JPH07309015A - Ink jet unit and ink jet recording apparatus - Google Patents

Abstract

PURPOSE:To prevent the fixing phenomenon in the vicinity of a filter by providing an ink jet recording head having the tank guide of an ink tank and a means hermetically closing the ink tank bonded part. CONSTITUTION:When a microswitch 81 comes into contact with an ink tank 57 when the operation capping a filter 54 is performed, the switch is turned ON and this ON state is detected as such a state that the tank is present. If the microswitch 81 does not come into contact with the ink tank 57 and is held to an OFF-state, the absence of the tank is detected. By this constitution, the presence of the ink tank can be discriminated at the same time on the basis of the operation capping the filter 54. Even when the ink tank 57 is not mounted on an ink jet recording head for a long time by capping the filter 54, the fixing phenomenon of ink in the vicinity of the filter is prevented and, when the ink tank 57 is mounted, ink can be absorbed within a short time and stable recording can be stably performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet unit and 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 a function such as a printer, a copier, a facsimile, or a recording device used as an output device such as a composite electronic device including a computer, a word processor, etc., a workstation, etc. The image (including characters and the like) is recorded on a recording material (recording medium) such as a sheet of paper or a plastic thin plate. The above recording apparatus can be classified into an ink jet type, a wire dot type, a thermal type, a laser beam type, etc., depending on the recording method. Among the above-described recording apparatuses, an inkjet recording apparatus (inkjet recording apparatus) performs recording by ejecting ink from a recording unit (inkjet recording head) onto a recording material, and the recording unit can be easily made compact. Therefore, it is possible to record high-definition images at high speed, and to record on plain paper without requiring special processing,
It has advantages such as low running cost, less noise due to the non-impact method, and easy recording of a color image using multicolor ink. Among them, the line type in which a large number of ejection openings are arranged in the paper width direction and the full-multi type recording means is used can further speed up the recording.

A conventional ink jet recording head used in the above ink jet recording apparatus generally has a liquid passage provided with a discharge heater, a common liquid chamber communicating with the liquid passage, and an ink for supplying to the common liquid chamber. Ink that has an ink tank that contains an absorber (porous material) to hold, an ink common path that connects the ink tank and the common liquid chamber, and a filter that traps dust in the ink The tank and the head had an integrated structure.

[0004]

When the ink tank is made replaceable, a discharge heater is provided from the filter that traps dust in the ink when the ink tank has not been attached to the ink jet recording head for a long time. The ink in the liquid passage, the common liquid chamber communicating with the liquid passage, and the ink in the supply passage communicating with the common liquid chamber may evaporate, which may cause a sticking phenomenon in which the ink near the filter solidifies. Once such sticking occurs, there is a problem that printing cannot be performed because suction is impossible even when an ink tank is attached.

FIG. 9 shows the results of a study on the relationship between the time when the ink tank is not attached to the ink jet recording head and the number of times of suction until ejection from all ink ejection ports after the ink tank is attached.

That is, it has been found that the longer the time when the ink tank is not attached, the more the number of times of suction until ejection from all ink ejection ports tends to increase.

The present invention has been made in view of the above problems, and in a structure in which the ink tank can be replaced, even if the ink tank is not attached to the ink jet recording head for a long time, the sticking phenomenon near the filter is prevented, and the ink An object of the present invention is to provide an ink jet head unit and an ink jet recording apparatus that can be sucked in a short time when a tank is attached and can always perform stable recording.

[0008]

In order to achieve the above object, the present invention provides an ink jet unit in which the ink tank can be replaced, in which the ink jet unit has an ink tank for holding ink therein and a filter for the ink tank. The ink jet recording head includes an ink tank joint portion that is joined via an ink jet port, an ink ejection port, and a tank guide of the ink tank, and a sealing unit that includes a sealing portion that seals the ink tank joint portion. Further, it is effective to provide a detector for detecting the presence or absence of the ink tank in the sealing means.

The sealing portion of the sealing means for sealing the ink tank joint is preferably attached to the tip of a support rod having a rotating shaft or attached to the tip of an elastic member provided on the tank guide and having a restoring force. . The elastic member is preferably a plate material, a rubber material, or a foam material having a spring property capable of being restored.

The sealing portion is preferably a cap or a convex elastic member. When a convex elastic member is used, the tip of the ink tank joint is concave. A wetting material may be provided inside the sealed portion. The wetting agent is preferably a non-volatile organic solvent, and the non-volatile organic solvent is preferably selected from polyhydric alcohols and their derivatives. The polyhydric alcohol and its derivative are preferably glycerin, ethylene glycol, diethylene glycol, polyethylene glycol and thiodiglycol.

