WO2007080806A1

WO2007080806A1 - Ink jet recording device

Info

Publication number: WO2007080806A1
Application number: PCT/JP2006/326240
Authority: WO
Inventors: Yoshinori Morooka
Original assignee: Canon Finetech Inc.
Priority date: 2006-01-10
Filing date: 2006-12-28
Publication date: 2007-07-19
Also published as: EP1972448A1; JP2007210327A

Abstract

An ink jet recording device uses a plurality of line-type ink jet recording heads for one-color ink and divides image data so as to correspond to the plurality of recording heads to form an image. Even if one of the recording heads has a nozzle of defective discharge, it is possible to perform a complementary recording operation with a simple configuration without significantly lowering the recording speed. When one (102) of the recording heads has a nozzle of defective ink discharge, the recording operation to be performed by the nozzle is complemented by a corresponding nozzle of other recording head (such as an auxiliary recording head (114)). Here, the same divided image data is supplied to the one recording head and the other recording head. For the one recording head, recording operation is disabled only at the timing when the nozzle of defective discharge is driven and for the other recording head, recording operation is enabled only at the timing when the corresponding nozzle is driven.

Description

Specification

Inkjet recording device

Technical field

[0001] The present invention relates to an inkjet recording apparatus (hereinafter referred to as a line-type inkjet recording apparatus or an inkjet recording head) using an inkjet recording head (hereinafter also referred to as a line head) in which nozzles are arranged over a range corresponding to the width of the recording medium to be conveyed. It simply relates to an inkjet recording apparatus.

Background art

[0002] In contrast to a general line-type ink jet recording device that uses one line head for one color ink, multiple line heads are used for one color ink, and image data is divided into multiple lines. There is a line-type ink jet recording apparatus that forms an image by dividing in accordance with a head. In a powerful line type ink jet recording apparatus, a plurality of line heads share the image formation. Accordingly, a recording operation exceeding the maximum driving frequency of one line head, that is, recording at a speed proportional to the number of line heads can be performed, so that high-speed recording can be realized.

[0003] In a line-type ink jet recording apparatus, there may be a case where a defectively ejected nozzle (hereinafter, also referred to as a defective nozzle) cannot be normally ejected to one line head for some reason. In such a case, a general line-type ink jet recording apparatus is to continue the recording in a state where the recording quality cannot be guaranteed, or to interrupt the recording and replace the line head. On the other hand, in a line type ink jet recording apparatus using a plurality of line heads for one color ink, in addition to such measures, if recording is continued using only a normal line head without a defective nozzle. ! / Can be supported. In addition, when a defective nozzle is detected, interpolation is performed between a plurality of line heads corresponding to one color of ink, that is, the normal nozzles in each of the plurality of line heads are used. There is also a technology that complements the movement (Patent Literature)

D o

However, a line-type ink jet using a plurality of line heads for one color ink. In the first place, the recording device is configured in response to a request for high-speed recording. However, if recording is continued using only a normal line head, the recording speed must be reduced to a speed proportional to the number of normal heads in order to meet the demand for high-speed recording. It will disappear. Also, considering the application of the technique disclosed in Patent Document 1 when a defective nozzle is detected, in order to perform complementary ejection operations between normal line heads, re-development of print data or mask data Need to be generated, and a means for storing the generated mask data is required. Therefore, there is a problem that the control mode and the configuration of the control system are complicated, and the circuit scale of the recording apparatus is increased.

Patent Document 1: Japanese Patent Application Laid-Open No. 10-6488

Disclosure of the invention

Problems to be solved by the invention

[0006] The present invention is more than that which occurs in a line-type inkjet recording apparatus that uses a plurality of line heads for one color ink and divides image data corresponding to the plurality of line heads to form an image. It was made in view of the problem. An object of the present invention is to suppress a decrease in recording speed as much as possible even when a defective nozzle occurs, and to obtain a complementary recording operation with a simple configuration.

Means for solving the problem

[0007] To this end, according to the present invention, a plurality of ink jet recording heads in which nozzles for ejecting ink are arranged in a direction intersecting the conveyance direction of the recording medium are juxtaposed with respect to the same color ink in the conveyance direction. An inkjet recording apparatus capable of recording by supplying divided image data obtained by dividing image data corresponding to the arrangement of the nozzles to the plurality of inkjet recording heads,

If one of the ink jet recording heads has a nozzle with an ink ejection failure, the ink jet recording head includes a complementing means for complementing the recording operation of the nozzle with the corresponding nozzle of the other ink jet recording head;

The complementing means supplies the same divided image data to the one ink jet recording head and the other ink jet recording head, and the ink ejection failure to the one ink jet recording head. Only when the nozzle is driven The operation is invalidated, and the recording operation is validated only at the timing when the corresponding nozzle is driven for the other ink jet recording head.

[0008] Here, the other ink jet recording head may be prepared to perform the complement.

[0009] Alternatively, the other ink jet recording head may be an ink jet recording head in which nozzles other than the corresponding nozzles are defective in ink ejection.

According to the present invention, when an ejection failure nozzle is generated in one recording head (line head), the same divided image data (raster data) is supplied to the line head and another line head. For the one line head, the recording operation is invalidated only at the timing when the defective nozzle is driven (for example, the timing of the time-division driving of the block including the defective nozzle), and the other line head is disabled. On the other hand, the recording operation is valid only at the timing at which the corresponding nozzle is driven (for example, the time-division driving timing of the corresponding block). As a result, it is not necessary to generate mask data for compensating for defective ejection nozzles, or to dispose mask data storage means. Here, if the above-mentioned other line heads are prepared for complementation, high-quality recording can be maintained without causing a decrease in recording speed. Also, if the other line head is a line head having a defective nozzle in a nozzle other than the corresponding nozzle, the complement is performed between the one line head and the other line head. The recording speed will not drop as much as when recording.

