JP2675908B2 - Ink jet recording device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an ink jet recording apparatus.

[Conventional technology]

2. Description of the Related Art Conventionally, a recording apparatus that performs recording on a recording medium such as paper and OHP sheet (hereinafter also referred to as recording paper or simply paper) has been proposed in a form in which recording pads according to various recording systems are mounted. The recording head includes a recording head system, a thermal system, a thermal transfer system, and an ink jet system.

In particular, the ink jet recording method, which jets ink directly onto recording paper, has attracted attention as a quiet recording method with low running cost.

In such an ink jet recording apparatus, a recording head in which fine air outlets are arranged is generally used. For this reason, when air bubbles and dust are mixed into the ejection port, or when the ink becomes unsuitable for ejection or recording due to viscosity increase due to evaporation of the ink solvent, the ink is to be refreshed. Thus, a process (ejection recovery process) for removing those discharge failure factors is performed.

As one mode of means for performing such an ejection recovery process,
There is a cap provided with a cap capable of covering a discharge head forming surface of a recording head and a pump communicating with the cap and acting on a suction force. Then, by driving the ink ejection energy generation element inside the ejection port toward the cap, ink is ejected from all ejection ports (hereinafter referred to as preliminary ejection), or suction is performed with the cap covering the ejection port formation surface. The ink is forcibly discharged by exerting a force to suck it from the ejection port, and the cause of ejection failure is not removed together with the ink (hereinafter, suction recovery).

Also, in order to avoid the effects of dust, etc. that may occur when the recording head is exposed to the air after the cap is opened, the recording head is capped after the power is turned on or while the recording head is open, or when the cap is opened during recording. In addition, when data from the host device is interrupted for a certain period of time or more, a process of capping the recording head (hereinafter referred to as capping) is performed.

[Problems to be solved by the invention]

However, if the detector for controlling the carriage position is defective,
An error may occur in the position of the recording head due to a machine assembly error or the like. At this time, when the ink ejection port of the recording head is capped, the position of the ink ejection port of the recording head, that is, the position of the carriage on which the recording head is mounted and the position of the cap do not match, and therefore the capping is possible. Absent.

For this reason, there have been problems such as defective ejection due to the influence of thickened ink and dust, and inability to suck ink through the cap during suction recovery.

Therefore, the present invention has been made to solve the above problems, and an object of the present invention is to provide an ink jet recording apparatus capable of reliably performing capping and suction recovery.

[Means for Solving the Problems] In order to solve the above problems, an ink jet recording apparatus according to the present invention includes a cap capable of covering an ink ejection port forming surface of a recording head means, and a first cap formed so as to interlock with the cap. An engaging portion, a second engaging portion formed on the recording head means so as to engage with the first engaging portion when the cap covers the ejection port forming surface of the recording head means, and the cap. Drive means for swinging the recording head means after the covering operation, and suction control means for operating the suction means after a predetermined period after the swinging operation of the recording head means by the driving means. And

[Action]

According to the above construction, the drive means swings the recording head means after the cap covering operation, so that the first engaging portion and the second engaging portion can be engaged even when the recording head means is not in the correct position. With this, the cap can cover the ejection port forming surface of the recording head means. Therefore, since it is possible to reliably perform the capping, it is possible to prevent ink ejection failure.

Further, since the suction means is operated after a predetermined period of time after the swinging operation, suction is performed after the cap elastically deformed by the swinging operation is restored, and reliable suction recovery is possible.

〔Example〕

Hereinafter, embodiments of the inkjet recording apparatus of the present invention will be described in detail with reference to the drawings.

 FIG. 1 shows an external configuration example of an embodiment of the present invention.

Here, 1 is a head card cartridge having ink, an ink ejection port, and an electrical connection portion inside, and 2 is a carrier for mounting the head cartridge and scanning it in the directions of arrows A and B in the figure. Numeral 3 is a hook for attaching the head cartridge 1 to the carrier 2 and numeral 4 is a lever for operating the hook 3.

