JP2006192611A - Inkjet recording apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recording apparatus equipped with a line type recording head capable of complementing a non-delivering nozzle. <P>SOLUTION: The inkjet recording apparatus is equipped with a plurality of recording heads H1-H4 equipped with nozzles delivering inks toward a recording medium, a carriage 5 carrying the recording heads H1-H4, a moving means 7 moving the carriage 5 in the width direction of the recording medium, a carrying means 2 carrying the recording medium, nozzle 10 etc., a non-delivering detecting mechanism 11 detecting non-delivering of the ink of the nozzle, and a controlling parts 12, 17 and 20 controlling the moving means 7 so that based on the detecting result of the non-delivering detecting mechanism 11, the recording heads H1-H4 are arranged along the width direction of the recording medium to form a longitudinal line head 6. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ink jet recording apparatus, and more particularly to an ink jet recording apparatus having a line type recording head.

  2. Description of the Related Art Conventionally, an ink jet recording apparatus including a line type recording head elongated along the width direction of a recording medium is known. In such an ink jet recording apparatus, when clogging occurs in the nozzles of the recording head, there is a problem that streaky recording unevenness occurs along the recording medium conveyance direction and the image deteriorates.

In order to prevent such image deterioration, an ink jet recording apparatus that includes an extra recording head for complementing non-ejection nozzles is known (see Patent Document 1 and Patent Document 2). Also known is an ink jet recording apparatus that controls the recording medium conveyance position to be shifted in the direction in which the recording head extends so that the recording medium is not conveyed directly under the non-ejection nozzle when a non-ejection nozzle is detected. (See Patent Document 3). Furthermore, there is also known an ink jet recording apparatus in which image data sent to a non-ejection nozzle is data shifted to a nozzle adjacent to the non-ejection nozzle and recorded from the nozzle (see Patent Document 4).
Japanese Patent Laid-Open No. 11-334047 JP 2000-255067 A JP 2000-334935 A JP 2002-248800 A JP 2003-127352 A

  However, line-type recording heads are expensive, and the ink jet recording apparatus described in Patent Document 1 or Patent Document 2 requires an extra recording head to supplement non-ejection nozzles, thus increasing the cost of the apparatus. It was connected. In addition, when nozzles in the same row as the non-ejection nozzles fail to eject, there is a problem that complementation cannot be performed.

  In the case of a line-type recording head, the higher the proportion of the recording medium in the area facing the recording head, the higher the recording efficiency. In the case of the inkjet recording apparatus described in Patent Document 3, However, since the image recording is performed by shifting the transport position of the recording medium, there is a problem that the recording efficiency is lowered.

  Further, as shown in Patent Document 4, when image recording is performed by shifting the image data sent to the non-ejection nozzles to other nozzles, the data should have been sent to the data-shifted previous nozzle and recorded. There was a problem that image data could not be recorded.

  By the way, in an ink jet recording apparatus having a line type recording head, an elongated recording head is required to cope with recording media of various width dimensions, but the elongated recording head is manufactured. Due to processing problems, it is difficult to increase the density of the nozzles, and it is difficult to improve the image quality because the recording head is bent.

  Therefore, as shown in Patent Document 5, there is an ink jet recording apparatus that forms one long line head by arranging a plurality of recording heads along the width direction of the recording medium. By adopting such a configuration, the length of the long line head and the length of the long line head can be changed by changing the overlap of the plurality of recording heads in accordance with the width of the recording medium on which the image is recorded and the desired image quality. The nozzle interval can be adjusted.

  The present invention has been made in view of the above points, and in an ink jet recording apparatus that forms one long line head using a plurality of shortened recording heads, image recording is performed by complementing non-ejection nozzles. The purpose is to perform.

In order to solve the above problem, an invention according to claim 1 is an inkjet recording apparatus,
A plurality of recording heads including nozzles that discharge ink toward the recording medium;
Moving means for moving the recording head in the width direction of the recording medium;
Conveying means for conveying the recording medium;
A non-ejection detection mechanism for detecting non-ejection of the nozzles;
A control unit that controls the moving unit to arrange the recording head based on a detection result of the non-ejection detection mechanism;
It is characterized by providing.

