JPH10193648A - Ink jet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten rising time at the time of turning ON a power source by selecting the state that a switch valve makes all a plurality of capping means communicate with a suction pump and the state that the valve communicates any one of the means with the pump. SOLUTION: A groove 39 of a rotating direction, a groove 40 of an axial direction communicating with the groove 39 and a groove 41 of a direction inclined to the axial direction communicating with the groove 40 are formed on an outer periphery of an inner race 36. Here, the groove 39 is formed at a position corresponding to a connecting port 38p for a suction pump, and the groove 40 is formed all at connecting ports 38y, 38m, 38c, 38k for cap means, and the groove 41 is formed at positions corresponding to the ports 38y, 38m, 38c, 38k for the means in response to rotating position of the race 36. Accordingly, the race 36 is rotated to select the state that the race 36 is rotated to communicate with all the caps of the heads, the state that it communicates with any one cap or the state that it communicates with no cap of the heads.

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 an ink jet recording apparatus provided with a head reliability maintaining means.

[0002]

2. Description of the Related Art An ink jet recording apparatus, such as a printer, a facsimile, or a copier, which records an image using an ink jet head, includes a plurality of nozzles for discharging ink droplets, and an electromechanical transducer provided for each nozzle. By using an ink jet head having an actuator element such as a heater or an electrothermal transducer as a recording head, ink droplets are ejected from a nozzle onto a recording medium (to which the ink droplets adhere) in response to a recording signal, thereby achieving high speed, It performs high-resolution and high-quality recording.

For this reason, paper residue,
If the discharge port becomes clogged with dust or ink, etc.
The direction of the ejected ink droplet is deflected, and the image quality is degraded.

Therefore, in general, in an ink jet recording apparatus, foreign matter adhering to a recording head is removed,
In order to recover the operation of the clogged recording head, a means for maintaining and recovering the reliability of the head is provided (for example, Japanese Patent Publication No. 7-50204, Japanese Unexamined Patent Publication No.
No. 47679, JP-A-7-11085, JP-A-7-13207, JP-A-7-137268, JP-A-7-17196, JP-A-7-810
No. 85, etc.).

The means for maintaining and recovering the reliability of the head include a wiping means for wiping the ejection surface of the recording head, and a capping means for capping the recording head. Then, in order to prevent drying and clogging of the recording head and to discharge bubbles in the ink liquid chamber of the recording head and bubbles upstream of the recording head, the recording head is covered with a cap and hermetically sealed. Negative pressure to forcibly suck the ink from the ejection port of the recording head, and wipe the ejection surface of the recording head with a blade made of an elastic material such as rubber to remove foreign matter adhering to the ejection surface. General.

When a plurality of recording heads are provided as in a conventional color ink jet recording apparatus, a plurality of independent capping means are provided for each recording head as described in Japanese Patent Application Laid-Open No. 2-1325. And a common suction pump communicating with each capping means, and a selection means for sequentially switching the communication system to each cap means is provided on the suction pump side, so that suction is performed sequentially even when suction is performed from a plurality of recording heads. Suction is performed one by one while sequentially switching the recording heads (cap means) to be performed.

[0007]

However, in the above-described conventional color ink jet recording apparatus, since the communication system between each cap means and the suction pump can be selected individually, it is difficult to select the communication system when power is turned on. Even when suction is performed from the cap means of all the recording heads, suction must be performed while switching one by one sequentially, and the suction operation takes time, and the start-up time (the time until printing becomes possible) becomes long. Inconvenience occurs.

[0008] The present invention has been made in view of the above points, and has as its object to provide an ink jet recording apparatus capable of shortening the start-up time when power is turned on.

[0009]

In order to solve the above-mentioned problems, an ink jet recording apparatus according to claim 1 includes a plurality of cap means for capping a plurality of recording heads, one suction pump, and one suction pump. A switching valve for switching the capping means to be communicated, wherein the switching valve has a state in which all of the plurality of capping means are communicated with the suction pump; and one of the plurality of capping means. The state in which the capping means is communicated with the suction pump can be selected.