Denoted at 5 is a concave portion into which a convex portion 24 for post-operation is inserted, and is formed on the carrier 2. Reference numeral 6 is a support plate for supporting an electrical connection portion to the head cartridge 1.
Reference numeral 7 denotes a flexible cable for connecting the electric connection section and the main body control section. Reference numeral 8 is a guide shaft for guiding the carrier 2 in the directions A and B, which is inserted through the carrier 2. Reference numeral 9 denotes a timing belt to which the carrier 2 is fixed and which transmits power for moving the carrier 2 in the directions A and B, and is stretched around pulleys 10A and 10B arranged on both sides of the device. Driving force is transmitted from one of the carrier motors 11 to one of the pulleys 10 via a transmission mechanism such as a gear. A platen roller 12 regulates the recording surface of a recording medium such as paper (hereinafter, also referred to as recording paper) and conveys the recording medium at the time of recording, and is driven by a conveyance motor 13. Reference numeral 14 is a paper pan for guiding the recording medium to the recording apparatus, and 15 is a feed roller which is arranged in the feeding path of the recording medium to press the recording medium toward the conveying roller 12 and convey the same.

A discharge roller 16 is disposed downstream of the recording position in the recording medium conveyance direction and discharges the recording medium toward a discharge port (not shown). A spur 17 is provided corresponding to the paper discharge roller 16, presses the paper discharge roller 16 through the recording medium, and causes the paper discharge roller 16 to convey the recording medium. A platen 18 is provided at a position corresponding to the ink ejection port of the head cartridge 1 and presses the recording medium against the paper pan front surface portion 19 by an elastic member (not shown).

In this apparatus, an ink jet recording head is used as a recording head for recording by ejecting ink. Therefore, the distance between the ink ejection port of the recording head and the recording surface of the recording medium is relatively small, and the feeling must be strictly controlled to avoid contact between the recording medium and the ejection port. Part 19
It is effective to regulate the position of the recording medium with. Reference numeral 20 denotes a release lever for releasing the bias of each of the feed roller 15, the spur 17, and the platen 18 when the recording medium is attached and detached. Reference numeral 21 is a sensor for detecting the position of the carrier 2, and detects the position of the carrier 2 by passing through a protrusion (not shown) of the carrier 2.

22 is a head cartridge 1 at home position
Is a cap that is provided at a position facing the ink ejection port forming surface and is formed of an elastic material such as rubber, and is supported so as to be able to come into contact with and separate from the head cartridge 1. The cap 22 is used for protection of the ink ejection port of the head cartridge 1 at the time of non-recording or for ejection recovery processing. The ejection recovery process is to eject ink from all ejection ports by driving an energy generating element provided inside the ejection port and used for ejecting ink (preliminary ejection), or a ejection port formation surface by a cap. The ink is forcibly discharged (suction recovery) by applying suction force with the cover covered to suck from the discharge port.
This is a process for removing the cause of ejection failure such as air bubbles, dust, or ink that has thickened and is no longer suitable for recording. Reference numeral 23 denotes a pump that acts as a suction force for forcibly discharging the ink and that is used for attracting the ink received in the cap 22 during the discharge recovery process by the forced discharge and the discharge recovery process by the preliminary discharge. On the outside of the pump 23, a convex portion 24 that enters the concave portion 5 of the carrier 2 is formed. 25 is a waste ink tank for storing the waste ink sucked by the pump 23, and 26 is a tube for connecting the pump and the lung ink tank 25. 27 is a blade for wiping the ejection port forming surface of the head cartridge 1 and a position for projecting to the head cartridge 1 side for wiping in the process of moving the head cartridge 1 and the ejection port forming surface. It is movably supported in a retracted position that does not engage with. Reference numeral 28 is a recovery system motor, and 29 is a cam system for receiving power transmitted from the recovery system motor 28 to move the drive system of the pump 23 and the cap 22 and the blade 27, respectively.

Next, details of the above-mentioned head cartridge 1 will be described.

FIG. 2 is an external perspective view of the head cartridge 1 in which the ejection unit 1a and the ink tank 1b, which form the main body of the ink jet recording head, are integrated. In the figure, 1e is a pawl that is hooked by a hook 3 provided on a carrier 2 when the head cartridge 1 is mounted. As is clear from the figure, the pawl 1e is arranged inside the entire extension of the recording head. Further, in front of the head cartridge 1 and in the vicinity of the discharge unit 1a, a positioning abutting portion (not shown in the figure) is provided. Reference numeral 1f is a head opening portion which is provided upright on the carrier 2 and into which a support plate 6 for supporting a flexible substrate (electrical connection portion) and a rubber pad is inserted.

