JPH08174805A - Ink jet printer - Google Patents

Abstract

PURPOSE: To improve the yield of a long recording head for a high speed printing ink jet printer having a plurality of discharge holes arranged in a lateral direction to print at once in a wide width and to reduce the cost by using the head even if faults occur at one or two discharge holes of the head. CONSTITUTION: An ink jet printer has an ink jet recording head having a first discharge hole array 21 which has a plurality of discharge holes 2 arranged in a lateral direction, and can print at once in a wide width. Accordingly, the second discharge hole array 22 having a plurality of discharge holes arranged at the same pitch as the first array 21 is provided in parallel with the first array, and switching means for using the substitute discharge holes 2b of the second array aligned with a defective discharge hole for printing if there is the defective discharge hole 2a of the discharge holes of the first array is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a facsimile, a copying machine,
The present invention relates to an inkjet printer used as a printer for OA equipment. More specifically, the present invention relates to an inkjet printer capable of printing at a time over a wide width without moving the inkjet head laterally.

[0002]

2. Description of the Related Art Ink jet printing is advantageous because it produces little noise and can be easily printed on plain paper.

A recording head used in an ink jet printer is provided with a fine ink discharge hole generally called an orifice and an energy generating means for generating a droplet forming energy in association with the discharge hole, and by controlling this energy generating means. Printing is performed by dropping ink only on the ejection holes required for printing. As the energy generating means, a method of using an electromechanical converter such as a piezo element, a method of irradiating electromagnetic waves such as a laser to generate heat for ejection, or a method of heating ink for ejection by an electrothermal converter such as a heating element and so on.

The conventional recording head 1 for an ink jet printer, as shown in FIGS. 3 (a) and 3 (b), ejects one or two columns of ink in the vertical direction with a length of one or two letters. Holes 2 are provided, and as shown in FIG. 3C, the recording head 1 is sequentially moved in the horizontal direction to perform printing in one row in the horizontal direction, and then the recording head 1 is returned to the original position to print the recording paper in the vertical direction. To print the next line while moving the recording head 1 in the horizontal direction.

[0005]

As described above, in the printer using the ink jet head having the ejection holes vertically arranged with the length of one to two characters, one line in the horizontal direction is printed on the recording paper. It is necessary to perform printing while moving the recording head sequentially in the horizontal direction, return to the left side again when the print head reaches the right end, feed the recording paper by one line, and again print while sequentially moving the recording head in the horizontal direction. Therefore, a drive system for moving the recording head to the left and right is required, and there is a problem that the printer becomes large and power consumption is large. Further, since it is necessary to print while moving the recording head to the left and right for every one or two lines, there is a problem that it takes a long time to print, for example, it takes about 15 seconds to print one page of 50 lines of A4 size.

On the other hand, Japanese Unexamined Patent Publication No. 4-193542 discloses an ink jet recording apparatus having a full line type recording head, and discloses a long head having the same width as a recording sheet. In order to prevent printing unevenness due to warpage of the plate that is the base of the recording head, which tends to occur as the length increases, a means for controlling the ejection timing of the recording head based on the recording data that is the image is provided. An apparatus for recording image quality is disclosed.

However, a recording head that simultaneously prints a wide width, for example, the same width as the recording paper, has an extremely large number of ink ejection holes. For example, to print an A4 size width at one time, The number of discharge holes in a row is about 2000, and there is a high probability that one or two of them will cause defects such as clogging or the liquid not being discharged in a set shape during manufacturing. The diameter of the discharge hole is about 30 to 60 μm, and it is difficult to repair the clogging, and if a defect such as a defective shape of the discharge hole occurs in one or two discharge holes, it cannot be corrected. However, there is a problem that the yield of the recording head is reduced and the cost is increased.

The present invention solves such a problem, and a plurality of ejection holes are arranged in the lateral direction and one or two recording heads of an ink jet printer for high speed printing capable of printing at a time over a wide width. An object of the present invention is to make it possible to use the recording head even if a defect occurs in each ejection hole, improve the yield of the recording head, and reduce the cost.

