JP6559029B2 - Recording apparatus and data editing method - Google Patents

Description

  The present invention relates to a recording apparatus and a data editing method.

  Some recording apparatuses such as an ink jet printer have a function of performing multi-pass recording in order to form a higher-quality image. In multi-pass recording, recording is performed by causing the recording head to scan the same area of a recording medium such as a recording sheet a plurality of times, and corresponding nozzles (ejection ports) of the recording head to correspond to the same area. One scan is called a pass, and in multi-pass printing, an image is formed by a plurality of passes. The pixels that are to be recorded in each pass, that is, the pixels that indicate dot-on, are in a mutually complementary relationship with the pixels that are to be recorded in other passes. A mask is used to define a pixel indicating dot-on in each pass so that this complementary relationship is realized.

  With the recent increase in definition of image data and the like, it is desired to form a higher quality image in the recording apparatus. Therefore, an increase in the capacity of mask data used for multipass printing is inevitable. Patent Document 1 discloses a method of reducing the capacity by encoding a mask provided in each pass, which is used for thinning print data during multi-pass printing.

Japanese Patent Application Laid-Open No. 2012-040781

  On the other hand, in a recording apparatus adopting an ink jet method, the remaining nozzles in the recording head are used in place of defective (discharge failure) nozzles of the recording head, which reduces or eliminates image defects. It has a function to compensate for vomiting. Non-discharge complementation in multi-pass printing is realized by editing mask data. In the technique described in Patent Document 1, encoded mask data is held in a ROM. One possible method for performing discharge failure compensation in such a situation is as follows. Each time recording on a recording medium such as paper is requested, the encoded mask data is read from the ROM and decoded, and the decoded mask data is held in the editing buffer. In this editing buffer, the mask data is subjected to necessary editing and sent to the mask buffer.

  However, with this technique, the editing buffer is required to have a capacity sufficient to hold the decoded mask data, so that the capacity of the editing buffer increases as the mask data capacity increases. This may squeeze the temporary storage resources of the recording apparatus or increase the cost due to the addition of such resources.

  The present invention has been made in view of these problems, and an object thereof is to provide a technique capable of reducing the capacity of a buffer related to mask data in a printing apparatus having a function of performing multi-pass printing.

  One embodiment of the present invention relates to a recording apparatus. This recording apparatus includes a recording head in which a plurality of recording elements are arranged, an editing buffer that stores encoded mask data obtained by encoding mask data used in multi-pass recording, and a defect among the plurality of recording elements in the recording head. And a processing unit that edits the encoding mask data held in the editing buffer based on the specific data that specifies the recording element determined to be. The encoding mask data held in the editing buffer includes a first code that specifies a dot-on pass based on the correspondence between the pass and the code. The specific data specifies a path in which a printing element determined to be defective based on the correspondence relation appears. When the path specified by the first code matches the path specified by the specific data, the processing unit changes the first code to a second code that specifies a path different from the path specified by the first code. replace.

  According to the present invention, the capacity of a buffer related to mask data can be reduced in a printing apparatus having a function of performing multi-pass printing.

1 is an external perspective view showing an outline of the configuration of a recording apparatus according to a first embodiment that performs recording using an inkjet recording head. FIG. 4 is a schematic diagram of the recording head viewed from the side where the nozzle rows are provided, an enlarged view of a portion surrounded by a broken line, and a block diagram illustrating the function and configuration of the recording apparatus. Explanatory diagram showing encoded mask data held in the second buffer, a data structure diagram showing an example of encoded information held in the first storage, and an explanation showing decoded mask data held in the third buffer The figure explaining the relationship between the nozzle of a nozzle row, mask data, and the dot location on paper. The flowchart which shows an example of the undischarge complementation process in a defect process part. Schematic diagram of nozzle row including one ejection failure nozzle, data structure diagram showing an example of ejection failure specification data held in the seventh buffer, schematic diagram of nozzle row including three ejection failure nozzles, held in the seventh buffer The data structure figure which shows an example of the undischarge specific data. Explanatory drawing of the detail of the undischarge complementation process corresponding to FIG. 5 (A) in a defect process part. Explanatory drawing of the detail of the undischarge complementation process corresponding to FIG.5 (C) in a defect process part. Explanatory diagram showing encoded mask data held in the second buffer, a data structure diagram showing an example of encoded information held in the first storage, and an explanation showing decoded mask data held in the third buffer FIG. 4 is a diagram for explaining the relationship between nozzles in a nozzle row, mask data, and dot positions on the paper, a schematic diagram of a nozzle row including one undischarge nozzle, and data indicating an example of discharge failure specifying data held in the seventh buffer Structural drawing. Explanatory drawing of the detail of the undischarge complementation process corresponding to FIG.8 (E) in a defect process part. The data structure figure which shows an example of the candidate table which concerns on a modification.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The same or equivalent components, members, processes, and signals shown in the drawings are denoted by the same reference numerals, and repeated descriptions are omitted as appropriate. In this specification, “recording” (hereinafter also referred to as “printing”) is not only for forming significant information such as characters and figures, but also for images on a wide range of recording media, regardless of significance. A case where a pattern, a pattern, or the like is formed or a medium is processed is also expressed. It does not matter whether it has been made obvious so that humans can perceive it visually.

  “Recording medium” refers not only to paper used in general recording apparatuses but also widely to cloth, plastic film, metal plate, glass, ceramics, wood, leather, and the like that can accept ink. Shall.

  The term “ink” should be broadly interpreted in the same way as the definition of “recording”. When applied to a recording medium, the “ink” forms an image, a pattern, a pattern, or the like, or processes the recording medium. It represents a liquid that can be subjected to the treatment. Examples of the ink treatment include solidification or insolubilization of the colorant in the ink applied to the recording medium.