  According to the first aspect of the present invention, the control unit arranges the plurality of recording heads along the width direction of the recording medium (hereinafter referred to as “main scanning direction”) based on the detection result of the non-ejection detection mechanism. The moving means is controlled to form a long line head. Therefore, the recording head can be arranged according to the presence or absence of a non-ejection nozzle.

According to a second aspect of the present invention, in the ink jet recording apparatus according to the first aspect,
When the non-ejection detection mechanism detects non-ejection of the nozzle, the control unit controls the recording head to stop ink ejection by the recording head including the non-ejection nozzle, and the position of the recording head The moving means is controlled to arrange another recording head.

  According to the second aspect of the present invention, when the non-ejection detection mechanism detects the non-ejection of the nozzles, the control unit stops the ejection of the ink by the recording head including the non-ejection nozzles, and the other position is changed to the position of the recording head. The recording head is arranged to form a long line head.

According to a third aspect of the present invention, in the ink jet recording apparatus according to the first aspect,
The control unit includes calculation means for calculating an unused nozzle group including non-ejection nozzles,
When the non-ejection detection mechanism detects a non-ejection nozzle, the calculation unit calculates the unused nozzle group, and controls the recording head to stop the ejection of ink from the unused nozzle group. The moving means is controlled so as to arrange another recording head so as to overlap the unused nozzle group.

According to the third aspect of the present invention, when the non-ejection detection mechanism detects the non-ejection nozzle, the control unit causes the calculation means to calculate the unused nozzle group including the non-ejection nozzle. Then, the ejection of ink from the unused nozzle group is stopped, and another recording head is arranged so as to overlap the unused nozzle group to form a long line head.
Here, the unused nozzle group means a nozzle group having a non-ejection nozzle as one end in the recording head, and the other end is a nozzle at the end of the nozzle group provided in the recording head and is more non-ejection. This is the nozzle closer to the nozzle.

According to a fourth aspect of the present invention, in the ink jet recording apparatus according to the first aspect,
The control unit includes analysis means for analyzing input image information and calculating an image information amount distributed to each nozzle based on the analysis result.
When the non-ejection detection mechanism detects non-ejection of the nozzle, the recording head is moved so that the non-ejection nozzle is arranged at a position with less image information based on the calculation result by the analysis unit. The moving means is controlled so as to make it happen.

  According to the fourth aspect of the present invention, the analysis unit analyzes the input image information and calculates the amount of image information distributed to each nozzle. When the non-ejection detection mechanism detects the non-ejection of the nozzles, the control unit moves the recording head so that the non-ejection nozzles are arranged at a position with less image information, thereby forming a long line head. Accordingly, the amount of image information distributed to the non-ejection nozzles is reduced.

  According to the first aspect of the present invention, since the recording head can be arranged according to the presence or absence of a non-ejection nozzle, it is possible to perform image recording by complementing the non-ejection nozzle with a simple configuration.

  According to the second aspect of the present invention, even when a non-ejecting nozzle is generated, a long line head is formed except for the recording head including the non-ejecting nozzle. Image recording can be performed.

  According to the third aspect of the present invention, since the long line head excluding the unused nozzle group including the non-discharge nozzle is formed even when the non-discharge nozzle is generated, the length of the long line head is formed. Image recording can be performed by complementing the non-ejection nozzles without significantly impairing the dimensions.

  According to the fourth aspect of the present invention, even when a non-ejection nozzle occurs, a long line head with a small amount of image information distributed to the non-ejection nozzle is formed. It is possible to perform image recording by complementing the non-ejection nozzles with a simple configuration without loss.

  Hereinafter, an ink jet recording apparatus according to the present invention will be described with reference to the drawings. However, the scope of the invention is not limited to the illustrated examples.

[First embodiment]
FIG. 1 is a diagram showing a main configuration of the inkjet recording apparatus 1 during non-image recording, and FIG. 2 is a diagram showing a main configuration of the inkjet recording apparatus 1 during image recording.

