JPH03184870A - Ink jet recorder - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an inkjet recording apparatus that performs recording by ejecting ink from a recording head onto a recording member.

[Prior Art] Liquid jet recording devices (inkjet recording devices) that record information such as characters and images by ejecting recording liquid from a recording head are widely known.

This type of device mainly uses paper, plastic snack sheets, etc. as the recording material, and has the advantage that the operating noise is low compared to other recording methods, and the basic mechanical structure is simple and inexpensive. It has been adopted in various fields as a recording/output device for computers, word processors, etc.

However, since this type of device performs printing by ejecting recording liquid (hereinafter referred to as ink) directly from the nozzles of the print head, it is necessary to keep the ink in a state where it can be ejected at all times, which is not the case with other types of devices. No special consideration is required.

In other words, since the ink remains in the nozzle of the print head even during printing, it is necessary to take measures to prevent the ink in the nozzle from drying out or deteriorating in quality, such as increasing viscosity due to evaporation. An apparatus is known that is provided with a so-called capping means that covers the orifice of the head with a lid to prevent ink from drying or evaporating.

However, in low-humidity environments or during long-term suspension, the viscosity of the ink cannot be prevented by using only the above-mentioned drying prevention means. A recovery mechanism is used that applies negative pressure through an orifice to suck out the ink stagnant inside the nozzle of the recording head, or uses a pump or the like to apply pressure inside the nozzle to discharge degraded ink from the orifice. I've been exposed to it. This recovery mechanism also has the function of removing air bubbles inside the nozzle and ink tube.

Furthermore, after the recovery operation is performed, ink adheres to the orifice surface and recording is impossible as it is, so a so-called orifice cleaning operation is performed in which an ink absorber such as a sponge is brought into contact with the orifice m1 to remove the adhered ink.

Furthermore, in a recording head with a large number of nozzles, the nozzles that are not used during recording can become clogged, so so-called nearly closed space discharge is performed, in which an orifice is inserted into a chamber in which the carrier is fixed with a certain clearance. ing.

[Problem to be solved by the invention] However, the above conventional example had the following drawbacks.

1) In order to cap the recording head, it is necessary to move the recording head to the cap position where the capping means is present. On the other hand, in a recording device, there are many opportunities to record again after leaving the power on for 3 to 10 minutes. In such a case, the recording head must move from the cap position to the recording position before recording, resulting in a recording apparatus that takes time to start recording.

2) If the capping condition is in a low humidity environment, the nozzle will become clogged relatively quickly, so drain the ink from the orifice with a pump and perform an orifice cleaning operation (recovery operation). These operation times are added to the travel time of the recording head, and it takes time to start recording, and wasteful ink consumption occurs due to discharged ink.

3) In a recording device that performs discharging in a nearly closed space formed by a container and a conveyor with a certain gap between the conveyor and the conveyor, during recording, considering the maximum number of consecutively recorded sheets, if the clothes are clogged or stuck for about 10 minutes, 1 - minutes, but it may last for more than an hour during non-recording periods, so there is a risk that the ink in the nozzles may dry up.

SUMMARY OF THE INVENTION An object of the present invention is to provide an ink jet recording apparatus that can prevent ink in nozzles from drying out for a long time without moving the recording head to a cap position or performing orifice cleaning.

[Means for Solving the Problems] The inkjet recording apparatus of the present invention includes a chamber in which the upper surface of the recording member conveyance body surrounds both sides, and the upper surface is provided with a hole into which the orifice surface of the recording head is inserted. The inkjet recording apparatus includes: an opening/closing means that blocks a substantially closed space formed by the chamber, the orifice surface, and the upper surface of the conveyance body from an outer surface thereof during non-recording to form a closed space.

The opening/closing means may be a shutter that is provided in the chamber and can come into contact with the upper surface of the carrier during Jl-recording.

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

Some devices are provided with a steam supply source that supplies water vapor into the substantially closed space.

