JP2815204B2 - Ink jet recording device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus that performs recording by discharging ink from a recording head to a recording member.

2. Description of the Related Art A liquid ejection recording apparatus (inkjet recording apparatus) that discharges a recording liquid from a recording head to record information such as characters and images is known.

Paper and plastic sheets are mainly used for the recording members of this type of apparatus. Particularly, compared to other recording methods, there is an advantage that operation noise is small, a basic mechanical structure is simple and inexpensive, and a computer is used. Have been adopted in various fields as recording output devices such as word processors.

However, in this type of apparatus, recording is performed by directly ejecting a recording liquid (hereinafter referred to as ink) from a nozzle of a recording head. Therefore, in order to maintain a state in which ink can always be ejected, this type of apparatus is used. No special consideration is needed. That is, since the ink remains in the nozzles of the print head even during printing, it is necessary to provide a device for preventing the ink in the nozzles from drying or changing in quality such as viscosity increase due to evaporation. There is known an apparatus in which a so-called capping means for covering the orifice of a head with a lid and preventing drying or evaporation of ink is provided.

However, in a low-humidity environment, or during a long period of non-operation, an increase in the viscosity of the ink is unavoidable only with the above-described drying prevention means. A recovery mechanism is used in which suction is applied to apply a negative pressure from the orifice, and ink remaining in the nozzles of the recording head is sucked out, or pressure is applied to the inside of the nozzles using a pump or the like, and deteriorated ink is discharged from the orifice. I have been. This recovery mechanism also has a function of removing bubbles in the nozzle and the ink tube.

Further, after the recovery operation is performed, ink adheres to the orifice surface and recording cannot be performed as it is, so that a so-called orifice screening operation is performed in which an ink absorber such as a sponge is brought into contact with the orifice surface to remove the adhered ink.

In a print head with many nozzles, nozzles that are not used during printing are clogged, so a so-called substantially closed space discharge is performed in which an orifice is inserted into a chamber in which a carrier is fixed with a certain clearance and discharge is performed. ing.

[Problems to be Solved by the Invention] However, the above conventional example has the following disadvantages.

1) In order to cap the recording head, it is necessary to move the recording head to a cap position where the capping means exists. On the other hand, in the recording apparatus, there are many chances of recording again after the power is on for 3 to 10 minutes. In such a case, since the recording is performed after the recording head moves from the cap position to the recording position, the recording apparatus requires a long time until the recording is started.

2) When the capping state is in a low-humidity environment, the nozzles are clogged in a relatively short time. Therefore, the ink is discharged from the orifice by the pump, and the orifice screening operation (recovery operation) is performed. Have to do it. These operation times are added to the movement time of the print head, and furthermore, it takes time to start printing, and waste ink is consumed due to the discharged ink.

3) In a recording apparatus that discharges in a substantially closed space formed by a conveyance body, a container having a certain clearance, and the conveyance body, it is sufficient if clogging can be prevented for about 10 minutes from the maximum value of the number of continuous recordings during printing. However, during non-printing, the ink in the nozzles may be dried because it may take up to one hour or more.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an ink jet recording apparatus capable of preventing ink in nozzles from drying for a long time without moving a recording head to a cap position or performing orifice screening.

[Means for Solving the Problems] An ink jet recording apparatus according to the present invention includes a chamber having an upper surface of a conveyance body of a recording member surrounding both sides, and having a hole on the upper surface into which an orifice surface of a recording head is inserted. An ink jet recording apparatus comprising: an opening / closing means for blocking a substantially closed space formed by the chamber, the orifice surface, and the upper surface of the transporting body from an outer surface thereof when not recording to form a closed space.

The opening / closing means may be a shutter provided in the chamber and capable of abutting on the upper surface of the transport body during non-recording.

In some cases, the opening / closing means is a chamber that can be brought into contact with the upper surface of the transport body during non-recording.

In some cases, the above-mentioned supply source for supplying steam into the substantially closed space is provided.

The recording head includes a thermal energy generating element as a discharge energy generating element that generates thermal energy used for discharging ink, and uses a rapid pressure change generated by bubbles generated by the thermal energy. Some of them eject ink. Some of the recording heads have ejection ports provided over the entire width of the recording member.

