JP3251113B2 - Image recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image recording apparatus used for an output device of a facsimile, a copying machine, a printer or a computer.

[0002]

2. Description of the Related Art Conventionally, there has been proposed an image recording apparatus of an ink jet type which discharges ink from nozzles of a recording head (Japanese Patent Laid-Open No. 3-27949), and an image forming apparatus provided with such an image recording apparatus. A device has been proposed (Japanese Patent Laid-Open No. 1-129667), and a device capable of recording an image on A0 size paper has been put to practical use.

In such a conventional ink jet image recording apparatus, when printing is not performed, the recording head is prevented from being clogged due to drying of the ink in the nozzles and mixing of dust and the like into the nozzles. The nozzle surface is covered with a rubber cap. Also, during printing, the recording head returns to the cap position at a required interval and performs idle discharge in which ink is discharged from all nozzles, thereby preventing clogging of nozzles that are not used or that are used less frequently during printing. Like that. When an ejection failure occurs, an ejection recovery operation for forcibly ejecting ink from the nozzles by a pump or the like has been performed.

[0004]

However, in such a conventional ink jet type image recording apparatus, a long time elapses from when the power is turned off to when the power is turned on again, or when the power is turned on. However, if the print standby time is long, the viscosity of the ink at the nozzle tip increases, and clogging is likely to occur. Further, in order to forcibly eject the ink having the increased viscosity, a large pumping capacity is required, and the time required for the ejection recovery operation may be increased.

An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide an image recording apparatus in which the reliability of printing is improved by reliably performing an ejection recovery operation regardless of the ink viscosity at the nozzle tip. I do.

[0006]

According to the present invention, there is provided an image recording apparatus for printing on paper by discharging ink from nozzles of a recording head. , connects the capping member whose inner space is formed in a region opposed to the nozzle when in close contact to the recording head, a tank organic solvent stored dissolving the above Symbol ink, and the inner space and the tank ,
A tube with a valve that connects and disconnects between them
And the capping member adhered to the recording head
When the nozzle with the organic solvent from the inner space
Suction means for sucking ink in the inside, the valve and the inside
It is provided at the part branched from the tube between the space
Open the vented air valve and open the
Predetermined suction operation by the suction means with the air valve closed
And then the suction means with the valve closed
A predetermined suction operation was performed, and the air vent valve was opened.
And a control unit for stopping the operation of the suction unit later (claim 1).

Further, the tank is disposed at a position higher than the space (Claim 2).

[0008] In the image recording apparatus according to claim 1 Symbol placement, is interposed said communication passage, in which with a supply means for supplying the organic solvent into the space from the tank (claim 3) .

[0009]

According to the first aspect of the present invention, when the capping member comes into close contact with the recording head, an inner space is formed in a region opposed to the nozzle, and the tank storing the organic solvent is formed in a tube.
Valve communicates with the internal space, the valve opens, and the air vent valve
With the closed , the ink in the nozzle is dissolved by the organic solvent. With the valve closed and the air vent valve closed,
The dissolved ink in the nozzle is sucked from the inner space together with the organic solvent. Then the valve closes and the air vent valve closes.
In the open position, more ink is sucked in with the organic solvent.
Then, the inner space is returned to the atmospheric pressure.

According to the second aspect of the present invention, the organic solvent flows from the tank into the inner space through the communication passage.

According to the third aspect of the present invention, the organic solvent is supplied from the tank to the inner space through the communication passage.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of an image recording apparatus according to the present invention will be described with reference to the drawings. FIGS. 1A and 1B are diagrams showing a schematic configuration of the inside of the apparatus of the present embodiment. FIG. 1A is a front view, and FIG. 1B is a right side view.

This apparatus is a printer for printing contents input from an external device such as a personal computer, for example, and includes a printing section 11 at an upper portion and a paper storage section 12 at a lower portion, and conveys a sheet from below to above. A paper transport system 13 is provided. In FIG. 1A, an ejection recovery mechanism 17 for maintaining the ink ejection performance is provided near the right end. Further, an operation panel 85 including a display unit 851 and an operation unit 852 for displaying the presence / absence of paper in each paper feed cassette and the shortage of the remaining amount of ink is provided at an appropriate position on the surface of the apparatus.