  As shown in FIG. 1, a conveying means 2 for conveying the recording medium is provided at a position facing the recording medium and upstream in the conveying direction. The transport unit 2 includes a transport motor 3 including a drive source such as a motor, and a transport roller 4 that is rotationally driven by the transport motor 3 to transport the recording medium in a predetermined transport direction.

  A moving unit 7 is provided at a position facing the recording medium and downstream of the conveying unit 2 to move a recording head described later in the main scanning direction. The moving means 7 is rotatably provided with a plurality of rotating shafts 9 extending in the main scanning direction. Further, the moving means 7 is provided with drive units 8 for rotating the rotary shaft 9 so as to be connected to the ends of the respective rotary shafts 9. Further, the moving means 7 is provided with a carriage 5 which is inserted through the rotary shaft 9 and moved in the main scanning direction along with the rotation so as to face the recording medium.

  Each carriage 5 is mounted with recording heads H1, H2, H3, and H4 that eject ink based on the input image information. On the surface of the recording heads H1 to H4 facing the recording medium, a plurality of nozzles 10 for ejecting ink droplets toward the recording medium are continuous along the main scanning direction with a predetermined interval p. Is formed.

  As shown in FIGS. 2 and 3, the moving means 7 rotates the rotary shaft 9 by the drive unit 8 and moves the carriage 5 in the main scanning direction, thereby moving the recording heads H <b> 1 to H <b> 4 to the nozzles at the respective ends. One long line head 6 is formed by being arranged along the main scanning direction so that the interval between 10 becomes p.

  Light is transmitted between the recording heads H1 to H4 and the recording medium at a position on the side of the recording medium and facing the recording heads H1 to H4 to detect the presence or absence of reflection by ink droplets. A non-ejection detection mechanism 11 that detects non-ejection of ink from the nozzle 10 is provided.

  FIG. 4 is a block diagram showing a control configuration of the inkjet recording apparatus 1. As shown in FIG. 4, the inkjet recording apparatus 1 includes a control unit 12 that is electrically connected to and controls the conveying unit 2, the recording heads H <b> 1 to H <b> 4, the moving unit 7, the non-ejection detection mechanism 11, and the like. Is provided. The control unit 12 includes a CPU, a ROM, a RAM, and the like (all not shown). The processing program recorded in the ROM is expanded on the RAM and is executed by the CPU.

  When the nozzle 10 is not clogged, the controller 12 moves the recording heads H <b> 1 to H <b> 4 together with the carriage 5 by the moving unit 7 to form the long line head 6. FIG. 3 is a view of the long line head 6 in this case as viewed from the recording medium side. The recording heads H1 to H4 are arranged so that the distance between the nozzles 10 at the respective ends is p and in the main scanning direction. Are arranged in order.

  The controller 12 starts image recording after the long line head 6 is formed. At the time of image recording, the control unit 12 ejects ink from the nozzles 10 of the recording heads H <b> 1 to H <b> 4 based on the input image information while transporting the recording medium in the transport direction by the transport unit 2.

  The control unit 12 appropriately detects ink non-ejection of the nozzle 10 by the non-ejection detection mechanism 11. When the non-ejection nozzle 13 is detected (see FIG. 5), the control unit 12 stops the ink ejection from the recording head H2 including the non-ejection nozzle 13. Further, as shown in FIG. 6, the control unit 12 uses the moving unit 7 to move the position of the recording head H <b> 2 in the main scanning direction to the end side of the long line head 6, and The position of the recording head H1 is moved to the position where the recording head H2 was disposed.

  In this embodiment, the recording medium is set with the right side in the main scanning direction on the drawing as a reference position, but the reference position is not limited to the above position. In this case, the moving direction of the recording heads H1 to H4 when the non-ejection nozzle 13 is generated may be a direction in which the long line head 6 is formed corresponding to the reference position. Here, the reference position is a position to be used as a reference when the recording medium is installed. By forming the long line head 6 by arranging the recording heads H1 to H4 corresponding to the reference position, The image recording efficiency on the recording medium can be improved.

  Next, the effect | action by the inkjet recording device 1 is demonstrated.

  First, the control unit 12 forms the long line head 6 by arranging the recording heads H1 to H4 at predetermined positions before starting image recording.

