JP2002029069A - Ink jet printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate color irregularities by new and old inks when an ink tank is replaced. SOLUTION: An ink lack detection sensor 14 is set to an ink supply path from an ink tank 11 to an ink jet head 17. An ink remaining quantity of the ink supply path is set to an ink quantity whereby one standard image can be recorded. After one image being recorded when an ink lack is detected is completely recorded, an ink lack alarm is sounded to urge replacing the ink tank 11. After the ink tank 11 is replaced, the old ink in the ink supply path is discharged and sucked by a cleaner head 31. Since a fresh image is recorded after the old ink is discharged from the ink supply path, color irregularities by a subtle color difference of production lots are eliminated. The head is cleaned when the ink is exchanged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet printer, and more particularly to an ink jet printer in which an ink tank filled with recording ink is detachably mounted on an ink jet head.

[0002]

2. Description of the Related Art In an ink jet printer, ink for recording is filled and supplied to an ink tank, and the ink tank is exchangeably mounted in the ink jet printer. The ink tank and the inkjet head are connected by an ink supply tube or the like, and the ink is supplied from the ink tank. An ink-jet printer is provided with an ink-out detection sensor and the like. When the ink runs out, an alarm is issued to instruct the user to replace the ink tank, and printing of an image is interrupted. When the user replaces the ink tank according to the alarm, printing of the image is restarted.

[0003]

However, in the above-mentioned ink jet printer, when the ink tank is replaced, the old ink before the ink tank replacement which remains in the ink supply path such as the ink supply tube is replaced with the ink. There is new ink after tank replacement. Even if the inks are of the same color, there are subtle color differences depending on the production lot. If one image is printed in the state where the old and new inks exist before and after the ink tank replacement as they are, a slight shift occurs in the color between the print area using the old ink and the print area using the new ink, causing color unevenness. There is fear.

An object of the present invention is to solve the above-mentioned problem, and to replace an ink tank with an ink-jet printer in which one image is not printed while old and new inks exist before and after ink tank replacement. It is intended to provide a printer.

[0005]

In order to achieve the above object, an ink jet printer according to the present invention supplies ink from an ink tank filled with ink to an ink jet head having a plurality of nozzles arranged through an ink supply path. ,
In an ink jet printer that discharges ink from each nozzle to record an image on recording paper, an ink discharge unit that discharges ink from an ink supply path, and an ink discharge unit that replaces the ink in the ink supply path when the ink tank is replaced. Control means for discharging the ink and recording an image after the discharge of the ink is completed.

The ink discharge means includes an ink receiving pad facing the nozzle and receiving the discharged ink, and the ink receiving pad includes a suction means for suctioning the discharged ink. Further, the ink supply path holds an ink amount for recording one standard image.
The control means issues an ink tank replacement alarm after the end of recording of the image being recorded when the out of ink is detected.

[0007]

FIG. 1 is a schematic view showing a main part of an ink jet printer embodying the present invention, and shows the configuration of an ink supply section to an ink jet head and a head cleaner section. The ink supply unit 10 includes an ink tank 11, a hollow needle 12, a first tube 13, and an out-of-ink detection sensor 14, and supplies the ink 15 stored in the ink tank 11 to the inkjet head 17. A rubber cap 19 is attached to the ink tank 11 in a liquid-tight manner. When the hollow needle 12 is inserted into the rubber cap 19 in a liquid-tight manner, the ink 15 passes through the hollow needle 12 and the first tube 13 so that the ink jet head 1
7 is supplied. In the middle of the first tube 13, an out-of-ink detection sensor 14 is provided. The out-of-ink detection sensor 14 optically detects the passage of air bubbles in the first tube 13 and, when the air bubbles pass, the ink tank 1
Ink 1 is detected as being out of ink. The detection signal indicating the out of ink is sent to the controller 20. The ink supply unit 10 is provided for each color of yellow (Y), magenta (M), cyan (C), and black (B).

The ink supply path to the ink jet head 17 holds an amount of ink slightly larger than the maximum amount of ink used in one standard image. For this reason, even if the out-of-ink detection signal is input from the out-of-ink detection sensor 14, the controller 20 continues printing without issuing an out-of-ink alarm if there is an image being printed, and finishes printing the image. A low ink alarm is issued later. As a result, color unevenness due to printing of a mixture of old and new inks in one image does not occur. In addition, even if the out-of-ink detection sensor 14 detects an out-of-ink condition during printing of an image, printing can be performed with the ink held in the ink supply path until the printing of the image is completed. This eliminates waste such as reprinting after replacing the ink tank.

Although not shown, nozzles for recording lines of yellow (Y), magenta (M), cyan (C), and black (K) are arranged on the ink ejection surface 17a of the ink jet head 17 in the main scanning direction. Piezo elements are arranged in the ink flow path near these nozzles. By supplying a driving signal corresponding to image data from the controller 20 to each piezo element via the inkjet head driving unit 21, ink droplets having a size and a quantity corresponding to the image data are ejected toward a recording paper (not shown). Adhere to. As a result, a full-color image is recorded on the recording paper by the Y, M, C, and K inks.