In the paper storage section 12, paper feed cassettes of different sizes that can store cut paper in a stacked manner are arranged in a stacked manner. Each paper cassette includes, for example, paper cassette 2
A4 and A2 size paper trays, B5 paper feed cassettes 23 and 24
A3 size paper is stored in the paper feed cassette 25, B4 size paper is stored in the paper feed cassette 26, and A2 size paper is stored in the paper feed cassette 27. Also, below the paper cassette,
A roll paper 29 is provided. This roll paper 29
The cutting device 28 can cut into a desired size such as A1 (vertical) or A2 (horizontal).

As described above, the small-sized and medium-sized paper cassettes are arranged in the horizontal direction, and the large-sized paper cassettes are disposed below them. Therefore, the size of the paper storage unit 12 can be reduced. it can.

The paper transport system 13 includes paper feed rollers 31 to 37 provided for the respective paper cassettes 21 to 27 for feeding paper, and resists for transporting the paper in accordance with the timing of image recording. A roller pair, a transport belt 38 and the like are provided. However, the paper feed rollers 32 to 34, 36
In FIG. 1B, the paper feed rollers 31 and 3
5 is arranged on the depth side of the drawing. Also, roll paper 2
9 is conveyed by conveying rollers 39 and 40.

The transport belt 38 is made of, for example, polyurethane rubber, has an endless shape stretched around transport rollers 381 and 382 at front and rear ends, is rotated by a transport belt motor 383, and is fed to the upper part of the apparatus. Paper cassettes 21 to 27
The paper or roll paper 29 from the printer is attracted and transported by static electricity, air suction force, or the like. Discharge roller pair 48
Is for guiding the paper transported by the transport belt 38 to the discharge tray 49 side and discharging the paper.

Next, the configuration of the printing unit 11 will be described with reference to FIGS. FIG. 2 is a perspective view illustrating a schematic configuration of the printing unit 11. 3A and 3B are diagrams showing a schematic configuration of the recording head 51 and the carriage 52. FIG. 3A is a plan view, and FIG. 3B is a right side view.

The ink cartridge 53 is filled with black ink and supplies ink to the recording head 51. In the ink cartridge 53, an ink remaining amount detecting unit 62 (see FIG. 6) for detecting the remaining amount of each ink is provided, and when the remaining amount of the ink falls below a predetermined level, the display unit 851 displays the remaining amount. It has become.

The recording head 51 is provided with, for example, a nozzle section 511 in which a large number of micro-diameter nozzles are arranged in a matrix. And discharge
This is for printing an image on paper. The configuration of the matrix of the nozzles is not limited to a checkerboard shape, but may be a staggered shape or another shape, for example, a one-row matrix, that is, one column.

The drive circuit 512 has a latch unit, and once latches, for example, a serial binary or multi-level image signal of one line, for example, sent by a flexible signal line 513 (FIG. 6), and outputs a parallel signal. After conversion to
The synchronous output is performed as a pulse drive signal to the corresponding piezoelectric elements 11.

The carriage 52 holds the recording head 51 and the ink cartridge 53, and has a through hole 520.
a and the fitting groove 520b are fitted to the stays 54 and 55,
It is supported reciprocally. The stays 54 and 55 are arranged side by side in the width direction of the conveyor belt 38, and both ends are supported by side plates 58 and 59 of the apparatus main body.

The carriage 52 includes stays 54, 5
A notch 521 having a U-shaped cross section is provided on the back surface (the right side in FIG. 3B) of the portion sandwiched by 5.
One of the side surfaces (lower surface in FIG. 3B in this embodiment)
Is connected to a drive belt 522. The drive belt 522 is connected to a pulley 52 disposed near the side plates 58 and 59.
3, 524, and is disposed in parallel with the stays 54, 55.

The pulley 524 is rotatably driven by a carriage driving motor 56 composed of, for example, a stepping motor. The carriage 52 includes a pulley 52
4, the rotation of the drive belt 522 causes the through-hole 520 to rotate.
a and the fitting groove 520b slide on the stays 54, 55 to move. The movement amount and speed of the carriage 52 can be controlled by a drive pulse supplied to a carriage drive motor 56. To return the carriage 52, that is, the recording head 51 to the home position, a reflection type optical sensor including, for example, a light emitting unit and a light receiving unit is provided near the home position.
May be detected to return to the home position.

Next, the ejection recovery mechanism 17 will be described with reference to FIGS. FIG. 4 is a perspective view showing a schematic configuration of the ejection recovery mechanism 17, and FIG. 5 is an explanatory view schematically showing the ejection recovery mechanism 17. The discharge recovery mechanism 17 includes a capping member 65, a pump 66, and a tank 7 in which an organic solvent is stored.
4 and so on.