  Further, unless otherwise specified, the “recording element (or nozzle)” collectively refers to an ejection port or a liquid path communicating with the ejection port and an element that generates energy used for ink ejection.

  The recording apparatus according to the embodiment employs an inkjet method and has a function of performing multi-pass recording and a discharge failure complement function. In this discharge failure complement function, the mask data is edited in the state of being encoded by specifying the discharge failure nozzle by the rule corresponding to the encoding rule used when encoding the mask data. Making it possible. As a result, the capacity of the editing buffer can be reduced.

(First embodiment)
FIG. 1 is an external perspective view showing an outline of the configuration of a recording apparatus 1 according to a first embodiment that performs recording using an inkjet recording head. The recording apparatus 1 mounts on a carriage 2 a recording head 3 that performs recording by discharging ink in accordance with an ink jet method, and performs recording by reciprocating the carriage 2 in the direction of arrow A. The recording apparatus 1 feeds a recording medium P such as recording paper through a paper feeding mechanism 5 and conveys the recording medium P to a recording position. At the recording position, recording is performed by ejecting ink from the recording head 3 to the recording medium P. Do.

  In addition to mounting the recording head 3 on the carriage 2 of the recording apparatus 1, an ink tank 6 for storing ink to be supplied to the recording head 3 is mounted. The ink tank 6 is detachable from the carriage 2.

  The recording apparatus 1 is capable of color recording. For this reason, the carriage 2 has four ink tanks 6 (inks) containing magenta (M), cyan (C), yellow (Y), and black (K) inks, respectively. It is also called a cartridge. These four ink tanks 6 can be attached and detached independently.

  The recording head 3 employs an ink jet system that ejects ink using thermal energy. For this reason, an electrothermal converter such as an electric heater is provided. The electrothermal transducer is provided corresponding to each of the ejection ports, and ink is ejected from the corresponding ejection port by applying a pulse voltage to the corresponding electrothermal transducer in accordance with the recording signal.

  FIG. 2A is a schematic view of the recording head 3 as viewed from the side where the nozzle row 202 is provided. FIG. 2B is an enlarged view of a portion surrounded by a broken line in FIG. The recording head 3 in which a plurality of recording elements are arranged includes a recording element array, that is, a nozzle array 202 in which a plurality of nozzles 203 are arranged in a line at substantially equal intervals. Each nozzle 203 ejects ink. In this embodiment, a case where eight nozzles Y1 to Y8 are used is described for the sake of simplicity. However, the present invention is not limited to this, and the number of nozzles 203 may be further increased. Further, the recording apparatus may include a plurality of nozzle rows for recording a plurality of colors. Hereinafter, the conveyance direction of the recording medium P such as paper is defined as the Y direction, and the scanning direction of the nozzle 203 relative to the recording medium P is the A direction. The A direction and the Y direction intersect and are particularly orthogonal.

  The recording apparatus 1 performs recording on the recording medium P by ejecting ink from the nozzles 203 in accordance with the conveyance timing while the carriage 2 carrying the recording head 3 is conveyed in the A direction. In the nozzle row 202, there may be a defective nozzle that does not operate normally due to a manufacturing defect or aging deterioration, for example, a non-discharge nozzle that cannot eject ink normally. The recording apparatus 1 includes an undischarge detection unit (not shown) including an optical sensor or the like configured to detect such an undischarge nozzle. In multipass recording, the recording target area of the recording medium P is scanned a plurality of times by the recording head 3. Therefore, by editing the mask data so that the recording data to be recorded by the non-discharge nozzle in one pass is recorded on the normal nozzle in another pass, the adverse effect on the recording by the non-discharge nozzle can be reduced or eliminated. Can do.

  FIG. 2C is a block diagram illustrating the function and configuration of the recording apparatus 1. The recording apparatus 1 includes a carriage 2, an ASIC 102 that is a control unit that controls functions, operations, and processing of the recording apparatus 1, a RAM 116 that is a readable / writable volatile memory, and a ROM 120 that is a non-rewritable nonvolatile memory. .

The carriage 2 includes a recording head 3, a third storage 125, and an encoder 127. The third storage 125 is a part of a storage area of a nonvolatile memory such as an EEPROM of the recording head 3. The third storage 125 retains undischarge specifying original data for specifying a nozzle determined to be an undischarge nozzle by the undischarge detection unit (hereinafter simply referred to as an undischarge nozzle) in relation to the nozzle row 202. The undischarge specifying original data represents the position of the undischarge nozzle in the nozzle row 202 as binary data. For example, when Y4 is a discharge failure nozzle in the nozzle row 202 shown in FIG. 2B, the discharge failure specification original data is “00001000”. Here, “1” indicates an undischarge nozzle, and “0” indicates an undischarge nozzle. The Y8 nozzle is the MSB, and the Y1 nozzle is the LSB.
The encoder 127 generates a position signal for determining the position of the recording head 3 in the scanning direction of the carriage 2. The encoder 127 may be configured using a known technique for detecting the position of the recording head 3 in the scanning direction.

The ROM 120 includes a first storage 120A and a second storage 120B. Mask data is generated in advance for each number of passes in multi-pass printing and for each number of transported recording media P (or the number of line feeds). The generated mask data is encoded according to an encoding rule based on the corresponding pass number and line feed number. Data obtained as a result of such encoding is referred to as encoding mask data.
The second storage 120B holds the number of passes, the number of line feeds, and the coding mask data corresponding to them in association with each other.
The first storage 120A stores a code that specifies a path or a combination of paths in association with the path or a combination of paths as encoded information. The encoding information represents a correspondence relationship between one pass or a combination of passes (that is, a plurality of passes) and one code. In the example of FIG. 3B, a correspondence relationship in which “first pass” corresponds to “00” is shown, but in another correspondence relationship, “first pass” may correspond to “01”.

