JPH1034980A - Ink jet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an ink jet recorder which can be assembled easily and positional shift of adhering ink drop due to inclination of a carriage at the time of movement can be corrected. SOLUTION: This ink jet recorder comprises a carriage 2 moving along a recording medium, a common supporting board 5 fixed rotatably to the part of the carriage facing the recording medium, an adjusting screw 10, a spring 11 and a protrusion 12 constituting means for adjusting the position of the carriage 2 by turning the common supporting board 5, and head parts 3C, 3M, 4Y, 4Bk arranged such that nozzles 15, 17 formed on the surface facing the recording medium are arranged along the moving direction (direction shown by an arrow (a)) of the carriage 2.

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 for recording an image by ejecting ink drops from nozzles in accordance with an image signal and attaching the ink drop to a recording medium such as recording paper.

[0002]

2. Description of the Related Art An ink jet recording apparatus provided with an ink jet head for discharging ink drops from nozzles has been known. In particular, as an ink jet recording apparatus for color printing, a carriage that moves along a recording medium is provided with a plurality of heads, and a color image is formed by ejecting inks of different colors from a plurality of nozzles of each of these heads. Has been put to practical use.

In order to form a high-quality color image with this type of ink jet recording apparatus, ink drops ejected from the nozzles of each head are accurately attached to desired positions on a recording medium, and color reproduction is strictly performed. There is a need to do. For that purpose, first, a plurality of nozzles of each head must be formed at correct positions. Also, when attaching each head having accurately formed nozzles to the carriage serving as a support member, it is required that the positional relationship between the nozzles of each head be set with high accuracy. Therefore, for example, when fixing each head on a common support plate which is a member to be attached to the carriage, it is necessary to ensure accuracy by using an appropriate jig or the like.

[0004]

However, even if the respective heads are arranged on the common support plate with high precision as described above, if there is a positional error when the common support plate is mounted on the carriage, each head may be displaced. The attachment position of the ink drop ejected from the nozzle is shifted in a direction orthogonal to the moving direction of the carriage. Therefore, in order to prevent this displacement, the attachment of the common support plate to the carriage also requires high precision, and as a result, the assembly work of the apparatus has been difficult.

In general, the carriage moves while sliding along a sliding axis. However, the carriage slightly tilts during movement due to slight backlash in a sliding portion and distortion around the sliding portion. There is. In this case, even if the common support plate is attached to the carriage with high accuracy, each head is also tilted together with the common support plate due to the inclination of the carriage during movement, so that the head is located at the position where the ink drop adheres on the recording medium. The same shift as described above occurs. Further, the carriage may be tilted due to wear of the sliding portion due to long-term use, which may cause displacement of the ink drop attachment position later. As described above, in the conventional ink jet recording apparatus, in order to attach an ink drop to a desired position in a desired state, high accuracy is required to attach the ink jet head to the support member, and it is difficult to assemble the apparatus. Also, there has been a problem that the ink drop adhesion position shift occurs after the head is attached.

[0006]

In order to solve the above-mentioned problems, an ink jet recording apparatus according to the present invention comprises: an ink jet head having a nozzle for discharging ink; a support member for supporting the ink jet head; An adjusting means for adjusting a relative position between the support member and the nozzle is provided.

[0007]

In the ink jet recording apparatus according to the present invention, after the ink jet head is mounted on the support member, the relative position of the nozzle with respect to the support member can be adjusted by the adjusting means. It is not required and the assembly of the device is easier.

Further, the position of the nozzle can be adjusted by adjusting means in accordance with the inclination of the support member. Accordingly, it is possible to correct the displacement of the position where the ink drop ejected from the nozzle adheres to the recording medium. Therefore, according to the present invention, it is possible to appropriately correct the displacement of the ink drop attachment position according to the actual use state, and to maintain the image quality.

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a schematic view of a main part of an ink jet recording apparatus for color printing according to an embodiment of the present invention. As shown in FIG. 1, the ink jet recording apparatus 100 includes a base 50. Base 5
A pair of side walls 51 facing each other at a predetermined interval are provided on the upper side. A backup roll 5 is provided between the side walls 51.
4. The guide rod 53 and the ball screw 52 are bridged in parallel. The backup roll 54 and the ball screw 52 are each rotatable, and are drivingly connected to motors 56 and 55, respectively. The carriage 2 is provided so as to engage with the guide rod 53 and the ball screw 52. The carriage 2 has a screw hole (not shown), and the combination of the screw hole and the ball screw 52 causes the carriage 2 to move along the guide rod 53 and the ball screw 52 along the arrow a based on the rotation of the ball screw 52. It can reciprocate in a direction (hereinafter, referred to as “main scanning direction”). The carriage 2 also has an ink jet head described later on a surface facing the backup roll 54, and prints ink from the ink jet head on a recording medium such as paper conveyed in the circumferential direction along the outer peripheral surface of the backup roll 54. An image is formed on a recording medium by discharging a drop. When forming an image, the carriage 2 moves at a constant speed in the main scanning direction.

