JP2726135B2 - Ink jet recording device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an ink jet recording apparatus, and more particularly, to a full line type ink jet recording head in which discharge ports are formed over the entire recordable width of a recording material. To an ink jet recording apparatus.

2. Description of the Related Art Conventionally, a recording head used in an ink jet recording apparatus is of a serial type that performs recording on a recording material such as recording paper while moving in a paper width direction.
A line type having an ejection port corresponding to the sheet width of the recording area of the recording material and a liquid path communicating with the ejection port and an arrangement of ejection energy generating elements is known. From the viewpoint of high-speed recording, a full line type is known. A recording head of the type is advantageous.

FIG. 6 shows an example of such a full-line type recording head. Reference numeral 1 denotes a large number of fine and high-density discharge ports 2 arranged on a discharge surface 1A of the print head. This is a first substrate on which a liquid passage (not shown) and an electric heat exchanger as a discharge energy generating element are formed. 3A and 3B are ink supply tubes for supplying ink to the recording head 10, and 4 is a second substrate for fixing and holding the first substrate 1, and the first substrate 1 and the second substrate 4 is usually adhered in a state where it is brought into close contact with an adhesive or the like.

Thus, the recording head 10 thus configured is accurately positioned and fixed at a predetermined position of the recording apparatus, and is supplied from an ink supply means (not shown) to the ink supply tube 3.
By supplying the ink through A and 3B, a heat energy generated by driving an electrothermal transducer as an ejection energy generating element in accordance with a recording signal is used,
The desired recording is performed by ejecting ink from the ejection port 2 and landing it on a recording material arranged opposite to the recording material. Further, for example, four such recording heads 10 are arranged in parallel, and full color recording can be performed by discharging cyan, yellow, magenta, and black inks from these recording heads.

[Problem to be Solved by the Invention] However, in the conventional full-line type recording head as described above, the length in the longitudinal direction is increased in accordance with the recording width, and the width in the lateral direction is reduced in manufacturing or production. From the above relationship, since a plurality of substrates are cut out from one substrate body (wafer), they tend to be formed shorter, as shown in FIGS. 8B and 8C. Warpage in the longitudinal direction tends to be large.

Therefore, in general, when bonding the first substrate 1 and the second substrate 4, the first substrate 1 is bonded and fixed to the second substrate 4 while applying an external force so as to correct the warpage of the first substrate 1. In many cases, the longer the first substrate 1 is in the longitudinal direction, the more difficult it is to completely correct the warp.

In particular, in the case where color printing is performed by arranging a plurality of full-line type recording heads as described above in parallel and overprinting a plurality of color inks, the recording to be performed is caused by the warpage generated in the longitudinal direction of each recording head. The landing position of the ink droplet from each recording head on the material is shifted, for example,
As shown in FIG. 3B, the degree of color overlap in the longitudinal direction is different, causing color misregistration and different colors. Especially,
When two recording heads having warpages in directions opposite to each other are incorporated in the recording apparatus as shown in FIGS. 8B and 8C, the two recording heads are driven to overlap the dots. When recording is performed, the dots overlap exactly at both ends of the row of the ejection openings 2, that is, both ends of the recording paper, but do not overlap at all near the center as shown in FIG. 7B. State.

As described above, when a recording is performed by attaching a warped line-type recording head to a recording device, not only linearity is lost, but also ink droplets of multiple colors are superimposed, especially using multiple recording heads. When performing color recording with
In the conventional apparatus, the landing position of the ink droplet differs depending on the position in the width direction of the recording paper due to the warp of each recording head. In particular, near the center in the width direction, uniform dot superposition may be very difficult, and However, the image quality was significantly reduced.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-described conventional problems by correcting the warpage of the recording head in the longitudinal direction, ensuring a highly accurate ink droplet landing position over the entire width of the recording material, and achieving high-quality recording. An object of the present invention is to provide an ink jet recording apparatus capable of obtaining an image.

[Means for Solving the Problems] In order to achieve the above object, an ink jet recording apparatus according to the present invention includes a conveying unit for conveying a recording medium in a predetermined direction, and a length in a direction intersecting the conveying direction of the recording medium. An ink jet recording apparatus having an ink jet recording head having a recording width of さ, and a head support member for supporting the head, wherein both ends of the head are fixed to the support member, and the center of the support member Is characterized by having a warp correcting means which can correct the warp of the head in the transport direction by sandwiching a central portion of the head at a position facing each other in the transport direction.