The recording head is equipped with a thermal energy generating element as an ejection energy generating body that generates thermal energy used to eject ink, and utilizes rapid pressure changes caused by bubbles generated by the thermal energy. There are some that eject ink by doing this. Some of the recording heads are provided with ejection ports over the entire width of the recording member.

[For A1] The nearly closed space formed by the chamber, the orifice direction, and the conveyor surface + Mi is shut off when not recording, making it a closed space, so this closed space is painted to prevent water vapor from escaping. . Therefore, the ink in the nozzle does not become turbulent even during long periods of time.

[Embodiments] Next, embodiments of the present invention will be described with reference to the drawings.

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

Although not shown in the drawings, the four-tree line type recording head 1 has 3456 nozzles on its bottom surface spaced at intervals of 16 dots/mm that utilize foaming of ink by heating the heater. Accordingly, recording with a width of 216 mm is sequentially performed line by line. The four recording heads 1 each correspond to the four colors black, cyan, magenta, and yellow, and are spaced one foot apart in the direction of arrow X1, which is the conveyance direction of the recording member 27. 1 with two holders 2 like this. 'i1 foot supported. 4-wooden recording head 1 and 2-wooden holder 2
The head unit 3 includes a head moving means 24.
It is possible to move up and down and in the directions of arrows XI and X2. Each of the four ink tanks 4 has black, cyan, and black ink corresponding to each d recording head 4.
Contains magenta and yellow ink. The ink in each ink tank 4 is guided to each recording head 1 through four ink supply duplexes 5, respectively. 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 water head of the ink in each ink tank 4 is set a certain distance lower than each orifice surface. has been done. The ink pumps 37 provided in each ink tank 4 are individually controlled by pump drivers 35, and push out ink from the nozzles when the nozzles become clogged. The ink valves 25 provided in each ink pump 4 are individually controlled by a valve driver 36 to open and close the flow path from each ink tank 4 to each recording pad 1, respectively.

Belt motor 8 controlled by motor driver 21
The belt 6 as a conveying body that operates by the rotation of is a seamless belt that conveys the recording member 27 in the direction of the arrow
approximately Ωcm>, and the inner surface is grounded. One charger 12a controlled by the charger driver 22 charges the surface of the belt 6 to about +1500V, and the other charger 12b also controlled by the charger driver 22 charges the recording member 27 with a negative charge. The recording material 27 is electrostatically attracted to the surface of the belt 6.

The belt guide 28 maintains the flatness of the belt 6 by contacting the belt near the recording position of each recording head 1. The registration roller 11 receives the fed recording member 27.
A bench roller has a resist function of stopping and looping the recording member 27 to ensure perpendicularity with the conveying direction of the leading end of the recording member 27, and presses the recording member 27 against the belt 6 to strengthen suction. It is. The conveyance roller 14 and the pinch roller 15 operated by the rotation of the paper feed motor 16 controlled by the motor driver 23 feed the recording member 27 and convey it to the position of the registration roller 11 . The cleaning unit 17 removes paper dust and the like on the belt 6. The paper discharge tray 18 is for stacking recorded members 27 that have been recorded, and is movable in the directions of arrows X1 and X2 under the control of a paper discharge tray moving means 38. The control circuit 19 comprehensively controls the operation order of the head driver 20, motor drivers 21, 23, 39, charger driver 22, head moving means 24, pump driver 35, valve driver 36, and discharge tray moving means 38. do. The web 29 is for wiping off ink adhering to the orifice surface of each recording head 1 (orifice cleaning), and is made of a nonwoven fabric with excellent liquid absorption properties. This web 29 is wound up by the operation of a web motor 33 controlled by a motor driver 36 so that a clean portion always comes into contact with each orifice surface when orifice cleaning is performed.

FIGS. 2(a) and 2(b) are a sectional view taken along the line AA and BB in FIG. 1, respectively. Figure 2 (a), (
In b), 40 is a chamber, and the leg portion 40b is fixed to a portion of the belt guide 28 other than the recording area where the belt 6 does not come into contact, and one of the belts 6
It surrounds the surface and both sides.