[0009]

An ink jet printer of the present invention is a first ink jet printer having a plurality of ejection holes arranged in a lateral direction.
An ink jet printer having an ink jet recording head provided with an array of ejection holes and capable of printing at a time over a wide width, wherein a plurality of ejection holes are arranged at the same pitch as the first ejection hole array. A second ejection hole array is provided in parallel with the first ejection hole array, and if there is a defective ejection hole among the ejection holes of the first ejection hole array, it is aligned with the defective ejection hole. Switching means is provided for using the substitute discharge holes of the second discharge hole array for printing.

It is preferable that the first ejection hole array is composed of two rows of ejection holes which are offset by a half pitch, because clear printing can be performed more quickly.

If the second ejection hole array has a plurality of rows of the same ejection hole array as the first ejection hole array, even if a substitute ejection hole of the second ejection hole array is defective, it is further replaced. It is preferable because it is possible.

[0012]

According to the ink jet printer of the present invention, the second ejection holes are formed in the same manner as the first ejection hole array in which a plurality of ejection holes are provided in the lateral direction so that printing can be performed at a time over a wide width. The array is provided vertically, and
Since the means for switching the ejection holes for printing is provided between the first and second ejection hole arrays, one or several ejection holes of the recording head having ejection holes arranged over a wide width are defective. Even if they occur, they can be replaced by the discharge holes of the second discharge hole array. As a result, it is not necessary to replace the entire recording head as a defective recording head or to collect defective ejection holes, which can reduce the number of working steps, improve the yield, and reduce the manufacturing cost.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an ink jet printer of the present invention will be described with reference to the drawings. FIG. 1 (a),
FIG. 2B is a diagram showing the arrangement of the ejection holes of the recording head of an embodiment of the inkjet printer of the present invention, and FIG. 2 is a block diagram of the control unit of the ejection holes of the embodiment of the inkjet printer of the present invention.

As shown in FIG. 1A, the recording head 1 of the ink jet printer of the present invention is, for example, A4 size.
Size 210 or 270 mm, which can print one line in the horizontal direction of B or B4 size at a time, and 2000 in the horizontal direction
About 3500 discharge holes 2 are provided to form the first discharge hole array 21, and the second discharge hole array 22 is arranged in parallel with the first discharge hole array 21 and has the same size. Is characterized in that they are formed by providing the same pitch. Of the ejection holes 2 of the first ejection hole array 21, in response to a drive signal from the printer driver 5 shown in FIG. 2, so that ink can be dropped from the ejection holes 2 according to an image to be printed such as characters. Signal oscillator circuit 3
In this way, the ink dripping in each ejection hole 2 is controlled. It should be noted that ink flow paths leading to the ink liquid chambers and the ejection holes are omitted and not shown.

In the present invention, the control section is further provided with a switching means 6
It is characterized by the provision of. This switching means 6
For example, when one ejection hole 2a of the first ejection hole array 21 is defectively clogged at the manufacturing stage and ink is not dropped from the ejection hole 2a, The ink is dropped from the substitute ejection holes 2b of the second ejection hole array 22 facing the 2a. By this switching, even if some of the ejection holes 2a of the first ejection hole array 21 become defective, the corresponding substitute ejection holes 2b of the second ejection hole array 22 are used to make the recording head 1 defective. In addition, it is not necessary to spend labor for collecting defective ejection holes 2a. As a result, a long recording head can be obtained at low cost, and one page of A4 size 50 lines can be printed at a high speed of about 5 seconds.

When the defective discharge hole 2a of the first discharge hole array 21 is used by switching to the substitute discharge hole 2b, the first discharge hole array 21 and the second discharge hole array 22 are used.
Since there is a gap between the recording sheet and the recording sheet, the recording sheet is printed at the position originally printed by the ejection hole 2a by advancing (or delaying) one timing of feeding the recording sheet.