Brief Description of Drawings

FIG. 1 is a conceptual diagram showing a schematic configuration example of a recording system to which the first embodiment of the present invention can be applied.

FIG. 2 is a block diagram showing a schematic configuration example of a control system of the line type ink jet recording apparatus according to the first embodiment of the present invention.

FIG. 3 is a conceptual diagram for explaining a normal recording operation of the ink jet recording apparatus shown in FIG. 2.

FIG. 4 is a circuit diagram showing an example of the electrical configuration of an electrothermal transducer within a predetermined section and its drive circuit in one head of the ink jet recording apparatus shown in FIG. [FIG. 5] FIG. 5 is a timing chart of each signal for performing block drive of the circuit shown in FIG.

FIG. 6 is an explanatory diagram showing correspondence between signals for performing block driving and nozzles.

FIG. 7 is a flowchart showing an example of a complementary operation procedure executed when a defective nozzle is detected in the first embodiment of the present invention.

FIG. 8 is a conceptual diagram for explaining a complementary operation using an auxiliary line head that is executed when a defective nozzle is detected in the first embodiment of the present invention.

[FIG. 9] FIG. 9 is a timing chart of each signal in the line head in which a defective nozzle is detected.

FIG. 10 is a timing chart of signals at various parts in the auxiliary line head.

[FIG. 11] FIG. 11 is a conceptual diagram for explaining an operation when recording is performed without using an auxiliary line head when a defective nozzle is detected in the first embodiment of the present invention.

FIG. 12 is a conceptual diagram showing a schematic configuration example of a recording system to which the second embodiment of the present invention can be applied.

FIG. 13 is a flowchart showing an example of a correction operation procedure executed when a defective nozzle is detected in the second embodiment of the present invention.

FIG. 14 is a conceptual diagram for explaining a complementary operation executed when a defective nozzle is detected in the second embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in detail with reference to the drawings.

[0013] (First embodiment)

FIG. 1 is a conceptual diagram showing a schematic configuration example of a recording system to which the present invention can be applied. The powerful system includes a line-type ink jet recording apparatus 107 that performs a recording operation on a recording medium, and a host computer 106 that exchanges various data with the ink jet recording apparatus 107. The host computer 106 and the ink jet recording apparatus 107 are connected via a communication cable 108. Then, the image data processed by the host computer 106 and various data such as cleaning commands are transmitted to the ink jet recording apparatus 107, whereby the ink jet recording apparatus 107 performs recording and other required operations. Is done. Further, the printer status such as error information of the ink jet recording apparatus 107 is transmitted to the host computer 106 so that the host computer 106 can recognize the state of the ink jet recording apparatus.

In the ink jet recording apparatus according to the present embodiment, four long ink jet recording heads (line heads) 101 to 104 in which nozzles are arranged over a range corresponding to the width of the recording medium to be conveyed are recorded. They are juxtaposed in the medium transport direction and are usually used for recording. Each of these line heads ejects black ink. The same color (black) image data is divided into raster units corresponding to the nozzle arrangement of the line head and supplied as recording data (divided image data), so that the monochrome (black) image is shared. Form. In the present embodiment, another line head 114 is arranged, and is used to perform ink ejection to compensate for a defective nozzle in the line heads 101 to 104 (hereinafter, referred to as “line ejection”). This line head is also called auxiliary line head). The line heads 101 to 104 and the auxiliary line head 114 are, for example, electrothermal conversion elements that generate thermal energy that causes film boiling in response to energization as energy used to eject ink. (Discharge heater) can be used.

[0015] The recording medium 109 is transported along a predetermined transport path passing below each of the line heads 101 to 104 and 114 by a transport unit 110 including an endless transport belt or a transport roller driven by a motor. The In this transport operation, when the front end portion of the recording medium 109 is detected by the recording medium sensor 111 disposed upstream of the line head 101 in the transport direction, the recording medium 109 is transferred to the recording medium 109 at a predetermined timing with reference to the detection time. The recording operation is started.

[0016] A light emitting unit 112 and a light receiving unit 113 are provided on one side and the other side of the line heads 101 to 104 and 114, respectively, which constitute a defective nozzle detection device. The light emitting unit 112 and the light receiving unit 113 have light emitting elements and light receiving elements arranged corresponding to the line heads 101 to 104 and 114, respectively. The light emitting elements are arranged on the lower surface of the head so as to project light in a direction along the nozzle discharge port array, and the corresponding light receiving elements can receive this light. When a defective nozzle is detected, it is received from the light emitting element. While the optical path is formed in the optical element, for example, the nozzle force located on one side of the head is sequentially ejected to the nozzle located on the other side to determine whether or not a light shielding state has occurred. To detect. Here, it can be determined whether or not each nozzle has normally performed a discharge operation from the drive (discharge) timing of each nozzle and the detection timing of whether or not the light has been blocked. Further, when non-ejection is detected, a cleaning operation is performed to improve the ink ejection performance, and then a defective nozzle is further detected. If the non-ejection is not eliminated by the cleaning operation, the cleaning operation is performed. It is also possible to determine that the nozzle is a defective nozzle.

As the cleaning operation, for example, a cap capable of cabling the nozzle forming surface of the head is provided, and ink is applied from the nozzle by applying an appropriate pressure to the ink supply system to the head in the cubbed state. Can be forcibly discharged.

[0018] Further, as an aspect of defective nozzle detection, it is not necessary to automatically perform the defective nozzle detection device as described above. For example, a predetermined test pattern may be printed, and the user may visually check the printing result to identify a defective nozzle and set this in the recording system.

Further, the recording apparatus of FIG. 1 can be selected as a recording target regardless of whether the recording medium is in the form of continuous paper or cut sheet. Further, the recording medium may be a mount and a label or tag sheet carried by the mount, and the like.