This chamber 40 is provided with four holes 40a on the top surface, and the tip of each recording head 1 including the orifice surface is inserted into each hole 40a when the power is off and during printing (recording). be done. The heat capacity of this chamber 40 is approximately 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 with the surface of the belt 6, and a seal plate 41, which is an elastic plate-like member that isolates the inside of the chamber 40 from the outside, is provided on the paper feeding side of the chamber 40. It is provided.

Further, on the paper discharge side of the chamber 40, a shutter 42 is provided as an opening/closing means that can be brought into contact with and retracted from the belt 6 by means of a shutter moving means (not shown) built into the chamber 2 bar 40. The chamber 40 and the belt 6 are capable of maintaining constant humidity in the vicinity of each orifice surface by inserting the portion of each recording head 1 near the orifice surface into each hole 40 during recording. Forms a nearly closed space.

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

Next, the operation of the embodiment shown in FIGS. 1 and 2 will be explained with reference to FIG. 3.

The power is turned on from the state shown in Figure 2 (step 101)
First, the shutter 42 is retracted from the belt 6 (step 102), and the head unit 3 is lifted about 1 mm outside the chamber 40 by the head moving means 24 (step 102).
Step 103). Next, it is checked whether or not there is a nozzle recovery signal (step 104), and if there is a nozzle recovery signal, the paper output tray 18 is first retracted in the direction of arrow X (step 105), and then the head unit 3 is a head moving means 24
The recording head 1 moves in the direction of the arrow X1 and stops at a position where the orifice surface of each recording head 1 faces the portion in contact with the web 29 (step 106). Next, the head unit 3 descends again, and the orifice surface of each recording head 1 comes into contact with the web 29 (step 107). Subsequently, each ink valve 25 opens (step 108), each ink pump 37 is driven for about 0.5 seconds, and ink is pushed out from each nozzle of each recording head 1. At the same time, the web motor 33 is driven to spread the web 29. It is sent a certain distance (step 109). As a result, the extruded ink is absorbed into the web 29. Here, the head unit 3 rises again (step 110). Next, each ink valve 25 is closed (step 111), and an ejection signal of about 10 pulses is applied to discard the ink past the heater of each recording head 1, causing 104 empty injections (step 112). In this state, the head unit 3 descends (step 113), and the web 2
9 is sent to completely wipe off the ink attached around each orifice (steps 114, 115). Subsequently, the head unit 3 rises, moves in the direction of arrow
is inserted into each corresponding hole 40a.

At the same time, the paper discharge tray 18 also returns to the recording position (step 116). Thereafter, or if there is no nozzle recovery signal as a result of the check in step 104 above, each ink valve 25 opens (step 117).

Next, the paper feed motor 16 is turned on, and one recording sheet 27 is fed between the conveyance roller 14 and the pinch roller 15 (step 118).

The fed recording member 27 is conveyed until its leading edge follows the registration rollers 11 and orthogonality with the conveyance direction is ensured (steps 119° 5 120). After that, the belt motor 8 and the charger 12
a, 12b are turned on (Step 121), the negatively charged recording member 27 is transferred to the positively charged belt 6.
After being attracted to and conveyed, the tip is pressed by the seal plate 41, and then enters the chamber 40. chamber 40
Inside, there is only a small opening communicating with the outside air on the paper ejection side, and the semi-sealed state is maintained, so the ink in each nozzle of each recording head 1 does not evaporate. .

The feeding of the recording member 27 is counted in synchronization with the activation of the belt motor 8, and recording (printing) of each color is performed from the time when the leading edge of the recording member 27 reaches each recording head 1 (step 122).

The recording member 27 on which recording has been completed is separated from the belt 6 by the curvature and is discharged to the paper discharge tray 18.

After paper ejection is completed (step 123), the belt motor 8 and the electric appliances 12a and 12b are turned off (step 124). Here, it is checked whether the next recording is to be performed or not (step 125), and if it is to be performed, the process returns to step 118 described above. If the next recording is not performed, steps 126 to 137, which are the same sequences as steps 105 to 116 above, are performed, and the head unit 3 is lowered (step 138).
After the orifice surface of each recording head 1 is inserted into each corresponding hole 40a of the chamber 40, the power is turned off (
Step 139).