  The RAM 116 includes a first buffer 116A, a second buffer 116B, a third buffer 116C, a fourth buffer 116D, a fifth buffer 116E, and a sixth buffer 116F. The second buffer 116B is an editing buffer in which the encoding mask data to be edited is temporarily stored. The third buffer 116C is a mask buffer in which the decoded mask data is temporarily stored.

  The ASIC 102 includes a host interface 111, a ROM controller 123, a CPU 112, a RAM controller 124, an encoder processing unit 122, an image data processing unit 115, a data transfer unit 121, a mask decoding unit 117, and a defect processing unit 118. And a receiving unit 126. They are connected to each other via a bus 113. The defect processing unit 118 includes a DF (Discharge Failure) data generation unit 119, an eighth buffer 503, and a seventh buffer 504. At least one of the eighth buffer 503 and the seventh buffer 504 may be provided in the RAM 116.

At the start of recording, the host interface 111 performs wireless communication or wired communication with the host device 900 that may be a personal computer or a portable terminal, and receives received data representing a recording target such as an image from the host device 900. The received data may include binary data that represents each dot as a binary value.
The RAM controller 124 stores the received data received by the host interface 111 in the fifth buffer 116E. The receiving unit 126 receives the undischarge specific original data from the third storage 125.

  The CPU 112 expands the received data stored in the fifth buffer 116E into image data and a print command, and stores the image data in the sixth buffer 116F. The CPU 112 determines the number of passes of the recording head 3 and the number of line feeds of the recording medium P in multi-pass recording from the print command. The CPU 112 selects encoding mask data corresponding to the determined pass number and line feed number from among a plurality of encoding mask data held in the second storage 120B. The CPU 112 reads out the selected encoding mask data from the second storage 120B, and writes it into the second buffer 116B while being encoded. The CPU 112 stores the undischarge specifying original data received by the receiving unit 126 in the first buffer 116A. After the storage, the CPU 112 notifies the failure processing unit 118 of the start of the discharge failure complement process together with the number of passes, the number of line feeds, and the encoded information held in the first storage 120A.

  Based on the number of passes, the number of line feeds, and the encoding information notified from the CPU 112, the DF data generation unit 119 converts the undischarge specifying original data held in the first buffer 116A into defect specifying data, that is, undischarge specifying data. Convert. The discharge failure specifying data is data for specifying a discharge failure nozzle according to a specific rule corresponding to a coding rule of coding mask data corresponding to the notified number of passes and line feed. The defect processing unit 118 edits the encoding mask data held in the second buffer 116B based on the discharge failure specifying data obtained as a result of the conversion so that the adverse effect of the discharge failure nozzle is alleviated or eliminated. . Thereafter, the failure processing unit 118 notifies the CPU 112 of the end of the discharge failure complement process.

After receiving the notification of the end of the discharge failure complement process, the CPU 112 notifies the mask decoding unit 117 of the number of passes and the encoded information held in the first storage 120A.
The mask decoding unit 117 reads out the encoded mask data after the discharge failure complement editing from the second buffer 116B, and decodes the read out encoded mask data based on the notified number of passes and the encoded information. Since the encoding rule of the encoded mask data and the decoding rule in the mask decoding unit 117 correspond to each other, the specific rule in the discharge failure specific data corresponds to the decoding rule in the mask decoding unit 117. That is, the mask decoding unit 117 decodes the encoded mask data after undischarge complementing editing according to a decoding rule corresponding to the specific rule in the undischarge specific data. The mask decoding unit 117 stores the binary mask data obtained as a result of decoding in the third buffer 116C.

The image data processing unit 115 acquires the image data held in the sixth buffer 116F, and converts the acquired image data into binary print data. The image data processing unit 115 stores the print data obtained as a result of the conversion in the fourth buffer 116D.
The encoder processing unit 122 receives the position signal of the carriage 2 from the encoder 127 and generates a recording timing signal based on the received position signal. The encoder processing unit 122 transmits the generated recording timing signal to the data transfer unit 121.

  The data transfer unit 121 reads mask data from the third buffer 116C and print data from the fourth buffer 116D in synchronization with the received recording timing signal. The data transfer unit 121 performs a logical product process of the read mask data and print data, and transfers the binary data obtained as a result to the recording head 3 as a recording signal.

  Hereinafter, the relationship between the encoding mask data and the dots on the paper surface will be described with reference to FIGS. 3A to 3D, and the discharge failure with respect to the encoding mask data will be described with reference to FIGS. 4, 5, 6, and 7. Details of the complement processing will be described.

  FIG. 3A is an explanatory diagram showing the coding mask data 20 held in the second buffer 116B. The encoded mask data 20 shown in FIG. 3A is a code when recording is performed with the recording head 3 performing 6-dot conveyance in the A direction, paper conveyance is line feed +2 in the Y direction for each pass, and the number of passes is 4. It is an example of data masking data. The size of the encoding mask data 20 is 6 (A direction) × 2 (Y direction) × 2 bits (code bit depth) = 24 bits. The first row 216 of the encoded mask data 20 corresponds to the first nozzle, and the second row 218 corresponds to the second nozzle.