 FIG. 3 is a sectional view showing the structure of the cap 22 and the like.

Here, in this embodiment, the ink suction port in the cap 22 is
An opening 221 is formed in the lower part in the vertical direction, and an ink flow path 22 is formed toward an ink introduction port 223 provided in an operating portion 222 of the chat lever.
Form 4 Further, the suction port 221 is not completely covered with the suction member 225.

With this configuration, even if the ink ejected in the ejection recovery process or the like flows downward due to gravity, the ink is sucked from the suction port 221 provided below the ink suction member 225.
The amount of ink remaining in the ink becomes extremely small. Therefore, it is possible to greatly delay the deterioration due to solidification and prolong the life of the ink suction body 225 or the cap 22 to which the ink suction body 225 is attached.

FIG. 4 is an explanatory diagram showing the axial contour curves of the cams of the cam device 29 and the operating positions of the respective parts corresponding to the cam positions.

In the figure, (a) shows the cam position and the state of each part when performing the recording operation, the cap 22 and the blade 27 are separated from the ejection port forming surface of the recording head, and the pump 23 is at the top dead center. The convex portion 24 is also separated from the concave portion 5 of the carrier 2.

(B) is the position where the home position switch 30 is turned off, and this position is the home position of the cam device 29. This is a position that is set during standby for recording, etc., and at this time, the cap 22 covers the discharge port forming surface, the blade 27 is retracted, and the pump 23 is also at the top dead center. Further, the convex portion 24 engages with the concave portion 5 of the carrier 2 to regulate the movement of the carrier 2.

When the cam is rotated from the position (b), the cap 22 is joined (capped on) to the discharge port forming surface, and the piston 231 moves toward the bottom dead center while the convex portion 24 is engaged with the concave portion 5, The negative pressure of the suction system up to 22 becomes large.
Eventually, after the piston 231 reaches the ink introduction port of the pump 23 and closes it (the valve is closed), the valve starts to open and opens completely, and then the piston 231 moves to a position near the bottom dead center ( to c). Sufficient suction (suction recovery) is performed by stopping the cam rotation for a predetermined time at this position in consideration of the fluid resistance of the ink suction system.

After that, when the cam is rotated again, the piston 231
Reaches the bottom dead center, the cap 22 begins to separate from the discharge port forming surface, and the convex portion 24 begins to separate from the concave portion 5. This position (d) is held for a predetermined time.

After that, when the cam is further rotated, the piston 231 starts heading to the top dead center again. During this process, the valve begins to close, reaching a point where it is completely closed. On the other hand, the cap 22 is completely separated from the ejection port forming surface at the position (e). By driving the piston 231 several times in the vicinity of this, the ink remaining in the ink suction system is sucked (empty suction) to the pump side. The left and right spaces of the piston 231 in the pump are connected by a flow path (not shown), and the flow path is closed when the piston goes from the top dead center to the bottom dead center, and the bottom dead center to the top dead center. It is opened when heading.
Further, the space on the right side of the piston communicates with the flow path provided on the pump shaft 232. Therefore, in the process of empty suction, the piston 231
When the ink flows from the bottom dead center to the top dead center, the ink introduced into the space on the left side of the piston is transferred to the space on the right side, and from the top dead center to the bottom dead center, the ink is introduced from the ink suction system to the left space. Also, the ink is discharged from the right side space to the waste ink tank.

After that, when the cam is further rotated in the forward direction, the blade 27 projects and becomes ready for one-pumping (position (f)). When the carrier 2 is moved to the recording area side in this state, the blade 27 engages with the ejection port forming surface of the head, the surface is wiped, and the ink or the like adhering to the ejection port forming surface is wiped. Then, the cam is further rotated to retract the blade 27 and set the cam at the position (a). In this state, the carrier 2 is moved to the cap side so that the discharge port forming surface of the head faces the cap 22. After that, move the cam to position (b) to turn on the cap, and
The recess 24 is engaged with the recess 5 and stopped.