According to another aspect of the present invention, there is provided an ink jet recording apparatus comprising: a plurality of cap means for capping a plurality of recording heads; a suction pump; and a switching valve for switching the capping means to communicate with the suction pump. In the recording apparatus, the switching valve includes a state in which all of the plurality of capping units are communicated with the suction pump, a state in which any one of the plurality of capping units is communicated with the suction pump, The state in which the communication between all of the capping means and the suction pump is cut off can be selected.

According to a third aspect of the present invention, there is provided the ink jet recording apparatus according to the first or second aspect, wherein
The suction pump is provided with means for controlling the suction amount of the suction pump in accordance with the number of the capping means communicating with the suction pump.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a schematic front view of a mechanism of an ink jet recording apparatus to which the present invention is applied, and FIG. 2 is a perspective view of a main part of the mechanism.

The mechanism of the ink jet recording apparatus is as follows.
The guide rod 3 is laid between the main frames 1 and 2 on both sides formed integrally, and a stay (not shown) is laid so that one end of the carriage 5 is slidably fitted and held on the guide rod 3. The other end is slidably mounted on the stay so that the carriage 5 can be moved in the main scanning direction. On the lower surface side of the carriage 5, a recording head 6 composed of an ink jet head is ejected from its ejection surface (nozzle surface) 6a.
The ink cartridge 7 for supplying ink to the recording head 6 is mounted on the upper surface side of the carriage 5.

Here, the recording head 6 is provided with a yellow (Y), a magenta (M), a cyan (C), and a black (B
k), which are composed of four heads (hereinafter, heads 6y, 6m, 6c, and 6k for description) capable of ejecting the four color inks. In addition, the ink cartridge 7
Also, as shown in FIG. 2, each of the heads 6y, 6m, 6c, 6k
The ink cartridges 7y, 7m, 7c, and 7k for supplying inks of the respective colors are mounted on the upper side.

The carriage 5 is connected to a timing belt 10 stretched between a driving pulley 8 and a driven pulley 9 which are rotated by a main scanning motor (not shown), and drives the main scanning motor to control the carriage. 5, that is, the recording head 6 is moved in the main scanning direction.

Further, sub-frames 12 and 13 are erected on a bottom plate 11 connecting the main frames 1 and 2, and a paper (not limited to paper) 14 is sub-scanned between the sub-frames 12 and 13. Roller 1 for feeding in the direction
5 is rotatably held. And subframe 1
A sub-scanning motor 16 is disposed on three sides, and a gear 17 fixed to the rotating shaft of the sub-scanning motor 16 and a gear 17 fixed to the shaft of the platen roller 15 to transmit the rotation of the sub-scanning motor 16 to the platen roller 15. Gear 18 is provided.

Further, the reliability of the recording head 6 is set in a non-printing area on the side of the sub-frame 12, that is, an area outside the area where an image is printed on the sheet 14 and in which the carriage 5 can be moved. The reliability maintenance device (subsystem) 20 for maintaining the reliability is arranged. This subsystem 20
Holds caps 21y, 21m, 21c, 21k constituting capping means 21 for capping the respective nozzle surfaces of the heads 6y, 6m, 6c, 6k with a cap case 22. This cap case 22 is a link mechanism 23. And the cap case 22
Is provided with a projection 22a that comes into contact when the carriage 5 is moved to the reliability maintenance / recovery area.

Then, caps 21y, 21m, 21
Each of c and 21k is formed of, for example, a rubber material and has a structure in which it is in close contact with the nozzle surface 6a of the recording head 6, and has a discharge port for connecting to a suction pump and an air opening port for opening to the atmosphere on the bottom surface. doing. Each cap 21y, 21m, 21
The outlets of c and 21k are tubes 24y and 24k, respectively.
m, 24c and 24k are connected to a suction switching valve 25, which is a switching valve according to the present invention, and further connected from the suction switching valve 25 to a suction pump 26 via a tube 27. Cap 21y, 2
The connection (communication state) between 1 m, 21 c and 21 k and the suction pump 26 is selected so that suction can be performed.