  FIG. 3B is a data structure diagram illustrating an example of encoded information held in the first storage 120A. 2 bits of each grid of the encoding mask data 20 shown in FIG. 3A is configured based on the encoding information shown in FIG. 3B, and is a code that particularly identifies a path for dot-on. . For example, the first grid 204 indicated by a thick frame is data indicating that the dot is turned on in the first pass at the position of coordinates (A, Y) = (0, 0), and the second grid 205 indicated by a thick frame is a coordinate. This is data indicating that dots are turned on at the position (A, Y) = (3, 1) in the fourth pass. The coding mask data held in the second storage 120B has the same configuration as the coding mask data shown in FIG.

  FIG. 3C is an explanatory diagram showing the decoded mask data 22 held in the third buffer 116C. The mask data 22 shown in FIG. 3C is obtained by decoding the encoded mask data 20 shown in FIG. The size of the mask data 22 is 6 (A direction) × 8 (Y direction) × 1 bit = 48 bits. One bit of each grid of the mask data 22 indicates a binary value to be recorded or not, and is logically processed with the print data. In FIG. 3C, hatched grids 212 indicate dots (locations) recorded by logical product processing with print data, and white grids 214 indicate dots not recorded by logical product processing with print data. The compression ratio of the encoded mask data 20 with respect to the mask data 22 (= the size of the encoded mask data / the size of the mask data) is 50%.

As shown in FIGS. 3A to 3C, in the present embodiment, mask data such as mask data 22 is defined based on the number of passes and the number of line feeds. The mask data is a binary value (1 bit) indicating whether the dot is on or off in each lattice of a matrix composed of a row corresponding to (number of line feeds × number of passes) nozzles and a column corresponding to the number of dots conveyed in the A direction. It is the arranged data. Accordingly, mask data is defined at least for each pass number and for each line feed number. The encoded mask data 20 is obtained by encoding the mask data 22 according to the encoding rule. This encoding rule is based on the number of passes and the encoding information held in the first storage 120A, and conceptually includes the following steps.
(1) The mask data 22 is decomposed into portions corresponding to the respective passes.
(2) Superimpose the decomposed parts.
(3) For each grid of the matrix obtained as a result of superposition, a code specifying a path on which the grid is dot-on is selected from the codes held in the first storage 120A, and the selected code is assigned to the grid. In the present embodiment, the mask data 22 is configured such that for each grid of the encoded mask data 20, there is one path where the grid is dot-on.

  FIG. 3D illustrates the relationship between the nozzles Y1 to Y8 of the nozzle row 202 of FIG. 2B, the mask data 22 of FIG. The recording medium P is conveyed downward with respect to the paper surface with the number of line feeds = + 2. The number of passes is four. Since the number of line feeds is +2, the recording medium P is conveyed by two dots downward with respect to the recording head 3 between the passes. Therefore, Y1 and Y2 are used in the first pass, Y3 and Y4 are used in the second pass, Y5 and Y6 are used in the third pass, and Y7 and Y8 are used in the fourth pass. In each pass, the nozzle row 202 is conveyed by 6 dots in the A direction. When the fourth pass is completed, as shown by the reference numeral 206, a dot portion of 6 × 2 100% duty is formed.

  In such a situation, if there is an undischarge nozzle in the nozzles Y1 to Y8, the print data cannot be recorded correctly. Therefore, the defect processing unit 118 converts the encoded mask data in an encoded state so as to allocate the portion assigned to the discharge failure nozzle to another normal nozzle along the flow shown in FIG.

  FIG. 4 is a flowchart illustrating an example of discharge failure complement processing in the defect processing unit 118. In S300, when the failure processing unit 118 receives a notification of completion processing start from the CPU 112 together with the number of passes, the number of line feeds, and the encoded information held in the first storage 120A, the failure processing unit 118 starts the discharge failure complement processing. In S301, the failure processing unit 118 that has received the start notification acquires the undischarge specific original data from the first buffer 116A. In S302, the failure processing unit 118 generates discharge failure specifying data whose number is managed from discharge failure specifying original data based on the number of passes, the number of line feeds, and encoding information. Thereafter, in S303, the failure processing unit 118 analyzes the discharge failure nozzle code value of the discharge failure specifying data and determines whether or not there is a discharge failure nozzle. As a result of S303, when it is determined that there is no discharge failure nozzle, the failure processing unit 118 proceeds to S310 and ends the process without performing discharge failure complement processing. On the other hand, when it is determined that there is a discharge failure nozzle, the failure processing unit 118 performs discharge failure complement processing in S304 to S309. S304 to S309 will be described later. After completion of the complementing process, the defect processing unit 118 notifies the CPU 112 of an end notification in S310. S303 to S309 constitute an undischarge complementing process, and S301 and S302 constitute an undischarge specifying data generation process.

  5A, 5B, 5C, and 5D relate to S301 and S302 in FIG. FIG. 5A is a schematic diagram of the nozzle row 202 including one discharge failure nozzle 222. The failure processing unit 118 that has received the notification of the start of the complementary processing together with the number of passes, the number of line feeds, and the encoding information from the CPU 112 acquires the undischarge specifying original data held in the first buffer 116A and transfers it to the DF data generation unit 119 To do. As described above, “1” is stored in the discharge failure specifying original data corresponding to the nozzle determined to be a discharge failure nozzle. For example, as shown in FIG. 5A, when Y4 is the non-discharge nozzle 222 and the other nozzles are normal nozzles 224, the non-discharge specification original data is “00001000”.

  The DF data generation unit 119 converts the discharge failure specifying original data into discharge failure specification data based on the notified number of passes, the number of line feeds, and the encoded information, and stores the discharge failure specification original data in the seventh buffer 504. The discharge failure specifying data specifies discharge failure nozzles according to a specific rule corresponding to a coding rule of coding mask data to be edited.