FIG. 2 is a perspective view showing the structure of the carriage 2 facing the recording medium. As shown in FIG. 2, a common support plate 5 is rotatably attached to a recording medium facing portion of the carriage 2 by a retaining screw 7. The common support plate 5 is engaged with an engagement portion 8 fixed to the carriage 2 on the side opposite to the attachment portion of the retaining screw 7, and is pressed so as to be in close contact with the carriage 2. Further, a bent portion 9 is formed on the common support plate 5 above the engagement portion 8. The tip of the adjusting screw 10 penetrating the bent portion 9 is screwed into a screw hole of a projecting portion 12 projecting from the carriage 2. A spring 11 is mounted around the adjustment screw 10 between the bent portion 9 and the protruding portion 12 and urges the bent portion 9 away from the protruding portion 12. These adjustment screws 1
The position adjustment means of the common support plate 5 is constituted by the spring 0, the spring 11, and the protruding portion 12. By rotating the adjustment screw 10 and rotating the common support plate 5 about the retaining screw 7, the carriage 2 is The position of the common support plate 5 can be adjusted. The adjusting means is not limited to that of the present embodiment, and various embodiments can be adopted as long as the mechanism can rotate the common support plate 5 to adjust the position with respect to the carriage 2.

On the common support plate 5, two multi-heads 3 and 4 are fixed at substantially the same height in the direction of arrow b (hereinafter referred to as "sub-scanning direction") which is parallel to each other and perpendicular to the main scanning direction. Have been. Multi heads 3 and 4
A plurality of heads are provided for each ink color. That is, as shown in FIG. 3, the multi-head 3 integrally includes a cyan head portion 3C and a magenta head portion 3M symmetrically with respect to a central cross section X thereof. Similarly, the multi-head 4 integrally includes a yellow head portion 4Y and a black head portion 4Bk. Since the multiheads 3 and 4 have the same configuration except that the supplied inks are different, the configuration of the multihead 3 will be described below, and the description of the configuration of the multihead 4 will be omitted. In addition, when the head unit of each color is divided into a plurality of heads and arranged as in the present embodiment, the processing of each head becomes easier than the case where the head unit of all colors is formed on one head. Therefore, this embodiment is advantageous in terms of manufacturing cost.

The multi-head 3 has a channel plate 20 at a portion facing the recording medium. Channel plate 2
Reference numeral 0 denotes a flat plate made of resin, metal, or the like, and a plurality of recesses are formed on the back surface thereof. This channel plate 20
As shown in FIG. 4, a partition 21 made of a thin film of metal, resin, or the like is adhered to the concave portion forming surface as shown in FIG. Channel plate 2 covered with this partition 21
The ink channel 22, the inlet 23, and the ink supply chamber 24 are respectively formed in the insides of the respective recesses of No. 0.

A plurality of ink channels 22 are arranged along the main scanning direction and at equal pitches in the sub-scanning direction.
Each ink channel 22 accommodates ink supplied from an ink supply chamber 24 via a corresponding inlet 23.

A plurality of small-diameter nozzles 15 and large-diameter nozzles 17 communicating with the respective ink channels 22 are formed on the recording medium facing surface of the channel plate 20 so as to be arranged on one straight line along the longitudinal direction of the ink channels 22. Have been. The nozzles 15 and 17 are connected to each ink channel 22
Is provided so as to communicate with the vicinity of an end opposite to the inlet 23 connection portion. Then, a small ink drop is ejected from the small diameter nozzle 15 and the large diameter nozzle 17 is discharged.
In this case, an ink drop larger than that discharged from the small-diameter nozzle 15 is discharged.

In this embodiment, the nozzle diameter is changed to eject large and small ink drops for the same ink. However, the present invention is not limited to this, and various means are employed to eject large and small ink drops. For example, the size of the ink drop may be changed by forming each nozzle to have the same size and changing the voltage application condition to the piezoelectric member described later. Further, the nozzles 15 and 17 may be arranged in a zigzag, for example, along the same straight line instead of on a straight line.
The row 16 of rows 5 and the row 18 of large-diameter nozzles 17 may be arranged slightly shifted in the main scanning direction.