The head cleaner section 30 comprises a cleaner head 31, second and third tubes 32 and 33, a suction pump 34, and a waste tank 35. The cleaner head 31 and the suction pump 34 are connected by a second tube 32, and the suction pump 34 and the waste tank 35 are connected by a third tube. Further, the cleaner head 31 is moved by the shift mechanism 36 between a suction position that is in close contact with the ink ejection surface 17 a of the inkjet head 17 and the ink ejection surface 17.
and is displaced between a and the retracted position shown in FIG. The suction pump 34 is driven by the driver 37, and sucks the ink 15 from the ink ejection surface 17a when the cleaner head 31 is displaced to the suction position. The piezo element of each nozzle is driven in accordance with the suction of the ink 15 to discharge old ink, and the ink jet head 1
Cleaning of each nozzle of No. 7 is performed. The ejected ink 15 is discharged to a waste tank 35 via a suction pump 34.

Next, the operation of the above configuration will be described.
As shown in FIG. 2, the controller 20 monitors the ink exhaustion by the ink exhaustion sensor 14 described above. If there is ink, a print permission signal is sent. In addition, when an out-of-ink condition is detected, an out-of-ink alarm is issued. This allows the user to use ink 1
Replace the missing ink tank 11 with an ink tank containing new ink. After replacement, hollow needle 1
2. The cleaner mechanism 31 is displaced by the shift mechanism 36 to the suction position in close contact with the ink ejection surface 17a so that the ink 15 remaining in the first tube 13 and the ink jet head 17 and the new ink do not mix. Then, the ink 15 is suctioned from the ink discharge surface 17a by the suction pump 34, and the piezo element of each nozzle is driven to discharge the old ink. Thus, the hollow needle 12, the first tube 13, the inkjet head 1
Old ink 1 before ink tank replacement remaining in 7
5 is discharged to the waste tank 35. Thereby, the hollow needle 1
2. Only the new ink 15 after the replacement of the ink tank is supplied into the first tube 13 and the ink jet head 17. When the discharge of the old ink 15 is completed, a print permission signal is sent.

In the above embodiment, the old ink is discharged when the ink tank is replaced by sucking the ink from the ink discharge surface by the suction pump and driving the piezo element of each nozzle to discharge the old ink. However, it is also possible to connect a suction pump to the ink supply path to directly suction old ink, and to discharge old ink in the ink supply path quickly by discharging old ink from each nozzle on the ink discharge surface. Good.

In the above-described embodiment, one ink is provided in the ink supply path.
Although a slightly larger amount of ink than the maximum amount of ink used in one standard image is held, the present invention may be implemented without such a definition. In this case, when the out of ink is detected, the printing of the image is interrupted and the ink tank replacement process is performed. Then, the interrupted print is discarded, and a new image is reprinted.

In the above embodiment, ink shortage was detected by detecting air bubbles in the ink supply path. However, ink shortage is not limited to this, and ink shortage is detected by various methods. Good.

In the above embodiment, the present invention is applied to a line printer that records one line at a time in the width direction of the recording paper. However, a serial printer that scans and records the inkjet head in the width direction of the recording paper using a head carriage. The present invention may be practiced.

In the above embodiment, the ink tanks of the four colors Y, M, C, and K are provided. In addition, an ink tank filled with a special color ink, for example, a sepia ink that enables a sepia tone expression is provided. Is also good. In this case, for example, instead of supplying black ink to the K nozzle, sepia ink is supplied to record a sepia tone image. Instead of using the K nozzle, a nozzle of another color or a dedicated nozzle may be used.

[0017]

As described above, according to the ink jet printer of the present invention, when the ink tank is replaced, the old ink remaining in the ink supply path from the ink tank to the ink jet head is discharged before the image is printed. Therefore, one image is not recorded with new and old inks, and color unevenness due to this can be eliminated. Further, the ink jet head can be cleaned every time the ink tank is replaced.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of an ink supply unit and a head cleaner unit of an ink jet printer embodying the present invention.

FIG. 2 is a flowchart of an ink tank replacement process in an ink supply unit and a head cleaner unit shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Ink supply part 11, 11a Ink tank 12 Hollow needle 13 First tube 14 Out-of-ink detection sensor 15 Ink 17 Ink jet head 17a Ink ejection surface 20 Controller 30 Head cleaner part 31 Cleaner head 34 Suction pump 35 Waste tank

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kiyotaka Kaneko 798, Miyadai, Kaisei-cho, Ashigara-gun, Kanagawa Photo Film Co., Ltd. Co., Ltd. F-term (reference) 2C056 EA27 EB16 EB52 EC26 JC06 JC13 JC20 JC23

Claims (4)

[Claims] 1. An ink tank filled with ink supplies the ink via an ink supply path to an ink jet head in which a plurality of nozzles are arranged, and discharges the ink from each nozzle to record an image on a recording paper. In the ink jet printer, an ink discharging means for discharging ink from the ink supply path, and discharging the ink in the ink supply path by the ink discharging means when the ink tank is replaced, the discharge of the ink being completed. An ink jet printer comprising: a control unit that records an image after the printing. 2. An ink jet printer according to claim 1, wherein said ink discharge means includes an ink receiving pad facing said nozzle and receiving the ejected ink. 3. The ink jet printer according to claim 2, wherein the ink receiving pad includes a suction unit that suctions the ejected ink. 4. The ink supply path holds an amount of ink for printing one standard image, and the control means controls the ink tank after printing of the image being printed when ink shortage is detected. 4. An ink jet printer according to claim 1, wherein a replacement alarm is issued.