  In the example of FIG. 5A, the DF data generation unit 119 uses the notified number of passes (4) and the number of line feeds (+2) as Y1 for the first nozzle in the first pass, Y2 for the second nozzle, and 2 passes. For each pass, the first nozzle is Y3, the second nozzle is Y4, the third nozzle is Y5, the second nozzle is Y6, the fourth nozzle is Y7, the second nozzle is Y8 Two nozzles are determined as assigned nozzles. In this example, since Y4 is a discharge failure nozzle (bit corresponding to Y4 of discharge failure specific original data is “1”), the DF data generation unit 119 determines that the second nozzle in the second pass is a discharge failure nozzle. decide. Data obtained by encoding the “second nozzle in the second pass” is discharge failure specifying data. For example, the assigned nozzle for each pass is encoded in 2 bits, and the first nozzle is encoded as “01” and the second nozzle as “10”. This code value is referred to as the assigned nozzle code value. The assigned nozzle code value “00” indicates that there is no discharge failure nozzle. Information indicating the number of passes is encoded based on the encoded information held in the first storage 120A. The path in which the discharge failure nozzle appears is specified by the code of the encoding information. The discharge failure specifying data includes a discharge failure nozzle code value (DFN code) 410 that is a assigned nozzle code value for the discharge failure nozzle, and a pass code value (Path) that is a code value for specifying a path in which the discharge failure nozzle appears. code) 412 are stored in association with each other. The DF data generation unit 119 stores the generated discharge failure specifying data in the seventh buffer 504.

  FIG. 5B is a data structure diagram showing an example of discharge failure specifying data held in the seventh buffer 504. FIG. 5B corresponds to FIG. The first entry 408 corresponds to the fact that the nozzle of Y4 in FIG. The discharge failure specifying data is composed of a number-managed table. In order to perform the complement processing, in addition to the data of the first entry 408, a second entry 409 indicating no data is added (the pass code value when there is no data may be arbitrary). Although not shown in the flowchart of FIG. 4, if it is determined that there is no discharge failure nozzle after acquisition of discharge failure specifying original data, that is, if discharge failure specifying original data is “00000000”, S310. The undischarge complementing process may be terminated by proceeding to.

  5A and 5B, the case where there is one discharge failure nozzle 222 has been described. However, when there are a plurality of discharge failure nozzles 222, the DF data generation unit 119 similarly generates discharge failure specifying data. FIG. 5C is a schematic diagram of the nozzle row 202 including three discharge failure nozzles 222. As shown in this figure, when Y4, Y5, and Y6 are discharge failure nozzles 222, discharge failure specific original data is binary data “00111000” and is stored in the third storage 125 in this format. . As in the case of FIGS. 5A and 5B, the DF data generation unit 119 determines which number of nozzles in which pass the discharge failure nozzle 222 appears, and sets the discharge failure nozzle code value 410 as the discharge failure nozzle code value 410. The combination with the pass code value 412 is specified. The DF data generation unit 119 stores the specified set in the seventh buffer 504 as discharge failure specifying data.

  FIG. 5D is a data structure diagram illustrating an example of discharge failure specifying data held in the seventh buffer 504. FIG. 5D corresponds to FIG. The first entry 415, the second entry 416, and the third entry 417 correspond to the nozzles Y4, Y5, and Y6 being undischarge nozzles in FIG. 5C, respectively. The fourth entry 418 corresponds to the second entry 409 in FIG. The storage order in the seventh buffer 504 is from the LSB side, that is, undischarge nozzle data corresponding to Y4 is NO1 (first entry 415), undischarge nozzle data corresponding to Y5 is NO2 (second entry 416), Y6. Although the discharge failure nozzle data corresponding to is NO3 (third entry 417), the storage order is not limited to this.

  FIG. 6 is an explanatory diagram illustrating details of the discharge failure complement process corresponding to FIG. 6 corresponds to S303 to S310 in FIG. In step S <b> 303, the failure processing unit 118 acquires the discharge failure nozzle code value of the first entry (number 1) of discharge failure specifying data held in the seventh buffer 504, and determines whether there is a discharge failure nozzle. The defect processing unit 118 determines that there is no discharge failure nozzle when the discharge failure nozzle code value is “00”, and that there is any other case. If it is determined “Yes” in S303, the failure processing unit 118 acquires the encoding mask data from the second buffer 116B and stores it in the eighth buffer 503 in S304. In FIG. 6, since the discharge failure nozzle code value is “10”, the failure processing unit 118 acquires a portion corresponding to the second nozzle in the encoded mask data. At that time, the defect processing unit 118 transmits a read request RR to the second buffer 116B, and after acquiring an acknowledge in S304, reads the target portion using the read data RD.

  In step S <b> 305, the failure processing unit 118 compares the pass code value of the discharge failure specifying data with the data in the eighth buffer 503. If there is no matching data (NO in S306), the failure processing unit 118 advances the process to S308. If there is matching data among the data held in the eighth buffer 503 (YES in S306), the defect processing unit 118 performs a complementing process on the matching data in S307. In this complementing process, the defect processing unit 118 changes the same code (first code) as the pass code of the discharge failure specifying data among the codes held in the eighth buffer 503. In particular, the failure processing unit 118 replaces the code (first code) with another code (second code) that specifies a path different from the path specified by the code. Here, as a simple complement, the next pass is passed, that is, the complementing process is performed by incrementing the matching data in the eighth buffer 503 by one. Further, when the pass code value of the discharge failure specifying data specifies the final path (pass code value “11”), it may be complemented with the first pass (pass code value “00”).