The capping member 65 includes the recording head 51
Is provided at the home position of the nozzle unit 511 and covers the ink ejection surface of the nozzle unit 511 to prevent drying of the ink and entry of foreign matter and bubbles into the nozzle.
A cap portion 651 formed according to the size of No. 11 is provided. The cap portion 651 is formed of a soft synthetic resin, rubber, or the like.
When it comes into close contact with the nozzle portion, it covers the nozzle portion 511 in a non-contact manner. In addition, an ink absorber 651a made of, for example, urethane foam is provided in the cap portion 651.

As shown in FIG. 4, the capping member 65 includes guide rods 65 provided at both ends in the longitudinal direction.
4,655 are penetrated by through holes 652,653.
The guide rod 655 is fixed to the motor shaft of the cap drive motor 84, and a male screw is formed in a required range thereof, while a female screw is formed in the through hole 653, and has a so-called ball screw structure. Further, the through hole 652 is guided while sliding on the guide rod 654.

The capping member 65 is mounted on the recording head 51 and retreated from the recording head 51 by moving up and down by the rotation of the guide rod 655 driven by the rotation of the cap driving motor 84. Further, when the guide rod 655 stops due to the stop of the cap drive motor 84, it is supported at that position.

The tip of the guide rod 655 is connected to the side plate 58.
Is fitted into the through hole 582 of the fixing member 581 extending from the shaft, so that the axis of the guide rod 655 does not swing.
The recording head 51 does not vibrate by abutting on the fixing member 581 at the home position.

With the above arrangement, when printing is performed, the capping member 65 is lowered by the cap drive motor 84, and the carriage 52 is retracted from the recording head 51.
Starts moving. When printing is completed and the carriage 52 returns to the home position, it rises and is attached to the recording head 51 to protect the tip of the nozzle portion 511.

During printing, the recording head 51 is returned to the home position at required intervals, and the capping member 65 is returned.
By performing idle discharge in which ink is discharged from all the nozzles, clogging of nozzles that are not used during printing or that are used less frequently is prevented. The idle discharge may be performed by attaching the capping member 65 to the recording head 51.

The bottom of the tank 74 has a nozzle portion 511.
Is disposed at a position higher than the contact position between the nozzle portion 511 and the cap portion 651, and stores an organic solvent such as methanol that dissolves the ink having the increased viscosity at the tip of the nozzle portion 511, and a small hole formed on the upper surface thereof. It is open to the atmosphere by.
The tube 76 is connected between the tank 74 and the cap portion 651, and has a valve 75 interposed therebetween for communicating and shutting off.

The tube 72 communicates between the cap 651 and the pump 66. The pump 66 generates a suction force to return a meniscus formed at the tip of the nozzle portion 511 to a normal position, or removes bubbles and foreign substances in the nozzle together with the ink, thereby eliminating defective ink ejection. is there. The ink sucked by the pump 66 passes through a waste ink tube 67 to a waste ink tank 68.
The ink is absorbed by an internal ink absorber.

The tube 76 is branched at a point A between the valve 75 and the cap portion 651, and is opened to the atmosphere through an atmosphere vent valve 73 for controlling communication with and shutoff to the atmosphere. After the suction operation, the inside of the cap portion 651 is at a negative pressure, so that the atmosphere vent valve 73 is returned to the atmospheric pressure so that the cap portion 651 can be easily separated from the nozzle portion 511. is there.

As described above, the tank 74 is connected to the nozzle 51
The organic solvent flows into the cap portion 651 by its own weight by opening the valve 75 because the organic solvent is disposed above the close contact position between 1 and the cap portion 651.

The tube 76 between the tank 74 and the cap 651 may be provided with a pump or the like for supplying an organic solvent toward the cap 651. In this case, it is not necessary to dispose the tank 74 at a position higher than the close contact position between the nozzle portion 511 and the cap portion 651.

Next, the control configuration of this device will be described with reference to FIG.
This will be described with reference to the block diagram of FIG. In this device, the operation of each unit is performed based on an operation signal and an image signal input from an external device such as a personal computer.

The control section 81 is composed of a microcomputer or the like, and controls the operation of the entire apparatus. Further, a storage unit 82 including a ROM in which a control program is stored, a RAM for temporarily storing data, and the like are incorporated. The timer 80 has a built-in backup battery and counts an elapsed time since the power of the apparatus is turned off, a standby time during which printing is not performed, and the like.