In addition, when shifting from the standby state to the recording, the cam may be rotated from the position (b) in the positive direction or the negative direction to cause the blade 27 to protrude, and the wiping may be performed before the recording.

Next, a control configuration for controlling each part of the embodiment configured as described above will be described with reference to FIG.

In the figure, 100 is a CPU that executes various control procedures,
Reference numeral 101 is a ROM for storing the control procedure, data, etc., and 102 is a RAM for storing the current position of the carrier 2 and used as a work area or the like in the control execution.

In the configuration of FIG. 1 described above, what is controlled by the CPU 100 is the head cartridge (recording head) 1, the carrier motor 11, the carry motor 13 and the recovery system motor 28, which are the head driver 1A and the motor driver 11A, respectively. , 1
Driven by 3A, 28A. Also, based on the detection of the recovery home sensor 30 and the carrier home sensor 21, the CPU1
00 can recognize the cap position and the movement position of the carriage 2.

Next, the control procedure of the ejection recovery process controlled by the CPU 100 will be described with reference to the flowcharts and timing charts shown in FIGS. 6 to 8 and 9, respectively.

In FIG. 6, first, in step S1, the carrier 2 is moved to the home position, the cap 22 is brought into contact with the recording head 1, and then the carrier 2 is swung. As a result, the cap 22 can surely cover the ejection port forming surface of the recording head 1. This capping method will be described in detail later.

After that, the process proceeds to step S2 and waits for a predetermined time. This is because the cap 22 formed of an elastic material such as rubber is temporarily deformed by the load generated by the movement of the carrier 2 while the cap 22 is in contact with the recording head 1 at step S1. It waits for a sufficient time (0.3 seconds in this case) to restore.

Next, proceeding to step S3, when the deformation of the cap 22 is restored, the ejection recovery process by the suction means is performed, that is, the CPU 10 drives the recovery system motor 28,
The suction recovery is performed by controlling the position of the cam device 29 to the suction recovery position (c).

FIG. 7 shows the details of step S1 of FIG.
3 is a flow chart showing the details of a capping control procedure for surely covering the ejection port forming surface of the recording head 1 with the cap 22.

First, in step S11, the position of the carrier 2 is detected by the carrier home sensor 21, and the carrier 2 is moved to the home position. The details will be described later. Then, the recovery system motor 28 is driven by step S12, and the cap 2
2 is operated so as to cover the ejection port forming surface of the recording head 1. This is performed by controlling the position of the cam device 29 from the recording operation position (a) to the home position position (b). At this time, if the carrier 2 is accurately located at the home position, the convex portion 24 engages with the concave portion 5, but if the position is deviated, it does not engage, and the cap 22 does not cover the discharge port forming surface. It will be.

Next, in step S13, the carrier 2 is moved leftward by 4 steps, and in step S14 the carrier 2 is moved rightward by 8 steps. Then, in step S15, the carrier 2 is moved to the left by 4 steps. That is,
Control for swinging the carrier 2 at the home position is performed.

By the rocking control in steps S13 to S15, the convex portion 24 is formed despite the capping control in step S12.
Even if the concave portion 5 and the concave portion 5 are in the non-engaged state, they are engaged with each other. Along with this, the cap 22 covers the ejection port forming surface of the recording head 1.

On the other hand, when the convex portion 24 and the concave portion 5 are in the engaged state at step S12, that is, when the recording head 1 and the cap 22 are in contact with each other, the cap 22 made of an elastic material is controlled by the above swing control. Is temporarily deformed, but is restored within a predetermined time (here, about 0.3 seconds).

FIG. 8 shows the details of step S11 in FIG. 7, in which the carrier is in the capping position (home position).
It is a flow chart that moves to.

First, in step S101, the sensor output from the carrier sensor 21 is detected to check whether the carrier 2 is on the left or right of the current sensor position. Here, the sensor output from the carrier sensor 21 changes in level 10 steps to the right of the position at which the cap 23 is performed, as shown in FIG. If the sensor output is not 1, the carrier 2 is on the right side of the sensor position, so in step S102 the carrier 2 is moved one step to the left, and in step S103 the sensor output is detected. Until the sensor output becomes 1, step S102, step Repeat S103. If the sensor output becomes 1 in step S103, step S1
Go to 04 and move left 5 steps.