With the recording head 6 capped by the cap means 21, the suction pump 26
This is for generating a negative pressure in y, 21m, 21c and 21k, and for opening the cap unit 21 to the atmosphere to suck waste ink. The suction pump 26 is composed of, for example, a piston type pump and is operated by driving the piston with a minute stroke by a driving source such as a pulse motor (not shown) and a cam mechanism. Further, as the suction pump 26, a pump capable of generating a negative pressure and controlling the suction amount is used. In the case of the above-described piston pump, the suction amount can be controlled by the stroke or the number of times. The amount of suction can be controlled by the amount of rotation. The waste ink sucked by the suction pump 26 is stored in a storage tank 28.

On the other hand, each cap 21y, 21m, 21
The atmosphere opening ports c and 21k are connected to an atmosphere opening valve 29 through a tube. This atmosphere release valve 29
Is performed by moving the carriage 5 to the extreme end so that the end face of the air release valve 29 and the rubber plate 30 provided on the main body side come into close contact with each other. In this way, it is possible to switch between opening to the atmosphere and shielding by adjusting the position of the carriage 5 by driving the main scanning motor that moves the carriage 5.

The reason why such opening to the atmosphere is performed is to keep the inside of the cap means 21 equal to the atmospheric pressure and maintain the balance of the ink meniscus surface of the nozzle hole except for the suction operation by the suction pump 26. For example, when the power is off, it is essential to keep the cap close to the nozzle surface and keep the temperature near the nozzle high to prevent the ink in the nozzle hole from becoming highly viscous. In this state, if the pressure inside the cap fluctuates to a higher value due to fluctuations in atmospheric pressure, environmental temperature, etc., air will be drawn into the nozzles and normal ink ejection will be impossible. The inside is made equal to the atmospheric pressure to prevent air from being drawn.

In the subsystem 20, a wiper 31 made of an elastic member such as a fiber member, a foam member, or rubber for cleaning the ejection surface 6a of the recording head 6 is disposed. Is installed.
The wiper 31 periodically removes ink accumulation on the nozzle surface which may be generated when the ink is filled in the head by the operation of the suction pump 26, or paper dust, dust and the like which may adhere to the nozzle surface during printing. It is for removing. This can also be operated by the main scanning movement of the carriage driven by the main scanning motor and the movement of the wiper 31 in the front-rear direction, and a configuration that does not require a special driving source can be adopted.

Next, details of the suction switching valve 25 will be described with reference to FIGS. As shown in FIG. 3, the suction switching valve 25 includes an outer cylinder 35 and the outer cylinder 3.
5, a rotating shaft 37 is fixed to the inner shaft portion 36, and is rotated by a driving source such as a motor (not shown). The position relative to the portion 36 can be changed.

The outer cylinder 35 has connecting ports 38y, 38m, 38c, 38k for connecting the tubes 24y, 24m, 24c, 24k connected to the outlets of the caps 21y, 21m, 21c, 21k. In addition, a connection port 38p for connecting the tube 27 connected to the suction pump 26 is provided. These connection ports 38
y, 38m, 38c, 38k, 38p are all outer cylinders 3.
5 and faces the outer peripheral surface of the inner shaft portion 36.

On the other hand, on the outer periphery of the inner shaft portion 36, as shown in an exploded view in FIG. 4, a groove 39 in the rotational direction (the direction of the arrow) and an axial groove 40 communicating with the groove 39 in the rotational direction. A groove 41 that is inclined with respect to the axial direction and communicates with the grooves 39 and 40 in the rotational direction and the axial direction is formed.
Here, the groove 39 in the rotation direction is a position corresponding to the connection port 38p for the suction pump 26 (see FIG. 5A), and the groove 40 in the axial direction is each connection port 38y, 38m,
At positions corresponding to all of 38c and 38k (see FIG. 5B), grooves 41 in the inclined direction are provided with respective connection ports 38y, 38m, and 3 for cap means 21 according to the rotational position of inner shaft portion 36.
Positions corresponding to 8c and 38k individually (see FIG. 5 (c))
Respectively.

