JP2006256185A - Color inkjet recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a plurality of heads from drying up in a recording mode where a part of a plurality of heads is selected and used in a color inkjet recorder equipped with a plurality of heads ejecting ink of the same color. <P>SOLUTION: Two heads K<SB>1</SB>and K<SB>2</SB>for black are provided. When the image of one page of color image data is formed, a decision is made whether the head used previous time is the K<SB>2</SB>or not (step S1). If it is the K<SB>2</SB>, the K<SB>1</SB>is used this time and stored as the head used previous time (step S2). If the head used previous time is not the K<SB>2</SB>, the K<SB>2</SB>is used this time and stored as the head used previous time (step S3). Subsequently, recording of one scan is carried out using the head which is determined to be used at step S2 or S3 (step S4). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a color inkjet recording apparatus provided with a plurality of heads that eject ink of the same color, and more specifically, the plurality of heads are dried during a recording mode in which a part of the plurality is selected and used. The present invention relates to a color ink jet recording apparatus that prevents clogging.

An ink jet recording apparatus used as an image forming apparatus such as a printer, a facsimile machine, a copying apparatus, or a plotter has a nozzle for ejecting ink droplets and an ink ink flow path (discharging chamber, pressure chamber, pressurized liquid) communicating with the nozzle. And a drive unit that pressurizes ink in the ink flow path.

  In such a head, due to the difference in energy generating means for generating energy for pressurizing the ink in the ink flow path, the diaphragm that forms the wall surface of the ink flow path is deformed by using a piezoelectric element to change the contents of the ink flow path. A so-called piezo type that discharges ink droplets by changing the product, or a so-called bubble type that discharges ink droplets with pressure generated by generating bubbles by heating ink in the ink flow path using a heating resistor. The diaphragm that forms the wall surface of the ink flow path and the electrode are arranged to face each other, and the diaphragm is deformed by an electrostatic force generated between the vibration plate and the electrode, thereby changing the volume of the ink flow path and An electrostatic type that discharges drops is known.

Conventionally, color ink jet recording apparatuses have used four heads for ejecting Y (yellow), M (magenta), C (cyan), and K (black) inks, respectively. There has been proposed a color ink jet recording apparatus capable of high-speed recording by providing two heads (hereinafter referred to as black heads) and using two black heads in the monochrome recording mode (Patent Document 1). reference).
JP 2000-71482 A

  However, since the color ink jet recording apparatus described in Patent Document 1 uses only one of the two black heads in the color recording mode, the black head that is not used is dried and the nozzles are clogged. Cause.

  The present invention has been made in order to solve such problems, and an object of the present invention is to provide a plurality of heads that eject ink of the same color and to form a color image by applying a plurality of colors of ink to a print medium. In the color ink jet recording apparatus that performs the above, the plurality of heads are prevented from drying in the recording mode in which a part of the plurality of heads is selected and used.

The invention according to claim 1 includes a plurality of heads that eject ink of the same color, and ejects the ink of the same color in a color inkjet recording apparatus that forms a color image by applying a plurality of colors of ink to a print medium. A color ink jet recording apparatus comprising: means for setting a recording mode in which a part of a plurality of heads is used; and means for changing the head to be used when the recording mode is set. It is.
According to a second aspect of the present invention, in the color ink jet recording apparatus according to the first aspect of the present invention, the changing unit changes the recording data in units of pages.
According to a third aspect of the present invention, in the color ink jet recording apparatus according to the first aspect, the changing means changes the main scanning unit.
According to a fourth aspect of the present invention, in the color ink jet recording apparatus according to the first aspect, the plurality of heads ejecting the same color ink eject black ink. .
According to a fifth aspect of the present invention, in the color ink jet recording apparatus according to the first aspect, the changing means changes the plurality of heads to be used evenly.
According to a sixth aspect of the present invention, in the color ink jet recording apparatus according to the first aspect of the present invention, the changing means is changed so as to use a head other than the head used last time.

(Function)
According to the first aspect of the present invention, when the mode is set to use a part of a plurality of heads that eject ink of the same color, the head to be used is changed, and the head that is not used is eliminated. Prevent drying out.
According to the second aspect of the invention, when the mode is set to use a part of a plurality of heads that eject the same color ink, the head to be used is changed in units of pages of the recording data, Prevents the head from drying.
According to the third aspect of the present invention, when the mode is set to use a part of a plurality of heads that eject the same color ink, the head to be used is changed by the main scanning unit, thereby drying the head. To prevent.
According to the fourth aspect of the invention, when the mode is set to use a part of the plurality of heads that discharge black ink, the head to be used is changed to prevent the head from being dried.
According to the fifth aspect of the present invention, when the mode is set to use a part of the plurality of heads for ejecting the same color ink, the plurality of heads are changed to be used evenly. Prevents the head from drying.
According to the sixth aspect of the invention, when the mode is set to use a part of a plurality of heads that eject the same color ink, the head is changed to use a head other than the head used last time. Prevents the head from drying.

  According to the present invention, in a color inkjet recording apparatus having a plurality of heads that discharge ink of the same color, the head to be used is not fixed in a recording mode in which a part of the plurality of heads is selected and used. It is possible to prevent the head from drying due to the fact that the head is not used.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a block diagram of a control unit of a color ink jet recording apparatus according to an embodiment of the present invention, and FIG. 2 is a flowchart of operations in the color recording mode.

The control unit corresponds to a microcomputer (hereinafter referred to as “CPU”) 10 that controls the entire recording apparatus, and each of the inkjet heads 14Y, 14M, 14C, 14K ₁ , and 14K ₂ constituting the recording head. It provided the five frame memories 11Y, _{respectively, 11M, 11C, 11K 1,} 11K 2, line buffers _{12Y, 12M, 12C, 12K 1} , 12K 2 and the head driver 13Y, 12M, @ 13 _C, and 13K 1, 13K ₂ A reception buffer 15 for receiving the recording image data transferred from the host side, a color processing circuit 16 for performing a process of separating the recording image data into necessary color data, and the color processed recording image data. An image memory 17 for accumulation and motor drivers 18 and 19 are provided. The inkjet heads 14Y, 14M, 14C, 14K ₁ and 14K ₂ are arranged side by side in the main scanning direction on the carriage 21. The motor driver 18 drives a main scanning motor 20 that moves the carriage 21 in the main scanning direction, and the motor driver 19 drives a platen 23 to drive a sub-scanning motor 22 that conveys recording paper.

  The color ink jet recording apparatus of the present embodiment having the above configuration discharges ink onto the recording paper that is stopped by driving the recording head according to the image data while moving the carriage 21 by the main scanning motor 20. For each page of image data, an image is formed (recorded) for one line, the platen 23 is driven by the sub-scanning motor 22 and the recording paper is conveyed by a predetermined amount, and then the image is formed for the next line. repeat.

When image formation is performed, the recording image data received by the reception buffer 15 is processed by the color processing circuit 16 and stored in the image memory 17, and each frame memory 11Y, as recording image data of a required color is stored. 11M, 11C, 11K ₁ and 11K ₂ are stored. Then the frame memory _{11Y, 11M, 11C, 11K 1} , 11K 2 of the recording image data of each color stored in, one main scan min data line buffers 12Y imaging at, 12M, _12C, 12K 1, 12K Forward to ₂ . Next, the line buffer _{12Y, 12M, 12C, 12K 1} , 12K 2 from the inkjet heads 14Y, 14M, _14C, 14K 1, sequentially reads the data corresponding to the number of nozzles of 14K ₂ by head driver 13Y, 13M, @ 13 C, By supplying to 13K ₁ and 13K ₂ , the head drivers 13Y, 13M, 13C, 13K ₁ and 13K ₂ drive the actuators of the inkjet heads 14Y, 14M, 14C, 14K ₁ and 14K ₂ in accordance with the recording image data. Ink droplets of the required color are ejected.

At this time, the monochrome recording mode and the color recording mode can be set by an instruction from an operation panel (not shown) or image data attribute determination (whether the image is a monochrome image or a color image). Image formation. That is, when set to the monochrome recording mode, the yellow inkjet head 14Y, magenta inkjet head 14M, the inkjet head 14C for cyan is not used, at the same time using two ink jet heads 14K for black ₁ and 14K ₂ As a result, image formation is performed at a higher speed than when only one black inkjet head is used. When the color recording mode is set, the yellow ink-jet head 14Y, the magenta ink-jet head 14M, the cyan ink-jet head 14C, and the black ink-jet head 14K ₁ or 14K ₂ are switched and used in page units or main scanning units. To do. In this way, by switching between the black inkjet head 14K ₁ or 14K ₂ and using the black inkjet head to be used, either the 14K ₁ or 14K ₂ is fixed. Since the ink is not dried, the black inkjet heads 14K ₁ and 14K ₂ are not clogged.

The one-page image forming process in the color recording mode will be described with reference to FIG.
First preceding the black head used is determined whether the head 14K ₂ (step S1), the head 14K ₁ black head used this time as long as head 14K ₂ as previously used head while the head 14K ₁ stores (step S2), and stores the head 14K ₂ as previously used head with a head which used this time unless heads 14K ₂ to head 14K ₂ (step S3). Next, recording for one scan (one line) is performed using the black head (14K ₁ or 14K ₂ ), which is the currently used head in step S2 or S3 (step S4). Since the ejection timing control by the head position is performed by hardware and does not depend on the recording data, the black head to be used can be easily changed.

  When image formation for one scan is completed, it is determined whether or not the switching of the head is a scan unit (step S5). If the scan unit is a scan unit (YES in step S5), the process returns to step S1 to change the head to be used. The operation for forming the scanned image is repeated until the recording of one page is completed (YES in steps S1 to S6). If the head switching is in units of pages instead of units of scan (NO in step S5), the process returns to step S4, and the operation of recording one scan without changing the head to be used is repeated until image formation for one page is completed. . When the image formation for one page is finished, the processing in this figure is finished. When image formation of a new page starts, the process of this figure is entered again, the head used last time is determined in step S1, and a head different from the previous one is used.

As described above, the color inkjet recording apparatus according to this embodiment has the following features (1) to (4).
(1) Even in the color recording mode, the two black heads 14K ₁ and 14K ₂ are alternately used in scan units or page units, so that the black heads are prevented from being used for a long time. The drying of 14K ₁ and 14K ₂ and the clogging of the nozzle can be reduced. For this reason, it is possible to reduce the number of times of maintenance such as idle ejection, and it is possible to improve recording efficiency and reduce ink consumption.
(2) By switching the black heads 14K ₁ and 14K ₂ in units of pages, occurrence of a difference in image quality due to a difference in heads in the same page unit can be reduced. Switching of the page unit may be performed for each page or for each of a plurality of pages.
(3) By switching the black heads 14K ₁ and 14K ₂ in scan units finer than pages, the load caused by not using the heads is more averaged and distributed. The scan unit may be switched every scan or every plural scans.
(4) By reducing the load caused by the state in which one of the black heads is not used and by equalizing the head quality, it is possible to maximize the overall head quality state.

In the above embodiment, two black heads are provided and used alternately. However, n black heads (n is an integer of 3 or more) are provided and used in a cyclic manner ( _{K 1, K 2, ··· K} n, K 1, K 2, ··· K n ···) as may be configured. In addition, two heads for all colors are provided, two heads for all colors are used in the high-speed color recording mode, and one head for all colors is used in the low-speed color recording mode. In the color ink jet recording apparatus, the head used in the low speed color recording mode may be changed alternately.

2 is a block diagram of a control unit of the color inkjet recording apparatus according to the embodiment of the present invention. FIG. 3 is a flowchart of an operation in a color recording mode of a color inkjet recording apparatus according to an embodiment of the present invention.

Explanation of symbols

10 ... CPU, 14Y ... yellow inkjet head, 14M ... magenta inkjet head, 14C ... cyan inkjet head, 14K ₁ ... first black inkjet head, 14K _2, ... Second ink jet head for black.

Claims (6)

In a color inkjet recording apparatus that includes a plurality of heads that eject ink of the same color and that forms a color image by applying a plurality of colors of ink to a print medium.
Means for setting a recording mode in which a part of the plurality of heads for discharging the same color ink is used, and changing means for changing the head to be used when the recording mode is set. A characteristic color ink jet recording apparatus. The color inkjet recording apparatus according to claim 1, wherein
The color ink jet recording apparatus according to claim 1, wherein the changing unit changes the page unit of the recording data. The color inkjet recording apparatus according to claim 1, wherein
The color ink jet recording apparatus according to claim 1, wherein the changing unit changes the main scanning unit. The color inkjet recording apparatus according to claim 1, wherein
A color inkjet recording apparatus, wherein the plurality of heads that eject the same color ink eject black ink. The color inkjet recording apparatus according to claim 1, wherein
The color ink jet recording apparatus according to claim 1, wherein the changing means changes the plurality of heads to be used evenly. The color inkjet recording apparatus according to claim 1, wherein
The color ink jet recording apparatus according to claim 1, wherein the changing means is changed to use a head other than the head used last time.

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