JPH0768788A - Ink jet recorder - Google Patents

Abstract

PURPOSE:To obtain an ink jet recorder in which an amount of ink remaining in a head is reduced when a cap is separated from the head for preventing contamination of paper surface and a body of the recorder. CONSTITUTION:When a cap 2 sealing a nozzle surface of an ink jet recording head 1b in a capping state (b) is to be separated from the nozzle surface, the cap 2 is gradually separated from one end 2a with the other end 2b abutted on the nozzle surface, and lastly the other end 2b is separated (c).

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, and more particularly to an ink jet recording apparatus having a cap member that seals the ink jet recording head during non-recording to maintain the performance of the ink jet recording head.

[0002]

2. Description of the Related Art Conventionally, in an ink jet recording apparatus, it is necessary to hermetically seal the nozzle surface of the head in order to prevent the nozzle surface of the ink jet recording head from drying during the pause of printing and maintain the performance of the head. Further, if dust or air enters the nozzles of the head, printing failure will occur, and it is necessary to suck the ink in the head in order to recover it. To meet these demands,
The inkjet recording apparatus is provided with a movable cap member that separates from the inkjet recording head during printing and seals the nozzle surface when printing is stopped. Further, a wiping operation using a blade is performed in order to remove the residual ink adhering to the nozzle surface of the inkjet recording head. Further, the inkjet recording apparatus is provided with a mechanism for adjusting the distance between the head and the recording medium (for example, paper) in order to perform optimum printing.

FIG. 9 is a diagram showing an example of a conventional cap mechanism. A carriage 91 for mounting the inkjet head 91b is provided.
1 can reciprocate in the direction perpendicular to the paper surface of the drawing along the axis 91a for the printing operation. The illustrated state is due to capping of the head 91b.
Is in the home position. Further, the carriage 91 is rotatable around a shaft 91a, and the distance between the front surface of the head 91b and the paper can be changed by an adjusting mechanism (not shown).

A cap 9 for sealing the head 91b
2 is attached to a cap base 93, and is supported by a cap holder 95 via a spring 94 so as to be tiltable. A drive cam 97 for driving the cap 92 is provided. During printing, the cap 92 is separated from the inkjet recording head 91b, but when printing is stopped, the cap 92 keeps the head 91b sealed while being tiltable toward the head 91b. When printing is started, the cap 92 separates from the head 91b. At this time, in order to prevent the ink sucked on the nozzle surface of the head 91b from remaining, a part of the cap 92 is communicated with the external atmosphere, It is necessary to suck the ink in 92.

[0005]

However, in the above-described conventional ink jet recording apparatus, when the cap is detached from the ink jet recording head, the ink in the vicinity of the air flow path in the cap is sucked, but as shown in FIG. As described above, a small amount of ink 90 remains in the vicinity of the contact portion between the head 91b and the cap 92, and the next printing operation is started with the ink 90 remaining on the entire periphery of the nozzle surface of the head 91b. As a result, the following problems occur.

During printing, that is, during scanning of the carriage, residual ink collects and easily drops from the head, and the paper surface or platen during printing is stained.

When wiping the head during the head recovery operation, the amount of ink scraped by the blade increases, and wiping in the vicinity of the nozzle of the head is not sufficiently performed.

The ink attached to the blade stains the peripheral mechanism.

An object of the present invention is to provide an ink jet recording apparatus which reduces the amount of ink remaining in the head when the cap is detached from the head and does not stain the paper surface or the body of the recording apparatus.

[0010]

An ink jet recording apparatus of the present invention is provided with an ink jet recording head for ejecting ink to form an image and a cap member for capping a nozzle surface of the ink jet recording head during non-recording. The recording apparatus has a cap member driving means for gradually separating the cap member in the capping state from the inkjet recording head.