  As shown in FIG. 3, when the non-ejection nozzle 13 is not detected by the non-ejection detection mechanism 11, the rotary shaft 9 is driven to rotate by the drive unit 8 to move the carriage 5 in the main scanning direction. Following the movement of the carriage 5, the recording heads H1 to H4 are moved in the main scanning direction, and the recording heads H1 to H4 are sequentially arranged along the main scanning direction to form the long line head 6. At this time, since the recording heads H1 to H4 are arranged so that the interval between the nozzles 10 at the end is p, the long line head 6 in which all the nozzles 10 are arranged at equal intervals along the main scanning direction. Let it form.

  On the other hand, as shown in FIG. 5, when the non-ejection nozzle 13 is detected by the non-ejection detection mechanism 11, the control unit 12 stops the ejection of ink from the recording head H <b> 2 including the non-ejection nozzle 13. Subsequently, as shown in FIG. 6, the recording head H <b> 2 is moved in the direction away from the reference position by the moving means 7. Similarly, the adjacent recording head H1 is moved to the reference position side, and moved to the position where the recording head H2 has been arranged. As a result, the recording heads H1, H3, and H4 are sequentially arranged along the main scanning direction to form the long line head 6. Also in this case, since the recording heads H1, H3, and H4 are arranged so that the distance between the respective end nozzles becomes p, the long line head in which all the nozzles 10 are arranged at equal intervals along the main scanning direction. 6 is formed.

  When the long line head 6 is formed, the control unit 12 starts recording the input image information. At the time of image recording, the recording medium is conveyed by the conveying means 2. Further, when the non-ejection nozzle 13 is not generated, ink is ejected to the recording medium by the recording heads H1 to H4, and when the non-ejection nozzle 13 is generated, ink is ejected to the recording medium. Record an image.

  In this way, even when the non-ejection nozzle 13 is generated, the long line head 6 in which the nozzles 10 are arranged at equal intervals is formed by using the plurality of recording heads H1, H3, and H4, thereby producing an image without stripe unevenness. It is possible to record. Therefore, in the ink jet recording apparatus that forms the long line head 6 using a plurality of shortened recording heads H1 to H4, it is possible to easily perform image recording by complementing the non-ejection nozzle 13.

[Second Embodiment]
Next, a second embodiment according to the present invention will be described. FIG. 7 is a block diagram showing a control configuration of the inkjet recording apparatus 15 in the present embodiment. The ink jet recording apparatus 15 has a configuration substantially similar to that of the ink jet recording apparatus 1 in the first embodiment, and the control unit 17 includes a calculation unit 16 that calculates the unused nozzle group 14 based on the position of the non-ejection nozzle 13. Is different. Hereinafter, this different point will be described.

  The control unit 17 includes a calculation unit 16 that calculates the unused nozzle group 14 in the recording head H2 where the non-ejection nozzle 13 is generated. When the calculation means 16 determines the position of the non-ejection nozzle 13 in the recording head H2, the calculation means 16 calculates the number of nozzles 10 from the non-ejection nozzle 13 to both end nozzles of the recording head H2, respectively, and the nozzle with the smaller number The group is an unused nozzle group 14. Here, as shown in FIG. 5, in the present embodiment, the non-ejection nozzle 13 is the fourth nozzle from the left in the main scanning direction in the drawing in the recording head H2, and therefore the calculating means 16 is the main scanning in the drawing of the recording head H2. Four nozzle groups from the left side in the direction are set as unused nozzle groups 14.

  The control unit 17 is configured to stop the ejection of ink from the unused nozzle group 14 based on the calculation result by the calculation unit 16. As shown in FIG. 8, the control unit 17 moves the recording head H1 to the reference position side so that the nozzles 10 of the recording head H1 overlap the unused nozzle group. At this time, the moving means 7 moves the recording head H1 by the width of the unused nozzle group 14. In this embodiment, since the unused nozzle group 14 is composed of four nozzles, the recording head H1 is moved to the reference position side by a distance four times the nozzle interval p.

  Next, the operation of the ink jet recording apparatus 15 will be described.