The operation of steps S102 to S104 is because if the sensor detection is not performed in the same direction, a positional shift occurs between the right direction detection and the left direction detection due to the backlash of the carriage drive system. In the present embodiment, an example in which detection is performed when the carrier 2 moves to the right has been described. Therefore, when the carrier 2 is to the left of the carrier sensor 21, the carrier 2 is to be brought to the right of the sensor position. Further, the 5 steps of step S104 may be any step amount that eliminates backlash when the moving aroma of the carrier 2 changes.

Next, in step S105, since the sensor output is 1, it can be seen that the carrier 2 is on the left side of the sensor position. In step S105, the carrier 2 is moved right by one step,
The sensor output is detected in step S106, and steps S105 and S106 are repeated until the sensor output becomes zero. When the sensor output becomes 0 at step S106, the process goes to step S107, moves the carrier 2 by 10 steps to the left as shown in FIG. 9, and brings it to the position of the cap 22 (home position).

As described above, in the present embodiment, when the recording head 1 is capped, the carrier 2 is controlled to swing after the capping operation. Therefore, even if the cap position is deviated due to a defect of the carrier home sensor 21 or an assembly error, The concave portion 24 and the concave portion 5 are engaged with each other, so that the cap 22 can be surely brought into contact with the recording head 1. Therefore, it is possible to prevent ejection failure that occurs when the position of the ink ejection port of the recording head 1, that is, the position of the carrier 2 mounting the recording head 1 and the position of the cap 22 are deviated.

Further, since the convex portion 24 and the concave portion 5 are engaged with each other, the carrier 22 does not move in the recording direction and the anti-recording direction even when an impact is applied, and the capping state can be maintained.

Further, in this embodiment, since the suction recovery is performed after waiting for a predetermined time for the capping, the temporary deformation of the cap 22 caused by the swinging of the carrier 2 while the cap 22 is in contact with the recording head 1 is restored. The empty suction will be performed later. Therefore, there is no problem such that the ink cannot be sucked through the cap 22 during the suction recovery process by the idle suction.

In the operation of steps S13 to S15 in the above embodiment, the carrier 2 is moved to the left / right / left.
Similar effects can be obtained by moving left and right. In this embodiment, the total amount of movement when the carrier 2 is moved to the left, right, and left (minus leftward) is set to 0, and the final position of the carrier is moved to the home position. If the recess 24 of the pump is in the recess 5 of the carrier 2, the carrier 2 is mechanically fixed to the home position, so that the left 4 steps and the right 8 steps or the upper right 4 steps and the left 8 steps. Step and carrier 2
Even if is moved, the same effect as the present invention can be obtained.

In addition, the amount of carrier movement is centered on the home position.
Although it corresponds to 4 STEPs, it depends on the structure of the gears and the like in the drive system of the carrier, and also depends on the load on the recess 24 of the pump and the recess 5 of the carrier 2.

Further, although the position of the carrier is detected by the home sensor 21 in step S11, if the position of the carrier 2 is known in advance during printing, even if the carrier is moved to the home position without detecting the position. Good.

Further, the convex portion 24 and the concave portion 5 may have any shape as long as they can fix the carrier 2 by engaging them.

Further, the present invention brings about an excellent effect particularly in a bubble jet type recording apparatus among ink jet recording apparatuses. This is because such a method can achieve high density variation and high definition recording.