Therefore, by rotating the inner shaft portion 36 by a driving source (not shown), the suction pump 26 is driven by all the heads 6y, 6m, 6m as shown in FIG.
c, 6k in communication with the caps 21y, 21m, 21c, 21k, as shown in FIG.
Are caps 21y, 2 of heads 6y, 6m, 6c, 6k.
1m, 21c, 21k, communicating with any one of them,
As shown in FIG. 3C, the suction pump 26 is provided with caps 21y, 21m,
It is possible to select a state of not communicating with (cutting off) 21c and 21k.

Next, a part related to control of a subsystem in the ink jet recording apparatus will be described with reference to FIG. The main control section 51 controls the overall operation of the ink jet recording apparatus and also controls the suction amount of the suction pump according to the present invention.
It comprises a microcomputer consisting of M, RAM, etc., input / output ports and buffers.

The main scanning motor drive circuit 52 drives the main scanning motor 53 to rotate and causes the carriage 5 to perform main scanning. The subsystem driving circuit 54 drives the pump driving means 55 such as the above-described pulse motor for driving the suction pump 37 to operate the suction pump 26 at a predetermined suction amount, and drives the valve driving means 56 such as the pulse motor. To switch the suction switching valve 25.

Next, the operation of the ink jet recording apparatus thus configured will be described with reference to FIGS. First, an initial recovery operation of the head is performed by turning on the power. In the initial recovery operation of the head, the carriage 5 is moved to move the recording head 6 to the position of the subsystem 20, and the cap 5 is raised by bringing the carriage 5 into contact with the projection 22 a of the cap case 22. , The nozzle surface 6 of the recording head 6 by the cap means 21
The operation of capping a is performed.

Then, after setting the suction amount of the suction pump 26 to a suction amount necessary to perform nozzle suction from all the recording heads 6, the valve driving means 56 is driven to drive the inner shaft portion of the suction switching valve 25. 36 is rotated, and FIG.
As shown in the figure, the connection port 38p for the suction pump 26 and the connection ports 38y, 38 for the heads 6y, 6m, 6c, 6k.
m, 38c, and 38k are all in a state of communicating with each other via the grooves 39, 40 of the suction switching valve 25 (full cap communication state).

By operating the suction pump 26 in this state, the caps 21y, 21m, 21c, 21k
The pressure inside becomes negative pressure, so that suction from the nozzles of the heads 6y, 6m, 6c, 6k can be performed. Thereafter, the carriage 5 is moved to the printing area side to perform wiping by the wiper 31, and the suction pump 26 is operated in a state of being released to the atmosphere to perform necessary initial operations such as suction of waste ink from the caps 21y, 21m, 21c, and 21k. Perform a recovery operation.

As described above, since the suction switching valve 26 can select the state in which all the capping means are connected to the suction pump, the suction switching valve 26 is different from the case where the nozzle suction is performed while switching the communication between the capping means and the suction pump one by one. In addition, the start-up time when the power is turned on can be reduced. In this case, it is possible to perform control for optimizing the content of the recovery operation according to the length of the off-time by measuring the power-off time using a timer.

After the completion of the initial recovery operation, the timer is reset and started. This timer is for determining whether or not a state in which the printing operation is not performed has passed a preset time. The set time of the timer (time from start to time up) is 10 sec.
A possible range is about 240 sec, preferably 10 sec.
It is in the range of ~ 60 sec.

Thereafter, it is determined whether or not a printing start command has been received. When the printing start command has been received, a printing operation is performed, and it is determined whether or not all the printing operations have been completed. If all the operations are not completed, that is, if the printing is temporarily stopped, the process returns to the reset start of the timer. If all the printing operations are completed, the recording head 6 is moved to the subsystem 20 side. After the capping is performed, a stop operation of the subsystem 20 and the like, for example, wiping, ejection of ink droplets, and the like are performed.

Then, the inner shaft portion 3 of the suction switching valve 25
6 is rotated, and the heads 6y and 6y are rotated as shown in FIG.
caps 21y, 21 sealing m, 6c, 6k
m, 21c, 21k and each connection port 38y, 38m, 38
Both c and 38k are grooves 39, of the suction switching valve 25,
41 so that each cap 21y, 21
The communication state between m, 21c, 21k and the suction pump 26 is cut off (all caps are not in communication state).