  Similarly to the first embodiment, first, the control unit 17 forms the long line head 6 by arranging the recording heads H1 to H4 at predetermined positions before starting the image recording. The process of forming the long line head 6 when the non-discharge nozzle 13 is not generated is substantially the same as that of the first embodiment, and the process of forming the long line head 6 when the non-discharge nozzle 13 is generated. Is described below.

  When the non-ejection nozzle 13 is detected by the non-ejection detection mechanism 11, the control unit 17 causes the calculation unit 16 to start calculating the unused nozzle group 14 in the recording head H <b> 2 where the non-ejection nozzle 13 is generated.

  When the position of the non-ejection nozzle 13 in the recording head H2 is detected by the calculation means 16, the number of nozzles 10 from the non-ejection nozzle 13 to both end nozzles of the recording head H2 is calculated. Subsequently, the calculation unit 6 sets the nozzle group having the smaller number of nozzles 10 among the two calculated nozzle groups as the unused nozzle group 14.

  When the unused nozzle group 14 is calculated, the control unit 17 stops the ejection of ink from the unused nozzle group 14. Then, the recording head H <b> 1 is moved to the reference position side by the width of the unused nozzle group 14 by the moving means 7. At this time, the moving amount of the recording head H1 is expressed by an amount obtained by multiplying the number of nozzles of the unused nozzle group 14 by the nozzle interval p, so that the recording head H1 is moved by a distance four times the nozzle interval p. A long line head 6 is formed. When the long line head 6 is formed, the control unit 17 starts recording the input image information as in the first embodiment.

  In this way, even when the non-ejection nozzle 13 is generated, the long line head 6 excluding the unused nozzle group 14 can be formed by using the recording heads H1 to H4 to record an image without stripes. it can. Therefore, in an ink jet recording apparatus that forms the long line head 6 using a plurality of shortened recording heads H1 to H4, image recording is performed by complementing the non-ejection nozzle 13 without significantly reducing the recording efficiency. Can be made.

[Third embodiment]
Next, a third embodiment according to the present invention will be described. FIG. 9 is a block diagram showing a control configuration of the inkjet recording apparatus 18 in the present embodiment. The ink jet recording apparatus 18 has substantially the same configuration as the ink jet recording apparatus 1 in the first embodiment, and the control unit 20 includes an analysis unit 19 that analyzes image information to be recorded (see FIG. 10). Is different. Hereinafter, this different point will be described.

  The control unit 20 of the ink jet recording apparatus 18 includes an analysis unit 19 that analyzes input image information and calculates the amount of image information distributed to each nozzle 10 based on the analysis result. When the non-ejection detection mechanism 11 detects the non-ejection nozzle 13, the control unit 20 determines the amount of image information distributed to the nozzle 10 corresponding to the position of the non-ejection nozzle 13 in the other recording heads H1, H3, and H4. The amount of image information distributed to the discharge nozzles 13 is compared. Further, when the control unit 20 detects the nozzle 10 having a smaller amount of image information than the non-ejection nozzle 13, the control unit 20 exchanges the position of the recording head H 1 including the nozzle 10 with the position of the recording head H 2 including the non-ejection nozzle 13. It has become.

  Here, in the present embodiment, when image recording is performed without complementing the non-ejection nozzles 13, an image having a stripe unevenness as shown in FIG. 11 is recorded. However, the amount of image information distributed to the nozzles 10 corresponding to the non-ejection nozzles 13 in the recording head H1 at this time is zero, and no ink is ejected from the nozzles 10. Therefore, as shown in FIG. 12, the control unit 20 is distributed to the non-ejection nozzles 13 by the moving means 7 by exchanging the positions of the recording head H2 and the recording head H1 to form the long line head 6. The amount of image information is made zero.

  Next, the operation of the ink jet recording apparatus 18 will be described.

  As in the first embodiment, the control unit 20 first forms the long line head 6 by arranging the recording heads H1 to H4 at predetermined positions before starting image recording. The process of forming the long line head 6 when the non-ejection nozzle 13 is not generated is substantially the same as that of the first embodiment, but the long line head 6 when the non-ejection nozzle 13 is generated is formed. The process is described below.