FIG. 2 is a block diagram showing a schematic configuration example of the control system of the line type ink jet recording apparatus according to the present embodiment.

[0021] Figure [J Control 201, CPU 202, ROM 203, RAM 204, Communication controller 208, Image memory 205, Head drive circuit 209, Motor driver 210, Input / output unit (I / O) 211 And a control circuit 212 and the like.

The CPU 202 performs various operations such as calculation, determination, and control according to a processing procedure described later with reference to FIG. The ROM 203 stores a control program corresponding to a processing procedure executed by the CPU 202 and other fixed data. The RAM 204 has a work area for processing various data by the CPU 202 and an area used as a send / receive buffer! / Speak. The communication controller 208 is connected to the host computer 106 and the recording device 1 via the communication cable 108. For example, a USB controller is used. Information communicated from the host computer 106 to the recording device 107 includes image data to be recorded, commands for instructing execution of recording (printing), and the like. For example, the status of recording device 107.

The image memory 205 is used as a developing unit for image data to be recorded (printed). The head driving circuit 209 drives the electrothermal conversion elements of the line heads 101 to 104 and the auxiliary line head 114 at a specified timing during conveyance of the recording medium according to the image data. The motor driver 210 is a motor that serves as a drive source for performing the tallying operation for the line heads 101 to 104 and the auxiliary line head 114 and the necessary driving required for the recording operation.

Drive 206. The IZ0211 is connected to a conveyance control interface (IZF) unit 207 for the conveyance unit 110 that feeds and conveys the recording medium, and inputs an output signal of the conveyance unit 110 and a detection signal from the recording medium sensor 111. .

[0024] The control circuit 212 controls the image memory 205, the head drive circuit 209, the motor driver 210, and the IZ0211, and controls the operations of the light emitting unit 112 and the light receiving unit 113 that constitute the defective nozzle detection device. . Further, the control circuit 212 controls the display unit 213 arranged to notify the user of the status of the recording apparatus 107 and an error.

A normal recording operation of the ink jet recording apparatus having the above configuration, that is, a shared recording operation by the line heads 101 to 104 for the divided image data will be described with reference to FIG. In FIG. 3, for the sake of explanation, each line head is shown as viewed from the side, and the recording medium is viewed from above. The same applies to FIGS. 8 and 9 described later.

Recording on the recording medium 109 is performed based on a detection signal at the front end of the recording medium 109 and a horizontal synchronization signal synchronized with the conveyance. Here, the horizontal synchronization signal is a signal used to determine the sequential drive timing of each line head.

[0027] When a horizontal synchronization signal is detected, data for one raster stored in the image memory 205 is transferred to the line head 101 located on the most upstream side in the recording medium conveyance direction, and one raster An image 301 is recorded. The next time the horizontal sync signal is detected, the image Image data for the next one raster read from the memory 205 is transferred to the line head 102 to form an image 302. When the next horizontal synchronization signal is detected, the image data for the next one raster read from the image memory 205 is transferred to the line head 103 to form a raster image 303. When the next horizontal synchronizing signal is detected, the image data for the next one raster read from the image memory 205 is transferred to the line head 104 to form a raster image 304. Thereafter, similarly, the line heads 101 to 104 are sequentially used to record image data divided in raster units.

Thus, in the present embodiment, when all four line heads that discharge black ink are in a state where ink can be discharged in an appropriate state, the auxiliary line head 114 is not used for recording. In other words, monochrome image data developed in the continuous area of the image memory 205 is sequentially read out in units of rasters in synchronization with the horizontal synchronization signal, and sequentially supplied to the four line heads 101 to 104. The sharing of images is performed. As a result, a monochrome image is recorded at a frequency that is four times the maximum drive frequency of a single line head. As a result, a recording operation using a single line head is possible. Double the recording throughput.

In the present embodiment, in each line head, time-division driving (block driving) is performed for each block grouped in units of a predetermined number of nozzles. Here, the configuration and control mode for block driving will be described.

[0030] Each of the line heads 101 to 104 and the auxiliary line head 114 in this embodiment includes 2560 nozzles arranged in the raster direction (hereinafter, the nozzle force located on one side is also the other side). Reference is made to the nozzle located at the position of segl to seg2560;). It is composed of four sections with one head as a unit, Nos, Nose segl to seg640, Nosnore 568641 to 5681280, Nos, Nore segl 281 to segl960 and Nozzle segl961 to seg2560. In each section, time-division driving is performed in units of blocks for the purpose of reducing the maximum power consumption and the voltage drop in the line head.

FIG. 4 shows an example of an electrical configuration of an electrothermal conversion element and its drive circuit in a section including nozzles segl to seg 640 in one head, and FIG. 5 shows a timing chart of signals of each part. Fig. 6 shows the correspondence between the block drive signal and the nozzles segl to seg640. Is shown. These configurations are the same for other sections including nozzle seg641 to segl280, nozzle seg 1281 to segl 960 and nozzle segl961 to seg2560, respectively. Driven at the same timing.

In FIG. 4, 222 is a transistor array for power supply control connected to the drive power supply (VH) line of the electrothermal conversion element provided in the nozzles segl to seg640 together with the electrothermal conversion element. Turns the conduction of the conversion element on and off.

[0033] The decoder 224 generates a signal for defining the timing of block selection. According to three input signals (3-bit parallel signals) BENB0 to BENB2, eight timing signals are sequentially output. One of the four inputs of each AND gate 223 connected to the transistor array 222 is supplied. ODD and EVEN are signals for selecting odd-numbered nozzles and even-numbered nozzles, and are supplied to the other one of the four input terminals of the corresponding AND gate 223. In other words, 640 electrothermal transducer elements are divided into 16 blocks (BLK1 ~ :) for every 40 electrothermal transducer elements based on 8 timing signals generated according to BENB0 ~ BENB2 and ODDZEVEN selection signal. BLK16: Divided into Fig. 6) and driven in a time division manner. In the following, a signal for selecting a block consisting of eight timing signals generated according to BENB0 to BENB2 and an ODDZEVEN selection signal is referred to as a “block selection signal”.