[Operation] Since the substantially closed space formed by the chamber, the orifice surface, and the surface of the transporting body is closed during non-recording to form a closed space, the closed space is capped so as not to allow water vapor to escape. Therefore, the ink in the nozzle does not dry even if left for a long time.

Example Next, an example of the present invention will be described with reference to the drawings.

 FIG. 1 shows a main part of a first embodiment of the present invention.

The four line-type recording heads 1 are provided with 3456 nozzles at intervals of 16 dots / mm (not shown) at intervals of 16 dots / mm on the lower surface by utilizing foaming of ink by heating a heater. Thus, recording with a width of 216 mm is sequentially performed on each line. The four recording heads 1
The two holders 2 each correspond to four colors of black, cyan, magenta and yellow, respectively, and have a constant interval in the direction of arrow X1, which is the transport direction of the recording member 27. Fixedly supported. A head unit 3 composed of four recording heads 1 and two holders 2 is moved up and down and arrow X1, X2 by head moving means 24.
It can be moved in any direction. Each of the four ink tanks 4 stores black, cyan, magenta, and yellow inks corresponding to each recording head 4. The ink in each ink tank 4 is guided to each recording head 1 via each of four ink supply tubes 5. The supply of ink from each ink tank 4 to each recording head 1 utilizes the capillary phenomenon of the nozzles of each recording head 1, and the head of ink in each ink tank 4 is set lower than each orifice surface by a certain distance. Have been. The ink pumps 37 provided in the respective ink tanks 4 are individually controlled by a pump driver 35, and push out ink from the nozzles when the nozzles are clogged. An ink valve 25 provided for each ink pump 4 is a valve driver.
The flow path from each ink tank 4 to each recording head 1 is individually controlled by 36 to open and close.

Belt motor 8 controlled by motor driver 21
Is a seamless belt that conveys the recording member 27 in the direction of arrow X1, and has a high-resistance layer (about 10 ¹⁴ Ωcm) with a thickness of about 50 μm on its surface, The inner surface is grounded. One charger 12a controlled by the charger driver 22 charges the surface of the belt 6 to about + 1500V.
Is charged into the recording member 27 to electrostatically attract the recording member 27 to the surface of the belt 6. The belt guide 28 abuts on a belt near the recording position of each recording head 1 to maintain the flatness of the belt 6. The registration roller 11 has a registration function of receiving the fed recording member 27 and looping the recording member 27 to ensure orthogonality of the leading end of the recording member 27 with the conveyance direction. Motor driver 23, which is a pinch roller that presses against
The conveyance roller 14 and the pinch roller 15 that are operated by the rotation of the paper feed motor 16 controlled to feed the recording member 27 and convey it to the position of the registration roller 11. The cleaning knit 17 removes paper dust and the like on the belt 6. The paper discharge tray 18 is for stacking the recorded members 27 to be recorded.
It can move in the 1, X2 directions. The control circuit 19 comprehensively controls the operation order of the head driver 20, the motor drivers 21, 23, 39, the charger driver 22, the head moving unit 24, the pump driver 35, the valve driver 36, and the discharge tray moving unit 38. I do. The web 29 is for wiping ink (orifice screening) attached to the orifice surface of each recording head 1, and is made of a nonwoven fabric having excellent liquid absorbing properties. The web 29 is wound by the operation of a web motor 33 controlled by a motor driver 36 so that a clean portion always contacts each of the orifice surfaces when orifice screening is performed.

2 (a) and 2 (b) are a sectional view taken along line AA and a sectional view taken along line BB of FIG. 1, respectively. 2 (a) and 2 (b), reference numeral 40 denotes a chamber, and the chamber 40 has a leg portion 40b fixed to a portion of the belt guide 28 other than the recording area where the belt 6 does not contact. And surrounding both sides. This chamber 40 has four holes on the top
The recording head 1 is inserted into each of the holes 40a when the power is off and during printing (recording). The heat capacity of the chamber 40 is almost the same as the capacity of four head substrates. The inner upper wall of the chamber 40 has a clearance of 2 to 3 mm from the surface of the belt 6.
A seal plate 41 is provided, which is a plate-like member having elasticity that separates the inside of 40 from the outside. A shutter 42 is provided on the paper discharge side of the chamber 40 as an opening / closing means that can be brought into contact with and retracted from the belt 6 by a shutter moving means (not shown) built in the chamber 40. The chamber 40 and the belt 6 can maintain the humidity near each orifice surface constant by inserting the portions near the orifice surface of each of the recording heads 1 into the holes 40 at the time of recording. A substantially closed space is formed.