  In S <b> 308, the defect processing unit 118 checks whether or not the discharge failure nozzle code value of the next entry (number 2) has been updated. If both values match, the failure processing unit 118 proceeds to the next entry of the discharge failure specifying data, and returns the process to S305. If the two values do not match, the defect processing unit 118 determines that there is an update, and writes the data in the eighth buffer 503 back to the second buffer 116B in S309. In FIG. 6, the defect processing unit 118 overwrites the data held in the eighth buffer 503 in the portion corresponding to the second nozzle in the encoded mask data. At that time, the defect processing unit 118 transmits a write request WR to the second buffer 116B, acquires an acknowledgment, and then overwrites the target portion with the write data WD.

  Thereafter, the failure processing unit 118 proceeds to the next entry of the discharge failure specifying data, and returns the process to S303. In S303, the failure processing unit 118 acquires the discharge failure nozzle code value of the second entry (number 2). In FIG. 6, since the acquired code value is “00”, the defect processing unit 118 advances the process to S310. In S310, the defect processing unit 118 ends the process and transmits an end notification CN to the CPU 112.

  The encoded mask data that has been subjected to the discharge failure complement process is decoded by the mask decoding unit 117. The mask data obtained as a result of decoding is supplemented so that the data to be recorded by the ejection failure nozzle is recorded by a normal nozzle in another pass. This mask data is stored in the third buffer 116C. Thereafter, the data transfer unit 121 reads out mask data from the third buffer 116C and print data from the fourth buffer 116D in synchronization with the recording timing signal, and performs a logical product process. The binary data obtained as a result of the logical product process is transferred to the recording head 3.

  FIG. 7 is an explanatory diagram illustrating details of the discharge failure complementing process corresponding to FIG. Although FIG. 6 illustrates the discharge failure complement process when there is one discharge failure nozzle, FIG. 7 illustrates the discharge failure complement process when there are a plurality of discharge failure nozzles. FIG. 7 corresponds to S303 to S310 in FIG. 7 is the same as that shown in FIG. 6, and the description thereof is omitted. When the processing related to the first entry 415 of the seventh buffer 504 is completed, in S303, the failure processing unit 118 sets the undischarge responsible nozzle code value of the second entry 416 of undischarge specific data held in the seventh buffer 504. Acquire and determine whether there is an undischarge nozzle. In FIG. 7, since the discharge failure nozzle code value of the second entry 416 is “10”, the defect processing unit 118 acquires a portion corresponding to the second nozzle in the encoded mask data. In step S <b> 305, the failure processing unit 118 compares the pass code value of the second entry 416 with the data in the eighth buffer 503. Here, since there are two pieces of data that match the pass code value “01” in the data in the eighth buffer 503, the two pieces of matching data are complemented in S 307.

  Here, the supplement processing is performed by assigning to the next pass as a simple complement, that is, by adding +1 to the matching data in the eighth buffer 503. When the pass code value of the discharge failure specifying data specifies the final path (pass code value “11”), it may be complemented with the first pass (pass code value “00”). Further, when the nozzle to be distributed is an undischarge nozzle, it may be distributed to another pass. As a result of repeating this, if there is no path that can be distributed, the process is terminated, and the CPU 112 is notified that the complement process could not be performed.

  Thereafter ((B) in FIG. 7), in S308, the failure processing unit 118 determines that the discharge failure nozzle code value of the next entry (third entry 417) is the discharge failure nozzle of the previous entry (second entry 416). It is determined that the code value is the same (“10”), that is, there is no update. The defect processing unit 118 proceeds to the next entry without overwriting the second buffer 116B. In step S <b> 305, the failure processing unit 118 compares the pass code value of the third entry 417 with the data in the eighth buffer 503. Thereafter, the same match determination and discharge failure complement processing as described above are performed, and when “00” occurs in the discharge failure nozzle code value, an end notification CN is transmitted to the CPU 112.

  According to the recording apparatus 1 according to the present embodiment, the capacity of the second buffer 116B can be reduced because editing for realizing discharge failure complement is performed on the encoded mask data. For example, in the present embodiment, encoded mask data having a compression rate of 50% is stored in the second storage 120B. By performing non-discharge complementation while encoding mask data is encoded, the capacity of the second buffer 116B can be 50% of the capacity required for non-discharge complementation after decoding.

  In particular, since the decoded mask data 22 is held in the third buffer 116C, the capacity of the second buffer 116B is smaller than the capacity of the third buffer 116C.

  In the recording apparatus 1 according to the present embodiment, since the encoding mask data is held in the ROM 120, the encoding mask data itself cannot be rewritten. There are various causes for the occurrence of an undischarge nozzle, such as defects during manufacturing and deterioration over time. In most cases, it is detected whether the undischarge nozzle occurs after the recording apparatus 1 is put into use. Therefore, when a discharge failure nozzle is detected, the original coding mask data held in the ROM cannot be corrected, but discharge failure compensation is performed by editing the read mask data each time recording is performed. be able to. At this time, in this embodiment, the area of the RAM 116 necessary for such editing is small, so that it is possible to achieve both the implementation of the discharge failure complement function and the cost reduction in multi-pass printing.

  Further, in the recording apparatus 1 according to the present embodiment, the undischarge specific original data is held in the third storage 125 of the recording head 3, and the DF data generation unit 119 stores the undischarge specific original data as the third non-discharge specific original data as necessary. It is read from the storage 125 and used. Accordingly, by holding undischarge specific original data, which is information unique to the recording head 3, on the recording head 3 side, the capacity of the RAM 116 of the main body of the recording apparatus 1 can be reduced accordingly.

(Second Embodiment)
In the first embodiment, a case has been described in which the mask data 22 has only one path for dot-on to the same pixel on the same sheet. This is mainly suitable for binary image data. Further, in order to form a higher quality image on a recording medium, multi-gradation multi-pass recording that allows the same pixel on the same sheet to be recorded a plurality of times is known. The second embodiment will be described for application to multi-gradation multi-pass printing, that is, a case where there are a plurality of passes for dot-on to the same pixel on the same paper for the mask data 622. In the present embodiment, the reception data received by the host interface 111 includes multi-value data that represents each dot as a multi-value.

