording apparatus.

FIG. 4 is a sectional view showing details of a capping unit in the recording apparatus.

FIG. 5 is a perspective view showing details of a suction recovery device in the recording apparatus.

FIG. 6 is a perspective view showing details of a suction recovery device in the recording apparatus.

FIG. 7 is a plan view for explaining the operation of the capping and atmosphere release valve in the recording device.

FIG. 8 is a plan view for explaining the operation of the capping and atmosphere release valve in the recording device.

FIG. 9 is a plan view for explaining the operation of the capping and atmosphere release valve in the recording apparatus.

FIG. 10 is a plan view for explaining the operation of the capping and atmosphere release valve in the recording apparatus.

FIG. 11 is an explanatory diagram of a rubbing member in the recording apparatus.

FIG. 12 is a timing chart for explaining the operation of an embodiment of the present invention.

FIG. 13 is a sectional view showing the state of the pump of the recording device when the piston is pulled up.

FIG. 14 is a sectional view showing the state of the pump of the recording device when the piston is pressed down.

FIG. 15 is a block diagram for explaining a suction recovery system according to a conventional example.

[Explanation of symbols]

1 Recording head 2 Carriage 6 Pulse motor 7 Pump carriage 7a Arm part 8 Guide shaft 10 Leaf spring 16 Pump gear 17 Cap 22 Rail 27 Pump 27s cylinder 28, 29 Pump cam 31 Piston 36 Rubbing lever 37 Rubbing member 80 O-ring 81 Pump ring

Claims (3)

[Claims] 1. A pump used to perform an ink transfer operation in an inkjet recording device that performs recording by ejecting ink onto a recording medium, the pump having a piston that reciprocates within a cylinder of the pump. A pump that operates to generate the transfer force in the ink transfer operation, and a transfer operation control means that starts the reciprocating movement of the piston in the ink transfer operation using the pump from a state in which the piston is pulled. An inkjet recording device characterized by: 2. The ink transfer operation is an operation of sucking ink from an ink ejection port in a recording head for ejecting ink and discharging the sucked ink to a predetermined location. The inkjet recording device described in . 3. The inkjet recording apparatus according to claim 1, wherein the ejection of the ink is performed by generating bubbles in the ink using thermal energy and based on the generation of the bubbles.