With regard to its typical structure and principle, it is preferable to use the basic principle disclosed in, for example, US Pat. Nos. 4,723,129 and 4740796. This method can be applied to any of a so-called on-demand type and a continuous type. In particular, in the case of the on-demide type, the electrothermal converter arranged corresponding to the sheet or the liquid path holding the liquid (ink) is adapted to the recorded information and has a rapid rate exceeding nucleate boiling. By applying at least one drive signal that gives rise, thermal energy is generated in the electrothermal converter, causing film boiling on the heat-acting surface of the recording head. As a result, bubbles can be formed in the liquid (ink) corresponding to the drive signals on a one-to-one basis, which is effective. By discharging the liquid (ink) through the discharge opening by the growth and contraction of the bubble, at least one droplet is formed. It is more preferable to make this drive signal in a pulse shape, because bubbles can be immediately grown and contracted appropriately, and the ejection of the liquid (ink) with excellent responsiveness can be grown. U.S. Pat. No. 44
Those described in 63359 and 43435262 are suitable. Further, when the conditions described in US Pat. No. 4,313,124 relating to the temperature rise rate of the heat acting surface are adopted, more excellent recording can be performed.

As a configuration of the recording head, in addition to a combination configuration of a discharge port, a liquid path, and an electrothermal converter (a linear liquid path or a right-angle liquid flow path) as disclosed in the above-mentioned respective specifications, a heat acting section A configuration using U.S. Pat. No. 4,558,333 and U.S. Pat. No. 4,459,600, which disclose a configuration in which the is bent, is also included in the present invention. In addition, Japanese Unexamined Patent Publication No. 59-123670, which discloses a configuration in which a slit common to a plurality of electrothermal converters is used as the discharge portion of the electrothermal converter, and an open hole discharge that absorbs a pressure wave of thermal energy The effect of the present invention is also effective as a recording head structure based on Japanese Patent Application Laid-Open No. 59-138461, which discloses a structure corresponding to each section.
That is, regardless of the form of the recording head, recording can be surely performed with high probability.

Further, by being attached to the apparatus main body, it can be electrically connected to the apparatus main body and can be supplied with ink from the apparatus main body, which is a convertible chip type recording head or is integrally provided on the recording head itself. The present invention is also effective when a cartridge type recording head is used.

Regarding the type or number of recording heads to be mounted, for example, only one recording head is provided corresponding to a single color ink, and a plurality of recording heads are provided corresponding to a plurality of inks having different recording colors and densities. May be used.

In addition, the form of the inkjet recording apparatus of the present invention may be a form used for an image output terminal of an information processing device such as a computer, a copying apparatus combined with a reader or the like, or a facsimile apparatus having a transmission / reception function. It may be something.

〔The invention's effect〕

As described above, according to the present invention, since capping and suction recovery can be reliably performed, it is possible to prevent defective ejection.

[Brief description of the drawings]

FIG. 1 is an external perspective view showing an embodiment of the ink jet recording apparatus of the present invention, FIG. 2 is an external perspective view of the head cartridge shown in FIG. 1, and FIG. 3 is the cap shown in FIG. 4 is a side cross-sectional view of a portion, FIG. 4 is a diagram showing the operation of each portion in the discharge recovery operation of the embodiment over time, FIG. 5 is a block diagram showing the control configuration of the embodiment, and FIGS. Flow chart showing the control procedure in the control configuration, No. 9
The figure is a timing chart showing the operation in the above configuration. 1 …… Head cartridge (record head) 2 …… Carrier 5 …… Concave 21 …… Carrier home sensor 22 …… Cap 23 …… Pump 24 …… Concave 28 …… Recovery motor 100 …… CPU 101 …… ROM 102 ……RAM

Claims (2)

(57) [Claims] 1. A recording head unit for performing recording by ejecting ink onto a recording medium, a cap formed so as to be able to cover an ink ejection port forming surface of the recording head unit, and the cap. A first engaging portion formed so as to interlock with each other, and a first engaging portion formed on the recording head means for engaging with the first engaging portion when the cap covers the ejection port forming surface of the recording head means. 2 an engaging portion, a driving means for swinging the recording head means after the covering operation of the cap, and a suction force acting on the inside of the cap with the cap covering the ejection port forming surface of the recording head. Suction means and a swinging operation of the recording head means by the driving means,
An ink jet recording apparatus comprising: a suction control unit that operates the suction unit after a predetermined period. 2. The recording head means is provided for each of a plurality of ejection ports for ejecting ink and corresponding ejection ports, and causes the ink to undergo a state change due to heat, and the ink is ejected based on the state change. The ink jet recording apparatus according to claim 1, further comprising: a thermal energy generating unit that discharges the droplets to form flying droplets.