In addition, during continuous printing, each recording head 1 moves onto the web 29 every 10 minutes (every 200 sheets printed) and prints 50 to 1
After firing 00 shots, resume recording. Considering that continuous printing of 200 sheets or more is rarely performed, blank printing every 10 minutes is considered to have little effect on printing speed.

In this embodiment, the ink is ejected by using the foaming of the ink caused by the heating of the heater, and since the ink easily evaporates, a chamber is used to form a gap between the ink and the ink to prevent the evaporation of the ink. It is extremely effective for suppression.

In the first embodiment shown in FIGS. 1 and 2, shutters were provided in seven chambers, but as shown in FIG. 4, a cylindrical chamber 62 is provided for each recording head 61, and a belt 63 The clearance between the chamber 62 and each chamber 62 is set to about 1+nn+, and when not recording, each recording head 61 is lowered and each chamber 62 is brought into contact with the belt 63 and capped, so that the chamber has a function as an opening/closing means. It is also possible to

Further, the present invention provides a transport drum 75 as shown in FIG.
It is also suitable for inkjet recording apparatuses equipped with Jll-jJ functions. This example is the same as the first example shown in FIGS. 1 and 2, except that a head 71, a chamber 72, a shutter 73, and a seal plate 74 are provided along the outer periphery of the conveyance drum 75. A similar configuration can be used.

Furthermore, in each of the above embodiments, if a steam supply source that supplies water vapor into the substantially closed space is provided, drying of the ink can be more reliably prevented.

As described above, the present invention brings about excellent effects particularly when applied to recording heads and recording apparatuses of the bubble jet method among ink jet recording methods. As for typical configurations and principles thereof, it is preferable to use the basic principles disclosed in, for example, US Pat. No. 4,723,129 and US Pat. No. 4,740,796. This method can be applied to both the so-called on-demand type and the continuous type, but especially in the case of the on-demand type, the ink is placed in correspondence with the sheet holding the liquid (ink) and the liquid path. By applying at least one drive (3, S3) that corresponds to the recorded information to the electrothermal converter in which the temperature rises rapidly to obtain nucleate boiling, thermal energy is generated in the ``1'' electrothermal converter. This is effective because it causes nucleate boiling on the heat-active surface of the recording head, resulting in the formation of bubbles in the liquid (ink) in one-to-one correspondence with this drive signal.The growth and contraction of this gas causes the ejection openings to form. Discharge liquid (ink) through the
Forming at least one liquid.

When this drive signal is in the form of a pulse, the growth and contraction of the bubbles is carried out immediately and appropriately, so that ejection of liquid (ink) with particularly excellent responsiveness can be achieved, which is more preferable. This pulse-shaped drive signal is described in US Pat.
63359 and 4345262 are suitable. In addition, US Patent No. 43131 of the invention regarding the temperature increase rate of the heat acting surface
If the conditions described in No. 24 are adopted, even better recording can be achieved. The configuration of the recording head includes: - an ejection port as disclosed in the above-mentioned specification;
U.S. Pat. No. 4,558,333, U.S. Pat. The configuration using the specification of No. 459600 is also included in the present invention. In addition, Japanese Patent Laid-Open No. 123670 of 1981 discloses a configuration in which a slit common to a plurality of electrothermal converters is used as a discharge part of the electrothermal converter, and a discharge opening that absorbs pressure waves of thermal energy is disclosed. The effects of the present invention are also effective with a structure based on Japanese Patent Application Laid-open No. 138461 of 1982 which discloses a structure corresponding to the part. Furthermore, 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, the length can be increased by combining multiple recording heads as disclosed in the above-mentioned specification. Either a configuration satisfying the above conditions or a configuration as a single recording head formed integrally may be used, but the present invention can more effectively exhibit the effects described above.