An ink jet recording apparatus having the above ink jet unit is suitable.

[0012]

When the ink tank is detached from the ink jet recording head, the ink sticking part of the ink jet recording head having the filter is sealed by the sealing means to prevent the ink sticking phenomenon in the vicinity of the filter. Suction can be done in a short time. The sealing portion of the sealing means is preferably a cap provided with an absorbent body impregnated with a wetting material or a convex elastic member. Further, the operation of the sealing means is preferably performed by a signal of a detection means for detecting the presence or absence of the ink tank, or by attaching or detaching the ink tank.

[0013]

EXAMPLES Examples of the present invention will be described below, but the present invention is not limited to the following examples.

(1) Description of Recording Device FIG. 1 is a perspective view showing a main structure of an ink jet recording device according to the present invention. An inkjet unit 11 having an ejection port array for ejecting ink is installed on a carriage 13. A recording material P made of paper, a thin plastic plate, or the like is nipped by a paper discharge roller 17 via a conveyance roller (not shown), and is fed in the direction of an arrow when a conveyance motor (not shown) is driven. The carriage 13 is guided and supported by the guide shaft 12 and the encoder (not shown). The carriage 13 is driven by a carriage belt 1 via a drive belt 14.
It is reciprocated along the guide shaft 12 by the drive of 5.

A heating element (electrical / thermal energy) that generates thermal energy for ink ejection is provided inside the ink ejection portion (liquid path) of the ink jet recording head (details will be described later with reference to FIGS. 2 and 3) of the ink jet unit 11. A converter) is provided. An image can be formed by driving the heating element based on a recording signal and causing ink droplets to fly and adhere onto the recording material P in accordance with the reading timing of an encoder (not shown).

A recovery unit having a cap portion 16 is arranged at the home position (HP) of the carriage 13 selected outside the recording area. When recording is not performed, the carriage 13 is moved to the home position (HP), the ink ejection port forming surface of the ink jet recording head is sealed by the cap portion 16, and ink is fixed due to evaporation of the ink solvent or dust, paper dust, or the like. Prevents clogging due to foreign matter adhering to.

Further, the capping function of the cap portion 16 is away from the ink ejection port in order to eliminate ejection failure and clogging due to ink thickening, sticking and the like of the ink ejection port which is infrequently recorded. It is used for a preliminary ejection mode for ejecting ink to the head or for recovering the ejection of the ink ejection port where ejection failure has occurred by operating a pump (not shown) in a capped state to suck the ink from the ink ejection port. Further, by disposing the blade at the position adjacent to the cap portion, it is possible to clean the ink ejection port forming surface of the inkjet recording head.

(2) Description of Inkjet Recording Head FIG. 2 is a schematic perspective view of the ink ejection port array of the ink ejection portion of the inkjet recording head 21 as seen from the recording material side, and FIG. 3 shows the ink ejection portion. It is a partial perspective view which shows an internal structure typically. The ink ejection portion has an ink ejection port surface 22 having a plurality of ink ejection ports 23, and generates the energy required to eject ink to a liquid path portion 31 communicating with the ink ejection port 23. The ejection energy generating elements 32 are arranged. The arrow y in FIG. 2 indicates the scanning direction of the carriage 13. Reference numeral 33 in FIG. 3 is a sensor for detecting the temperature of the recording head. In the present embodiment, the thermistors 33 are provided at both ends of the ejection port array. The temperature detecting means is not particularly limited to this,
Other sensors such as diode sensors may be used,
Further, the head temperature may be calculated from the duty of the print dots.

(3) Description of Control Configuration FIG. 4 is a block diagram of an embodiment of the present invention. An image input unit 403 for accessing the main bus line 405, and an image signal processing unit 40 corresponding to the image input unit 403.
4, software processing means such as central control unit CPU 400, operation unit 406, recovery system control circuit 407, inkjet head temperature control circuit 414, head drive control circuit 4
It is roughly divided into hardware processing means such as 15. CPU
400 is a normal ROM 401 and a random memory (RA
M) 402, the recording head 413 is driven by applying appropriate recording conditions to the input information to perform recording. Also,
A program for executing the above-described recovery timing chart is stored in advance in the RAM 402, and the recovery system control circuit 40 sets recovery conditions such as preliminary ejection conditions as necessary.
7, the recording head 413, the heater, etc. The recovery system motor 408 drives the above-described recording head 413 and the cleaning blade 409, the cap 410, and the suction pump 411 facing and separated from the recording head 413. The head drive control circuit 415 executes the drive conditions of the electrothermal converter for ink ejection of the thermal head, and normally causes the recording head 413 to perform preliminary ejection and recording ink ejection.