As described above, by selecting the state in which the communication between all of the plurality of capping means and the suction pump is cut off, the evaporation of water in the cap when left unattended can be reduced, and the reliability of the head can be reduced. Can be increased.

On the other hand, after resetting and starting the timer, if there is no printing start command, as shown in FIG.
It is determined whether or not the timer has timed out (timed up). Here, when the timer expires, it means that the printing operation has not been performed for a predetermined time, so that the recording head 6 is moved to the subsystem 20 side to perform the reliability maintaining operation. Nozzle surface 6
a is capped by cap means 21. In this case, it is also possible to discharge ink droplets that do not contribute to printing at regular intervals during the measurement by the timer.

Then, after the capping operation, the suction amount of the suction pump 26 is set to a suction amount necessary for performing suction from one recording head, and the inner shaft portion 36 of the suction switching valve 25 is rotated to rotate the suction pump 26 as shown in FIG. As shown in (b), the nozzle suction is performed such that the connection port 38y to the head 6y communicates with the connection port 38p of the suction pump 26 via the grooves 41 and 39 corresponding to the groove 41. Similarly, by rotating the inner shaft portion 36 of the suction switching valve 25, the connection ports 38m, 38c, 38k of the recording heads 6m, 6c, 6k are sequentially formed.
Are sequentially connected to the connection port 3 of the suction pump 26 through the grooves 41 and 39.
Nozzle suction is performed so as to communicate with 8p.

In this way, all the heads 6y, 6y
After the nozzles are individually suctioned sequentially from m, 6c, and 6k, wiping is performed, and the process returns to the determination process of FIG.

As described above, the state in which the cap means of each recording head and the suction pump can be individually communicated with the suction switching valve can be selected, so that individual suction from each head can be performed. In addition, by performing nozzle suction every time a predetermined time elapses while the recording head is capped by the cap unit, the ejection failure due to evaporation of water from the nozzles, particularly, high viscosity of the ink in a high temperature and low humidity environment is eliminated. As a result, the ejection stability of the recording head can be ensured, and wasteful consumption of ink can be reduced.

Next, another example of the suction switching valve according to the present invention will be described with reference to FIGS. 9 and 10. FIG. The suction switching valve 60 is, as shown in FIG.
1 and a rotating disk 62 rotatably superimposed on the fixed disk 61. The rotating shaft 63 of the rotating disk 62 is inserted through the fixed disk 61 and rotated by a driving source such as a motor (not shown). The relative position between the fixed disk 61 and the rotating disk 62 can be changed.

The fixed disk 61 has connection ports 64y, 64m, 64c for connecting tubes 24y, 24m, 24c, 24k connected to the discharge ports of the caps 21y, 21m, 21c, 21k of the above embodiment. 64k are provided on the same circumference, and a connection port 64p for connecting the tube 27 connected to the suction pump 26 is provided. These connection ports 64y, 64m, 64c, 64k,
64p passes through the fixed disk 61 and the rotating disk 62
Facing the end face.

On the other hand, as shown in FIG. 10, an annular groove 65 is formed on the surface of the rotating disk 62 on which the fixed disk 61 overlaps.
And a partial annular groove 66 communicating with the annular groove 65.
And a partially annular groove 67 communicating with the annular groove 65. Here, the annular groove 65 is formed at a radial position corresponding to the connection port 64p for the suction pump 26, as shown in FIG. Also, the partial annular groove 66
Are connected ports 64 for the cap 21 as shown in FIG.
They are formed at radial positions corresponding to all of y, 64m, 64c, and 64k and have a circumferential width.

Further, as shown in the drawing, the partially annular grooves 67 are provided with respective connection ports 64y, 64m, 6 for the cap 21.
4c and 64k, and has a width corresponding to each of the connection ports 64y, 64m, 64c and 64k for the cap 21 in accordance with the rotational position of the rotary disk 62. ing.