[Operation] According to the present invention, in a state where the recording head is mounted on the recording apparatus, the recording head is corrected by applying a force in a direction corresponding to the recording head to cancel the warping by the recording head warpage correcting means. Can be. As a result, it is possible to remove a warp of the full-line type recording head and obtain a high-quality image with a high accuracy of impact points.

Further, when color printing is performed using a plurality of printing heads, the point of impact between the respective printing heads on the recording material can be reliably corrected, and high-quality color printing can be performed.

[Example] Hereinafter, an example of the present invention will be described in detail and specifically with reference to the drawings.

1A and 1B show the configuration of an ink jet recording head and its warpage correcting means as one embodiment of the present invention.
In these figures, reference numeral 11 denotes a recording head fixing table for fixing and holding the recording head 10 at a predetermined position of the recording apparatus, and 12A.
And 12B connect the both ends of the recording head 10 to the recording head
A fixing screw 13 fixed to the arm is provided so as to extend from the center of the recording head fixing base 11 to the upper surface of the recording head 10, and 14 and 15 are fixed to the fixing base 11 so as to face each other. This is a fine adjustment screw whose tip protrudes toward the recording head 10 from the corresponding position of the center and the arm 13.

That is, these fine adjustment screws 14 and 15 are screwed to the fixed base 11 and the arm 13 in the form shown in the figure, respectively, and are screwed to each other and screwed back to each other, so as to pass through the tips thereof. The warpage in the longitudinal direction of the recording head 10 can be freely adjusted to maintain a flat posture without warpage as shown in FIG. This is because the amount of warpage generated in the long recording head tends to be the largest at the center in the longitudinal direction.
I have 4,15. A plurality of adjustment screws may be provided on one surface in order to more accurately adjust the warpage of the entire long recording head.

As a specific method, first, the fine adjustment screws 14 and 15 are loosened, and the recording head 10 is maintained in a fixed state as it is, and as shown in FIG. Full-line recording is performed, and the amount of warping Δl1 and the direction of the warping with respect to the virtual straight line indicated by the broken line of the recording line L are measured. Then, based on the result, the fine adjustment screw on the convex side of the fine adjustment screws 14 and 15 is tightened according to the warpage amount Δl1, and then a full line is recorded again at several dot intervals, and the recording line is recorded. The amount of warpage of L and its direction are measured. In this way, the fine adjustment screw is operated by trial and error so as to reduce the amount of warp, and when the amount of warp becomes equal to or less than the predetermined amount of warp, both fine adjustment screws 14 and 15 are fixed.

The above description has been made on the case where a single print head 10 is used. Next, a color ink jet printing apparatus using a plurality of print heads will be described.

FIG. 3 schematically shows a recording apparatus of this embodiment using four recording heads. Reference numerals 10C, 10M, 10Y and 10BK denote recording heads for recording in cyan, magenta, yellow and black colors. Although not shown in detail, the recording heads are respectively fixed to a fixing table 11 including fine adjustment screws as shown in FIG. 1, and reference numerals 21 and 22 denote paper feeds for feeding a continuous recording sheet 20. Roller.

First, these four recording heads 10C, 10M, 10Y and 10B
As shown in FIG. 2, full-line recording is performed at intervals of several dots using any one of the recording heads K, and the amount of warping Δl1 of the line L and the direction of the warping are measured. Thus, fine adjustment screws 14 and 15 are adjusted in accordance with the amount of warp Δl1 and the direction. Then, the amount of warpage of the one recording head is adjusted so as to be equal to or less than a predetermined amount of warpage. Next, when full lines which are four-color overprinted by the four recording heads 10C to 10BK are recorded at several dot intervals, the recording lines recorded in this case are the other three lines as shown in FIG. A dot shift should occur in the paper feed direction for each color according to the amount of warpage of the recording head. Therefore, with respect to the three recording heads other than the first recording head whose warpage was corrected first, the recording lines of the first recording head whose warpage was corrected and the recording lines of the other three recording heads were all in the longitudinal direction. The fine adjustment screws provided on the respective heads are adjusted so as to overlap with each other to correct the warpage of the three recording heads.