On the other hand, the recording head 413 is provided with a heat-retaining heater on a substrate provided with an electrothermal converter for ejecting ink, and the ink temperature in the recording head 413 is adjusted by heating to a desired set temperature. You can The thermistor 412 is also provided on the substrate, and is for measuring the ink temperature substantially inside the recording head. Similarly, the thermistor 412 may be provided not outside the substrate but outside the substrate, or may be near the periphery of the recording head 413.

(Embodiment 1) FIG. 5 is a schematic view of an ink jet recording head in which the ink tank 57 of the present invention can be replaced.

Atmosphere communication port 58 for exchanging ink and atmosphere
The ink tank 57 including the suction member 59 for holding the ink is configured to be attached to the ink jet recording head along the tank guide 56. The ink is supplied to the ink jet recording head from the ink tank 5
Dust in the ink is trapped from 7 to the liquid passage 52 in which the ejection motor is provided inside the ink ejection port 55, the common liquid chamber 53 communicating with the liquid passage, and the ink supply portion 51 communicating with the common liquid chamber. It is performed through the filter 54.

FIG. 6 is a flow chart showing an example of the operation when the ink tank 57 is replaced in the first embodiment, which is executed by the central control unit CPU 400 of FIG.

First, a tank exchange button is provided to select whether or not the tank exchange button is turned on (step S60).
If 1) is present and the answer is "Yes", the carriage on which the inkjet unit is placed moves from the home position to the tank replacement position in the center of the guide shaft (step S602). Replacing the ink tank 57 (step S
603), and there is a selection as to whether or not the tank replacement button is turned on again (step S604). If “Yes” is selected or “No” is selected, one minute has elapsed since the first tank replacement button was turned on. Yes (step S60
5), the carriage moves to the home position (step S606). When the carriage is moved to the home position (step S606), the filter 54 is capped (step S607), but when it is determined that the ink tank 57 is installed (step S608), the normal recovery operation (step S608) is performed. S609) is performed, and the print standby state (step S610) is entered and the process ends. If it is determined that the ink tank 57 is not installed, a tank-less display (step S611) is performed and the filter 5
4 is capped (step S612). When the tank is attached because the tank is not displayed is displayed, when the tank replacement button is turned on again, the capping of the filter 54 is released (step S614) and the carriage moves to the tank replacement position (step S602).

7 (a) and 7 (b) are schematic views showing the concrete means of the first embodiment. When the ink tank 57 is not installed at the home position, the filter 54 of the ink jet recording head is shown. It is the schematic which provided the mechanism which caps.

A supply unit 51, a liquid passage 52, a common liquid chamber 53, a filter 5 provided in the ink jet recording head.
4, the ink outlet 55, the atmosphere communication port 58 provided in the ink tank 57, and the absorber 59 are based on the description of FIG.

FIG. 7A shows the print standby state (step S610) at the home position when the ink tank 57 is attached, and FIG. When not attached, the filter 54 is capped at the home position (step S612). The operation of capping the filter 54 is performed by the cap 71 supported by the support rod 72 from the position A in FIG. 7A around the rotation shaft 73 to the position B in FIG. 7B where the filter 54 is located. Rotate for capping.

Ink tank 5 in step S608 of FIG.
Whether or not 7 is attached can be determined by providing a microswitch 81 or the like at the tip of the cap of FIG. 7A as shown in FIG.

In FIG. 8, when the micro switch 81 comes into contact with the ink tank 57 when the cap 54 is capped, the switch is turned on. ), The micro switch 81 turns the ink tank 57
If the switch remains in the OFF state if it does not come into contact with, it is detected that there is no tank, and the state shown in FIG.

Thus, the presence or absence of the ink tank can be determined at the same time by the capping operation of the filter.

In the first embodiment, by capping the filter 54 in step S612 of FIG. 6 described above,
Even when the ink tank 57 has not been attached to the inkjet recording head for a long time, the phenomenon of ink sticking in the vicinity of the filter is prevented, and when the ink tank 57 is attached, suction can be performed in a short time and stable recording can be always performed. .

In the first embodiment, a single color ink has been described as an example for convenience of explanation, but the present invention is not limited to this, and a color ink jet recording apparatus having a plurality of different colors such as cyan, magenta, yellow and black. The present invention can also be applied to an inkjet head unit, and by providing a means for capping each color with a filter, the presence or absence of the ink tank 57 for each color can be determined.

(Embodiment 2) FIG. 10 is a schematic view of an ink jet recording head and a cap showing Embodiment 2 and showing a state in which the filter 54 of FIG. 6 is capped (step S612).