The plasticity of the ink used in this example is 55% water, 40% diethylene glycol, and 5% dye, and the saturated vapor pressure at 50 ° C. balances with 88% humidity.

Next, the operation of the embodiment shown in FIGS. 1 and 2 will be described with reference to FIG.

The power is turned on from the state of FIG. 2 (step 101).
First, the shutter 42 retracts from the belt 6 (step
102), the head unit 3 is lifted about 1 mm out of the chamber 40 by the head moving means 24 (step 10).
3). Next, it is checked whether or not there is a nozzle recovery signal (step 104). If there is a nozzle recovery signal, the discharge tray 18 is first retracted in the direction of arrow X1 (step 105).
Thereafter, the head unit 3 is moved by the arrow by the head moving means 24.
It moves in the X1 direction and stops at the orifice surface of each recording head 1 or at a position facing the abutting portion of the web 29 (step 106). Next, the head unit 3 descends again, and the orifice surface of each recording head 1 is
(Step 107). Subsequently, each ink valve 25 is opened (stitch 108), each ink pump 37 is driven for about 0.5 seconds, ink is pushed out from each nozzle of each recording head 1, and simultaneously, the web motor 33 is driven, and the web 29 is moved for a predetermined distance. Sent (step 109). Thus, the extruded ink is absorbed by the web 29. Here, the head unit 3 moves up again (step 110).
Next, each ink valve 25 is closed (step 111), an ejection signal of about 10 pulses is given, and the ink ahead of the heater of each recording head 1 is discarded, and ten idle ejections are performed (step 11).
2). In this state, the head unit 3 descends (step 113), and the web 29 is fed to completely wipe off the ink attached around each orifice (steps 114 and 11).
Five). Subsequently, the head unit 3 moves upward, moves in the direction of the arrow X2 and stops at the recording position, and then the head unit 3 descends again, and the orifice surface of each recording head 1 is moved to the corresponding position hole 40a of the chamber 40. Is inserted into. At the same time, the discharge tray 18 returns to the recording position (step 11).
6). Thereafter, or as a result of the check in step 104, if there is no nozzle recovery signal, each ink valve 25 is opened (step 117).

Next, the paper feed motor 16 is turned on, and one sheet of the recording 27 is fed between the transport roller 14 and the pinch roller 15 (step 118). The fed recording member 27 follows the registration roller 11 at the leading end, and is conveyed until orthogonality with the conveyance direction is ensured (steps 119 and 120). Thereafter, the belt motor 8 and the chargers 12a and 12b are turned on (step 121), and the negatively charged recording member 27 is turned on.
Is attracted to the positively charged belt 6 and conveyed,
After the tip is pressed by the seal plate 41, it enters the chamber 40. The inside of the chamber 40 has only a small-area communication port with outside air on the paper discharge side, and maintains a semi-sealed state, so that the ink in each nozzle of each recording head 1 is less likely to evaporate. . The feeding of the recording member 27 is counted in synchronization with the start of the belt motor 8, and the recording member 27 is counted.
The recording (printing) of each color is performed from the time when the leading end of each of the recording heads 1 reaches each recording head 1 (step 122).

The recording member 27 on which the recording has been completed is separated from the belt 6 by curvature and discharged to the paper discharge tray 18. After the paper ejection is completed (step 123), the belt motor 8 and the chargers 12a, 12
2b is turned off (step 124). Here, it is checked whether or not the next recording is to be performed (step 125), and if so, the process returns to step 118. If the next recording is not performed, steps 126 to 137, which are the same sequence as the above steps 105 to 116, respectively, are performed, and the head unit 3 is lowered (step 138) so that the orifice surface of each recording head 1 is raised. After being inserted into the corresponding holes 40a of the chamber 40, the power is turned off (step 139).

When printing continuously, every 10 minutes (every 200 sheets)
Then, each recording head 1 moves on the web 29 to perform 50 to 100 idle shots, and then resumes recording. Considering the low number of continuous printing of 200 sheets or more, it is considered that the blanking every 10 minutes hardly affects the printing speed.

In this embodiment, the ink is ejected by utilizing the bubbling of the ink by the heating of the heater. Since the ink is easily evaporated, forming a substantially closed space using a chamber is extremely effective in suppressing the evaporation of the ink. It is valid.

In the first embodiment shown in FIGS. 1 and 2, the chamber is provided with a shutter. However, as shown in FIG. 4, a cylindrical chamber 62 is provided for each recording head 61, and a belt 63 is provided at the time of recording. 1m clearance with each chamber 62
m, the recording head 61 is lowered at the time of non-recording, and each chamber 62 is brought into contact with the belt 63 for capping, so that the chamber can have a function as an opening / closing means.

In addition, the present invention, as shown in FIG.
The present invention can also be applied to an ink jet recording apparatus provided with.
In this example, the recording head
The configuration can be the same as that of the first embodiment shown in FIGS. 1 and 2 except that a chamber 71, a shutter 72, and a seal plate 74 are provided.

Further, if a steam supply source for supplying steam to the substantially closed space is provided for each of the above embodiments, the drying of the ink can be more reliably prevented.

As described above, the present invention brings about an excellent effect particularly in a recording head and a recording apparatus of a bubble jet system among the ink jet recording systems. Regarding the typical configuration and principle, it is preferable to use the basic principle disclosed in, for example, US Pat. Nos. 4,723,129 and 4,740,796. This method can be applied to both the so-called on-demand type and the continuous type. In particular, in the case of the on-demand type, it is arranged corresponding to the sheet or liquid path holding the liquid (ink). That corresponds to the recorded information on the electrothermal transducer
By applying at least one drive signal that gives a rapid temperature rise to obtain nucleate boiling, heat energy is generated in the electrothermal transducer, causing nucleate boiling on the heat-acting surface of the recording head. This is effective because air bubbles in the liquid (ink) can be formed one by one. The liquid (ink) passes through the discharge opening due to the growth and contraction of this gas.
To form at least one liquid.

When the drive signal is formed into a pulse shape, the growth and shrinkage of the bubble are performed immediately and appropriately, so that the ejection of a liquid (ink) having particularly excellent responsiveness can be achieved, which is more preferable. As the pulse-shaped drive signal, those described in U.S. Pat. Nos. 4,463,359 and 4,434,262 are suitable. Further, if the conditions described in US Pat. No. 4,313,124 relating to the temperature rise rate of the heat acting surface are adopted, more excellent recording can be performed. As the configuration of the recording head, in addition to the combination configuration of the discharge port and the liquid path electrothermal converter (linear liquid flow path or right-angled liquid flow path) as disclosed in the above specification, the heat acting portion is bent. A configuration using U.S. Pat. No. 4,558,333 or U.S. Pat. No. 4,591,600, which discloses a configuration arranged in a region to be formed, is also included in the present invention. In addition, JP-A-59-123670 discloses a configuration in which a slit common to a plurality of electrothermal transducers is used as a discharge section of the electrothermal transducer.
The effect of the present invention is also effective in a configuration based on Japanese Patent Application Laid-Open No. 138461/1984, which discloses a configuration in which an opening for absorbing a pressure wave of thermal energy corresponds to a discharge portion. Further, as a full line type recording head having a length corresponding to the width of the maximum recording medium that can be recorded by the recording apparatus,
As disclosed in the above-mentioned specification, either a configuration that satisfies the length by combining a plurality of recording heads or a configuration as a single recording head integrally formed may be used. The effect described above can be exhibited more effectively. In addition, it is provided integrally with a replaceable chip-type recording head or the recording head itself, which can be electrically connected to the apparatus main body and supplied with ink from the apparatus main body by being attached to the apparatus main body. The present invention is also effective when a cartridge type recording head is used. It is preferable to add recovery means, preliminary auxiliary means, and the like to the printhead provided as a configuration of the printing apparatus, because the effects of the present invention can be further stabilized. If these are specifically raised, capping means for the recording head, cleaning means,
Pressurizing or absorbing means, preheating means using an electric heat exchanger or another heating element or a combination thereof, and performing a predischarge mode in which discharge is performed separately from recording is also effective for performing stable recording. It is. Further, the recording mode of the recording apparatus is not limited to the recording mode of only the main color such as black, and the recording head may be integrally configured or a combination of a plurality of recording heads. The present invention is very effective for an apparatus having at least one of the full colors.

[Effects of the Invention] As described above, according to the present invention, capping can be performed at the recording position and the recording head is moved from the cap position to the recording position by blocking the substantially closed space from the outside when the recording is not performed to form a closed space. Time and the time required for the nozzle recovery operation can be saved, and the recording can be started earlier. Also, since the tightness of the substantially closed space increases,
It is possible to prevent nozzle clogging for a long time. Further, the number of times the ink is pushed out by the pump to recover the nozzles is reduced, so that the ink can be saved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a main part of a first embodiment of an ink jet recording apparatus according to the present invention, and FIG.
2 (b) is a sectional view taken along the line BB of FIG. 1, FIG. 3 is an operation flowchart, and FIGS. 4 and 5 show the second and third embodiments, respectively. FIG. DESCRIPTION OF SYMBOLS 1 ... Recording head, 2 ... Holder, 3 ... Head unit, 4 ... Ink tank, 5 ... Ink supply tube, 6 ... Belt, 8 ... Belt motor, 11 ... Registration roller, 12a, 12b ... Charging device, 14 ... Convey roller, 15 ... Pinch roller, 16 ... Paper motor, 17 ... Cleaning unit, 18 ... Discharge tray, 19 ... Control circuit, 20 ... Head driver, 21 , 23,39 …… Motor driver, 22… Charge driver, 24 …… Head moving means, 25 …… Ink valve, 27 …… Recording member, 28 …… Belt guide, 29 …… Web, 33 …… Web motor, 35 ... Pump driver, 36 ... Valve driver, 37 ... Ink pump, 38 ... Discharge tray moving means, 40 ... Chamber, 40a ... Hole, 40b ... Leg, 42 ... Shutter, 61 ... Recording head, 62: Chamber, 63: Belt, 71: Recording head, 72: Chamber, 73: Shutter, 74: Seal plate, 75: Conveying drum, 101 to 139: Step.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masafumi Wataya 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Ken Doi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon (72) Inventor Shujiro Kadowaki 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Toshiyuki Yanaka 3-30-2, Shimomaruko 3-chome, Ota-ku, Tokyo Canon Inc. ( 58) Fields surveyed (Int.Cl. ⁶ , DB name) B41J 2 / 01,2 / 165

Claims (6)

(57) [Claims] 1. An ink jet recording apparatus comprising: a chamber having an upper surface surrounding a side portion of a conveying body of a recording member and a hole provided on an upper surface thereof for inserting an orifice surface of a recording head; An ink jet recording apparatus, comprising: an opening / closing means for blocking a substantially closed space formed by a surface and an upper surface of the transporting body from an outer surface thereof when recording is not performed, and forming a closed space. 2. An ink jet recording apparatus according to claim 1, wherein said opening / closing means is a shutter provided in said chamber and capable of abutting on the upper surface of said transport body during non-recording. 3. The ink jet recording apparatus according to claim 1, wherein said opening / closing means is a chamber which can be brought into contact with the upper surface of said transport body during non-recording. 4. An ink jet recording apparatus according to claim 1, further comprising a steam supply source for supplying water vapor into said substantially closed space. 5. The recording head has a thermal energy generating element as a discharge energy generating element for generating thermal energy used for discharging ink, and a rapid energy generated by bubbles generated by the thermal energy. 5. The ink jet recording apparatus according to claim 1, wherein the ink is ejected by utilizing a pressure change. 6. An ink jet recording apparatus according to claim 1, wherein said recording head is provided with a discharge port over the entire width of said recording member. .