If there is a head manufactured so that the amount of warpage of the recording head is equal to or less than a predetermined amount of warpage, the recording lines of the other three colors are superimposed on a predetermined color, for example, a black recording line. The warpage of the three heads may be adjusted by combining them.

FIGS. 4A and 4B show an ink jet recording head warpage correcting means according to another embodiment of the present invention. In this example, instead of the fine adjustment screw 14 on the side of the recording head fixing base 11 shown in FIGS. 1A and 1B, the adjustment head formed between the recording head 10 and the upper surface of the center of the fixing base 11 is used. A bent leaf spring 17 is provided in the space 16 as shown in the drawing, and the recording head 10 is forcibly biased toward the tip of the upper fine adjustment screw 15 by the spring force of the leaf spring 17. . Therefore, according to this example, the pressing force of the fine adjustment screw 15 on the recording head 10 is increased or reduced by simply operating the fine adjustment screw 15 against the spring force of the leaf spring 17. The recording head 10 can be pushed upward by the spring force.

As is clear from the above description, in the present invention, it is necessary to forcibly correct the warpage by applying a force to the recording head at the center in the longitudinal direction. Therefore, it is desirable that the recording head be relatively easily deformed by an external force in a direction perpendicular to the ink ejection direction.

FIGS. 5A to 5C show embodiments each of which is a recording head suitable for the recording apparatus of the present invention. In these embodiments, the first substrate 1 on which a plurality of ejection energy generating elements are arranged in the longitudinal direction of the recording head 10 is formed to be easily bent by the second substrate 4 which is held and fixed. In FIG. 5A, the thickness of the second substrate 4 in the longitudinal direction is smoothly changed so as to be minimum at the center and maximum at both ends. In addition, FIG.5B shows the thickness of the central portion in the longitudinal direction reduced with a step, and FIG.5C shows the thickness gradually reduced from both ends in the longitudinal direction toward the central portion. It is. In addition, as a form in which the second substrate 4 easily bends,
It is needless to say that the present invention is not limited to these examples.

In the ink jet recording head configured as described above,
Even if a large additional force is not used at the center in the longitudinal direction, it can be easily deformed in the vertical direction in the figure, and fine adjustment of the warpage can be easily performed.

(Others) The present invention brings about an excellent effect particularly in a recording head and a recording apparatus of a bubble jet system among ink jet recording systems. This is because according to such a method, it is possible to achieve higher density and higher definition of recording.

As for the representative 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 a sheet or a liquid path holding a liquid (ink). Applying at least one drive signal corresponding to the recording information and providing a rapid temperature rise exceeding nucleate boiling to the electrothermal transducer, thereby causing the electrothermal transducer to generate thermal energy, thereby causing the recording head to emit heat energy. This is effective because a film in the liquid (ink) corresponding to the driving signal can be formed one by one by causing film boiling on the heat acting surface. The liquid (ink) is ejected through the ejection opening by the growth and contraction of the bubble to form at least one droplet. 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. U.S. Pat. No. 44
Those described in JP-A-63359 and JP-A-4345262 are suitable. Further, when 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 a configuration of the recording head, in addition to a combination configuration (a linear liquid flow path or a right-angled liquid flow path) of a discharge port, a liquid path, and an electrothermal converter as disclosed in the above-mentioned specifications, A configuration using U.S. Pat. No. 4,558,333 and U.S. Pat. No. 4,459,600, which disclose a configuration in which is disposed in a bending region, is also included in the present invention. In addition, Japanese Unexamined Patent Publication No. 59-123670 discloses a configuration in which a common slit is used as a discharge portion of an electrothermal transducer for a plurality of electrothermal exchangers, and an aperture for absorbing a pressure wave of thermal energy. The effect of the present invention is effective even if the configuration is based on JP-A-59-138461, which discloses a configuration corresponding to a discharge unit. That is, recording can be performed reliably and efficiently regardless of the form of the recording head.

Further, the present invention can be effectively applied to a full-line type recording head having a length corresponding to the maximum width of a recording medium on which a recording apparatus can record, but such a recording head includes a plurality of recording heads. Either a configuration that satisfies the length by combination or a configuration as one recording head formed integrally may be used.

Further, it is preferable to add recovery means for the print head, preliminary auxiliary means, and the like provided as a configuration of the printing apparatus in the present invention since the effects of the present invention can be further stabilized. If these are specifically mentioned, capping means for the recording head, cleaning means, pressurizing or suction means, preheating means using an electrothermal transducer or another heating element or a combination thereof, Performing a preliminary ejection mode in which ejection is performed separately from printing is also effective for performing stable printing.

