JP2003205625A - Inkjet recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that a cleaning operation performed during a recording operation improves reliability in image quality but causes lowering of a substantial recording speed because the recording operation is interrupted when the cleaning operation is performed in an inkjet recorder that comprises a recording head for performing the recording by ejecting ink drops from a plurality of nozzle openings by driving an energy conversion member according to a recording signal and a nozzle recovery means for recovering a nozzle having ejection trouble and periodically performs a nozzle recovery operation during the recording operation. <P>SOLUTION: In this inkjet recorder, as the cleaning operation during the recording operation and its frequency are optimized based on the environmental condition and a kind of a recording medium, it is possible to provide the inkjet recorder that can suppress the time period for interrupting the recording operation to a minimum necessary level and achieves the substantially high speed recording. <P>COPYRIGHT: (C)2003,JPO

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 by driving an energy conversion member in response to a recording signal and ejecting ink droplets from a nozzle opening. Regarding

[0002]

2. Description of the Related Art An ink jet recording apparatus carries out recording by ejecting ink droplets from a nozzle opening of a recording head, which will be described in detail below, to a recording material facing the nozzle opening.

FIG. 3 is a sectional view of the recording head. The recording head 1 includes a plurality of nozzle openings 2 through which ink droplets are ejected,
Pressure chamber 3 communicating with each nozzle, provided for each pressure chamber,
An energy conversion member 4 for changing the pressure of the pressure chamber 3 and a common ink chamber 6 communicating with each pressure chamber 3 through the restrictor 5 are provided, and the energy conversion member 4 is driven according to the recording signal to drive the pressure chamber 3. By changing the pressure of 3,
Ink is ejected from the nozzle openings 2, and the common ink chamber 6 is supplied with ink from an ink cartridge (not shown) or the like as needed.

As shown in FIG. 4, in such a recording head, when a foreign matter 7 adheres to the vicinity of the nozzle opening 2, the ejected ink droplet is deflected by the foreign matter 7 and landed at a target ink droplet landing position. This leads to deterioration of recording quality. Further, when the foreign matter 7 covers the nozzle opening 2, the ink droplet may not be ejected at all.

Therefore, in the conventional ink jet recording apparatus, when the recording operation is continued for a fixed time, the nozzle recovery operation is forcibly performed to ensure the reliability of the image quality.

As shown in FIG. 5, the nozzle recovery operation when foreign matter adheres to the vicinity of the nozzle opening 2 is performed by a wiping blade 8 made of rubber or the like, which is an elastic member movable relative to the recording head 1. A so-called wiping operation for wiping the opening surface is performed.

Here, 9 is a recording unit having an ink cartridge 10 for supplying ink to the recording head. Usually, the foreign matter is removed by this wiping operation.

However, when the ink adheres to the foreign matter such as paper dust or dust adhering to the vicinity of the nozzle opening and solidifies, or when the foreign matter enters the inside of the nozzle, it is open to the atmosphere. If the ink at the tip of the nozzle opening has dried, the nozzle will not recover in the wiping operation. In such a case, the purging operation described below is performed to recover the nozzle.

The purging operation will be described with reference to FIG. A cap 11 made of rubber or the like is an elastic member that seals the nozzle opening 2 of the recording head 1. Cap 11
At the bottom, two tubes 12 and 13 are connected to the bottom surface, and the tube 12 is connected to the atmosphere release valve 14. The tube 13 can supply a negative pressure into the cap via the suction pump 15.

First, by closing the atmosphere opening valve 14 and supplying a negative pressure, foreign matters near the nozzle openings are caused to flow together with the ink flowing out from the recording head, and the atmosphere opening valve 14 is opened to supply a negative pressure. The ink accumulated in the space 16 inside the cap is sucked. The waste ink is discharged to a waste ink chamber 17 provided at the tip of the tube 13. After the purging operation, the nozzle opening surface is soiled with ink, so the nozzle opening surface is cleaned by the wiping operation described above.

[0011]

However, when such a nozzle recovery operation is performed during the recording operation, it is necessary to interrupt the recording operation once.