  First, the input image information as shown in FIG. 10 is analyzed by the analysis means 19, and the amount of image information for each nozzle 10 is calculated. When the non-ejection nozzle 13 is detected by the non-ejection detection mechanism 11, the amount of image information distributed to the nozzle 10 corresponding to the position of the non-ejection nozzle 13 in the other recording heads H1, H3, H4 by the analysis means 19. And the amount of image information distributed to the non-ejection nozzles 13 are compared. When the nozzle 10 having an image information amount smaller than the image information amount distributed to the non-ejection nozzles 13 is detected, the recording head H1 and the recording head H2 provided with the nozzle 10 are moved by the moving means 7 to change their arrangement. Thus, the long line head 6 is formed. When the long line head 6 is formed, the control unit 20 starts recording the input image information as in the first embodiment.

  Thus, even when the non-ejection nozzles 13 are generated, the amount of image information distributed to the non-ejection nozzles 13 without controlling the ink ejection from the nozzles 10 using the recording heads H1 to H4 is reduced. A few long line heads 6 can be formed. Accordingly, it is possible to perform image recording by complementing the non-ejection nozzles 13 while preventing the long line head 6 from being shortened and reducing the recording efficiency.

1 is a plan view showing a configuration of a main part of an ink jet recording apparatus according to the present invention. It is a top view at the time of image recording of the inkjet recording device concerning this invention. It is a bottom view of the long line head at the time of image recording in the ink jet recording apparatus according to the present invention. It is a block diagram which shows the control structure of the inkjet recording device in 1st embodiment. FIG. 6 is a bottom view of the long line head when a non-ejection nozzle is generated in the ink jet recording apparatus according to the invention. It is a bottom view of the long line head after non-ejection nozzle complementation in a first embodiment. It is a block diagram which shows the control structure of the inkjet recording device in 2nd embodiment. It is a bottom view of the long line head after non-ejection nozzle complementation in a second embodiment. It is a block diagram which shows the control structure of the inkjet recording device in 3rd embodiment. It is explanatory drawing which shows the image recorded in 3rd embodiment. It is explanatory drawing which shows the image recorded when a non-ejection nozzle generate | occur | produces in 3rd embodiment. It is explanatory drawing which shows the image recorded after non-ejection nozzle complementation in 3rd embodiment.

Explanation of symbols

1, 15, 18 Inkjet recording apparatus 2 Conveying means 5 Carriage 6 Long line head 7 Moving means 10 Nozzle 11 Non-ejection detection mechanism 12, 17, 20 Control unit 13 Non-ejection nozzle 14 Unused nozzle group 16 Calculation means 19 Analysis means H1, H2, H3, H4 Recording head p Nozzle spacing

Claims (4)

A plurality of recording heads including nozzles that discharge ink toward the recording medium;
Moving means for moving the recording head in the width direction of the recording medium;
Conveying means for conveying the recording medium;
A non-ejection detection mechanism for detecting non-ejection of the nozzles;
A control unit that controls the moving unit to arrange the recording head based on a detection result of the non-ejection detection mechanism;
An ink jet recording apparatus comprising:   When the non-ejection detection mechanism detects ink non-ejection of the nozzle, the control unit controls the recording head to stop ink ejection by the recording head including the non-ejection nozzle, and stops ink ejection. 2. The ink jet recording apparatus according to claim 1, wherein the moving unit is controlled so that another recording head is disposed at the position of the recording head that has been moved. The control unit includes calculation means for calculating an unused nozzle group including non-ejection nozzles,
When the non-ejection detection mechanism detects a non-ejection nozzle, the calculation unit calculates the unused nozzle group, and controls the recording head to stop the ejection of ink from the unused nozzle group. 2. The ink jet recording apparatus according to claim 1, wherein the moving unit is controlled to dispose another recording head so as to overlap the unused nozzle group. The control unit includes analysis means for analyzing input image information and calculating an image information amount distributed to each nozzle based on the analysis result.
When the non-ejection detection mechanism detects non-ejection of the nozzle, the recording head is moved so that the non-ejection nozzle is arranged at a position with less image information based on the calculation result by the analysis unit. The inkjet recording apparatus according to claim 1, wherein the moving unit is controlled so as to cause the movement.

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