[0034] Image data for one raster (2560-bit data) D ATA divided in accordance with the line head is synchronized with the clock signal DCLK, and is sent to shift registers 226 connected in series and connected in series. Transferred serially. Then, when the data alignment corresponding to the nozzles is completed, the data is latched in the latch circuit 225 according to the latch signal DLT. The latched data is sent to the other one of the four inputs of AND gate 223.

[0035] In FIG. 4, * PHX, * PHA, and * MH1 (* indicates negative logic) are pulses of the heat signal, and at the timing specified by the logic state of the block selection signal. It defines the time for energizing the air-heat conversion element. These signals are input to the OR gate 227, and the OR output is further sent to the other one of the four inputs of the AND gate 223. The signal * MH1 corresponds to the nozzles segl to seg640. other The nozzles seg641 to seg 1280, the nozzles seg 1281 to seg 1960, and the nozzles seg 1961 to seg2560 are supplied with * MH2, * MH3, and * MH4, respectively (FIG. 5). And when the electrothermal transducer of each nozzle has data to perform the discharge operation, the preceding heat pulse (pre-pulse) * PHA and the following pulse (main pulse) * any one of MH1 ~ * MH4 signals Double pulse driving is performed. In addition, when there is no data to perform the discharge operation, a heat pulse * PHX that defines the drive time that does not cause the discharge operation is supplied, reducing the temperature difference from the nozzle performing the discharge operation, and image In order to suppress the occurrence of unevenness.

[0036] The block selection signal and the heat signal are individually supplied to the line heads 101 to 104 and the auxiliary line head 114 from the control circuit 212 in FIG. 2, and can be controlled independently. When the electrothermal conversion element of each nozzle is selected by the block selection signal, it is energized for the time specified by the heat pulse according to the presence or absence of data. In this embodiment, since one raster is divided into 16 times and the discharge operation is performed, the maximum number of simultaneously driven nozzles per line head is 160.

Next, a complementary operation when a defective nozzle is generated using the above configuration will be described. The complementary operation of the present embodiment is performed in units of blocks divided as described above using the auxiliary line head 114.

FIG. 7 is a flowchart showing an example of a complementary operation procedure executed when a defective nozzle is detected. When a defective nozzle is detected by the defective nozzle detection device (step S601), it is determined whether or not the supplement using the auxiliary line head 114 is possible (step S606). This determination can be performed, for example, by the following steps.

That is, it is first determined whether or not all the nozzles belonging to the block in the auxiliary line head 114 corresponding to the block of the line head including the defective nozzle that has occurred can be ejected normally. If it is possible to discharge normally, supplementation using the auxiliary line head 114 is performed. However, if there is a defective nozzle even in the block of the auxiliary line head, it is determined whether the auxiliary line head section to which the defective nozzle belongs corresponds to the line head section to which the defective nozzle belongs. To do. If it does not correspond, Completion using the in-head 114 is performed, and if it is! In other words, when a defective nozzle is detected in a certain line head, the both forces of the block and section to which the nozzle belongs are determined. Only in this case, supplementation using the auxiliary line head 114 is disabled.

[0040] If the supplement using the auxiliary line head 114 is possible, the setting for performing the supplement processing as described later is performed (step S607), and this procedure is terminated. On the other hand, if the supplement using the auxiliary line head 114 is impossible, it is determined whether or not the force is sufficient to execute the recording (step S608). The determination can be performed as follows. In other words, if all line heads have defective nozzles, and all the defective nozzles belong to the corresponding blocks and sections (overlapping in the transport direction), it is judged as impossible. Otherwise, it is possible. Make a decision.

If recording can be executed, it is determined whether or not it is necessary to reduce the conveyance speed of the recording medium in accordance with the number of remaining line heads that can normally perform recording (step S603). It is necessary to decelerate, for example, when there are fewer than four line heads that can be used. In this case, set the transport speed corresponding to the remaining line heads and the maximum drive frequency of each line head. To do. Then, the process of changing the number of divisions of the image data corresponding to the number of remaining line heads regardless of whether or not the conveyance speed needs to be reduced is performed, and this procedure is completed.

On the other hand, if it is determined in step S608 that recording cannot be performed, the recording operation is stopped, and the display unit 213 of the ink jet recording apparatus is driven to display an error. Then, an error signal is transmitted to the host computer 106 side and an error is displayed on the display of the host computer 106 side (step S609). At this time, detailed error information such as the position of the line head where the defective nozzle has occurred can be presented, and an instruction on how to deal with the user can be included. If it is determined in step S603 that a reduction in the conveyance speed of the recording medium is necessary, the conveyance speed is reduced, that is, the recording speed is displayed via the display unit 213 of the ink jet recording apparatus or the display on the host computer 106 side. It is also possible to notify that a reduction will occur. Furthermore, if such a reduction in recording speed occurs, the user's ability S is inquired whether this is acceptable, It may be possible to continue recording if acceptable, and to present an error message otherwise.

[0043] Next, the complementary operation when a defective nozzle is detected will be described more specifically. Here, it is assumed that a defective nozzle is detected in the line head 102 and the defective nozzle belongs to BLOCK 1 in the section of segl to seg 640 (see FIG. 6).

[0044] In this case, if there is no defective nozzle in BLOCK1 of the section of segl to seg640 in the auxiliary line head 114, it is possible to complement using the nozzle group belonging to BLOCK1 of the section of the auxiliary line head 114. I can judge. Further, if there is a defective nozzle in BLOCK 1 in the section of segl to seg 640 in the auxiliary line head 114, it is determined that complementation using the auxiliary line head 114 is impossible.