Therefore, by rotating the rotating shaft 63 to rotate the rotating disk 62, as shown in FIG. 10A, the connection ports 64y, 64m,
64c and 64k communicate with the connection port 64p of the suction pump 26. As shown in FIG. 3B, one of the connection ports 64y, 64m, 64c and 64k of the recording head is connected to the connection port 64p of the suction pump 26. In the communication state, as shown in FIG. 10C, the connection ports 64y, 64m, and 64 of the recording head.
A state in which all of c and 64k are cut off from the connection port 64p of the suction pump 26 can be selected.

In the above embodiment, the present invention is applied to the serial type ink jet recording apparatus. However, the head is fixed by using a line type head having a paper width (for example, A4 size) as the recording head. The present invention is also applicable to a page printer that performs printing while transporting paper.

[0047]

As described above, according to the ink jet recording apparatus of the first aspect, the switching valve has a state in which all of the plurality of capping means are in communication with the suction pump.
Since it is possible to select a state in which any one of the plurality of capping means is communicated with the suction pump, the start-up time when performing suction from all the heads at the time of turning on the power is shortened. be able to.

According to the ink jet recording apparatus of the second aspect, the switching valve allows all of the plurality of capping means to communicate with the suction pump, and allows any one of the plurality of capping means to communicate with the suction pump. The start-up time when performing suction from all the heads when turning on the power, etc. is shortened because the state and the state in which communication with all of the plurality of capping means and the suction pump are shut off can be selected. And the evaporation of water from inside the cap when left unattended can be reduced, and the reliability of the head can be increased.

According to the ink jet recording apparatus of the third aspect, in the ink jet recording apparatus of the first or second aspect, the suction amount of the suction pump is controlled according to the number of capping means communicating with the suction pump. In addition, it is possible to prevent a reduction in the suction amount when suction is performed from all the heads.

[Brief description of the drawings]

FIG. 1 is a schematic front view of a mechanism of an ink jet recording apparatus to which the present invention is applied.

FIG. 2 is a perspective view of a main part of the mechanism.

FIG. 3 is a perspective view showing an example of a suction switching valve.

FIG. 4 is a development view of an inner shaft portion of the suction switching valve.

FIG. 5 is an explanatory view illustrating different selection states of the suction switching valve.

FIG. 6 is a block diagram of a control unit of the recording apparatus.

FIG. 7 is a flowchart for explaining the operation of a subsystem of the recording apparatus.

FIG. 8 is a flowchart for explaining the operation of the subsystem.

FIG. 9 is a perspective view showing another example of the suction switching valve.

FIG. 10 is an explanatory diagram illustrating different selection states of the suction switching valve.

[Explanation of symbols]

5 carriage, 6 recording head, 6y, 6m, 6c,
6k head, 20 subsystem, 21 cap means, 21y, 21m, 21c, 21k cap, 25
... Suction switching valve, 26 ... Suction pump, 35 ... Outer cylinder,
36 ... Inner shaft part, 39-41 ... Groove, 60 ... Suction switching valve, 61 ... Fixed disk, 62 ... Rotating disk, 65-67 ...
groove.

Claims (3)

[Claims] 1. An ink jet recording apparatus comprising: a plurality of cap means for capping a plurality of recording heads; a suction pump; and a switching valve for switching the capping means communicating with the suction pump. Is capable of selecting a state in which all of the plurality of capping units are connected to the suction pump and a state in which any one of the plurality of capping units is connected to the suction pump. Ink jet recording device. 2. An ink jet recording apparatus comprising: a plurality of cap means for capping a plurality of recording heads; a suction pump; and a switching valve for switching the capping means to communicate with the suction pump. Is a state in which all of the plurality of capping means are in communication with the suction pump, a state in which any one of the plurality of capping means is in communication with the suction pump, and a state in which all of the plurality of capping means are in communication with the suction pump. An ink jet recording apparatus characterized in that a state in which communication with a suction pump is cut off can be selected. 3. The ink jet recording apparatus according to claim 1, further comprising: means for controlling a suction amount of the suction pump according to the number of the capping means communicating with the suction pump. Ink jet recording device.