The difference in "substantial printing speed" between when the nozzle recovery operation is performed and when the nozzle recovery operation is not performed will be described with reference to FIG. The horizontal axis represents the passage of time, t is the time until the recording of the recording amount A is completed, V is the actual recording speed (hereinafter referred to as the recording speed), and the subscripts a and b indicate the nozzle recovery operation. If not, the case of performing the nozzle recovery operation is shown.

When the nozzle recovery operation is performed during the recording operation
Time t from recording start to recording end _bIs the nozzle recovery operation
Time when not performing_aNozzle recovery operation compared to
It becomes longer as much as you do. As a result, the actual recording speed (
Recording amount / time from recording start to recording end)
In addition, the longer the nozzle recovery operation time, the slower the longer
It

Particularly, a lot of time is required for the suction operation of the ink in the recording head, the suction of the ink accumulated in the space 16, and the purging operation which requires the wiping operation for cleaning the nozzle opening surface.

Further, the recording head is fixed so that a large number of nozzle openings are arranged in a direction orthogonal to the sheet conveying direction,
In the so-called line system, which forms an image by ejecting ink droplets while conveying the paper at a constant speed,
Due to its structure, a large amount of time is required for the nozzle recovery operation, and the recording speed is also significantly reduced.

An object of the present invention is to minimize the time spent for the nozzle recovery operation during the printing operation and prevent the printing speed from decreasing.

[0017]

In order to solve the above-mentioned problems, according to the present invention, a recording head for recording by driving an energy conversion member according to a recording signal and ejecting ink droplets from a plurality of nozzle openings. In an inkjet recording apparatus that includes a nozzle recovery unit that recovers a defective ejection nozzle, and that periodically performs a nozzle recovery operation during a recording operation, the frequency of performing the nozzle recovery operation is variable according to the usage environment. And

Further, it is characterized in that the frequency of the nozzle recovery operation is changed according to the amount and type of paper dust or dust accumulated near the recording head.

Further, it is characterized in that the frequency of the nozzle recovery operation is changed according to the kind of the recording material.

Further, the recording head is provided with a recording head for recording by driving the energy converting member in response to the recording signal and ejecting ink droplets from the nozzle opening, and a nozzle recovery means for recovering defective ejection nozzles. In the ink jet recording apparatus that regularly performs the nozzle recovery operation, the time of the nozzle recovery operation is variable according to the usage environment.

Further, it is characterized in that the nozzle recovery operation is changed in accordance with the amount and type of paper dust or dust accumulated near the recording head.

Further, it is characterized in that the nozzle recovery operation is changed according to the type of the recording material.

Further, the nozzle recovery operation is characterized in that the nozzle opening surface of the recording head is wiped by a wiping blade capable of moving relative to the recording head.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIG.

FIG. 8 is a front view of the ink jet recording apparatus of the present invention, and the hatched portion is a sectional view. The recording unit 1 including the recording head 1 and the ink cartridge 10 for supplying the ink to the recording head 1 is slidably supported on the guide shaft 18 and is connected to the power transmission member 19. The drive source 20 reciprocates along the guide shaft 18. On the other hand, the recording medium 21 faces the nozzle opening 2 surface of the recording head 1 and is conveyed by a conveying roller 22 in a direction orthogonal to the moving direction of the recording unit 9. Ink is ejected onto the recording object 21 from the nozzle openings 2 of the recording head 1 in accordance with a recording signal,
An image is formed.

Reference numeral 11 provided outside the recording area is a cap made of elastic rubber or the like for capping the recording head 1. At the time of non-recording, the recording unit 9 moves to a position above the cap 11 provided in the non-recording area, and the cap 11 caps the recording head 1 by a power source (not shown) so that the ink in the recording head 1 is as much as possible. To prevent dryness. An ink absorbing sheet 23 may be provided in the cap for facilitating suction at the time of sucking ink and for moistening the atmosphere in the cap. Further, two tubes 12 and 13 are connected to the bottom surface of the cap 11, and the tube 12 is connected to the atmosphere release valve 14. The tube 13 can supply a negative pressure into the cap through the suction pump 15,
It is possible to initially fill the recording head 1 with ink by closing the atmosphere opening valve 14, and by sucking the ink accumulated in the space 16 in the cap by opening the atmosphere opening valve 14. The waste ink is discharged to a waste ink chamber 17 provided at the tip of the tube 13.