FIG. 8 is an explanatory diagram of a complementary operation using the auxiliary line head 114, and FIGS. 9 and 10 are timing charts of respective signals in the line head and the auxiliary line head in which a defective nozzle is detected, respectively.

[0046] When the conveyance operation of the recording medium 110 is started and the leading edge of the recording medium is detected by the recording medium sensor 111, a horizontal synchronization signal synchronized with the conveyance of the recording medium is started. The horizontal synchronization signal is generated by converting the output signal of a rotary encoder (not shown) provided in the conveyance path, for example, if the resolution of the recording head is 600 dots Z inches (reference value). Each time the recording medium 110 advances by 42.3 (m), the horizontal sync signal is sent one pulse. If the design value of the distance from the recording medium sensor 111 to the line head 101 located on the most upstream side is 2 inches, the distance from the end of the recording medium detected by the recording medium sensor 111 to the line head 101 is 1200. A pulse horizontal sync signal is sent.

When the recording start position force reaches the lower side of the line head 101 further, the data of the first raster stored in the image memory 205 is transferred, and the image of the first raster is recorded. After that, the line head 101 performs intermittent image recording when one raster recording is performed every time the horizontal synchronization signal force pulse advances.

[0048] When the second raster position from the top reaches the lower side of the line head 102, the image of the second raster from the top is recorded. If the design value of the distance between each line head is 1 inch If it is H, recording by the line head 102 is started after the recording start force of the line head 101 is counted and a horizontal synchronizing signal is sent for about 600 pulses. After that, the line head 102 performs intermittent image recording so that one raster is recorded each time the horizontal synchronization signal power pulse advances.

[0049] Similarly, every time about 600 pulses of horizontal synchronization signal are sent, the recording in the intermittent raster portion is filled in the order of the downstream line heads 103, 104, and 114, and the image starts to be completed. .

[0050] Description will be made by paying attention to portions of rasters 701 to 704 in the middle of further image recording.

When the raster 702 position reaches the lower part of the recording head 102, the image data of the corresponding raster is read from the image memory 205 and transferred to the line head 102. At this time, by appropriately controlling the block selection signal and the heat signal, the nozzles belonging to BLO CK2 to 16 in the segl to seg640 section are driven, and the seg641 to segl280, segl281 to segl960, and segl961 to seg2560 sections are driven. Enables the drive of all nozzles belonging to BLOCKl ~ 16. That is, only the main pulse MH1 is invalidated at the timing of BEO = 0, BE1 = 0, BE2 = 0, ODD = 1, EVEN = 0 of the line head 102 (FIG. 9). As a result, the raster portion 702 (a group of dots indicated by black circles) is formed. At this time, the force that advances without recording in the corresponding block 705 in which there is a defective nozzle. After the raster 70 2 passes through the recording head 102, when the horizontal sync signal is sent for about 1800 pulses, the auxiliary line head 114 Reach the bottom.

[0052] Since the same data as the image data read for the recording head 102 is read in the same order in the auxiliary line head 114, the image data of the raster 702 is read from the image memory 205. To the auxiliary line head 114.

At this time, by appropriately controlling the block selection signal and the heat signal, only the driving of the nozzles belonging to BLOCK 1 in the section of segl to seg 640 is enabled. That is, only the main norse MH1 is enabled at the timing of BE0 = 0, BE1 = 0, BE2 = 0, ODD = 1, EVEN = 0 of the auxiliary line head 114 (FIG. 10). As a result, a raster image portion (dots with hatching) 705 is formed and the image is complemented.

[0054] Next, in the auxiliary line head 114, there is a defect in BLOCK1 in the section of segl to seg640 The operation when there is a nozzle and it is determined that the supplement using the auxiliary line head 114 is not possible will be described.

Here, it is assumed that the remaining line heads 101, 103, and 104 do not include defective nozzles, and it is determined that recording can be continued by these three line heads. In this case, it is determined from the cycle of the horizontal synchronization signal whether the current conveyance speed of the recording medium 109 is one that can be recorded by the remaining three line heads. If the speed is not recordable, the conveyance speed is controlled to be reduced to a recordable speed. The maximum recordable transport speed is proportional to the number of printheads, and the maximum printable speed corresponding to the number of each printhead is set in a table in advance in the control program and read and used as appropriate. Just do it. After the recordable speed is set, the division number of the image data is changed from “4” to “3”.

FIG. 11 shows a result of recording by three line heads 101, 103, and 104 capable of recording the portions of rasters 801 to 803 during image recording.

Recording start position force When reaching the lower side of the line head 101, the data of the first raster stored in the image memory 205 is transferred, and the image of the first raster is recorded. Thereafter, the line head 101 performs intermittent image recording so that one raster is recorded every time the horizontal synchronizing signal advances by three pulses.

[0058] Subsequently, when the second raster position from the top reaches the lower side of the line head 103, the image of the second raster from the top is recorded. Since the design value of the distance between each line head is l [inch], the recording start force of the line head 101 is counted and the horizontal synchronization signal is sent for about 1200 pulses, and then the recording by the line head 103 is performed. Will be started. After that, in the line head 103, every time the horizontal synchronizing signal advances by 3 pulses, if one raster is recorded, V and so on, intermittent image recording is performed.

[0059] Further, when approximately 600 pulses of the horizontal synchronizing signal are transmitted, the image starts to be completed by the recording of the line head 104.

