JPH0569558A - Ink jet recording apparatus - Google Patents

Abstract

(57) [Abstract] [Purpose] Even when the drive source reverses, by reliably preventing the back flow of the ink in the tube to the recording head side,
It is possible to prevent deterioration of image quality due to ink overflow and ink adhesion, and to eliminate reverse drive to improve tube durability and pump reliability. [Structure] A tube pump that crushes a flexible tube communicating with a discharge port of a recording head with a pressure roller to generate a negative pressure at the discharge port, and a one-way mechanism is provided in a driving force transmission system of the tube pump. As a result, the driving force is transmitted to the pressure roller only in the direction in which negative pressure is generated at the discharge port.

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 for recording by ejecting ink from a recording means onto a recording material.

[0002]

2. Description of the Related Art A recording device having functions such as a printer, a copying machine, and a facsimile, or a recording device used as an output device of a composite type electronic device including a computer, a word processor, etc. An image is recorded on a recording material (recording medium) such as a plastic thin plate. The recording device can be classified into an ink jet type, a wire dot type, a thermal type, a laser beam type and the like depending on the recording type.

In a serial type recording apparatus which employs a serial scan system in which main scanning is performed in a direction intersecting a conveying direction (sub-scanning direction) of a recording material, the recording material is set at a predetermined recording position and then the recording material is recorded. An image is recorded (main scanning) by a recording unit (generally mounted on a carriage) that moves along the material, and a predetermined amount of paper is fed (conveyed material to be recorded) after one line of recording is completed, After that, the operation of recording (main scanning) the image of the next row is repeated on the recording material that has stopped again, thereby recording the entire recording material. On the other hand, in a line type recording apparatus that records only by sub-scanning in the conveyance direction of the recording material, the recording material is set at a predetermined recording position and the
After recording for one line, the paper is fed by a predetermined amount (recording material is conveyed), and then the recording of the next row is collectively performed. Be done.

Among the above recording apparatuses, an ink jet type recording apparatus (ink jet recording apparatus) performs recording by ejecting ink from a recording means (recording head) onto a recording material, and the recording means can be made compact. Easy and
High-definition images can be recorded at high speed, plain paper can be recorded without requiring special processing, running costs are low, and the non-impact method reduces noise, and multicolor It has an advantage that it is easy to record a color image using ink. Above all, the line type apparatus using the line type recording means in which a large number of ejection openings are arranged in the paper width direction can further speed up the recording.

In particular, an ink jet type recording means (recording head) for ejecting ink by utilizing heat energy,
Through the semiconductor manufacturing process such as etching, vapor deposition, and sputtering, the electrothermal converter formed on the substrate, the electrode,
By forming the liquid passage wall, the top plate and the like, it is possible to easily manufacture a liquid discharge device having a high-density liquid passage arrangement (discharging port arrangement), and to further reduce the size. On the other hand, there are various requirements for the material of the recording material,
In recent years, ordinary recording materials such as paper and resin thin plate (OHP)
Etc.), thin paper and processed paper (paper with punched holes for filing, perforated paper, paper of any shape, etc.) have been required to be used.

In the above ink jet recording apparatus,
A recovery pump is provided in order to maintain the normal ink ejection state of the recording means (recording head) or to eliminate the clogging at the ejection port and recover the ink ejection state to the normal ink ejection state. However, a recovery unit (recovery device) that sucks ink from the discharge port by the negative pressure of the pump is used. In addition, as the recovery pump, a tube pump that generates a negative pressure by utilizing a volume change in a flexible tube may be used. This tube pump has an advantage that it has a simple structure and can form a small-sized and lightweight pump at low cost.

8 and 9 are longitudinal sectional views showing the structure of a conventional tube pump. FIG. 8 shows a state where the tube is crushed and FIG. 9 shows a state where the tube is crushed. 8 and 9, first, the opening of the cap 2 is brought into contact with the ejection port forming surface 51 of the recording head 1 to seal the ejection port 52. A tube 3 is connected to a through hole on the back surface of the cap 2, and the tube 3 extends to a tube pump 4. Tube pump 4 is pump base 5
In addition, the guide roller 6 is rotatably supported, and the pressure roller 7 is rotatably supported by the guide roller 6. That is, the shaft 8 of the pressure roller 7 for pressurizing the tube 3 is rotatably supported by the guide roller 6, and the shaft 9 of the guide roller 6 is rotatably supported by the pump base 5. The pump base 5 is provided with a groove 10 concentric with the shaft 9 of the guide roller 6, and the tube 3 is mounted in the groove 10. Further, the other end (downstream end) of the tube 3 is provided with a waste ink processing member 11 for storing the ink sucked from the ejection port 52.

In the above structure, when the guide roller 6 is rotated in the direction of the arrow a by the driving means (not shown), the pressure roller 7 on the guide roller 6 is at the X position in FIG.
And the tube 3 is pressed. The tube 3 is crushed until the inner space of the pressing portion becomes zero. When the guide roller 6 further rotates in the direction of the arrow a from this state, the pressure roller 7 rotates (revolves) in the direction of the arrow a while rotating (driven) in the direction of the arrow b while crushing the tube 3. Then, when the pressure roller 7 reaches the Y position shown in FIG. 9, the pressure roller 7 is temporarily stopped. At this time, the negative pressure generated by the volume change in the tube 3 crushed by the pressure roller 7 between the X position and the Y position acts on the ejection port 52 of the recording head 1,
Ink is sucked (sucked) from the ejection port 52.
The sucked ink is sequentially sent to the waste ink processing member 11 side.