As shown in FIG. 4, the lower surface of the partition 21 is fixed via a spacer member 30, 31, 32 to a substrate 33 made of a highly rigid material such as ceramic. Substrate 3
A plurality of piezoelectric members 25 which are opposed to the ink channel 22 via the partition wall 21 and are respectively arranged along the longitudinal direction of the ink channel 22 are fixed on 3. The piezoelectric member 25 is a pressurizing unit that presses the ink contained in the ink channel 22 through the partition 21 based on the deformation at the time of voltage application, and discharges ink drops from the nozzles 15 and 17.

The piezoelectric member 25 has a rectangular body made of a piezoelectric material such as lead zirconate or lead titanate and has electrodes formed on upper and lower surfaces, respectively, and has a length and width smaller than those of the ink channel 22. It is formed small.
The piezoelectric member 25 is polarized, and is deformed by applying a voltage to electrodes provided above and below. Piezoelectric member 2
The electrode on the upper surface of 5 is connected to ground via a conductive partition 21 in contact therewith. On the other hand, the electrodes on the lower surface are electrically connected to individual lead lines patterned on the substrate 33 so as to correspond to the piezoelectric members 25, and are connected to drivers (not shown) via the lead lines. The driver applies a voltage to the piezoelectric member 25 according to an image signal. In addition, the method of drawing out each electrode of the piezoelectric member 25 is not limited to that of the present embodiment, and various changes can be made.

Next, adjustment of the ink drop attachment position before color printing is performed by the ink jet recording apparatus 100 having the above configuration will be described. Cyan head section 3C and magenta head section 3 of multi-head 3
M, cyan and magenta inks are respectively supplied to ink supply chambers 24, 24 via ink supply ports 26, 26, and each ink channel 22 is supplied through an inlet 23.
Is housed in Similarly, the yellow and black inks are also supplied to the respective ink channels 22 to the yellow head portion 4Y and the black head portion 4Bk of the multi-head 4.
Each is housed.

The common support plate 5 to which the multi-heads 3 and 4 are fixed is set at a reference position when it is mounted on the carriage 2. At the reference position, the heads are arranged such that the nozzles 15 or 17 of the heads 3C, 3M, 4Y, and 4Bk are arranged one by one on a straight line along the main scanning direction.

In this state, before starting printing, the carriage 2 is moved in the main scanning direction and the piezoelectric member 25 is moved.
Is applied to the nozzles to eject ink drops from the nozzles, and the degree of overlap of ink dots of each color formed on the recording medium is checked. For example, ink drops are ejected from the large-diameter nozzles 17 located at the most upstream side in the sub-scanning direction of the yellow head section 4Y and the cyan head section 3C, respectively, at the timing when they adhere to the same position on the recording medium. It is only necessary that the dots formed on the recording medium by the two ink drops substantially overlap.

However, as shown in FIG. 5, ink drops are ejected from the nozzles 17 while the multi-heads 3 and 4 are slightly inclined with respect to the main scanning direction due to the inclination of the carriage 2 during movement. Therefore, when the positions where the two ink dots are attached are shifted, the position of the common support plate 5 with respect to the carriage 2 is adjusted. Specifically, FIG.
As shown in (a), when the cyan dot (C) is shifted above the yellow dot (Y), the retaining screw 7 and the adjusting screw 10 are loosened, and the common support plate 5 is moved to the arrow in FIG. Rotate slightly in direction A. On the contrary, FIG.
If the cyan dot (C) is shifted below the yellow dot (Y), as shown in FIG.
To slightly rotate the common support plate 5 in the direction of arrow B in FIG. In this way, the adjustment is performed so that the two dots are accurately overlapped, the retaining screw 7 is tightened, and then printing is started.

As described above, according to the ink jet recording apparatus 1, after the common support plate 5 to which the multi-heads 3 and 4 are fixed is attached to the carriage 2, the common support plate 5 Can be adjusted, the mounting of the common support plate 5 does not require high accuracy, and the assembly of the apparatus becomes easy. In particular, the present invention is effective when a plurality of inkjet heads are provided as in the present embodiment. Because, when there are a plurality of heads, the head mounting error occurs for each head, so the head mounting error tends to be large,
This is because the mounting of the head requires high accuracy.

In addition, the positional displacement of the ink drop caused by the inclination of the carriage 2 during the movement can be corrected in the same manner. Further, even when the ink drop attachment position shift occurs lately due to long-term use, it can be similarly corrected. As described above, the displacement of the ink drop can be appropriately corrected according to the actual use state, so that a high-quality image can be maintained.