[0060] As described above, when the complementary operation using the auxiliary line head 114 is impossible, the recording speed is reduced by executing the recording using the remaining line head, that is, the normal line head without a defective nozzle. Although this occurs, an image is formed without deteriorating the recording quality. [0061] As described above, in this embodiment, the auxiliary line head is used, and based on the timing of the block selection signal, the unit of blocks in the section corresponding spatially, that is, positionally corresponding in the transport direction. Added completion. As a result, complementary operations can be performed by controlling the reading and transfer of image data in raster units developed in the image memory and the signal state of the heat signal (main heat pulse). This eliminates the need for re-development of image data, mask data generation, and mask data storage to compensate for defective nozzles, making it possible to record high quality images with a simple configuration that does not reduce the recording speed. The effect that can be maintained is obtained.

Further, in the present embodiment, even when supplementation by the auxiliary line head is impossible, the number of divisions of the image data is changed in accordance with the number of line heads that can execute the recording operation, and An appropriate recording medium conveyance speed was set. This makes it possible to form an image without reducing the recording quality while minimizing the decrease in recording speed.

In the above embodiment, the operation when a defective nozzle is detected by one line head other than the auxiliary line head has been described, but the present invention is not limited to the above. Even when two or more recording heads other than the auxiliary line head detect defective nozzles, if the blocks where the defective nozzles are generated do not overlap, the auxiliary line head is used to reduce the quality without reducing the recording speed. High recording is possible.

[0064] In the above example, four line heads are used for normal recording and one auxiliary line head is used. However, these numerical values are examples, and it is needless to say that an appropriate number can be used for each. .

[0065] Power! In the above-described embodiment, the dedicated auxiliary line head is fixedly provided. However, a plurality of line heads that function as auxiliary line heads may be appropriately changed. That is, for example, for every certain amount of image recording, a plurality of line heads that are used as auxiliary line heads can be prepared cyclically or randomly. Alternatively, if a defective nozzle occurs in one line head, it will be set as an auxiliary line head for the next recording, and it will be prepared as an auxiliary line head until then, and the head will be switched to the line head used for normal recording. It is also possible to . After that, if a defective nozzle occurs in any of the line heads, the block where the defective nozzle is generated is compared with the block to which the defective nozzle belongs but is set as an auxiliary line head. Similar processing can be performed.

[0066] (Second Embodiment)

FIG. 12 is a conceptual diagram showing a schematic configuration example of a recording system according to the second embodiment of the present invention. Here, for each part configured in the same manner as in the first embodiment, the same reference numerals are assigned to corresponding parts. As is apparent from this figure, the system according to this embodiment is not provided with an auxiliary line head, and is provided with only four line heads 101 to 104 that are normally used for recording. .

[0067] The control system of the profitable system is configured similarly to FIG. However, this corresponds to having an auxiliary line head 114.

[0068] The normal recording operation of the recording system is also the operation described with reference to FIG. 3 in the first embodiment, that is, shared recording by the line heads 101 to 104 performed in a state where the auxiliary line head 114 is not used. The operation is the same.

[0069] In this embodiment, the block driving is performed in each line head.

The configuration for that purpose and the mode of control during normal recording are the same as those in the first embodiment described with reference to FIGS.

Next, a supplementary operation when a defective nozzle is generated using the above configuration will be described.

. The complementing operation of this embodiment is performed in units of blocks divided as described above.

FIG. 13 is a flowchart showing an example of a complementary operation procedure executed when a defective nozzle is detected. When a defective nozzle is detected by the defective nozzle detection device (Step S70)

1) Determine whether there is only one line head with a defective nozzle (step S70).

2).

[0072] If there is only one, recording is executed using the remaining three line heads that can perform normal recording, and it is necessary to reduce the conveyance speed of the recording medium according to the number (three). It is determined whether or not (step S703). In other words, when the number of line heads that do not include defective nozzles decreases, four lines are used according to the maximum recordable frequency that can be recorded by the remaining line heads. The recording speed must be lower than the maximum recording speed when recording with this line head. Therefore, it is determined whether the recording operation can be executed with the currently set transport speed. Deceleration is necessary when the maximum recording speed was initially set. In this case, the conveyance speed corresponding to the remaining line heads and the maximum drive frequency of each line head is set. Thereafter, the image data division number changing process corresponding to the number of line heads to be used is performed regardless of whether or not the conveyance speed needs to be reduced (step S705), and this procedure is terminated.

[0073] If there are two or more line heads with defective nozzles in step S702, it is determined whether or not complementing is possible using the relationship between the line heads (step S706). This determination can be made, for example, according to the following steps.

That is, first, it is determined whether or not the blocks including the defective nozzle are overlapped with each other in relation to the line heads including the defective nozzle. If it overlaps! /, If it is not, it will be judged that complementation is possible immediately. On the other hand, if they overlap, it is determined whether the sections to which the defective nozzle belongs correspond to each other. If it does not correspond, it will be complemented. If it is supported, it will be impossible to complement. In other words, if a defective nozzle is detected in two or more line heads, it is determined whether both the block and the block to which the nozzle belongs overlap, and complementation is disabled only when they overlap. .

If complementing is possible, a setting for performing a complementing process as described later is performed (step S707), and this procedure is terminated. On the other hand, if the supplement is impossible, it is determined whether or not the force is sufficient to execute the recording (step S708). The determination can be performed as follows. In other words, if there is a defective nozzle in all the line heads and the defective nozzle belongs to the corresponding block and section (overlapping in the transport direction), it is determined as impossible, otherwise it is determined as possible. Like that.