An image signal is sent from an external device to the recording control unit 8.
11, an operation signal such as a paper size and a recording mode described later is input to the scanning control unit 812, and the recording control unit 811 and the scanning control unit 812 perform control operations in synchronization with each other.

The recording control unit 811 serially transmits the input image signal to the drive circuit 512 via the signal line 513. The parallel signal converted by the drive circuit 512 is synchronized with the scan control
The output is performed to the piezoelectric element provided in each of the nozzles 11 to control the ejection of ink. The cycle of the ink ejection, that is, the cycle of the signal output to the piezoelectric element is suitably set.

The scanning control unit 812 drives the paper feed system and the discharge system 86 via the drive circuit 83 based on the input operation signal to feed paper from a predetermined cassette.
It drives each motor of the other drive system.

When the paper of the input size is fed from a required paper feed cassette, the transport belt motor 38
Reference numeral 3 repeats paper transport and stop, and during carriage stop, the carriage drive motor 56 causes the carriage 52 to scan within the range of the paper width to print an image for each line.

The ejection recovery key 854 is arranged on the operation unit 852, and when pressed when an ink ejection failure occurs, inputs a signal to that effect to the ejection recovery control unit 814.

The discharge recovery control section 814 controls the operation of the cap drive motor 84, the pump 66, the atmosphere ventilation valve 73, the valve 75, and the like via the drive circuit 83. The ejection recovery operation is performed when the elapsed time from turning off the printer or the standby time during which printing is not performed is equal to or longer than a predetermined time or when the ejection recovery key 854 is pressed. The display control unit 813 detects presence / absence of paper in each paper feed cassette, insufficient ink remaining amount, and the like, and displays the detection result on the display unit 851.

Next, the ejection recovery operation will be described with reference to the flowchart of FIG. In a standby state in which printing is not performed, the capping member 65 is raised and attached to the recording head 51 (step S1), the air vent valve 73 is closed (step S2), and the valve 75 is also closed. (Step S3).

First, it is determined whether the elapsed time since the power of the apparatus is turned off or the standby time during which printing is not performed is longer than a predetermined time set in advance. (YES in step S4), and proceeds to step S6. Further, it is determined whether or not the ejection recovery key 854 is turned on. If the key 854 is turned on (YES in step S5), the process proceeds to step S6. On the other hand, if the predetermined time has not elapsed (NO in step S4) and the ejection recovery key 854 has not been turned on (N in step S5).
O), end. The key input determination may be performed before the elapsed time determination.

Next, if step S4 or S5 is YES, the valve 75 is opened (step S6), the pump 66 starts operating (step S7), and a predetermined time elapses (step S7). (NO in S8), the operation is continued. When a predetermined time has elapsed and the organic solvent flowing from the tank 74 has filled the inside of the cap portion 651 (YES in step S8), the pump 66 is stopped (step S9), and the valve 75 is closed (step S10).

Next, a predetermined time (a few seconds) set in advance
Elapses (NO in step S11).
After a lapse of a predetermined time, the nozzle 5
11 When the high-viscosity ink at the tip dissolves (step S11)
YES), the pump 66 operates, and the organic solvent in which the ink is dissolved is sucked together with the ink (step S12).
Until a predetermined time set in advance (step S1)
(NO in 3), the operation is continued. Then, when a predetermined time has elapsed and the suction of the organic solvent is completed (Y in step S13).
ES), after the atmosphere vent valve 73 is opened to return the inside of the cap portion 651 to the atmospheric pressure (step S14), the pump 66 stops (step S15), and the discharge recovery operation ends.

As described above, since the tank 74 in which the organic solvent is stored is provided, even if the viscosity of the ink at the tip of the nozzle portion 511 increases due to a longer standby time during which no printing operation is performed, the ink is dissolved. can do. Further, the ink absorber 651a in the cap portion 651 can be cleaned.

Therefore, the required capacity of the pump 66 can be reduced, so that the size and power consumption can be reduced. In addition, since clogging can be reliably prevented by dissolution of the ink, the ejection recovery operation is reliably performed, and the printing reliability of the present image recording apparatus can be improved.

Although the present embodiment has been described with reference to a black-and-white printing apparatus, an apparatus capable of performing color printing may be used. In this case, yellow (Y),
Magenta (M), cyan (C), and black (K) inks are sealed, and four nozzles for discharging yellow, magenta, cyan, and black inks are arranged in the nozzle section 511, and the capping member 65 is provided. In this case, four cap portions 651 may be provided corresponding to the nozzles of each color, and a tube connecting the cap portions 651 and the pump 66 may be provided.

[0052]

As described above, according to the first aspect of the present invention, the capping member is brought into close contact with the recording head to form an inner space in a region facing the nozzle, and the tank in which the organic solvent is stored is formed in the inner space. Since the ink is communicated with the space, even if the ink viscosity increases, it can be dissolved. Further, the ink in the nozzle was dissolve since sucked from the inner space together with an organic solvent, it is possible to reliably discharge recovery operation. Open the air vent valve and suction
Can return the inner space that is under negative pressure to atmospheric pressure
That allows the capping member to be
Can be easily separated.

According to the second or third aspect of the present invention,
The organic solvent can be reliably supplied from the tank to the internal space.

[Brief description of the drawings]

FIGS. 1A and 1B are diagrams showing a schematic internal configuration of an image recording apparatus according to an embodiment of the present invention, wherein FIG. 1A is a front view and FIG. 1B is a right side view.

FIG. 2 is a perspective view illustrating a schematic configuration of a printing unit 11;

3A and 3B are diagrams showing a schematic configuration of a recording head 51 and a carriage 52, wherein FIG. 3A is a plan view and FIG. 3B is a right side view.

FIG. 4 is a perspective view showing a schematic configuration of a discharge recovery mechanism 17;

FIG. 5 is an explanatory diagram schematically showing an ejection recovery mechanism 17.

FIG. 6 is a block diagram illustrating a control configuration of the apparatus according to the present embodiment.

FIG. 7 is a flowchart illustrating a procedure of an ejection recovery operation.

[Explanation of symbols]

 REFERENCE SIGNS LIST 11 printing unit 12 paper storage unit 13 paper transport system 21 to 27 paper feed cassette 31 to 37 paper feed roller 38 transport belt 51 recording head 52 carriage 53 ink cartridge 54, 55 stay 56 carriage drive motor 58, 59 side plate 65 capping member 66 Pump 67 Waste ink tube 68 Waste ink tank 72, 76 Tube 73 Air vent valve 74 Tank 75 Valve 80 Timer 81 Control unit 82 Storage unit 83, 512 Drive circuit 84 Cap drive motor 85 Operation panel 383 Transport belt motor 511 Nozzle unit 513 Signal Line 811 Record control unit 812 Scan control unit 813 Display control unit 814 Discharge recovery control unit 851 Display unit 852 Operation unit 854 Discharge recovery key

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Koichi Baba 1-2-2, Tamazo, Chuo-ku, Osaka-shi Mita Kogyo Co., Ltd. (72) Inventor Yoshiko Kawachi 1-2-28, Tamazo, Chuo-ku, Osaka Mita Kogyo Inside (72) Inventor Setsuo Hori 1-2-2, Tamazo, Chuo-ku, Osaka-shi Inside Mita Kogyo Co., Ltd. (56) References JP-A-3-138157 (JP, A) JP-A-58-173670 (JP) , A) (58) Field surveyed (Int. Cl. ⁷ , DB name) B41J 2/165-2/185

Claims (3)

(57) [Claims] In an image recording apparatus for printing on paper by ejecting ink from nozzles of a recording head, the image recording apparatus can be in close contact with the recording head, and is provided in an area opposed to the nozzle when the recording head is in close contact with the recording head. and the capping member which space is formed, a tank organic solvent stored dissolving the above Symbol ink, and the space and the tank connection,
A tube with a valve that connects and disconnects between them
And the capping member adhered to the recording head
When the nozzle with the organic solvent from the inner space
Suction means for sucking ink in the inside, the valve and the inside
It is provided at the part branched from the tube between the space
Open the vented air valve and open the
Predetermined suction operation by the suction means with the air valve closed
And then the suction means with the valve closed
A predetermined suction operation was performed, and the air vent valve was opened.
An image recording apparatus comprising: a control unit for stopping the operation of the suction unit later . Wherein said tank is an image recording apparatus according to claim 1 Symbol mounting, characterized in that it is arranged at a position higher than the space. In the image recording apparatus 3. A process according to claim 1 Symbol placement,
An image recording apparatus, comprising: a supply unit provided in the communication path to supply the organic solvent from the tank to the internal space.