In the second embodiment, the filter 71 can be always kept in a wet state by providing an absorbent body impregnated with a wetting material in the cap 71 for capping the filter 54 and the support rod 72.

For example, a non-volatile organic solvent may be used as the wetting agent, preferably one selected from polyhydric alcohols and derivatives, more preferably glycerin, ethylene glycol, diethylene glycol, polyethylene glycol, thiodiglycol, ink It is good that there is no reaction with.

Therefore, even a slight amount of ink adhered near the filter can be redissolved, and the ink tank 57 can be re-dissolved.
When is attached, suction can be performed in a shorter time, and stable recording can always be performed.

(Embodiment 3) FIGS. 11 (a) and 11 (b) show Embodiment 3 in which the ink tank 57 is replaceable and the ink jet recording head tank guide itself has no ink tank attached to the filter 54. FIG. 6 is a schematic view of an inkjet recording head provided with a mechanism for capping.

A supply passage 51, a liquid passage 52, a common liquid chamber 53, a filter 5 provided in the ink jet recording head.
4, the ink discharge port 55, the atmosphere guide port 58 provided in the tank guide 56 and the ink tank 57, and the absorber 59 are based on the description of FIG. FIG. 11A is a diagram in which the filter 54 is capped by the cap 111 attached to the elastic member 112 having a restoring force when the ink tank 57 is not attached.

FIG. 11B shows that the ink tank 57 is being mounted when the ink tank 57 is moving in the direction of arrow A, and at the same time, the capping from the filter 54 is released. Further, when the ink tank 57 is moving in the direction of arrow B, it shows that the ink tank is being removed.
It is the figure which is capping to No. 4.

FIG. 12 is a diagram in which the ink tank 57 is mounted and the capping on the filter 54 is released.

In the third embodiment, since the capping mechanism for sealing the filter 54 uses the elastic member 112 having a restoring force to provide the ink tank 54 on the tank guide itself of the replaceable ink jet recording head, the ink tank The filter 54 can be capped at the same time as the removal. With such a simple structure, the ink sticking phenomenon near the filter can be prevented, and even when the ink tank 57 is mounted, the ink cannot be sucked, and stable recording can always be performed.

As the elastic member 112 having a restoring force, a plate material having elasticity, a rubber material, a foam or the like can be used. here,
When a rubber material or a foam is used, the slipperiness of the surface is poor, so it is desirable to perform a slipperiness improving treatment on the portion in contact with the ink tank 57. For example, a fluorine treatment such as Teflon processing is preferable.

(Embodiment 4) FIG. 13 is a schematic view of a tank joint portion of an ink tank and an ink jet recording head showing Embodiment 4 of the present invention. The ink tank and the ink jet recording head are connected at an ink tank 57 on the tank side.
The absorbent body 59 is provided with the ink derivative 121 to form a convex state, and the ink jet recording head side is formed to have a concave state by arranging the filter 54 toward the supply unit 51.

FIGS. 14A and 14B are schematic views showing a structure for sealing the tank joint portion of the ink jet recording head when the ink tank 57 in the fourth embodiment is not installed.

In FIG. 14A, when the ink tank 57 is not mounted, the convex elastic member 131 is moved in the direction of arrow A, so that the tank joint portion of the ink jet recording head is formed in a concave shape. It is the figure which is going to seal.

FIG. 14B is a view in which the tank joint portion of the ink jet recording head having the concave shape is sealed by the convex elastic member 131 when the ink tank 57 is not mounted. The elastic member 131 is preferably a rubber material, a foam of closed cells, or the like, and is preferably one having excellent sealing properties.

FIG. 15 shows the concave filter 5 of FIG.
4 is a diagram in which an absorbent body 141 impregnated with a wetting material is provided at the tip of the elastic member 131 in a convex state that seals 4 in FIG.

For example, as the wetting agent, there is a non-volatile organic solvent as shown in the above Example 2, preferably one selected from polyhydric alcohols and derivatives, more preferably glycerin, ethylene glycol, diethylene glycol, There are polyethylene glycol and thioglycol, and it is good that they do not react with ink.

In the fourth embodiment, even if the joint portion of the ink tank of the ink jet recording head is in a concave shape, it can be sealed with a convex elastic member or the like, and the convex elastic member is wetted. The filter can always be kept in a wet state by providing an absorbent body impregnated with a material and sealing the absorbent body.
As described above, the configuration of the fourth embodiment also has the same sealing effect as that of the first to third embodiments, and the use of the first to third embodiments also enables a simple configuration, and the ink tank 57 has the same structure as the inkjet recording head. Even if the ink is not attached for a certain period of time, it is possible to prevent ink from adhering to the vicinity of the filter, and when the ink tank 57 is attached, the ink can be sucked in a short time, and stable recording can always be performed.