[0011]

[Operation] When the cap is removed from the head capping,
Since the cap is forcibly released from the nozzle surface gradually from the predetermined position, the amount of ink remaining on the nozzle surface is reduced and the paper surface and the machine body are not contaminated. That is, as shown in FIG. 7, when the cap 82 is removed from the nozzle surface of the inkjet head 81b, one end 82a of the cap 82 is kept in contact with the nozzle surface, and the other end 82b of the cap 82 is moved to the nozzle surface. Try to get away from. Finally, the one end 82a is separated from the nozzle surface. As a result, a very small amount of ink 80
Ink remains only on one end 82a side, and almost no ink remains on the nozzle surface.

In order to further reduce the amount of ink remaining on the nozzle surface, the nozzle surface is arranged in a direction not horizontal to the direction of gravity, and the cap is removed from the uppermost point side of the nozzle surface in the direction of gravity. Good.

In the present invention, as the ink jet recording head, for example, one having an electrothermal converter for generating thermal energy for ejecting ink can be used. As such an ink jet recording head, for example, there is one that ejects the ink from the ejection port by utilizing the film boiling generated in the ink by the thermal energy applied by the electrothermal converter.

[0014]

Embodiments of the present invention will now be described with reference to the drawings. First, the configuration of the capping mechanism in the inkjet recording apparatus according to the embodiment of the present invention will be described.
FIG. 1 is a main overall view of the capping mechanism as seen from the moving direction side of the carriage, FIG. 2 (a) is a diagram for explaining the details of the capping mechanism, and FIG. 2 (b) is a side view of the capping mechanism. It is a figure explaining the detail of.

The carriage 1 on which the ink jet recording head 1b is mounted can reciprocate along the guide shaft 1a in a direction perpendicular to the plane of the drawing for printing operation. The illustrated state is a state in which the head 1b is located at the home position due to capping of the head 1b. Further, the carriage 1 is rotatable around the guide shaft 1a, and the distance between the front surface (nozzle surface) of the head 1b and the paper can be changed by an adjusting mechanism (not shown).

A cap 2 for sealing the head 1b
Is attached to the cap base 3 and supported by the cap holder 5 via the spring 4 so as to be tiltable. A drive cam 7 for driving the cap 2 is provided.

The base side of the cap base 3, that is, the drive cam 7 side has two parallelly extending foot portions 3b,
Protrusions 3a facing outward are provided at the tip of the foot 3b. On the other hand, the cap holder 5 is provided with two projecting portions 5a corresponding to the leg portions 3b of the cap base 3, and the side surfaces of the projecting portions 5a are groove portions 5e capable of engaging with the projecting portions 3a. Protrusion 5a
Is formed by a first slope 5c connected to the groove 5e and a second slope 5d that is substantially integrated with the first slope 5c but is longer than the first slope 5c. . The second slope 5d is not connected to the groove 5e.

In this apparatus, the paper is fed by a paper feeding mechanism (not shown), and the carriage 1 carrying the head 1b reciprocates along the guide shaft 1a for printing. Then, while the printing is stopped, the carriage 1 moves to the home position and the cap mechanism operates to seal the nozzle surface of the head 1b. The nozzle surface is horizontal.

Next, the operation of the cap mechanism will be described.

When the carriage 1 moves to the home position, the drive cam 7 is driven by the drive motor (not shown).
Rotates. The initial position of the drive cam 7 is detected by a leaf switch (not shown), and the position of the drive cam 7 is controlled by a pulse from the main body with reference to this.

FIG. 3A shows the state of the cap 2 before capping, that is, during printing. Cap base 3
Is urged by the spring 4 and is most protruded from the cap holder 5. The cap base 3 can move freely in the vertical direction along the groove 5e of the cap holder 5. The cap base 3 is rotated clockwise in the drawing by the urging force of the spring 4, and the cap holder 5
It abuts against the wall 5b and is locked. When the cap holder 5 is raised in this state, head capping is performed from the one end 2a of the cap 2. As the cap holder 5 rises, the spring 4 is compressed, and the projection 3a of the foot b of the cap base 3 has the first slope 5c of the cap holder 5.
Ride on. The cap 3 is evenly attached along the nozzle surface of the head 1b. As a result,
As described in Japanese Patent No. 1249, capping can be performed with good airtightness.

