JP2005262651A - Printer, image printing system, and printing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively shorten a printing time even when image data having a larger data amount than the size of a buffer memory is printed by rotating it. <P>SOLUTION: This printer 2 reads the image data for which data is arranged for each line having a height for the portion of a specified number of pixels, and prints the image. The printer 2 has at least the same number of image data buffers 72 as the number of lines of the image in the image data. A requesting means 93 demands data corresponding to a printing region conforming to the printing sequence of the image. A reading means 92 reads the data for the portion of the size of the image data buffers 72 including the data related to the demand when there is no data related to the demand in a plurality of the image data buffers 72, and stores the data in a plurality of the image data buffers 72 conforming to the first read first output rule. An outputting means 92 outputs the data related to the demand to the requesting means 93. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a printer, an image printing system, and a printing method.

  Patent Documents 1 and 2 disclose a printing system. In these conventional printing systems, a USB storage class device digital camera and a USB host printer are directly connected by a USB (Universal Serial Bus). In this conventional printing system, the camera generates a print request for the printer in response to an operation on the button, and the printer reads an image data file necessary for the printing process from the camera based on the request. Then, an image is printed based on the image data.

JP 2003-259274 A (drawings, detailed description of the invention) JP 2002-56676 A (drawings, detailed description of the invention)

  By the way, in a conventional printing system, a printer reads an image data file stored in a camera and prints an image based on the image data.

  Therefore, if this printer is provided with a buffer memory, the image data files are read into the buffer memory and the data necessary for printing is read out from the buffer memory, the data necessary for image printing occurs. Since it is not necessary to read image data from the camera each time, printing time is shortened.

  Further, even if such a buffer memory is provided in the printer, image data having a data amount larger than the size of the buffer memory can be read into the buffer memory multiple times to print the image data. it can.

  However, even if such a buffer memory is provided in the printer, when an image of image data having a data amount larger than the size of the buffer memory is rotated by 90 degrees and printed, a printing time of a certain time or more is required. The shortening effect cannot be expected. This is due to the following reason.

  The image data stored in the semiconductor memory is data obtained by collecting data in units of one pixel or data obtained by collecting data in units of blocks every several pixels. Further, the plurality of pixel unit data or the plurality of block unit data are stored in an image data file in a line-by-line manner.

  In the printer, data necessary for printing an image is generated based on scanning of the carriage. Therefore, when the image of the image data file is rotated 90 degrees and printed, the printer is discretely stored in separate rows in the image data in order to generate print control data for one scan of the carriage. It is necessary to use data sequentially.

  When the image data used for printing is read into the buffer memory in a plurality of times, after generation of print control data for one scan with a carriage is completed, one scan for the next carriage is completed. When generation of print control data is started, image data required at that time may not remain in the buffer memory. In that case, it is necessary to read image data from the camera again.

  Therefore, when the printer prints an image of the image data file rotated 90 degrees, the image data is frequently read from the camera to the buffer memory every time print control data for one scan of the carriage is generated. To do. For this reason, it is not possible to expect an effect of shortening the printing time beyond a certain level.

  The present invention has been made in view of the above problems, and even when an image based on image data having a data amount larger than the size of the buffer memory is rotated and printed, the printing time is effectively shortened. An object of the present invention is to provide a printer, an image printing system, and a printing method.

  The printer according to the present invention is a printer that reads image data in which data is arranged for each row having a height of a predetermined number of pixels and prints the image. A data buffer, request means for requesting data corresponding to the print area in accordance with the print order of the image, and, if there is no data related to the request in a plurality of image data buffers, an image data buffer including the data related to the request It has reading means for reading data of size and storing it in a plurality of image data buffers in accordance with pre-read-first-out rules, and output means for outputting the data related to the request to the request means.

  In the configuration of the present invention, the plurality of image data buffers has the same number as the number of lines in the image data or more than the number of lines. Therefore, when the image is rotated and printed, for example, when the reading unit reads the data of the first column of the image into the image data buffer, the data of the second column is read together, and the two columns according to the data request of the request unit When printing the eye, the output means can read out the second column data read together with the first column data from the image data buffer and output it without reading the image data buffer by the reading means. it can.

  As a result, if this configuration is adopted, the printing time can be effectively shortened even when an image based on image data having a data amount larger than the size of the plurality of image data buffers is rotated and printed. it can.