  FIG. 8A is an explanatory diagram showing the coding mask data 620 held in the second buffer 116B. The encoded mask data 620 shown in FIG. 8A is a code when recording is performed with the recording head 3 performing 6-dot conveyance in the A direction, paper conveyance is line feed +2 in the Y direction for each pass, and the number of passes is 4. It is an example of data masking data. The size of the encoding mask data 620 is 6 (A direction) × 2 (Y direction) × 3 bits (code bit depth) = 36 bits.

  FIG. 8B is a data structure diagram showing an example of encoded information held in the first storage 620A. The 3 bits of each grid of the encoding mask data 620 shown in FIG. 8A are configured based on the encoding information shown in FIG. 8B, and particularly specify at least one path for dot-on. Sign. For example, the first grid 604 indicated by a thick frame is data indicating that dots are turned on twice at the position of coordinates (A, Y) = (0, 0) in the first pass and the fourth pass. A second grid 605 indicated by a thick frame is data indicating that the dot is turned on once in the fourth pass at the position of coordinates (A, Y) = (3, 1).

    FIG. 8C is an explanatory diagram showing decoded mask data 622 held in the third buffer 116C. The mask data 622 shown in FIG. 8C is obtained by decoding the encoded mask data 620 shown in FIG. 8A by the mask decoding unit 117. The size of the mask data 622 is 6 (A direction) × 8 (Y direction) × 1 bit = 48 bits. One bit of each lattice of the mask data 622 indicates a binary value to be recorded or not, and is logically processed with the print data. The compression ratio of the encoded mask data 620 with respect to the mask data 622 is 75%.

  FIG. 8D illustrates the relationship between the nozzles Y1 to Y8 of the nozzle row 202 in FIG. 2B, the mask data 622 in FIG. 8C, and the dot locations on the paper. The recording medium P is conveyed downward with respect to the paper surface with the number of line feeds = + 2. The number of passes is four. Since the number of line feeds is +2, the recording medium P is conveyed by two dots downward with respect to the recording head 3 between the passes. Therefore, Y1 and Y2 are used in the first pass, Y3 and Y4 are used in the second pass, Y5 and Y6 are used in the third pass, and Y7 and Y8 are used in the fourth pass. In each pass, the nozzle row 202 is conveyed by 6 dots in the A direction. The hatched grid 612 in FIG. 8D indicates dots (locations) that are recorded once by the logical product process with the print data, and the black grid 616 is recorded twice by the logical product process with the print data. Dot (location). In the present embodiment, since the grid of the coding mask data 620 includes codes that specify a plurality of passes, the portion 701 after the fourth pass includes dots that have been recorded twice. Thus, the mask data 622 is configured to form multiple gradations on the recording medium P.

  FIG. 8E is a schematic diagram of the nozzle row 202 including one discharge failure nozzle 222. FIG. 8F is a data structure diagram illustrating an example of discharge failure specifying data held in the seventh buffer 654. The defect processing unit 118 that has received the notification of the start of the complementary processing together with the number of passes, the number of line feeds, and the encoding information from the CPU 112 acquires the stored undischarge specifying original data held in the first buffer 116A, and the DF data generation unit Forward to 119. As shown in FIG. 8E, when Y5 is the non-discharge nozzle 222 and the other nozzles are normal nozzles 224, the non-discharge specification original data is “00010000”.

  The DF data generation unit 119 converts the discharge failure specifying original data into discharge failure specifying data based on the notified number of passes, the number of line feeds, and the encoding information, and stores the converted discharge failure specification data in the seventh buffer 654. From the notified number of passes and the number of line feeds, the DF data generation unit 119 uses Y1 for the first nozzle in the first pass, Y2 for the second nozzle, Y3 for the first nozzle in the second pass, Y4 for the second nozzle, The first nozzle in the pass is Y5, the second nozzle is Y6, the first nozzle in the second pass is Y7, the second nozzle is Y8, and two nozzles are determined as the assigned nozzles for each pass. In this example, since Y5 is an undischarge nozzle (bit corresponding to Y5 of undischarge specific original data is “1”), the DF data generation unit 119 determines that the first nozzle in the third pass is an undischarge nozzle. decide.

  Based on the encoding information in FIG. 8B, “third pass” corresponds to “001”, “011”, “101”, and “110”. The DF data generation unit 119 stores each of them in the seventh buffer 654 as a separate entry. Therefore, the seventh buffer 654 has four entries, a first entry 708, a second entry 709, a third entry 710, and a fourth entry 711. In addition, a fifth entry 712 indicating the end of data is added to perform the complement processing. As described above, since some of the codes of the encoded information held in the first storage 620A specify a plurality of passes with one code, the number of discharge failure data (first entry) equal to or greater than the number of discharge failure nozzles. 708 to fourth entry 711) are generated.

  FIG. 9 is an explanatory diagram illustrating details of the discharge failure complementing process corresponding to FIG. The flow here is equivalent to the flow described with reference to FIGS. The main difference is that both the second buffer 116B and the eighth buffer 503 are configured in units of 3 bits, and the defect processing unit 118 does not have a matching data in S306 for the portion (丙) in FIG. In some cases, the process proceeds to the determination of whether or not to update the discharge failure nozzle code value of the next entry (fourth entry 711). The complementing process of S307 in the present embodiment is the same as the complementing process of FIG.