If it is determined in step S708 that it is possible, the process proceeds to step S703, and a conveyance speed reduction process or the like is executed. On the other hand, if it is determined in step S708 that recording cannot be performed, the recording operation is stopped, the display unit 213 of the ink jet recording apparatus is driven to display an error, and an error is displayed on the host computer 106 side. The signal is transmitted and an error is displayed on the display on the host computer 106 side (step S709). On this occasion In addition, detailed error information such as the position of the line head where the defective nozzle has occurred can be presented, and it is also possible to include instructions on how to deal with the user. In addition, if it is determined in step S603 that it is necessary to reduce the conveyance speed of the recording medium, the conveyance speed is reduced, that is, the recording speed is reduced via the display unit 213 of the inkjet recording apparatus or the display on the host computer 106 side. It is also possible to notify. In addition, when such a reduction in recording speed occurs, the user's ability S is inquired whether this is acceptable, and if it is acceptable, the recording is continued, otherwise an error message is presented. It is also possible.

Next, the recording operation when a defective nozzle is detected will be described more specifically. Here, it is assumed that a defective nozzle is detected only in the line head 102, and the remaining line heads 101, 103, and 104 include a defective nozzle.

In this case, it is determined from the period of the horizontal synchronization signal whether the current conveyance speed of the recording medium 109 is capable of recording by the remaining three line heads. If the recording speed is unrecordable, control is performed so that the conveyance speed is reduced to a recordable speed. Note that the maximum transportable recording speed is proportional to the number of recording heads. The maximum recording speed corresponding to the number of each recording head is set in a table in advance in the control program, and is read and used as appropriate. That's fine. After the recordable speed is set, change the number of image data divisions from “4” to “3”.

[0079] Thereafter, a recording operation is performed by the three recordable line heads 101, 103, and 104. For example, this is the same as the operation described with reference to FIG. 11 in the first embodiment, that is, the shared recording operation by the line heads 101, 103, and 104 performed in a state where the auxiliary line head 114 is not used.

That is, in this embodiment, if only one line head has a defective nozzle, recording is performed using the remaining three line heads. In this case, when the maximum recording speed using the four line heads is initially set, the recording speed is reduced from that speed, but the raster line using a normal line head that does not include a defective nozzle is generated. Since units are recorded, an image is formed without degrading the recording quality.

However, after that, for example, it is assumed that a defective nozzle is detected also in the line head 103. This In this case, in step S706 described above, it is determined whether or not complementation is possible in the mutual relationship between the line heads 102 and 103 in which the defective nozzle has occurred. Here, it is assumed that the sections and blocks to which the defective nozzles detected in the line head 102 and the line head 103 belong do not overlap. Then, the defective nozzle complementary operation in the line head 102 and the line head 103 can be performed by appropriately controlling the respective driving.

FIG. 14 is an explanatory diagram of a complementary operation using the mutual relationship between the line heads in which defective nozzles are generated. The timing chart of each signal in the line heads 102 and 103 in which the defective nozzle is generated is the same as that in FIGS. 10 and 9 referred to in the first embodiment. Here, the defective nozzles detected in the line head 103 are those of seg65 belonging to BLOCK1 in the section of segl to seg640 (see FIG. 6), and these sections and blocks are the defective nozzles detected in the line head 102. It shall be obscured by overlapping the block and block to which it belongs.

[0083] When a horizontal synchronization signal is detected, data for one raster stored in the image memory 205 is transferred to the line head 101 located on the most upstream side in the recording medium conveyance direction, and one raster Image 901 is recorded.

Next, when the horizontal synchronization signal is detected, the image data for the next one raster read from the image memory 205 is transferred to the line head 102. At this time, by appropriately controlling the block selection signal and the heat signal, only the driving of the nozzles belonging to BLOCK 1 in the section of segl to seg 640 is enabled. That is, only the main pulse MH1 is enabled at the timing of BE0 = 0, BE1 = 0, BE2 = 0, ODD = 1, EVEN = 0 of the line head 102 (see FIG. 10). As a result, a raster 902 portion (hatched dots) 905 is formed. This is a portion where the line head 103 cannot perform recording. At this time, the nozzles belonging to the sections and blocks other than the block should not be driven including the sections and blocks to which the defective nozzles generated in the line head 102 belong.

When the next horizontal synchronizing signal is detected, the same data as the data for one raster transferred to the line head 102 is transferred to the line head 103. At this time, by appropriately controlling the block selection signal and the heat signal, it belongs to BLOCK 2 to 16 in the section of seg 1 to seg 640. And the nozzles of seg641 to segl280, segl281 to segl960 and segl961 to seg2560 are enabled. In other words, only the main pulse MH1 is disabled at the timing of BEO = 0, BE1 = 0, BE2 = 0, ODD = 1 and EVEN = 0 of the line head 102 (see Fig. 9). As a result, a raster portion 902 (a group of dots indicated by black circles) is formed, and the line head 102 performs recording, and complementation including the best portion is performed.

When the next horizontal synchronizing signal is further detected, the image data for the next one raster read from the image memory 205 is transferred to the line head 104 to form a raster image 903.

Thereafter, the line heads 101 to 104 are similarly used, and an image is formed without greatly reducing the recording quality and the recording speed.

[0088] As described above, in the present embodiment, the relationship between the line heads in which defective nozzles are generated is used, corresponding to the space based on the timing of the block selection signal, that is, in the transport direction. The complement was done in the unit of the block in the corresponding partition. As a result, a complementary operation can be performed by controlling the reading and transfer of the raster unit image data developed in the image memory and the signal state of the heat signal (main heat pulse). This eliminates the need for re-development of image data, mask data generation, mask data storage means, etc. for performing the complementary operation for defective nozzles, and provides an effect of maintaining high-quality recording with a simple configuration.

[0089] In the present embodiment, as described above, when defective nozzles are generated in two line heads, one raster image data is recorded by complementing the nozzles of normal blocks. Three line rasters are recorded with four line heads. Therefore, even if a defective nozzle occurs in the two line heads, recording can be executed at the same recording speed as when the three line heads are normal. That is, there is an effect that recording can be continued without lowering the recording speed to a speed proportional to the number of normal heads as in the past, that is, without significantly reducing the recording speed.