The switching means 6 is, for example, a changeover switch equipped with a delay circuit for delaying the printing time by one timing, and substitutes the defective ejection holes 2a of the first ejection hole array 21 to the second ejection hole array 22. A switching control circuit for sending a drive signal to 2b and the drive of all the ejection holes 2 of the first ejection hole array 21 and the second ejection hole array 22 are controlled by a computer. It is also possible to use only the ejection hole 2 and to switch the driving signal to the substitute ejection hole 2b instead of the defective ejection hole 2a only when there is a defective ejection hole 2a by a program of the computer.

FIG. 1B is a diagram showing the arrangement of the ejection holes 2 of the recording head of another embodiment of the ink jet printer of the present invention. In this embodiment, the first discharge hole array 21 has two
The ejection holes are formed in rows, and the ejection holes in the second row are formed by arranging the ejection holes that are offset by a half pitch from the ejection holes in the first row. The second ejection hole array 22 is arranged in the same arrangement as the arrangement (the diameter and pitch of the ejection holes 2 are the same). It is preferable that the first ejection hole array 21 has such a configuration because the dots can be narrowed and clear printing can be performed, but the number of ejection holes is doubled, and one to several ejection hole defects occur. The possibility of doing so increases. However, according to the present invention, since the second ejection hole array 22 is provided, even in such a case, the recording head 1 is not defective, and much labor is not required for the recovery work.

The first ejection hole array 21 is not limited to the one shown in FIG. 1B, but the same arrangement as that shown in FIG. The two columns shown may be used as a set and a plurality of sets may be repeated. In this case as well, by using the second ejection hole array 22 having the same arrangement as that of the first ejection hole array 21 or an arrangement having less repetition than that of the first ejection hole array 21, it is possible to cope with a partial defect as in the above-described embodiment. can do.

Further, although the second ejection hole array 22 having the same arrangement as the first ejection hole array 21 is used in each of the embodiments, the first ejection hole array 21 is used as the second ejection hole array 22. A plurality of sets having the same arrangement may be provided.
In this case, the defective ejection holes 2 of the first ejection hole array 21
When the ejection hole 2b in place of a is also defective, the ejection hole 2b can be used in place of the ejection hole 2b, which is more preferable.

[0021]

According to the ink jet printer of the present invention, even if a defect occurs in a part of the ejection holes of the recording head in which ejection holes are formed over a wide width so that printing can be performed at a time over a wide width, the ink jet printer can be used as a recording head. It can be used without any abnormality, and a long recording head having a large number of ejection holes formed in the lateral direction can be formed with a high yield.

Since printing can be performed over a wider width at a time, it is not necessary to move the recording head to the left and right, high-speed printing can be performed, and a recording head drive mechanism is not required, and the printer can be downsized. .

As a result, an ink jet printer capable of high speed printing can be obtained in a small size and at a low cost.

[Brief description of drawings]

FIG. 1 is a diagram showing an arrangement of ejection holes in a recording head of an embodiment of an inkjet printer of the present invention.

FIG. 2 is a block diagram of a control unit that controls ejection holes of an embodiment of the inkjet printer of the present invention.

FIG. 3 is a diagram showing an arrangement of ejection holes of a conventional recording head.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 recording head 2 ejection hole 2a defective ejection hole 2b substitute ejection hole 6 switching means 21 first ejection hole array 22 second ejection hole array

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location B41J 2/125 B41J 3/04 104 F 104 K

Claims (3)

[Claims] 1. An ink jet printer having an ink jet recording head provided with a first ejection hole array in which a plurality of ejection holes are arranged in a lateral direction and capable of printing at a time over a wide width, A second discharge hole array in which a plurality of discharge holes are arranged at the same pitch as the first discharge hole array is provided in parallel with the first discharge hole array, and discharge of the first discharge hole array is performed. An ink jet printer provided with a switching means for using a substitute ejection hole of the second ejection hole array, which is aligned with the defective ejection hole, for printing when there is a defective ejection hole among the holes. 2. The ink jet printer according to claim 1, wherein the first array of ejection holes comprises two rows of ejection holes that are offset by a half pitch. 3. The second discharge hole array has a plurality of rows of the same discharge hole array as the first discharge hole array.
Or the inkjet printer described in 2.