[0009]

However, in the above conventional example, when another driving source such as a driving source for conveying the recording material is shared as the pump driving source, the driving direction of the other driving source is positive. May use both inversion and inversion,
When the guide roller 6 in FIG. 8 is driven in the reverse rotation direction indicated by the arrow f, the waste ink processing member 11 is the ink discharged from the recording head 1 by suction during the normal rotation drive.
If the ink that has not reached to the end remains in the tube 3, a phenomenon occurs in which this ink flows back to the cap 2 side, and the ink overflows from the cap 2 or the waste ink is formed on the ejection port forming surface in the capping state. However, there are inconveniences such as adherence of ink or waste ink mixed into the ejection port to cause recording failure.

As a countermeasure against the above inconvenience, after the suction operation,
In order to move the sucked ink to the waste ink processing member 11 side as much as possible, there is a method of rotating the guide roller 6 in the arrow a direction in the non-capping state. However, in this method, the waste ink processing member 11 causes the tube pump 4 to
When the guide roller 6 is arranged at a position distant from the position, it is necessary to rotate the guide roller 6 in the direction of the arrow a considerably.
The inconvenience that the recovery operation becomes very long occurs. Further, if a dedicated drive source is used as the drive source of the tube pump 4 and the rotation direction of the drive source is limited to one direction, the ink backflow phenomenon can be solved, but the cost is increased and the size of the apparatus is increased. There was an inconvenience.

The present invention has been made in view of the inconveniences of the above-mentioned prior art, and an object of the present invention is to prevent backflow of ink and improve image quality with a simple structure. It is an object of the present invention to provide an ink jet recording apparatus provided with a suction pump for recovering ejection performance, which can improve the durability of a tube and the reliability of a pump by eliminating rotation.

[0012]

According to the present invention, in an ink jet recording apparatus for recording by ejecting ink from a recording means to a recording material, a tube communicating with a discharge port of the recording means is deformed by a pressure roller. The above object is achieved by providing a recovery tube pump for generating a negative pressure at the discharge port and transmitting a driving force to the pressure roller only in a direction in which a negative pressure is generated at the discharge port. To do.

According to another aspect of the present invention, in addition to the above configuration, a one-way clutch is provided between the tube pump and its drive source, or a conveying roller is provided between the drive source and the tube pump. , Wrap a clutch spring around the conveyor roller shaft, abut one end of the clutch spring on a part of the gear on the conveyor roller shaft, and tighten the clutch spring when the conveyor roller rotates in the direction to generate negative pressure at the discharge port. The driving force is transmitted to the tube pump, and when the conveying roller rotates in the opposite direction, the clutch spring is loosened so that the driving force is not transmitted to the tube pump. To do.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing a main configuration of an embodiment of an ink jet recording apparatus to which the present invention is applied. In the inkjet recording apparatus of FIG. 1, the recording material 12 is intermittently fed in a predetermined direction by a transport (sub-scanning) mechanism, and recording is performed while moving the recording means 1 in the direction intersecting with the direction (main scanning). It is configured.

In FIG. 1, a recording material 12 made of paper or a plastic thin plate is conveyed in the direction of arrow A by a paper feeding device (not shown) and fixed to a bottom plate 13 by an upper guide 14.
And is guided between the lower guide 15. Further, the recording material 12
Is guided in the traveling direction by both guides 14 and 15, and enters between a pair of conveying rollers composed of a conveying roller (sub-scanning roller) 16 and a conveying driven roller (sub-scanning driven roller) 17. The pair of conveying rollers 16 and 17 are rotationally driven by a conveying motor 18. The recording material 12 is carried out onto the platen 19 fixed to the bottom plate 13 by drivingly controlling the pair of conveying rollers 16 and 17, and the paper discharge roller 20 and the paper discharge driven roller 21 are supported while being supported by the platen 19. The sheet reaches the space between the pair of paper discharge rollers, and the conveyance is temporarily stopped there. The paper discharge roller pairs 20 and 21 are driven by the carry motor 18 in synchronization with the carry roller pairs 16 and 17.

A paper discharge guide 22 is supported on the bottom plate 13, and the pair of paper discharge rollers 20 and 21 are used to form an arrow A.
The recording material 12 conveyed in the direction is ejected from the paper ejection guide 22.
It is discharged to the outside of the device body while being guided by. Aluminum particles having a grain size of 1000 to 2000 are adhered to the surfaces of the transport roller 16 and the paper discharge roller 20, and the driven rollers 17 and 21 are baked with chloroprene rubber. Therefore, it is possible to convey the recording material 12 with a high conveying force and with high accuracy.

A main scanning rail (guide rail) 2 is provided above the platen 19 in parallel with the axial direction of the transport roller 16.
3 is fixed. The recording means 1 is a carriage 24
The carriage 24 is mounted on the bearing portion 2 of the carriage 24.
The guide rail 23 is inserted through the guide rail 5, and is movable along the guide rail 23. The recording means 1 mounted on the carriage 24 in the present embodiment is composed of a plurality of (four) recording means using different inks, and in the case of full color recording, for example, black, cyan, magenta, yellow. 4 colors of ink are used. Also,
Each recording means (recording head) 1 of the present embodiment is of a cartridge type in which an ink tank and a recording portion (ink ejection portion) are integrated, and each of them is positionably mounted on a carriage 24 in a replaceable manner.

An ink ejecting portion (ejection port forming surface) is provided below each recording means 1, and a plurality of ejection ports are formed in the ink ejecting portion in a direction intersecting with the moving direction of the carriage 24. Has been done. Each ink ejecting section is arranged so as to eject ink toward the platen 19 side through the opening at the bottom of the carriage 24.

The recording means (recording head) 1 is an ink jet recording means for ejecting ink by utilizing heat energy, and is provided with an electrothermal converter for generating heat energy. Further, the recording head 1 is
Recording is performed by ejecting ink from the ejection port by utilizing the pressure change caused by the growth and contraction of bubbles caused by film boiling caused by the heat energy applied by the electrothermal converter.

FIG. 2 is a partial perspective view schematically showing the structure of the ink ejection portion of the recording means (recording head) 1.
In FIG. 2, a plurality of ejection openings 52 are formed at a predetermined pitch on the ejection opening formation surface 51 that faces the recording material 12 with a predetermined gap (for example, about 0.5 to 2.0 mm). Each liquid path 5 that connects the common liquid chamber 53 and each discharge port 52
Electrothermal converters (heat generating resistors, etc.) 55 for generating energy for ejecting ink are arranged along the wall surface of No. 4. In this example, the recording head 1 is mounted on the carriage 24 in such a positional relationship that the ejection ports 52 are arranged in a direction intersecting the moving direction (main scanning direction) of the carriage 24. In this way, the corresponding electrothermal converter 55 is driven (energized) based on the image signal or the ejection signal to cause the ink in the liquid path 54 to film-boil, and the pressure generated at that time causes the ink to be ejected from the ejection port 52. A recording unit (recording head) 1 is configured.

In FIG. 1, a carriage motor (main scanning motor) 26 as a drive source for reciprocating the carriage 24 is fixed to the main body of the apparatus (side plate thereof, etc.). A motor pulley 27 is fixed to the rotary shaft of the carriage motor 26 and can rotate integrally with the rotary shaft. An idler pulley 28 is axially supported on the opposite side of the motor pulley 27, and a main scanning belt (carriage drive belt) 29 is stretched between the motor pulley 27 and the idler pulley 28. Carriage 2
Reference numeral 4 is connected to the carriage drive belt 29, and is reciprocally driven by the rotation of the carriage motor 26.

A home position HP of the carriage 24 is set at a position outside the recording area (or the platen 19) within the movement range of the carriage 24. In the vicinity of the home position HP, a cap 2 made of a rubber-like elastic material capable of sealing (capping) the ejection port forming surface of each recording head 1 is arranged. Further, in the vicinity of the cap 2, the ejection port 52 of each recording head 1 is provided.
A recovery device 30 is provided for eliminating defective ejection due to clogging of the paper. The recovery device 30 is configured so that the ejection port forming surface 51 is closed by the cap 2 and each ejection port 5 is closed.
2 is configured to generate a negative pressure and suck out foreign matters such as bubbles, adhered ink, and dust from the ejection port 52 together with the ink.

In the ink jet recording apparatus of FIG. 1, the recovery device 30 performs the ink suction operation from the ejection port 52.
It is carried out by driving a tube pump 4 (FIGS. 3 and 4) configured to convert the rotational driving force into a negative pressure therein. Further, the tube pump 4 is configured to be rotationally driven by the rotational driving force of the conveying roller 16 via a one-way clutch (FIG. 3) and gears 31 and 32. The tube pump 4 will be described later with reference to FIGS. 3 to 7.

A roller (not shown) is rotatably supported on the lower portion of the carriage 24, and the roller rolls on the upper surface of the recording material 12 on the platen 19 so that each recording head 1 The distance between the ejection port forming surface 51 and the recording surface of the recording material 12 is always regulated to be constant. Further, since the cap 2 is disposed near the home position HP of the carriage 24, the platen 19 cannot be extended to the home position HP. Therefore, when the carriage 24 moves toward the home position HP, the rollers of the carriage 24 are disengaged from the platen 19. Therefore, at a position outside the platen 19, the carriage 24 rides on a guide plate (not shown) provided in the recovery device 30 via the rollers.

During the recording operation, the carriage motor 26 moves the carriage 24 and the recording head 1 is driven in response to an image signal, whereby the platen 19 is moved.
Ink is ejected onto the recording material 12 stopped above to form an image for one line (main scanning). When the recording for one line is completed, the pair of conveying rollers 16 and 17 are rotated by a predetermined amount to convey the recording material 12 by a predetermined amount (for example, an amount corresponding to the height of one line) (sub scanning), and the carriage 24 again. And the recording head 1 is driven to perform recording (main scanning) of the next row. Thereafter, by repeating these main scanning and sub scanning alternately, an image is recorded on the entire recording material 12.
Then, when the rear end of the recording material 12 is detected by a sensor (not shown) arranged at a predetermined position, the recording operation is ended, and the recording material 12 is rotated by rotation of the pair of discharge rollers 20 and 21.
Is discharged to the outside of the apparatus main body along the paper discharge guide 22.

Each of the four recording means 1 comprises an ink tank portion in which yellow, magenta, cyan and black inks are stored and an ink ejection portion (recording head portion) for ejecting these inks. The section is connected to each ink ejecting section. Then, in accordance with each color-separated image signal, the four color inks are ejected from each ink ejection section (recording head section), and these four colors are superposed to form a full-color image. Note that the recording material 12 is not only fed from the paper feeding device, but also when the operator causes the recording material to enter the abutting portion of the pair of discharge rollers 20 and 21 and reversely rotates the transport motor 18. A method (manual feeding) in which the sheet is once conveyed from the paper discharge side into the sheet feeding device and then fed from the sheet feeding device again can be adopted.

The cap 2 is a discharge port 52 of the recording means 1.
The inside of the nozzle is kept in a wet state to prevent the ejection port 52 from being clogged due to ink drying or ink sticking. Further, the tube pump 4 (FIGS. 3 and 4) in the recovery device 30 connected to each cap 2 is connected to each cap 2, and each cap 2 forms the discharge port forming surface 5
By driving 1 in a sealed state, impurities such as bubbles, adhered ink, and dust generated inside the ejection port 52 are sucked and removed together with the ink, and ejection failure is eliminated.

Between the recording area (platen 19) and the cap 2, a rubber-like material for wiping and removing foreign matters (adhered matters) such as ink droplets and dust adhering to the ejection port forming surface 51 of each recording head 1. A cleaning member 33 formed of an elastic blade is arranged. This cleaning member 33
Is held by a holder 34 and is driven by a drive source (not shown).
It is configured such that it can be driven between a protruding position where it can slide on the ejection port forming surface 51 and a retracted position which is separated from the ejection port forming surface 51.

FIG. 3 is a plan view of the tube pump according to an embodiment of the present invention, FIG. 4 is a longitudinal sectional view of the tube pump of FIG. 3, and FIG. 5 is an operation of the tube pump of FIGS. 6 is a vertical cross-sectional view of FIG. 6, and FIG. 6 shows line 6 in FIG.
6 is a partial cross-sectional view taken along line -6 of FIG. 7, and FIG.
FIG. 7 is a front view of the one-way clutch viewed from 7. When the ejection port 52 of the recording unit (recording head) 1 is clogged or may be clogged, the suction recovery operation is performed at the non-recording position (normal home position HP).

3 to 5, in the non-recording position, the opening of the cap 2 is connected to the ejection port forming surface 5 of the recording means 1.
1, and the discharge port 52 is sealed. A flexible tube 3 is connected to a through hole formed in the back portion of the cap 2, and the tube 3 extends toward the tube pump 4 side.
The tube pump 4 includes a pump base 5 and guide rollers 6
Is rotatably supported, and a pressure roller 7 is rotatably supported on the guide roller 6. In the present embodiment, as shown in FIG. 3, the cap 2, the tube 3, the pressure roller 7, the shaft support structure of the pressure roller 7, etc., corresponding to the number of recording means (recording heads) 1 (four). Are provided for each four.

A detailed description will be given below. 3 to 6, the shaft 35 of the guide roller 6 is provided with a bearing 36,
It is rotatably attached to the pump base 5. An E-shaped retaining ring 37 is attached as a retainer for the bearing 36. The pressure roller 7 for pressing the tube 3 is rotatably supported by fitting a shaft 38 of the pressure roller 7 into a roller bearing 39. The roller bearing 39 is attached to the hole 42 formed in the guide roller 6 with the compression spring 41 attached to the vertical axis 40, and positioned and fixed by the E-shaped retaining ring 43. At this time, the pressure roller 7 is
A force in the direction of pressing the tube 3 is applied by the compression spring 41.

In order to position the roller bearing 39, the positioning pin 44 provided on the roller bearing 39 is used to guide the guide roller 6.
Is performed by being guided by the guide groove 45 provided in the guide roller 6 and by being guided by the guide hole 42 of the guide roller 6 on the vertical axis 40 described above. In this case, in order to make the space of the tube pump 4 as small as possible, as shown in FIG. 6, a configuration is adopted in which the heights of the positioning pins 44 are alternately changed so that the guide pins 45 overlap each other. There is.

