JPH08300686A - Ink jet recording apparatus - Google Patents

Abstract

PURPOSE: To extend the life of an ink jet recording head by reducing the deterioration of the ink emitting surface and wiper of the ink jet recording head. CONSTITUTION: An ink jet recording apparatus has the wiper wiping the emitting surface of an ink jet recording head 2, a detection means 4 detecting the emitting surface state of the ink jet recording head 2, a control means 12 having the first level compared with the detection output of the detection means 4 and wiping the emitting surface by the wiper when the detection output is the first level or less and a wiping operation means 4. The detection means 4 is arranged at a recording folding back point or detects the presence of a recording head.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording apparatus for recording a pattern such as a character or an image on a recording surface of an object to be recorded, and more particularly to improvement of an ink jet recording apparatus for ejecting ink droplets for recording. .

[0002]

2. Description of the Related Art Conventionally, in an ink jet recording head,
When ink is ejected for recording, fine mist-like droplets are generated in association with the ejected droplets, or the ejection surface of the recording head gets wet and dirty due to bounce of the droplets from the recording object. . Therefore, the ejection surface of the head is cleaned by wiping the ejection pulse number or at regular intervals.

[0003]

However, in the actual print head, the influence of the external temperature, the height of the print duty, the deterioration of the water repellency of the head surface, the variation of the ejection characteristics of the head, the use state of the head, the use of the head, The way the head surface gets wet varies depending on the time and the like. On the contrary,
When the head ejection surface is wiped at a fixed number of ejection pulses or at a fixed time, the shortest number of ejection pulses due to these factors,
Alternatively, the head ejection surface must be wiped in the shortest time. For this reason, it is necessary to wipe even when there is no need to wipe, and the number of times the head ejection surface is wiped increases, and the wiper or the head ejection surface deteriorates due to the wiping. Further, there is a drawback that an increase in the number of wiping increases the wiping time, which is added to the recording time and the apparent recording speed (throughput) becomes slow.

In view of the above-mentioned conventional drawbacks, an object of the present invention is to provide an ink jet recording apparatus which reduces deterioration of an ink ejection surface and a wiper of an ink jet recording head to prolong the life thereof and also has an apparent recording speed. It is in.

[0005]

In order to solve this problem, the present invention provides a wiper for wiping the surface of an ink jet recording head, a detecting means for detecting the ejection surface state of the ink jet recording head, and a detecting means for the detecting means. An inkjet recording apparatus having a first level to be compared with a detection output, and including a wiping operation control means for wiping an ejection surface with the wiper when the detection output is equal to or lower than the first level. Further, it has a second level to be compared with the detection output, and has means for issuing a warning when the detection output is equal to or lower than the second level. Further, the detecting means is installed at the recording turnaround point.

[0006]

According to the present invention, by directly detecting the wet state of the head discharge surface, even if the wet state of the head discharge surface due to various factors changes with the number of discharge pulses and time, at a constant wet state, A wiping operation can be performed by detecting wetness. By doing so, since the head ejection surface is good when the head is new, the number of times of wiping is small, and the number of times of wiping can be appropriately increased if the head ejection surface condition gradually deteriorates. Furthermore, even if there is a difference in the head surface state due to variations in the ejection characteristics of the recording head itself, appropriate wiping can be performed due to the variations.

[0007]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a partial external appearance of an inkjet recording apparatus according to the present invention.

In FIG. 1, reference numeral 1 is a part of an ink jet recording apparatus. Reference numeral 2 denotes an inkjet recording head mounted on a carriage (not shown), which moves while being guided in the left-right direction on the paper surface and ejects ink droplets onto the recording medium 5, which is the recording medium 5, to perform recording. Reference numeral 3 denotes a wiper installed at the home position (right side in the drawing) of the recording head. When wiping the head ejection surface, the head 2 can be moved to the right to wipe. Reference numeral 4 denotes a detection unit provided at a turning point (left side in the drawing) of the print scan, and detects the wet state of the head ejection surface for each print scan of the head in a normal print operation. Furthermore, when there is no detection output, it can be detected that there is no recording head.