In the above embodiment, the operation when a defective nozzle is detected by two line heads has been described. However, when a defective nozzle is detected by three or more recording heads, the defective nozzle If the blocks where the slippage occurs do not overlap, it is possible to perform high-quality recording without recording at all or without greatly reducing the recording speed. In other words, even if there are defective nozzles in all four line heads, it is possible to continue recording as long as the blocks where the defective nozzles occurred overlap in all the line heads. For example, if all the line heads have different blocks with defective nozzles, or if the blocks with defective nozzles overlap only between two line heads! Recording can be executed at the same recording speed as when two line heads are normal by using the relationship between a pair of line heads where the blocks do not overlap.

[0091] Further, complementation is performed in the relationship between the line heads in which defective nozzles are generated, but when a defective nozzle occurs in one line head, another normal line head is used, and Even if the same completion action is performed.

Furthermore, in the above-described embodiment, the processing when a defective nozzle is initially generated in one line head and then a defective nozzle is generated in the other one line head has been described. However, if a defective nozzle is detected in two or more line heads from the beginning, it is possible to set the recording medium conveyance speed accompanying the supplementary operation at that time.

[0093] In the above example, the force with four line heads used in normal recording is an example, and it is a matter of course that an appropriate number can be used for each.

[0094] (Other)

In the first embodiment, an auxiliary line head is prepared. When a defective nozzle is generated in a line head used for normal recording, the recording operation of the line head is complemented by the auxiliary line head. When the supplementation is impossible, recording is continued using only normal line heads. In the second embodiment, the recording operation for one line head is complemented by using the relationship between two line heads having defective nozzles without preparing an auxiliary line head. However, it is possible to appropriately combine these embodiments. For example, while an auxiliary line head is prepared, if a defective nozzle occurs in a line head, the recording operation is complemented by the auxiliary line head. If this is not possible, other line heads can be used to supplement.

Further, in the ink jet recording apparatus according to each of the embodiments described above, a line head in which nozzles are arranged over a range corresponding to the width of the recording medium to be conveyed is used. However, the arrangement range of the nozzles is not limited to this, and may be one that satisfies at least a part of the width of the recording medium. Also, the nozzle arrangement direction may be any direction that intersects the recording medium conveyance direction.

Furthermore, in the above example, in each line head, time-division driving (block driving) is performed for each block grouped in units of a predetermined number of nozzles. However, at the time of complementation, the same divided image data is supplied to one recording head and the other recording head, and recording is performed only at the timing when a defective ejection nozzle is driven. In light of the idea of the present invention that the operation is disabled and the recording operation is enabled only for the other recording heads when the corresponding nozzle is driven, the nozzles are driven in a time-sharing manner. It is not always necessary to perform block driving in which a predetermined number of nozzles are grouped as a unit. In other words, the number of nozzles included in one block can be determined as appropriate.

In the above-described embodiment, the case where a monochrome image is recorded using black ink has been described. However, a plurality of line heads are also provided for ink other than black ink, and color data is divided while appropriately dividing image data. The present invention is also applicable when recording an image. In this case, of course, the number of types of colors to be used can be determined as appropriate.

Further, in the above-described embodiment, an ink jet recording apparatus using an ink jet recording head having an electrothermal conversion element that generates thermal energy as energy used for ejecting ink has been described. . However, it goes without saying that the present invention can also be applied to an ink jet recording apparatus using an ink jet recording head having a piezoelectric element that generates other energy, for example, mechanical energy.

Claims

The scope of the claims

[1] A plurality of inkjet recording heads in which nozzles for performing ink ejection are arranged in a direction intersecting the conveyance direction of the recording medium are juxtaposed in the conveyance direction for the same color ink, and the plurality of inkjet recording heads An inkjet recording apparatus capable of performing recording by supplying divided image data obtained by dividing image data corresponding to the nozzle arrangement to a head,

The complementing means supplies the same divided image data to the one ink jet recording head and the other ink jet recording head, and the ink ejection failure to the one ink jet recording head. Inkjet, wherein the recording operation is invalidated only at the timing when the nozzle is driven, and the recording operation is validated only at the timing when the corresponding nozzle is driven for the other inkjet recording head. Recording device.

2. The ink jet recording apparatus according to claim 1, wherein the other ink jet recording head is prepared to perform the complement.

[3] When recording the divided image data, the inkjet recording head is divided into a plurality of blocks including a plurality of nozzles, and driving means for driving in time division is provided.

The complementary means invalidates the recording operation only at the timing of the time-division driving of the block including the nozzles with poor ink ejection with respect to the one inkjet recording head, and with respect to the other inkjet recording head. 3. The ink jet recording apparatus according to claim 2, wherein the driving unit is controlled so that the recording operation is valid only at the timing of the time-division driving of the block including the corresponding nozzle.

4. The ink jet recording apparatus according to claim 1, wherein the other ink jet recording head is an ink jet recording head in which nozzles other than the corresponding nozzles are defective in ink discharge.

[5] When recording the divided image data, the inkjet recording head is connected to a plurality of nozzles. Drive means for driving in a time-division manner by dividing into a plurality of blocks including, the complementary means for the one inkjet recording head, the time-division driving of the block containing the nozzles with poor ink ejection The drive unit is controlled so that the recording operation is invalidated only at the timing of the above, and for the other ink jet recording heads, the recording operation is validated only at the timing of the time-division driving of the block including the corresponding nozzle. 5. The ink jet recording according to claim 4, wherein the nozzles that cause ejection failure in the other ink jet recording head are included in a block other than the block in which the corresponding nozzle is included. apparatus.

6. The ink jet recording apparatus according to any one of claims 1 to 5, wherein the recording operation is validated or invalidated depending on whether or not a drive signal for causing ink ejection is supplied.