A guide roller 6 is provided on the pump base 5.
An arcuate groove 48 concentric with the shaft 35 is formed. The pump base 5 is attached to the base 46 of the apparatus main body in such a posture that the opening of the arc-shaped groove 48 is on the lower side. The reason is that the pump base 5 is provided with a cover function and the pump operating portion is covered with the pump base 5 to prevent the user from touching the pump operating portion. This is to prevent foreign matter from entering the pump operating unit. The tube 3 is fixed while being sandwiched in tube fixing grooves 47 formed on the front side and the rear side of the guide roller 6 of the pump base 5. The end of the tube 3 on the downstream side (the side opposite to the cap 2) is connected to a waste ink processing member 11 for storing the ink sucked from the ejection port 52 by suction.

3, 5, and 5, a coiled clutch spring 61 and the gear (driving gear) 31 are fitted to the shaft 49 at the end of the conveying roller 16 (FIG. 1) in a fitted state. Has been done. The drive gear 31 is rotatably supported by a shaft 49, and the clutch spring 61 is a protrusion 6 of the drive gear 31.
2 regulates thrust direction. Further, the inner diameter of the clutch spring 61 is smaller than the outer diameter of the shaft 49 and has an appropriate amount of interference. When the transport roller 16 rotates in the arrow e direction, the clutch spring 61 acts in the tightening direction on the shaft 49 and rotates in the arrow e direction together with the transport roller 16. In this case, the end portion of the clutch spring 61 (the portion that is bent in an L shape as shown in FIG. 7) abuts on the stopper portion 63 of the drive gear 31, whereby the conveyance roller 1
The rotational driving force of 6 is transmitted to the drive gear 31. This rotational driving force is transmitted to a gear (a driven gear fixed to the shaft 35 of the guide roller 6) 32 meshing with the driving gear 31, and the pressure roller 7 moves in the direction of arrow a in FIGS. 4 and 5. It is driven to rotate in the forward direction.

On the other hand, when the transport roller 16 rotates in the direction of arrow k, the clutch spring 61 acts on the shaft 49 of the transport roller 16 in the slack direction. At this time, the torque at which the transport roller 16 and the clutch spring 61 slip is not zero, but there is some idling torque. This idling torque is the torque when the shaft 49 starts slipping with respect to the clutch spring 61 when rotating in the slack direction. Therefore, when the transport roller 16 rotates in the direction of arrow k, if the torque for rotating the tube pump 4 in the reverse direction (rotation in the direction opposite to the arrow a in FIGS. 4 and 5) is larger than the idling torque, the clutch spring 61 and the shaft 49 slip, the rotational driving force of the conveying roller 16 is not transmitted to the driving gear 31, and therefore the driving force in the reverse rotation direction is not transmitted to the pressure roller 7. In the present embodiment, the torque for rotating the tube pump 4 in the reverse direction is set to be larger than the idling torque, and the driving force in the reverse rotation direction is not transmitted to the pressure roller 7. Thus, the clutch spring 6
1 constitutes a one-way clutch. In addition,
The shaft 49 is equipped with a quinte 64 for preventing the drive gear 31 from coming off.

In the above construction, when the carry motor 18 (FIG. 1) rotationally drives the carry roller 16 in the paper feed direction (forward rotation direction indicated by arrow e) during recording, the drive gear 3
The guide roller 6 is rotationally driven in the direction of the arrow a via 1 and the driven gear 32. In this embodiment, the transport roller 1
Although the rotation of the guide roller 6 is transmitted to the guide roller 6, the rotational force of the guide roller 6 may be obtained from another roller of the recording material conveying system, another rotating part of the recording apparatus, or a driving source. When the guide roller 6 rotates in the direction of arrow a,
The pressure roller 7 axially supported by the guide roller 6 is a tube fixing groove 4 on the recording head 1 side (upstream side) of the pump base 5.
It contacts the roller guide portion 65 formed integrally with 7. This state is indicated by the position Z in FIG. At this time, the pressure roller 7 is guided by the roller guide portion 65,
It moves in the direction of arrow f while being driven to rotate (rotates) in the direction of arrow b, and moves to the position where the pressure roller 7 is pressing the tube 3.

When the guide roller 6 further rotates in the direction of arrow a, the pressure roller 7 comes into contact with the tube 3 at the position X in FIG. Press and crush until the space inside the tube of the pressing part becomes zero. When the pressure roller 7 moves (revolves) from the position Z to the position X, the pressure roller 7 has moved in the direction of the arrow f to the position where the pressure roller 7 has already pressed the tube 3 at the position Z. At the position X, the increase in pressure acting on the pressure roller 7 is suppressed within a certain range. Rather, the pressure roller 7 gradually presses the tube 3 along the roller guide portion 65, and the pressure roller 7 causes the tube 3 to move.
The fluctuation of the torque applied to the transport roller 16 when it comes into contact with can be made very small.

The tube fixing groove 47 has a shape in which the groove width increases near the roller guide portion 65. This is to prevent the reaction force of the tube 3 crushed by the pressure roller 7 from being transmitted to the pressure roller 7 side at the point where the pressure roller 7 starts to contact the tube 3. That is, as shown in FIG. 4, the tube 3 in the portion where the groove width is small near the roller guide portion 65 (the portion having the groove width h).
It is desirable to make the outer diameter of the tube 3 larger than the outer diameter of the wide portion i when the tube 3 is pressed by the pressure roller 7. However, in this case, since it also has the function of the roller guide portion 65, the width h of the arc-shaped groove portion needs to be smaller than the thickness g of the pressure roller 7.

As the guide roller 6 rotates, the pressure roller 7
When is further rotated (revolved) from position X in the direction of arrow a,
The pressure roller 7 moves while rotating (spinning) following the direction of the arrow b while the tube 3 is crushed. And Figure 4
Pause at position Y in the middle. At this time, a negative pressure is generated at the ejection port 52 of the recording unit (recording head) 1 due to the volume change in the tube 3 crushed by the pressure roller 7 between the position X and the position Y, and the ejection port 52. A suction operation for sucking ink from the ink is performed. After the suction, the guide roller 6
Is further rotated in the direction of arrow a, the pressure roller 7 is gradually separated from the tube 3 along the roller guide portion 66 on the downstream side (waste ink processing member 11 side). The movement of the pressure roller 7 at this time is substantially opposite to the movement when the tube 3 is contacted. Therefore, the pressure roller 7 is attached to the tube 3
The torque fluctuation when released from the pressed state can be made very small.

By the negative pressure suction operation described above, the ink is sucked from the ejection port 52 of the recording head 1, and the sucked ink is sequentially passed through the tube 3 to the waste ink processing member 11.
And is stored in the waste ink processing member 11.
Further, the series of operations described above is detected by the sensor protrusion 67 provided on the guide roller 6 passing through the sensor 68 provided on the pump base 5, as shown in FIGS. 3 and 5. The pressure roller 7 is positioned based on the detection result.

In the embodiments shown in FIGS. 3 to 7, since the one-way clutch composed of the clutch spring 61 is provided on the shaft 49 of the conveying roller 16, when the conveying roller 16 rotates in the direction of arrow e in the forward direction. , The rotational force is transmitted to the guide roller 6 to perform the suction operation as described above.
When the transport roller 16 reversely rotates in the direction of arrow k, its rotational force is not transmitted to the drive gear 31, and the guide roller 6 does not rotate. Therefore, the reverse driving force is not transmitted to the pressure roller 7, and the backflow phenomenon of the ink in the tube 3 as described in the conventional example does not occur.

As described above, even when the transport roller 16 reverses in the direction of arrow k, some idling torque is generated between the clutch spring 61 and the shaft 49. In this embodiment, the home position of the pressure roller 7 is set in the non-pressure area of the tube 3, and the idling torque of the clutch spring 61 is set to 40.
The drive torque of the tube pump 4 in the reverse direction (the drive torque when the pressure roller 7 rushes into the tube 3) is set to 250 to 650 g-cm. That is, when the transport roller 16 reverses in the direction of arrow k, the pressure roller 7 rotates (revolves) to a position where it contacts the tube 3, but the pressure roller 7 rushes into the tube 3 more than the idling torque. Since the torque at that time is larger, the pressure roller 7 remains stopped at this position. Therefore,
No positive pressure that causes the ink in the tube 3 to flow back to the recording head 1 side is generated. At this time, the clutch spring 61 is in a slip state with respect to the shaft 49.

According to the embodiment described above, the tube 3
In the configuration in which the tube pump 4 that performs suction recovery utilizing deformation of the tube pump 4 is provided, and the drive source of the tube pump 4 rotates normally and reversely, the tube 3 is pressed only during normal rotation when suction negative pressure is generated in the recording head. Since the driving force is transmitted to the deforming pressure roller 7, the backflow of the ink in the tube pump 4 is prevented, so that the ink overflows from the cap 2 and the ink adheres to or discharges from the ejection port forming surface 51. It has become possible to improve the quality of a recorded image by eliminating invasion of waste ink into the outlet 52.
Further, since there is no reverse rotation drive, the rotation amount of the tube pump 4 can be reduced, and the durability of the tube 3 and the reliability of the pump can be improved. further,
By using a spring clutch as a one-way mechanism for preventing reverse rotation drive, a one-way mechanism with a simple structure and light weight could be obtained.

In the above-described embodiment, the case where the tube pump 4 is driven by the rotational force of the conveying roller 16, that is, the case where the tube pump 4 is driven by the same drive source as the recording material conveying system has been described. Is, for example, a carriage motor for serially scanning the recording head,
It may be driven by using another drive source in the recording apparatus. Also in that case, a one-way mechanism is provided between the drive source and the tube pump 4.

Further, in the above-described embodiment, the clutch spring 6
The case of using the one-way mechanism using No. 1 has been described, but other types of clutches may be used as long as they have a one-way function. Further, an electromagnetic clutch, ratchet, or the like may be used as long as it is configured to transmit only the driving force in the normal rotation direction to the tube pump 4. Further, in the above-described embodiment, the shaft 49 of the transport roller 16 is
Although the configuration having the one-way mechanism has been described above, the one-way mechanism may be disposed in the pump 4 or anywhere in the drive transmission mechanism from the drive source to be used to the pressure roller 7. Good.

In the above-mentioned embodiment, an ink jet recording apparatus for color recording using a plurality of recording means 1 for recording with different color inks has been described as an example, but the present invention is one recording means. The same applies regardless of the number of recording means, such as an inkjet recording apparatus for single-color recording using the same or an inkjet recording apparatus for gradation recording using a plurality of recording means for recording with inks of the same color but different densities. It is possible to achieve the same effect.

Further, in the above-described embodiment, the serial type recording apparatus in which the recording means 1 is mounted on the carriage 24 has been described as an example, but the present invention is the whole area or a part of the recording material 12 in the width direction. The present invention can be similarly applied to a line type recording apparatus which uses a line type recording means having a length to cover the above and performs recording only by sub-scanning, and similar effects can be obtained. Further, the recording unit 1 is a cartridge type in which an ink ejection unit (recording head) and an ink tank unit are integrated, or an ink ejection unit (recording head unit) and an ink tank unit are separately provided. The same effects can be achieved regardless of the structure of the recording means, such as those connected by means of the like.

The present invention can be applied to an ink jet recording apparatus using a recording means (recording head) using an electromechanical transducer such as a piezo element, but among them, thermal energy is used. In this way, an excellent effect can be obtained in an ink jet recording apparatus of the type that ejects ink. This is because such a system can achieve high density recording and high definition recording.

Regarding the typical structure and principle thereof, see, for example, US Pat. Nos. 4,723,129 and 4740.
This is preferably done using the basic principles disclosed in US Pat. No. 7,967. This method can be applied to both the so-called on-demand type and the continuous type, but particularly in the case of the on-demand type, a liquid (ink) is used.
By applying at least one drive signal to the electrothermal converter arranged corresponding to the sheet or liquid path holding the Since the electrothermal converter generates heat energy to cause film boiling on the heat acting surface of the recording means (recording head), as a result, bubbles can be formed in the liquid (ink) in a one-to-one correspondence with this drive signal. It is valid.

Due to the growth and contraction of the bubbles, the liquid (ink) is ejected through the ejection openings to form at least one droplet. It is more preferable to make this drive signal into a pulse shape, because the bubble growth and contraction are immediately and appropriately performed, so that the ejection of the liquid (ink) with excellent responsiveness can be achieved. As this pulse-shaped drive signal, US Pat.
Those described in US Pat. Nos. 4,633,359 and 4,345,262 are suitable. Incidentally, US Pat. No. 43131 of the invention relating to the rate of temperature rise of the heat acting surface
If the conditions described in No. 24 are adopted, even more excellent recording can be performed.

As the constitution of the recording head, in addition to the combination constitution of the discharge port, the liquid passage, and the electrothermal converter (the linear liquid passage or the right-angled liquid passage) as disclosed in the above-mentioned specifications, US Pat. No. 4,558,333 and US Pat. No. 4, which disclose a configuration in which a heat acting portion is arranged in a bending region.
The structure using the specification of 459600 is also included in the present invention. In addition, Japanese Laid-Open Patent Publication No. 123670/1984 discloses a configuration in which a common slit is used as a discharge portion of a plurality of electrothermal converters, and an opening for absorbing a pressure wave of thermal energy. The present invention is also effective as a configuration based on Japanese Patent Application Laid-Open No. 138461/1984, which discloses a configuration in which the above is associated with the discharge portion. That is, according to the present invention, recording can be reliably and efficiently performed regardless of the form of the recording head.

Further, 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 material (recording medium) which can be recorded by the recording apparatus. Such a recording head may have a configuration that fills the length by combining a plurality of recording heads or a configuration as one recording head integrally formed. In addition, even with the serial type as in the above example, it is possible to electrically connect to the device body or supply ink from the device body by mounting it on the recording head fixed to the device body or on the device body. The present invention is also effective when a replaceable chip type recording head or a cartridge type recording head in which an ink tank is integrally provided in the recording head itself is used.

Further, it is preferable to add recovery means for the recording head, preliminary auxiliary means, etc., which are provided in the present invention as a configuration of the recording apparatus, because the effects of the present invention can be further stabilized. If these are specifically mentioned,
Capping means, cleaning means, pressurizing or suctioning means, electrothermal converter or other heating element or preheating means by a combination thereof, and ejection different from recording are applied to the recording head. Performing the preliminary ejection mode is also effective for stable recording.

Regarding the type or number of recording heads to be mounted, for example, only one is provided corresponding to a single color ink, or a plurality of inks having different recording colors and densities are supported. And a plurality of them may be provided. That is, for example, the recording mode of the recording apparatus is not limited to the recording mode only for mainstream colors such as black,
The recording head may be integrally configured or a combination of a plurality of recording heads may be used. However, the present invention is extremely effective for an apparatus having at least one of a mixed color of different colors or a full color of mixed colors.

In addition, in the above-described embodiments of the present invention, the ink is described as a liquid, but it is an ink that solidifies at room temperature or lower and softens or liquefies at room temperature, or an ink jet. In the method, the temperature of the ink itself is generally adjusted within a range of 30 ° C. or higher and 70 ° C. or lower to control the temperature of the ink so that the viscosity of the ink is within a stable ejection range. Any liquid may be used. in addition,
Whether the temperature rise due to thermal energy is positively used as the energy for changing the state of the ink from the solid state to the liquid state, or the ink that solidifies when left standing for the purpose of preventing ink evaporation is used. In any case, the ink is liquefied by applying the thermal energy according to the recording signal and the liquid ink is ejected,
The present invention is also applicable to the case of using an ink which has a property of being liquefied only by thermal energy, such as one which has already started to solidify when it reaches the recording medium.

The ink in such a case is described in JP-A-54-
As described in JP-A-56847 or JP-A-60-71260, a mode in which it is held as a liquid or a solid in a concave portion or a through hole of a porous sheet and faces the electrothermal converter. May be In the present invention, the most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.

In addition, as the form of the ink jet recording apparatus according to the present invention, besides the one used as an image output terminal of information processing equipment such as a computer, a copying apparatus combined with a reader or the like, and further a facsimile apparatus having a transmitting / receiving function. It may be in the form of the above.

[0058]

As is apparent from the above description, according to the present invention, in the ink jet recording apparatus for recording by ejecting ink from the recording means to the recording material, the tube communicating with the ejection port of the recording means is pressed. A recovery tube pump for generating a negative pressure at the discharge port by deforming with a roller is provided, and a driving force is transmitted to the pressure roller only in a direction in which a negative pressure is generated at the discharge port. Therefore, with a simple configuration, it is possible to prevent backflow of ink and improve the image quality, and it is possible to improve the durability of the tube and the reliability of the pump by eliminating the reverse rotation of the pump. An inkjet recording device provided with a suction pump is provided.

According to another aspect of the present invention, in addition to the above configuration,
A configuration in which a one-way clutch is provided between the tube pump and its drive source, or a carrying roller is provided between the drive source and the tube pump, and a clutch spring is wound around the carrying roller shaft, and one end of the clutch spring is provided. Abutting against a part of the gear on the transport roller shaft, and when the transport roller rotates in the direction to generate a negative pressure at the discharge port, the clutch spring is closed and the driving force is transmitted to the tube pump. Since the clutch spring is loosened and the driving force is not transmitted to the tube pump when rotating in the direction of, the above effect can be achieved more efficiently.

[Brief description of drawings]

FIG. 1 is a perspective view showing a main configuration of an embodiment of an inkjet recording apparatus to which the present invention is applied.

FIG. 2 is a partial perspective view schematically showing the structure of an ink ejection portion of the recording means in FIG.

FIG. 3 is a plan view showing the configuration of an embodiment of a suction recovery device according to the present invention.

FIG. 4 is a vertical cross-sectional view of the suction recovery device of FIG.

5 is a schematic vertical sectional view showing an operation of the suction recovery device of FIG.

6 is a partial cross-sectional view taken along the line 6-6 in FIG.

FIG. 7 is a front view of the one-way mechanism taken along the line 7-7 in FIG.

FIG. 8 is a vertical cross-sectional view showing a state at the start of the suction operation of the conventional suction recovery device.

9 is a vertical cross-sectional view showing a state at the end of the suction operation of the suction recovery device of FIG.

[Explanation of symbols]

 1 Recording means (recording head) 2 Cap 3 Tube 4 Tube pump 5 Pump base 6 Guide roller 7 Pressurizing roller 11 Waste ink processing member 12 Recording material 16 Conveying roller 18 Conveying motor 19 Platen 20 Paper discharging roller 23 Guide rail 24 Carriage 26 Carriage Motor 30 Recovery Device 31 Drive Gear 32 Driven Gear 39 Roller Bearing 40 Vertical Axis 41 Compression Spring 47 Tube Fixing Groove 48 Arc-Shaped Groove 49 Conveyor Roller Shaft 51 Discharge Port Forming Surface 52 Discharge Port 55 Electrothermal Converter 61 Clutch Spring 65 Roller guide portion 66 Roller guide portion 68 Sensor

Claims (5)

[Claims] 1. In an inkjet recording apparatus for recording by ejecting ink from a recording means onto a recording material, a negative pressure is generated at the ejection port by deforming a tube communicating with the ejection port of the recording means with a pressure roller. An ink jet recording apparatus, wherein a recovery tube pump is provided, and the driving force is transmitted to the pressure roller only in a direction in which a negative pressure is generated at the ejection port. 2. The ink jet recording apparatus according to claim 1, wherein a one-way clutch is provided between the tube pump and its drive source. 3. A conveying roller is arranged between the drive source and the tube pump, a clutch spring is wound around the conveying roller shaft, and one end of the clutch spring is abutted against a part of a gear on the conveying roller shaft, When the conveying roller rotates in the direction of generating a negative pressure at the discharge port, the clutch spring is closed to transmit the driving force to the tube pump, and when the conveying roller rotates in the opposite direction, the clutch spring is loosened. The ink jet recording apparatus according to claim 2, wherein the driving force is not transmitted to the tube pump. 4. The ink jet recording apparatus according to claim 1, wherein the recording means is an ink jet recording means including an electrothermal converter that generates thermal energy used for ejecting ink. 5. The ink jet recording apparatus according to claim 4, wherein the recording means ejects the ink from the ejection port by utilizing film boiling generated in the ink by the thermal energy generated by the electrothermal converter. ..