A wiping blade 8 made of an elastic material such as rubber is arranged between the cap 11 and the recording area. The wiping blade 8 is held by a blade holder 18 and is configured to be able to move forward and backward along the movement path of the nozzle opening 2 surface. Although normally retracted, when a wiping operation is required, the wiping blade 8 is moved by a drive source (not shown) onto the movement path of the nozzle opening 2 surface of the recording unit 9, and the nozzles are reciprocated as the recording unit 9 reciprocates. The two surfaces of the opening are cleaned.

Generally, the recording head of an ink jet recording apparatus is not easily affected by dust or dust from the outside of the recording apparatus due to an outer cover or the like, and foreign matter adhering to the vicinity of the nozzle opening of the recording head is generated from the recording material. Occupy most. In the present embodiment, the amount of foreign matter adhering to the vicinity of the nozzle opening largely depends on the recording material, so the frequency of performing the nozzle recovery operation is variable depending on the recording material. Further, the paper-only recording device will be described below.

FIG. 1 shows a flow chart of the operation control for varying the frequency of performing the nozzle recovery operation according to the present invention.

First, the operator inputs the type of paper to be printed (step S101). Then, the period s for performing the wiping operation to the extent that defective ejection nozzles do not occur is determined from the easiness of generation of foreign matter (mainly paper dust) from the recording material obtained in advance by experiments, etc. (step). S102). This cycle s is selected from a data table prepared in advance by the operator inputting the recording object. For example, as the cycle s, a relatively small value is selected when plain paper or recycled paper is input as recording paper, and a large value is selected when OHP paper is input as recording paper.

Here, the period s for performing the nozzle recovery operation is determined from the data table prepared in advance by the operator inputting the type of paper, but the amount of foreign matter such as paper dust is detected in the vicinity of the recording head. A sensor is provided so that the amount of foreign matter detected automatically
May be determined.

When recording is started (step S103;
Yes) The elapsed time t from the start of printing is counted in the print control unit (not shown) (step S10).
4) At the time when the print head finishes printing for m scans (m: integer), if the period s is exceeded (step S10)
6; Yes), the recording operation is interrupted (step S10).
7), the recording unit 9 moves to the non-recording area provided to the right of the wiping blade 8 (step S10).
8).

Next, the wiping blade 8 is moved by a driving source (not shown) onto the movement path of the nozzle opening 2 surface of the recording head 1 (step S109), and the recording head 1 is moved.
When returning to the recording area again (step S110), the surface of the nozzle opening 2 is wiped by the wiping blade 8 (step S111). As described above, by performing the wiping operation when the recording unit moves from the non-recording area to the recording area, it is possible to prevent the wiped ink or the foreign matter from scattering on the recording object in the recording area. When recording is restarted after the nozzle recovery operation, the elapsed time t is reset, recording is restarted (step S113), and if t ≧ s at the end of m scanning, the nozzle recovery operation is performed again. This operation is repeated until the recording is completed, and when the recording is completed (step S105; No), the recording head 1 is capped with the cap 11 (step S114), and the next print command is waited.

Here, the method of varying the frequency of performing the nozzle recovery operation according to the recording medium has been described, but the frequency of performing the nozzle recovery operation may be variable depending on the environment in which the recording apparatus is used. However, the cycle s for performing the nozzle recovery operation may be shortened when is used in a dusty environment without being protected from the external atmosphere by an exterior cover or the like. As a method of determining s at this time,
The input may be made by an operator, or as described above, a sensor for detecting the amount of foreign matter may be provided in the vicinity of the recording head and the amount of foreign matter may be automatically determined.

Next, the operation control for making the nozzle recovery operation variable will be described. When it is difficult to recover the nozzle by the wiping operation, for example, when a foreign substance has entered the inside of the nozzle or when the ink at the tip of the nozzle opening that is open to the atmosphere has dried, the purge operation is performed. There is a need. Therefore, a purging operation may be performed instead of the wiping operation (steps S109 to S112) described with reference to FIG.

FIG. 2 shows a flow chart of an example of operation control for making the nozzle recovery operation variable according to the present invention.

First, the operator inputs a use environment such as an atmosphere of the outside air and a kind of a recording object (step S201).
These may be automatically detected by the sensor. Then, the period s for performing the nozzle recovery operation and the ratio n for performing the purge operation as the nozzle recovery operation are determined from the data obtained in advance from the experiment (step S20).
2). The smaller the value of n, the easier the purging operation is,
For example, when recording is performed in a dry atmosphere, a small value is selected.

When recording is started (step S203;
Yes), in the print control unit not shown,
The elapsed time t from the start of printing is counted (step S
204), if the period exceeds the period s when the print head finishes printing for m scans (step S206; Ye
s) The recording operation is interrupted (step S207). Here, if the initial value is 0 and the variable x to which 1 is added when the wiping operation is performed has not reached n (step S20).
8; No), the wiping operation is performed as the nozzle recovery operation (step S209).

After the wiping operation is performed, 1 is added to the variable x (step S210), t is reset and recording is restarted (step S211). If the variable x has reached n (step S208; Yes), the purge operation is performed (step S212). After the purging operation is performed, x = 0 is set (step S213),
t is reset and recording is restarted (step S21).
1). This operation is repeated until the recording is completed, and when the recording is completed (step S205; No), the recording head 1 is capped with the cap 11 (step S21).
4) Wait for the next print command.

Further, more detailed operations such as changing the ink suction time and suction pressure to be performed as the purging operation and the number of wiping operations to be performed as one nozzle recovery operation depending on the use environment such as the outside air atmosphere and the kind of the recording material are performed. If the case is divided, the nozzle recovery operation is performed more efficiently.

[0041]

According to the present invention, since the frequency and the recovery operation of the nozzle recovery operation are variable according to the use environment, the nozzle recovery operation during the recording operation that causes a substantial decrease in the recording speed is required. It is possible to provide an inkjet recording device that can be minimized and that supports high-speed printing.

Furthermore, according to the present invention, since the nozzle recovery operation is regularly performed according to the usage environment such as the recording object, it is possible to provide a highly reliable ink jet recording apparatus.

[Brief description of drawings]

FIG. 1 is a flow chart of operation control in which a frequency of performing a nozzle recovery operation (wiping) of the present invention is variable.

FIG. 2 is a flow chart of operation control in which the frequency of performing a nozzle recovery operation (purge) according to the present invention is variable.

FIG. 3 is a cross-sectional view of a recording head.

FIG. 4 is a perspective view of the vicinity of a nozzle opening to which foreign matter is attached.

FIG. 5 is an explanatory diagram illustrating a wiping operation.

FIG. 6 is an explanatory diagram illustrating a purging operation.

FIG. 7 is an explanatory diagram illustrating a substantial recording speed.

FIG. 8 is a front view of the inkjet recording apparatus.

[Explanation of symbols]

Reference numeral 1 is a recording head, 2 is a nozzle opening, 4 is an energy conversion member, and 8 is a wiping blade.

Claims (7)

[Claims] 1. A recording head comprising: a recording head for recording by driving an energy conversion member in response to a recording signal to eject ink droplets from a plurality of nozzle openings; and a nozzle recovery means for recovering defective ejection nozzles. In an inkjet recording device that periodically performs a nozzle recovery operation during operation,
An ink jet recording apparatus, wherein a frequency of performing the nozzle recovery operation is variable according to a use environment. 2. The ink jet recording apparatus according to claim 1, wherein the frequency of performing the nozzle recovery operation is changed according to the amount and type of paper dust or dust accumulated near the recording head. 3. The frequency for performing the nozzle recovery operation is changed according to the type of the recording material.
The inkjet recording device described. 4. A recording head comprising: a recording head for recording by driving an energy conversion member in response to a recording signal to eject ink droplets from a nozzle opening; and a nozzle recovery means for recovering defective ejection nozzles. In an inkjet recording apparatus that regularly performs a nozzle recovery operation, an inkjet recording apparatus is characterized in that the time of the nozzle recovery operation is variable according to the usage environment. 5. The ink jet recording apparatus according to claim 4, wherein the nozzle recovery operation is changed according to the amount and type of paper dust or dust accumulated near the recording head. 6. The ink jet recording apparatus according to claim 4, wherein the nozzle recovery operation is changed according to the type of recording material. 7. The nozzle recovery operation comprises wiping the nozzle opening surface of the recording head with a wiping blade capable of moving relative to the recording head.
7. The inkjet recording device according to any one of 6 to 6.