[0050]

Since the present invention is constructed as described above, it has the following effects.

Even when the ink tank has not been attached to the ink jet recording head for a long time, the phenomenon of ink sticking in the vicinity of the filter is prevented, and when the ink tank is attached, the ink can be sucked in a short time and stable recording can always be performed.
The presence or absence of the ink tank can be determined at the same time by the capping operation of the filter by the detector provided in the sealing means. Capping is easily possible by pressing the tank replacement button or in conjunction with the removal of the ink tank.

Since the cap or the convex elastic member is used for the sealing portion of the sealing means, the sealing performance is good, and the absorbent body impregnated with the wetting material is provided inside the cap or the convex elastic member. Can keep the filter wet when closed.

[Brief description of drawings]

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

FIG. 2 is a schematic perspective view of an ink ejection unit of an inkjet recording head.

FIG. 3 is a partial perspective view schematically showing the internal structure of the ink ejection portion of the inkjet recording head.

FIG. 4 is a block diagram of an embodiment of the present invention.

FIG. 5 is a schematic view of an ink jet recording head of an ink tank exchange type according to the present invention.

FIG. 6 is a flowchart showing an operation of the first embodiment when the ink tank is replaced.

FIG. 7 is a schematic diagram of an inkjet recording head and a cap according to the first embodiment.

FIG. 8 is a schematic diagram of an ink jet recording head and a cap provided with the presence / absence detection of an ink tank according to the first embodiment.

FIG. 9 is a diagram showing a relationship between the number of suctions after the ink tank is mounted and the time when the ink tank is not mounted.

FIG. 10 is a schematic diagram of an ink jet recording head and a cap according to the second embodiment when an ink tank is not attached.

FIG. 11 is a schematic diagram of an ink jet recording head according to a third embodiment.

FIG. 12 is a schematic diagram of an ink jet recording head according to a third embodiment.

FIG. 13 is a schematic view of a tank joint portion of the ink tank and the inkjet recording head of the fourth embodiment.

FIG. 14 is a schematic view showing a mechanism for sealing the tank joint portion of the inkjet recording head of the fourth embodiment.

FIG. 15 is a schematic diagram in which a member for sealing the tank joint portion of the inkjet recording head of the fourth embodiment is provided with an absorbent body impregnated with a wetting material.

[Explanation of symbols]

 11 Inkjet unit 20 Ink ejection part 21 Inkjet recording head 23,55 Ink ejection port 50 Ink tank joint part 51 Supply path 54 Filter 56 Tank guide 57 Ink tank 59 Absorber 70 Sealing means 71,111 Cap (sealing part) 72 Support bar 73 Rotation axis 81 Micro switch (detector) 101, 141 Wetting material absorber 112 Elastic member 121 Ink derivative 131 Convex elastic member

Claims (12)

[Claims] 1. An ink jet unit in which an ink tank can be exchanged, which has an ink tank for holding ink therein, an ink tank joining portion joined to the ink tank through a filter, an ink ejection port, and a tank guide for the ink tank. An inkjet unit comprising an inkjet recording head and a sealing means having a sealing portion for sealing the ink tank joint. 2. The ink jet unit according to claim 1, wherein a detector for detecting the presence or absence of an ink tank is provided in the sealing means. 3. The sealing portion is attached to the tip of a support rod having a rotating shaft.
The described inkjet unit. 4. The ink jet unit according to claim 1, wherein the hermetically sealed portion is attached to a tip of an elastic member provided on the tank guide and having a restoring force. 5. The elastic member is a plate material, a rubber material, or a foam material having a spring property capable of being restored.
The described inkjet unit. 6. The ink jet unit according to claim 1, wherein the sealing portion is a cap. 7. The ink jet unit according to claim 1, wherein the closed portion is a convex elastic member and the tip of the ink tank joint portion is concave. 8. The ink jet unit according to claim 1, wherein an absorbent body impregnated with a wetting material is provided inside the sealed portion. 9. The ink jet unit according to claim 8, wherein the wetting material is a non-volatile organic solvent. 10. The ink jet unit according to claim 9, wherein the non-volatile organic solvent is selected from polyhydric alcohols and their derivatives. 11. The ink jet unit according to claim 10, wherein the polyhydric alcohol and its derivative are glycerin, ethylene glycol, diethylene glycol, polyethylene glycol and thiodiglycol. 12. An inkjet recording apparatus comprising the inkjet unit according to claim 1.