FIG. 3B shows the state of the cap 2 at the end of capping. At this time, since the protrusion 3a of the cap base 3 is separated from the cap holder 5,
The cap 2 can reliably follow the nozzle surface.

FIG. 3C shows the state of the cap 2 when the cap 2 is removed from the capped state. Contrary to the above, the cap holder 5 descends. Along with this, the spring 4 extends, and the protrusion 3a of the cap base 3 relatively rises along the second slope 5d of the cap holder 5. At this time, the cap 2 tries to separate from the nozzle surface while rotating counterclockwise due to the sliding of the protrusion 3a. The ink remaining on the contact surface between the nozzle surface and the cap 2 is collected in the other end 2b which is to be separated at the end of the cap 2 due to the capillary phenomenon in the gap between the head 1b and the cap 2 which are gradually separated. To be by this,
Most of the remaining ink can be absorbed by the absorber inside the cap 2, and the ink remaining on the nozzle surface of the head 1b is greatly reduced.

Next, another embodiment of the present invention will be described. In the above-described embodiment, the cap and the nozzle surface are arranged substantially horizontally with respect to the direction of gravity, but by utilizing the fact that ink easily flows in the direction of gravity, it is possible to further reduce the amount of residual ink. it can. In the example shown in FIG. 4, the nozzle surface of the inkjet recording head 1b is parallel to the gravity direction, that is, vertical. And by providing a capping mechanism similar to the above-mentioned embodiment,
When the cap 2 is detached from the nozzle surface, the portion 12 which is the lowermost end in the gravity direction comes to be detached last, and the residual ink is easily collected in the portion 12. This makes it possible to collect the residual ink more effectively.

Further, in each of the above-described embodiments, the part where the cap first comes into contact with the nozzle surface in the capping operation and the part where the cap comes off last when the cap is separated from the nozzle surface are different. However, it is also possible to make the first contacting part and the last separating part the same. The example shown in FIG. 5 has a capping mechanism similar to the conventional one, but the nozzle surface is in the vertical direction, and the portion 22a where the cap 22 first abuts the nozzle surface and the portion 22b where the cap 22 comes off last are separated. All of them are configured so as to be on the lowermost end side of the nozzle surface. According to this structure, the effect of the present invention can be obtained even if the conventional capping mechanism is used.

Next, an ink jet recording apparatus equipped with the above-mentioned capping mechanism will be described with reference to FIG.

An ink jet head cartridge (IJC) 20 having a nozzle group for ejecting ink is provided facing the recording surface of the recording paper fed onto the platen 24. The inkjet head cartridge is an integrated one of an inkjet recording head and an ink tank that holds ink to be ejected from the inkjet recording head. The IJC 20 includes an electrothermal converter for generating thermal energy for ejecting ink, and the ink is ejected from an ejection port (nozzle) due to film boiling generated in the ink by the thermal energy applied by the electrothermal converter. It is configured to fly. IJC
A carriage 16 that holds 20 is provided. The carriage 16 is connected to a part of the drive belt 18 that transmits the driving force of the drive motor 17, and is arranged in parallel with each other.
It is slidable with the guide shafts 19A and 11B of the book. With this configuration, the IJC 20 can reciprocate over the entire width of the recording paper.

A head recovery device 26 is provided at one end of the movement path of the IJC 20, for example, at a position facing the home position. The head recovery device 26 is equipped with the capping mechanism as described above. The head recovery device 26 is operated by the driving force of the motor 22 via the transmission mechanism 23, and the IJC 20 is capped. The cap portion 26A of the head recovery device 26
In association with the capping of the IJC 20 by the ink, ink is sucked by an appropriate suction means provided in the head recovery device 26 or ink is pressure-fed by an appropriate pressurizing means provided in the ink supply path to the IJC 20 to discharge the ink. Ejection recovery processing such as removing the thickened ink in the nozzle by more forcibly discharging is performed. Also, the IJC 20 is protected by capping the nozzle surface of the IJC 20 by the capping portion 26A at the end of recording or at the time of non-printing.

On the side surface of the head recovery device 26, a blade 30 made of silicon rubber as a wiping member.
Is provided. The blade 30 is held by the blade holding member 30A in the form of a cantilever, and similarly to the head recovery device 26, is operated by the motor 22 and the transmission mechanism 23 and can be engaged with the ejection surface of the IJC 20. This allows the blade 30 to be projected into the movement path of the IJC 20 at an appropriate timing in the recording operation of the IJC 20 or after the ejection recovery process using the head recovery device 26, and the ejection surface of the IJC 20 is moved along with the movement operation of the IJC 20. It is possible to wipe off dew condensation, wetness, dust, etc.

The present invention provides excellent effects especially in an ink jet recording type recording head and recording apparatus for recording by forming flying droplets by utilizing thermal energy among the ink jet recording systems.

Typical constitutions and principles thereof are disclosed in, for example, US Pat. Nos. 4,723,129 and 4,740,796, and the present invention uses these basic principles. preferable. This recording method is applicable to both so-called on-demand type and continuous type.

To briefly explain this recording method, the electrothermal converter arranged corresponding to the sheet or liquid path holding the liquid (ink) is changed to the liquid (ink) corresponding to the recording information. Heat energy is generated by applying at least one driving signal for giving a rapid temperature rise that causes the film boiling phenomenon beyond the nucleate boiling phenomenon, and causes the film boiling on the heat acting surface of the recording head. . In this way, bubbles can be formed in one-to-one correspondence with the drive signal applied from the liquid (ink) to the electrothermal converter, which is particularly effective for the on-demand recording method. The liquid (ink) is ejected through the ejection holes by the growth and contraction of the bubbles 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 the pulse-shaped drive signal, U.S. Patent Nos. 4,463,359 and 4,345,262 are used.
Those described in the specification are suitable. If the conditions described in US Pat. No. 4,313,124 relating to the rate of temperature rise on the heat acting surface are adopted, more excellent recording can be performed.

The structure of the recording head is a combination of a discharge hole, a liquid flow path, and an electrothermal converter as disclosed in the above-mentioned specifications (straight liquid flow path or right-angled liquid flow path). In addition, as disclosed in U.S. Pat. No. 4,558,333 and U.S. Pat. No. 4,459,600, the present invention includes those having a configuration in which a heat acting portion is arranged in a bending region.

In addition, Japanese Laid-Open Patent Publication No. 59-123670 discloses a structure in which a common slit is used as a discharge hole of an electrothermal converter for a plurality of electrothermal converters, and a pressure wave of thermal energy is absorbed. The present invention is also effective in a configuration based on Japanese Patent Application Laid-Open No. 59-138461, which discloses a configuration in which an opening corresponds to a discharge portion.

Further, as a recording head in which the present invention is effectively used, there is a full line type recording head having a length corresponding to the maximum width of a recording medium which can be recorded by the recording apparatus. The full line head may be a full line configuration formed by combining a plurality of print heads as disclosed in the above specification, or may be a single full line print head integrally formed.

In addition, by being attached to the apparatus main body, it can be electrically connected to the apparatus main body and can be supplied with ink from the apparatus main body by a replaceable chip type recording head or the recording head itself. The present invention is also effective when a cartridge-type recording head that is specially provided is used.

Further, it is preferable to add recovery means for the recording head, preliminary auxiliary means, etc. to the recording apparatus of the present invention because the recording apparatus of the present invention can be made more stable. Specific examples thereof include capping means, cleaning means, pressure or suction means, an electrothermal converter or a heating element other than this, preheating means for the recording head, recording means for the recording head, and recording means. It is also effective to perform stable recording by adding a means for performing a preliminary ejection mode for performing ejection different from the above.

Further, the recording mode of the recording apparatus is not limited to the mode in which only the mainstream color such as black is recorded, and either the recording head may be integrally formed or a plurality of recording heads may be combined. However, the present invention is also extremely effective for an apparatus provided with at least one of a multicolor of different colors or a full color by color mixing.

In the embodiments of the present invention described above, the liquid ink is used for explanation, but in the present invention, either the ink which is solid at room temperature or the ink which is softened at room temperature is used. Can be used. In the above-mentioned inkjet device, the temperature of the ink itself is generally adjusted within the 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 the stable ejection range. Any liquid may be used as long as the ink is liquid.

In addition, the excessive temperature rise of the head or ink due to thermal energy is positively prevented by using it as the energy of the state change of the ink from the solid state to the liquid state, or the evaporation of the ink is prevented. It is also possible to use an ink that solidifies when left as it is. In any case, liquefaction occurs only when heat energy is applied, such as when the ink is liquefied by applying heat energy according to the recording signal and ejected as an ink liquid, or when it begins to solidify when it reaches the recording medium. The use of an ink having such a property is also applicable to the present invention.

Such an ink is as described in JP-A-54-56847 or JP-A-60-71260.
It may be configured to face the electrothermal converter in a state of being held as a liquid or a solid in the recess or the through hole of the porous sheet.

In the present invention, the most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.

[0043]

As described above, according to the present invention, when the cap is removed from the head capping, the ink remaining on the nozzle surface of the head can be reduced by gradually removing the cap from the predetermined position. Have an effect. The ink remaining from the head does not drop during scanning of the carriage, and the paper surface or platen during printing is not contaminated. Since the amount of ink scraped by the blade during wiping of the head is reduced, wiping can be effectively performed. Particularly in a color printer using a plurality of heads, color mixing between different heads is unlikely to occur.

[Brief description of drawings]

FIG. 1 is a front view showing the configuration of a capping mechanism in an inkjet recording apparatus according to an embodiment of the present invention.

2 (a) and 2 (b) are a front view and a side view, respectively, for explaining the details of the capping mechanism.

3A to 3C are diagrams for explaining the operation of the capping mechanism.

FIG. 4 is a diagram illustrating a capping mechanism in an inkjet recording apparatus according to another embodiment of the present invention.

FIG. 5 is a diagram illustrating a capping mechanism in an inkjet recording apparatus according to still another embodiment of the present invention.

FIG. 6 is a perspective view showing an example of an inkjet recording apparatus according to the present invention.

FIG. 7 is a diagram illustrating the principle of the present invention.

FIG. 8 is a diagram illustrating ink remaining on a nozzle surface in a conventional inkjet recording apparatus.

FIG. 9 is a diagram illustrating a cap drive mechanism in a conventional inkjet recording apparatus.

[Explanation of symbols]

 1, 16 Carriage 1a, 19A, 19B Guide shaft 1b Inkjet recording head 2 Cap 3 Cap base 4 Spring 5 Cap holder 7 Drive cam 3a Projection 3b Foot 5a Projection 5b Wall 5c, 5d Slope 5e Groove 17 Drive motor 18 Drive Belt 20 Inkjet head cartridge 22 Cleaning motor 23 Transmission mechanism 24 Platen 26 Head recovery device 26A Cap portion 30 Blade 30A Blade holding member

Claims (5)

[Claims] 1. An ink jet recording apparatus comprising an ink jet recording head for ejecting ink to form an image and a cap member for capping a nozzle surface of the ink jet recording head during non-recording, wherein the cap member in a capping state is used. An inkjet recording apparatus comprising a cap member driving means for gradually separating from the inkjet recording head. 2. The cap member driving means separates the cap from the nozzle surface from the other end of the cap while keeping one end of the cap in contact with the nozzle surface, and finally, the one end of the nozzle is connected to the nozzle surface. The inkjet recording apparatus according to claim 1, wherein the inkjet recording apparatus is detached from the surface. 3. The ink jet recording apparatus according to claim 2, wherein the nozzle surface is arranged in a direction that is not horizontal to the direction of gravity, and the other end corresponds to the uppermost point of the nozzle surface with respect to the direction of gravity. 4. The inkjet recording apparatus according to claim 1, wherein the inkjet recording head includes an electrothermal converter for generating thermal energy for ejecting ink. 5. The ink jet recording head, by the thermal energy applied by the electrothermal converter,
The ink jet recording apparatus according to claim 4, wherein the film boiling generated in the ink is used to eject the ink from the ejection port.