Regarding the type or number of print heads to be mounted, for example, in addition to one provided for single color ink, a plurality of print heads are provided corresponding to a plurality of inks having different print colors and densities. May be used.

In addition, as the form of the ink jet recording apparatus of the present invention, in addition to a form used as an image output terminal of an information processing device such as a computer, a copy apparatus combined with a reader or the like, and a facsimile apparatus having a transmission / reception function are employed. It may be something.

[Effects of the Invention] As described above, according to the ink jet recording apparatus of the first aspect, the recording head is prevented from warping in the transport direction by sandwiching the central portion of the print head at a position facing each other in the transport direction. Since the correction means capable of correction is provided, even if the recording head in the mounted state has a warp, it can be easily adjusted to a predetermined amount of warpage or less, and as a result, the linearity of the recording in the longitudinal direction is maintained and improved. be able to. In particular, when color printing is performed by superimposing dots of a plurality of colors by using a plurality of recording heads by using the ink jet recording apparatus of claim 2, it is possible to eliminate overlapping displacement of dots over the entire area in the longitudinal direction and to obtain extremely accurate overlapping of dots. As a result, the color tone becomes uniform, and high-quality image recording can be performed. In addition, since it is not necessary to regulate the warpage to a predetermined amount or less in the manufacture of the recording head, not only the manufacturing process is facilitated, but also the yield is improved and the cost is significantly reduced.

Furthermore, according to the ink jet recording apparatus of the third aspect, the thickness of the recording head in the transport direction is different between the both ends and the central part, so that the adjustment of the warpage can be further facilitated.

[Brief description of the drawings]

1A and 1B are a front view and a sectional view taken along the line AA of a front view showing a configuration of a recording head fixing table according to an embodiment of the present invention. FIG. 2 is a recording pattern for measuring the amount of warpage of the recording head. FIG. 3 is a perspective view showing an application example of the present invention having a plurality of recording heads. FIGS. 4A and 4B are plan views showing the configuration of a recording head fixing table in another embodiment of the present invention. FIG. 5A, FIG. 5B and FIG. 5C are perspective views each showing a configuration example of the recording head of the present invention, FIG. 6 is a perspective view showing a conventional example of an ink jet recording head, FIG. 7 is an explanatory diagram showing the displacement of dots due to the warpage of the recording head, and FIG. 8 is an explanatory diagram of the state of the warpage occurring in the recording head. 1 ... first substrate, 2 ... discharge port, 3A, 3B ... fixing screw, 4 ... second substrate, 10, 10C, 10M, 10Y, 10BK ... recording head, 11 ... recording head fixing stand, 12A, 12B: fixing screw, 13: arm, 14, 15: fine adjustment screw, 16: space, 17: leaf spring, 20: recording material.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hidemi Kubota 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Hiroshi Koizumi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Incorporated (72) Inventor Mineo Kaneko 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) References Japanese Utility Model Sho 59-59343 (JP, U) Japanese Utility Model Sho 63-56636 (JP) , U)

Claims (5)

(57) [Claims] A transport unit for transporting a recording medium in a predetermined direction; an inkjet recording head having a recording width in a direction intersecting with the transport direction of the recording medium; a head support member for supporting the head; An ink jet recording apparatus comprising: a head, wherein both ends of the head are fixed to the support member, and a center portion of the head is sandwiched at a center of the support member at positions opposed to each other in the transport direction. An ink jet recording apparatus, comprising: a warp correction unit capable of correcting the warpage of the head in the transport direction. 2. The ink jet recording apparatus according to claim 1, wherein a plurality of said recording heads and a head supporting member are provided, and said plurality of recording heads are arranged in parallel in a conveying direction of said recording medium. . 3. The ink jet recording apparatus according to claim 1, wherein the thickness of the recording head in the conveying direction is different at both end portions and a central portion. 4. An ink jet recording apparatus according to claim 3, wherein the thickness of said recording head is minimum at a central portion. 5. The recording head according to claim 1, wherein the recording head ejects ink by using thermal energy, and includes an electrothermal converter for generating thermal energy. 2. The ink jet recording apparatus according to claim 1.