In the ink jet recording apparatus 100 of this embodiment, the heads 3C and 3 corresponding to each ink color are used.
M, 4Y, and 4Bk are integrally formed two by two to form multi-heads 3 and 4. However, these four heads may be integrally formed, or conversely, each head may be formed separately. Good. When all the heads are integrally formed, the relative displacement between the nozzles on the head does not matter if sufficient processing accuracy is provided, but the head is attached to a support member such as a carriage. The error that occurs in this case and the displacement that occurs later in the process of actual use have the same problems as those described in the present embodiment. In the present embodiment, the ink jet recording apparatus for color printing has been described. However, the present invention can be applied to a recording apparatus for monochromatic printing.

The adjusting screw 10 and the spring 11
The adjusting means for the common support plate 5 is preferably provided on the side of the multi-heads 3 and 4 for the purpose of saving space in the recording apparatus, but is provided above or below each of the heads 3 and 4. You may. Further, in the present embodiment, the support plate is rotated about an axis provided at one end of the rectangular support plate to which the inkjet head is fixed. However, the present invention is not limited to this. For example, as shown in FIG. As described above, the rotary shaft 7 may be disposed at the center of the circular support plate 5 so that the relative position between the support plate 5 and the carriage 2 does not change even when the nozzle position is adjusted.

In this embodiment, an example has been described in which the nozzle position is adjusted in a plane parallel to the recording medium. However, the present invention is not limited to this, and as shown in FIG. The position may be adjusted in the direction toward. In the embodiment of FIG. 8, a threaded portion 60 is provided at one end of the common support plate 5, and an adjustment screw 61 is provided at an end opposite to the portion where the threaded portion 60 is formed. By rotating the adjusting screw 61, the threaded portion 6
The common support plate 5 rotates so as to approach and separate from the carriage 2 about 0 as an axis. A spring 62 similar to that described with reference to FIG. 2 is fitted on the adjustment screw 61 and is sandwiched between the carriage 2 and the common support plate 5. Therefore, the common support plate 5 can be brought closer to the carriage 2 by tightening the adjustment screw 61, and conversely, the position can be adjusted in a direction away from the carriage 2 by loosening the adjustment screw 61. In this way, by enabling the nozzle position to be adjusted in the direction from the head to the recording medium, it is possible to adjust the angle at which the ink drop enters the recording medium, the flying distance, and the like, so that the ink drop can be adjusted in a desired state. It can be attached to a recording medium.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a main part of an ink jet recording apparatus according to an embodiment of the present invention.

FIG. 2 is a perspective view illustrating a configuration of a recording medium facing surface of a carriage provided in the inkjet recording apparatus of FIG.

FIG. 3 is a front view of a multi-head provided on the carriage of FIG. 2;

4 is a cross-sectional view of the multi-head of FIG. 3, taken along the line III-III.

FIGS. 5A and 5B are diagrams showing a state in which the attachment positions of two ink drops having different colors are shifted when they are superimposed on a recording medium.

FIG. 6 is a diagram illustrating position adjustment of each head for correcting a position shift between two ink drops.

FIG. 7 is a perspective view of the vicinity of a head according to another embodiment of the present invention.

FIG. 8 is a perspective view of the vicinity of a head according to still another embodiment of the present invention.

[Explanation of symbols]

2 ... carriage, 3 ... multihead, 3C ... cyan head, 3M ... magenta head, 4 ... multihead, 4Y ... yellow head, 4Bk ... black head, 5 ... common support plate, 10 ... Adjusting screw (adjusting means), 11: spring (adjusting means), 12: projecting portion (adjusting means), 15, 17: nozzle, 100: ink jet recording apparatus.

Claims (5)

[Claims] 1. An ink jet recording apparatus comprising: an ink jet head having a nozzle for discharging ink; a support member for supporting the ink jet head; and adjusting means for adjusting a relative position between the support member and the nozzle. apparatus. 2. The ink jet recording apparatus according to claim 1, wherein the support member is a carriage that moves along a recording medium. 3. The ink jet recording apparatus according to claim 1, wherein said support member supports a plurality of ink jet heads. 4. The ink jet recording apparatus according to claim 1, wherein said ink jet head has a plurality of nozzles. 5. The adjusting means includes: a support plate fixedly supporting the ink jet head and rotatably provided with respect to the support member; and holding means for holding the support plate at a rotated position. The inkjet recording apparatus according to claim 1, further comprising: