JPH02108547A - Inkjet recording method and apparatus therefor - Google Patents

Abstract

PURPOSE:To stabilize image quality by so arranging that a recording mode is not started until a pre-discharge process is conducted after a cleaning process, and discharging liquid drops by the amount not less than predetermined dots from a recording discharge port in said pre-discharge process. CONSTITUTION:A recording head 1 is allowed to pass a set position of a cleaning blade 8, so that an orifice surface of the recording head 1 is cleaned by the cleaning blade 8. And, the recording head 1 is stopped at a set position of an ink absorbing member 15, where a blind discharge is conducted. The number of blind discharge is good to be 30 dots or more after cleaning is effected one time, and effective to be 60 dots or more when cleaning is done two times. After the blind discharge is completed, recording is carried out in accordance with recording data by scanning the recording head 1, whereby an image part 5 is formed. Since the blade cleaning, blind discharge and recording are carried out at all times in this order, the orifice surface can be effectively cleaned by the effect of the blade cleaning.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to an inkjet recording method that allows good recording operation by effective or leaning of the orifice surface, and is particularly suitable for recording using multicolor ink. Regarding the method.

[Prior Art] An inkjet recording method is a method in which ink is ejected as droplets from minute holes (orifices) provided in a recording head, and the droplets are attached to a recording material such as paper to perform recording.

Various recording methods are applied to image formation using the inkjet recording method, and a common method is to eject ink from the print head in accordance with print information while scanning the print head against the recording material. .

Furthermore, when ink is ejected from the recording head, ink droplets etc. adhere to the orifice surface (the surface where the orifices are arranged), and if the amount increases, it will affect the ink ejection from the orifice, for example. This may cause misalignment of the ink ejection direction, non-ejection of ink, or contamination of images due to ink adhering to the orifice surface scattering together with the ink from the orifice.

Therefore, in order to continuously perform a good recording operation, blade cleaning is performed to wipe away ink adhering to the orifice surface of the recording head.

[Problem to be solved by the invention] Blade cleaning of the orifice surface of the recording head is
This is done by bringing a cleaning blade made of silicone rubber or various rubbers into contact with and sliding on the orifice surface of the recording head to wipe off ink adhering to the orifice surface.

However, during the blade cleaning process, ink, dust, etc. may be forced into the orifice by the blade.

In particular, when cleaning the orifice surfaces of these print heads at once with the same blade in multi-color printing using multiple print heads that eject ink of different colors arranged adjacent to each other, ink from the blade enters the orifice. When kneading occurs, different color inks adhering to the blade are mixed and pushed into the orifice, and when the mixed color ink is ejected onto the recording material during recording operation, undesired mixed color dots are formed. Put it away.

Conventionally, it has been proposed to perform preliminary ejection after cleaning the orifice surface of the print head at the beginning of printing or at a time corresponding to a printing defect during printing.

However, in sequences where continuous recording is performed for a long period of time or sequences where a single small-sized recording is performed, simply performing the same conventional processing is unstable and cannot adequately cope with the next recording. .

In particular, when producing full-color images using multiple inks on large-sized recording paper (for example, A2° AI, AO size), instability of inkjet recording can be seen for each line of recording. has not been obtained yet.

The present invention has been made in view of these problems, and it is an object of the present invention to provide an inkjet recording method and apparatus that are extremely practical and can stabilize image quality in various recording modes.

[Means for Solving the Problems] An inkjet recording method of the present invention includes a step of cleaning an orifice surface of an inkjet recording head with a blade, after cleaning the orifice surface of the recording head with a blade. It is characterized in that recording is performed after preliminary ejection (dry ejection) is performed.

The preliminary ejection is performed by ejecting droplets of 30 or more dots from a recording ejection opening (orifice).

The inkjet recording device of the present invention includes a preliminary ejection droplet collecting section provided at one end of the recording area, a cleaning member provided at the other end of the recording area, and an inkjet recording means that performs recording in the recording area. and a control means for cleaning the orifice surface of the inkjet recording means with the cleaning member, and then performing preliminary ejection in the collection section after maintaining a non-recording state in the recording area, the preliminary ejection being performed once. It is characterized by ejecting droplets of 30 or more dots from one recording ejection port.

Further, the control means cleans the orifice surface of the recording means N times (N≧22N is an integer) using the cleaning member.
After cleaning, the preliminary ejection described above may eject droplets of 30 or more dots.

Note that in the case where the recording head has a large number of recording discharge ports that discharge different inks, and the cleaning step cleans all of these recording discharge ports with a cleaning blade, the preliminary droplet discharge teeth,
It is preferable that the droplet corresponds to the volume of ink contained in the ink flow path until it communicates with the recording ejection port and reaches the common liquid chamber of the recording head.

According to the method of the present invention, even if color mixture of ink occurs in the orifice during blade cleaning, the mixed color ink in the orifice is removed from the orifice by idle ejection performed immediately after blade cleaning, so that the mixed color ink does not change to the recorded image. effects are avoided.

In particular, according to the method of the present invention, a complicated configuration is not required for blade cleaning, such as simultaneous blade cleaning of multiple orifice surfaces with a wooden blade.

〔Example〕

Hereinafter, the method of the present invention will be explained in more detail with reference to the drawings.

FIG. 1 shows an example of an inkjet apparatus of the present invention.

In this apparatus, a recording head 1 is arranged on a carriage 2, and as the carriage 2 moves on a guide rail (not shown) by pulling a belt 10 as a roller 10 rotates, it moves horizontally with respect to a recording material 14. is scanned.

Various configurations of recording heads are available, but
A typical example is one that uses thermal energy as energy for ejecting droplets. As a thermal energy generating element for generating this thermal energy,
There are those described in No. 11, No. 61-61985, and No. 59-43312.

The ink used for recording is supplied to a belt 1 which is rotated by a roller 9 on a guide rail (not shown) in the same way as the carriage.
The recording head 1 is supplied via an ink supply pipe 3 from an ink tank in an ink tank unit 4 that can be moved by pulling the recording head 1.
is supplied to

In the illustrated example, there are four recording heads that eject ink of different colors [for example, black (BK), yellow (Y),
magenta (M), cyan (C)] are arranged,
The number of recording heads can be changed depending on the desired number of colors.

The recording material 14 is moved in the direction of arrow A by the paper feed roller 6.7.
It is sent every time recording of one line in the direction is completed.

At the scanning start position of the recording head, a cleaning blade 8 and an ink absorption member IS made of porous resin or the like that absorbs ink ejected during idle ejection are provided.

The cleaning blade 8 is fixed at a position where it can clean the orifice surface of the recording head 1 when the recording head 1 passes in front of it.

The main operations of the method of the present invention using this apparatus will be explained below.

First, the recording head 1 is caused to pass through the installation position of the cleaning blade 8, the orifice surface of the recording head 1 is cleaned by the cleaning blade 8, and stopped at the installation position of the ink absorbing member 15 to perform idle ejection.

Conditions during blade cleaning, such as the speed of the recording head relative to the blade, may be selected as appropriate depending on the structure and material of the blade used, the size and shape of the recording rad orifice surface, etc. , 50
It is preferable to set the speed to about 800 mm/sec.

The number of idle ejections varies depending on the diameter of the orifice of the recording head 1, but for example, when using an orifice with a diameter of IO to IOOP, more than 30 shots (dots) can be emitted after one cleaning. After cleaning twice (reciprocating cleaning), a sufficient effect can be obtained by emptying 60 times or more. That is, when the number of times of cleaning is N, it is preferable to eject 30N or more from each orifice. This means that the ink adhering to the surface of the cleaning blade is pushed into each orifice of the head, and this amount is roughly equal to 1 ink of the color assigned to that orifice, and other inks (mixed color ink). This is because it can be assumed that it will be 0.1 or less.

Note that the idle ejection may be performed while operating the recording head 1.

Due to this idle ejection operation, even if mixed color ink has been pushed into the orifice, it is removed from the orifice.

At the stage when the idle ejection is completed, a recording operation according to the recording information is performed while scanning the recording head 1, and the image area (5) is
form.

When one line of recording is completed by one scan (scanning from left to right in the figure), the recording material is fed upward by one line, and the recording head is again passed through the cleaning blade 8 installation position, and then The recording operation continues by reversing the above operation.

As described above, by always performing blade cleaning, dry ejection, and recording operations in this order, you can take advantage of the effects of blade cleaning, perform effective leaning operations on each orifice surface, and always perform good recordings. can.

In the example described above, the cleaning blade and the empty ejection position were placed adjacent to each other, and printing was performed only on the outward path of the print head operation, but the present invention is not limited to this. The ejection position can be arranged in various ways as long as it allows blade cleaning, idle ejection, and recording operations to be performed in this order at all times. Further, printing may be performed in the forward and/or backward path during scanning of the print head.

In such cases, depending on the paper size and paper passing position, multiple cleaning blades and blank discharge sections may be installed on both sides of the printing section as shown in Figure 2. You may also use That is, it is possible to use both sides for reciprocating printing and to use one side for small size printing.

Note that in actual images, each color exists randomly, so it is not a big problem if the ink gets mixed in. However, if the color is uniformly pale, for example, the entire surface is yellow, the pressed ink will stain the image, which can be a problem. be.

Therefore, the present invention is particularly effective in such cases.

[Effects of the Invention] The amount of ink that has changed in characteristics and concentrates inside the ejection port due to cleaning mixes with the ink in the ink flow path after cleaning and before entering the preliminary ejection recovery operation, and the orifice surface is cleaned. On the contrary, this causes an abnormal condition inside the ink flow path. Conventionally, it was thought that merely sporadic or about 10 preliminary ejections were sufficient, but this recovery operation had little meaning as a recovery after cleaning.

In the present invention, when we focused on this recovery and examined it, we found that it was unstable even after about 25 shots after repeating character output and image output. Normally, extremely stable recording was made possible for the first time by ejecting 30 shots from each orifice. Taking into consideration the conditions of fluctuations in the recording environment, 100 shots or more is suitable, and when cleaning is performed twice when the carriage is reciprocated and reversed, 30×2 60 or more shots are necessary for stable recording. Optimally, it is better to eject ink approximately equivalent to the volume of ink held in the ink flow path from each ejection port to the so-called common liquid chamber through which each ink flow path communicates, but it is preferable to eject ink approximately equal to the volume of ink held in the ink flow path from each ejection port to the so-called common liquid chamber through which each ink flow path communicates. On the contrary, it is not desirable.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of the main parts of the inkjet recording apparatus of the present invention, and FIG. 2 is a diagram showing another aspect of the idle ejection position in the present invention. 1: Recording head 2: Carriage 3: Ink supply tube 4: Ink tank unit 5: Recording image section 6.7: Paper feed roller 8: Cleaning blade 9a110a: Drive rollers 9b, 10b: Roller 11.12: Belt 13: Head ')')-=Fugu unit 14: Recording material 15: Ink absorbing material

Claims (1)

[Scope of Claims] 1) An inkjet recording method comprising the steps of cleaning an orifice surface of an inkjet recording head and performing preliminary ejection from the inkjet recording head, wherein the preliminary ejection step is performed after the cleaning step. An inkjet recording method characterized in that the preliminary ejection involves ejecting droplets of 30 dots or more from one recording ejection port when entering a printing mode for the first time. 2) The recording head has a large number of recording discharge ports that discharge different inks, and in the cleaning step, all of these recording discharge ports are cleaned with a cleaning blade, and the preliminary droplet discharge ports include: 2. The inkjet recording method according to claim 1, wherein the droplets are equivalent to the volume of ink contained in the ink flow path until they communicate with the recording ejection ports and reach the common liquid chamber of the recording head. 3) The inkjet recording method according to claim 2, wherein the ink flow path has a heat acting section formed by an element that generates thermal energy for forming droplets. 4) A preliminary ejection droplet collecting section provided at one end of the recording area, a cleaning member provided at the other end of the recording area, and a cleaning member provided after the inkjet recording means performs recording in the recording area. control means for cleaning the orifice surface of the inkjet recording means, and then performing preliminary ejection in the collection section after maintaining a non-recording state in the recording area, and the preliminary ejection is performed from one recording ejection port. 3
An inkjet recording device characterized by ejecting droplets of 0 dots or more. 5) The control means causes the cleaning member to clean the orifice surface of the recording means N times (N≧2: N is an integer), and the subsequent preliminary ejection ejects droplets of 30N dots or more. The inkjet recording apparatus according to claim 4. 6) The recording head has a large number of recording outlets that discharge different inks, and in the cleaning step, a cleaning blade cleans all of these recording outlets, and the droplet discharge Claim 4: The droplet corresponds to the volume of ink contained in the ink flow path until it reaches the common liquid chamber of the recording head.
The inkjet recording device described in Section 1. 7) The inkjet recording apparatus according to claim 6, wherein the ink flow path is provided with a heat acting section formed by an element that generates thermal energy for forming droplets.