Next, the case where the detection means detects the wet state of the head ejection surface will be described. FIG. 2 is a diagram showing a usage situation of the optical detecting means. In FIG. 2, reference numeral 6 denotes a head ejection surface of the head 2, which is provided with a plurality of ejection ports 8 through which ink droplets are ejected. Normally, the head surface is clean, but when ejection is continued, the ejection surface 6 of the head gradually gets wet due to fine droplets or bounce of droplets from the recording object, and an ink pool 7 is formed. If the ink reservoir 7 becomes large, the ejection port 8 is blocked, or if an ink droplet drips on the recording medium 5, recording becomes defective. Before that happens, the light emitting element 9, the light receiving element 10, and the condenser lens 1
The wet state of the head ejection surface is detected by the optical detecting means consisting of 1, and if it is below a certain level, the head 2 is moved to the right and wiped with the wiper 3.

FIG. 3 is a block diagram showing the configuration of the embodiment of the present invention. As described above, the ejection surface 6 of the recording head 2
Is detected by the detection means 4. Reference numeral 12 denotes a CPU 12 having a built-in A / D converter, which has first and second levels to be compared with the detection output of the detection means 4, and outputs by comparing and judging. Thirteen
Is a warning means for warning that the print head is not mounted on the carriage when the detection output is equal to or lower than the second level. Reference numeral 14 is a wiping operation means for wiping the head ejection surface 6 with the wiper 3 when the detection output is higher than the second level and lower than the first level.

The operation of the embodiment will be described with reference to the flowchart of FIG.

In step 1, it is judged whether or not the recording start signal is inputted. If it is not inputted, the process returns to step 1 again. . When it is below the second level, it is determined that the head 2 is not mounted on the carriage, and the process proceeds to step 3 to activate the warning means 13. When the level is equal to or higher than the second level, the process proceeds to step 4 and it is determined whether the level is equal to or higher than the first level. If it is equal to or higher than the first level, the process proceeds to step 6 and the ejection operation is performed to set the recording state. When the recording is performed in the left and right scanning directions, the process proceeds to step 7 and it is determined whether the recording is completed. If the recording ends, it ends. If recording has not ended, the process returns to step 4. When it is below the first level in step 4, the process proceeds to step 5 to operate the wiping operation means 14 to start the wiping operation, and the wiper 3 wipes the head ejection surface 6. After finishing the wiping, return to step 4. In the following, the operation described above is repeated from step 4.

[0013]

As described above, according to the ink jet recording apparatus of the present invention, the wet state of the head discharge surface is directly detected. Therefore, even if the wet state of the head discharge surface is different due to various factors. It is possible to wipe by detecting wetness in a constant wet state. By doing this,
The number of times the head ejection surface is wiped is significantly reduced, deterioration of the head ejection surface is reduced, and the head life is extended. Similarly, deterioration of the wiper is reduced and the life of the wiper is extended. Further, since the detection means is installed at the recording turnaround point, recording can be performed in a normal operation time, and the wiping time is shortened, so that the apparent recording speed is increased. Further, since the head ejection surface is detected, the presence or absence of the recording head can be detected with little cost by observing the detection output.

[Brief description of drawings]

FIG. 1 is a diagram showing a partial external appearance of an inkjet recording apparatus according to the present invention.

FIG. 2 is a diagram showing a usage situation of an optical detection means.

FIG. 3 is a block diagram showing a configuration of an embodiment.

FIG. 4 is a flowchart showing the operation sequence of the embodiment.

[Explanation of symbols]

 1 Part of Inkjet Recording Device 2 Inkjet Recording Head 3 Wiper 4 Detection Means 5 Recording Object (Paper) 6 Head Ejection Surface 7 Ink Reservoir 8 Ejection Port 9 Light Emitting Element 10 Light Receiving Element 11 Focusing Lens 12 CPU 13 Warning Means 14 Wiping operation means

Claims (5)

[Claims] 1. A wiper for wiping the surface of an ink jet recording head, a detection means for detecting the ejection surface state of the ink jet recording head, and a first level to be compared with the detection output of the detection means. An ink jet recording apparatus comprising a wiping operation control means for wiping an ejection surface with the wiper when the ejection surface is below the first level. 2. The ink jet recording apparatus according to claim 1, further comprising a unit having a second level to be compared with the detected output, and issuing a warning when the detected output is equal to or lower than the second level. 3. The ink jet recording apparatus according to claim 1, wherein the detecting means is installed at a recording turnaround point. 4. The ink jet recording apparatus according to claim 1, wherein the detecting means is an optical detecting means for optically detecting. 5. The ink jet recording apparatus according to claim 1, wherein the optical detecting means includes a light emitting element and a light receiving element.