In addition, a replaceable chip-type recording head that is attached to the device body enables electrical connection to the device body and ink supply from the device body, or a chip-type recording head that is installed integrally with the recording head itself. The present invention is also effective when using a cartridge type recording head. Further, it is preferable to add recovery means, preliminary auxiliary means, etc. to the recording head provided as a component of the recording apparatus in the present invention, since the effects of the present invention can be further stabilized. Specific examples of these include capping means for the recording head, cleaning means, pressure or absorption means, preheating means using an electrothermal transducer or another heating element or a combination thereof, and recording. It is also effective to perform a preliminary ejection mode in which ejection is performed in a manner different from that for stable printing. Furthermore, the recording mode of the recording device is not limited to a recording mode that only records colors such as black, but it is also possible to configure the recording head integrally or by combining multiple pieces, but it is also possible to use multiple colors of different colors or mixed colors. The present invention is also extremely effective for devices equipped with at least one full color image.

[Effects of the Invention] As explained above, the present invention is capable of capping at the recording position by blocking a substantially closed space from the outside world and making it a closed space during non-recording, and moving the recording head from the cap position to the recording position. It is possible to save time and the time required for nozzle recovery operations and to start recording earlier. Furthermore, since the airtightness of the substantially closed space is increased, clogging of the nozzle can be prevented for a long period of time. Furthermore, the number of times the nozzle must be recovered by pushing ink out with a pump is reduced, which has the effect of saving ink.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the main parts of a first embodiment of the inkjet recording apparatus of the present invention, and FIG. 2(a) is a line A-A in FIG.
2(b) is a sectional view taken along the line BB in FIG. 1, FIG. 3 is an operation flowchart, and FIGS. It is an explanatory view showing a third example. ■... Recording head, 2... Holder 310 head unit, 4... Ink tank, 5... Ink supply tube, 6... Belt, 8... Belt motor 11... Registration roller 12a, 12b---Charger, 14... Conveyance roller 15... Pinch roller - 16... Paper feed motor 3 17... Cleaning unit, 18... Paper ejection tray, 19... Control circuit, 20...Head driver 21.23.39...Motor driver 22...
Charger driver 24... Head moving means, 25... Ink valve, 27... Recorded member, 28... Belt guide, 29... Web, 33... Web motor 35... Pump Driver 36... Valve driver 37... Ink pump, 38... Paper ejection tray moving means, 40... Chamber 40a... Hole portion, 40b... Leg portion, 42... Shutter 4 61 ...Recording head, 62...Chamber 63...Belt, 71...Recording head, 72...Chamber 3...Shutter 74...Seal plate, 75...Transport drum, 101 ~139...step.

Claims (1)

[Scope of Claims] 1. An inkjet recording apparatus comprising a chamber whose both sides are surrounded by the upper surface of a conveying member for a recording member, and which has a hole in the upper surface into which an orifice surface of a recording head is inserted, the chamber comprising: An inkjet recording apparatus comprising an opening/closing means for shielding a substantially closed space formed by the orifice surface and the upper surface of the conveying body from an outer surface thereof during non-recording to form a closed space. 2. The inkjet recording apparatus according to claim 1, wherein the opening/closing means is a shutter provided in the chamber and capable of coming into contact with the upper surface of the conveying body during non-recording. 3. The inkjet recording apparatus according to claim 1, wherein the opening/closing means is a chamber that can come into contact with the upper surface of the conveying body during non-recording. 4. The inkjet recording apparatus according to claim 1, 2 or 3, further comprising a steam supply source that supplies water vapor into the substantially closed space. 5. The recording head is equipped with a thermal energy generating element as an ejection energy generating body that generates thermal energy used for ejecting ink, and rapid pressure changes caused by bubbles generated by the thermal energy. 5. The inkjet recording apparatus according to claim 1, wherein the inkjet recording apparatus ejects the ink by utilizing. 6. Claim 1, wherein the recording head is provided with ejection ports over the entire width of the recording member.
, 2, 3, 4 or 5.