  According to the recording apparatus according to the present embodiment, the same operational effects as the recording apparatus 1 according to the first embodiment are exhibited.

  The configuration and operation of the recording apparatus according to the embodiment have been described above. These embodiments are exemplifications, and it is understood by those skilled in the art that various modifications can be made to each component and combination of processes, and such modifications are within the scope of the present invention. .

  In the first and second embodiments, the case where the second storage 120B is provided in the ROM 120 has been described. However, the present invention is not limited to this, and the second storage may be provided in another type of nonvolatile memory. For example, the second storage may be provided in a flash memory. In this case, it is possible to transfer the encoding mask data after the complement processing from the second buffer 116B to the second storage and rewrite the encoding mask data in the second storage. In this case, the defect processing unit 118 may store and manage the generated discharge failure specifying data in the second storage 120B. The defect processing unit 118 may compare the previous and current undischarge specifying data and, if there is no update, may transfer the previously used non-discharge complementing encoded mask data to the mask decoding unit.

  In the first and second embodiments, the case where the nozzle arrangement direction of the recording head 3 coincides with the conveyance direction of the recording medium P has been described. However, the present invention is not limited to this. The technical idea of form can be applied.

  In the first and second embodiments, a case has been described in which the supplementary processing is performed by moving to the next pass as a simple complement in S307, that is, by performing the complement process by incrementing the complement target data in the eighth buffer 503. I can't. For example, the pass code value of the replacement destination may be arbitrarily selected from a candidate table holding codes that are replacement destination candidates. FIGS. 10A, 10B, and 10C are data structure diagrams showing examples of candidate tables 802 according to modifications corresponding to FIGS. 5B, 5D, and 8F, respectively. It is. The candidate table 802 shown in FIG. 10A may be generated simultaneously with the generation of discharge failure specific data shown in FIG. For example, with reference to FIG. 5B, it has been described that the failure processing unit 118 determines that the “second nozzle in the second pass” is a discharge failure nozzle. In other words, the failure processing unit 118 performs the second nozzle (code value) of the first pass (code value “00”), the third pass (code value “10”), and the fourth pass (code value “11”). “01”) is a normal nozzle and can be determined to be complementary. The defect processing unit 118 encodes the above-described complementable portion with reference to the first storage 120A, and stores the encoded portion in the candidate table 802 shown in FIG. The same applies to FIGS. 10B and 10C. The defect processing unit 118 may select a smaller pass code value from the candidate table 802 in S307 and replace the complement target data in the eighth buffer 503 with the selected pass code value. The method for selecting the pass code value is not limited to this.

  Further, although the recording apparatus used in the embodiment described above is a single-function apparatus, the present invention is not limited to this. For example, a multi-function printer (MFP) equipped with a scanner function, a copying function, a facsimile function, etc. may be used.

1 recording device, 2 carriage, 3 recording head, 5 paper feed mechanism, 6 ink tank, 102 ASIC, 116 RAM, 120 ROM.

Claims (10)

A recording head in which a plurality of recording elements are arranged;
An edit buffer that holds encoded mask data obtained by encoding mask data used in multi-pass recording;
A processing unit that edits encoding mask data held in the editing buffer based on specific data that specifies a recording element determined to be defective among the plurality of recording elements of the recording head; and
The encoding mask data held in the editing buffer includes a first code that specifies a path for dot-on based on a correspondence between a path and a code,
The specific data specifies a path where a printing element determined to be defective based on the correspondence relationship appears,
When the path specified by the first code matches the path specified by the specific data, the processing unit specifies the first code and a path different from the path specified by the first code The recording apparatus is replaced with a second code.   The recording apparatus according to claim 1, further comprising a control unit that reads out encoding mask data from a nonvolatile memory and writes the encoded mask data in the editing buffer. A decoding unit for decoding the encoding mask data edited by the processing unit;
The recording apparatus according to claim 1, further comprising: a mask buffer that holds mask data obtained as a result of decoding by the decoding unit.   4. The recording apparatus according to claim 3, wherein a capacity of the editing buffer is smaller than a capacity of the mask buffer.   5. The recording according to claim 1, wherein the recording head includes a memory that holds data relating to a recording element determined to be defective among the plurality of recording elements of the recording head. apparatus.   The recording apparatus according to claim 5, wherein the processing unit generates the specific data based on data held in the memory. A receiver for receiving the recorded data;
The recording apparatus according to claim 1, wherein the recording data received by the receiving unit includes multi-value data in which each dot is expressed in multi-values. The correspondence relationship associates a plurality of paths with one code,
The first code identifies a plurality of paths that are dot-on,
The specific data specifies a plurality of paths in which recording elements determined to be defective based on the correspondence relationship appear,
When the plurality of paths specified by the first code and the plurality of paths specified by the specific data match, the processing unit determines the first code as a plurality of paths specified by the first code. The recording apparatus according to claim 7, wherein a plurality of paths different from the above are replaced with a second code that specifies a plurality of paths. A candidate table that holds codes that are candidates for replacement destinations;
The recording apparatus according to claim 1, wherein the processing unit selects the second code from codes held in the candidate table. Reading the encoded mask data obtained by encoding the mask data used in multi-pass recording from the memory and writing it to the editing buffer;
Editing coding mask data held in the editing buffer based on specific data for specifying a recording element determined to be defective among a plurality of recording elements included in the recording head;
Decoding the edited coding mask data; and
The encoding mask data held in the editing buffer includes a first code that specifies a path for dot-on based on a correspondence between a path and a code,
The specific data specifies a path where the recording element appears based on the correspondence,
The editing means that if the path specified by the first code and the path specified by the specific data match, the first code is changed to a path different from the path specified by the first code. A data editing method comprising: replacing with a specified second code.