  Another printer according to the present invention is a printer that reads image data in which data is arranged for each row having a height corresponding to a predetermined number of pixels and prints the image. When the data amount of data is larger than the size of the buffer memory, a first number of image data buffers that are at least the same as the number of image lines in the image data are formed in the buffer memory, and the data amount of the image data is If the memory size is less than or equal to the size of the memory, a forming means for forming a second number of image data buffers smaller than the first number in the buffer memory, and a request for requesting data corresponding to the print area in accordance with the printing order of the images Means and an image data buffer containing the requested data if the requested data is not in a plurality of image data buffers. Loading the size of the data §, and has a reading means for storing a plurality of image data buffer in accordance with the preliminary read-out Sakide rules, and output means for outputting the data related to the request to the requesting means.

  If this configuration is adopted, if the data amount of the image data is larger than the size of the buffer memory, the first number of image data buffers equal to or larger than the number of image lines in the image data can be used. The printing time can be effectively shortened.

  In this configuration, when the amount of image data is equal to or smaller than the size of the buffer memory, a plurality of image data buffers having a number smaller than the second number and smaller than the second number are used. Therefore, when this configuration is adopted, when the amount of image data is equal to or smaller than the size of the buffer memory, a plurality of image data buffers having the same number as or more than the number of lines in the image data are used. Compared to the case, the number of times of reading image data from the image supply device can be reduced, and the printing time can be shortened more effectively.

  A third printer according to the present invention includes a buffer memory having a predetermined size in a printer that reads image data in which data is arranged for each row having a height corresponding to a predetermined number of pixels and prints the image; An acquisition unit that acquires the number of rows of image data; a formation unit that forms, in the buffer memory, a plurality of image data buffers having at least the same number as the number of rows based on the number of rows of communication data acquired by the acquisition unit; In accordance with the print order, the request means for requesting data corresponding to the print area, and if the data related to the request is not in a plurality of image data buffers, the data corresponding to the size of the image data buffer including the data related to the request Reading means for reading and storing in a plurality of image data buffers in accordance with a pre-read first-out rule, and request data to the request means And output means for force, and has a.

  If this configuration is adopted, the number of image data buffers equal to or larger than the number of image lines in the image data related to printing is used, so an optimum printing time reduction effect corresponding to the image data to be used is expected. can do.

  A fourth printer according to the present invention is a printer that reads a plurality of image data in which data is arranged for each row having a height corresponding to a predetermined number of pixels, and prints the images side by side in the carriage driving direction. Image data buffers having at least the same number as the total number of image lines in the plurality of image data, request means for requesting data corresponding to the print area in accordance with the printing order of the images, and data related to the requests in the plurality of image data buffers If not, read means for reading the data corresponding to the size of the image data buffer and storing it in a plurality of image data buffers according to the pre-read first-out rule, and the data related to the request to the request means Output means for outputting.

  In this configuration, the plurality of image data buffers has the same number as the total number of image lines in the image data to be printed side by side in the carriage driving direction or a number larger than the total number of lines. Therefore, if this configuration is adopted, even when a plurality of images based on a plurality of image data having a data amount larger than the size of the plurality of image data buffers are rotated and printed (for example, in the case of a 4up layout). The printing time can be effectively shortened.

  A fifth printer according to the present invention is a printer that reads a plurality of image data in which data is arranged for each row having a height corresponding to a predetermined number of pixels, and prints the images side by side in the carriage driving direction. When the total data amount of the buffer memory having a predetermined size and the plurality of image data is larger than the size of the buffer memory, the buffer memory has a first number that is at least the same as the total number of image rows in the plurality of image data. Forming a plurality of image data buffers, and forming a second number of image data buffers smaller than the first number in the buffer memory when the data amount of the plurality of image data is less than or equal to the size of the buffer memory Means, requesting means for requesting data corresponding to the print area in accordance with the printing order of the image, and the data related to the request include a plurality of image data. If it is not in the buffer, it reads the data corresponding to the size of the image data buffer including the data related to the request, and stores the data related to the request in a plurality of image data buffers according to the pre-read first-out rule. Output means for outputting to the request means.

  If this configuration is adopted, when the total data amount of a plurality of image data to be printed side by side in the carriage drive direction is larger than the size of the buffer memory, the same number as the total number of image lines in the plurality of image data or By using a larger number of image data buffers than the total number of lines, the printing time can be effectively shortened. If this configuration is adopted, if the total amount of the plurality of image data is less than or equal to the size of the buffer memory, the number of times the image data is read from the image supply device is reduced, and the printing time is more effectively achieved. It can be shortened.

  A sixth printer according to the present invention is a printer that reads a plurality of image data in which data is arranged for each row having a height of a predetermined number of pixels, and prints the images in the carriage drive direction. A buffer memory having a predetermined size, an acquisition means for acquiring the number of lines of image data, and at least the same number of image data as the total number of lines based on the number of lines of image data acquired by the acquisition means in the buffer memory Including forming means for forming a buffer, request means for requesting data corresponding to the print area in accordance with the printing order of the images, and data relating to the request if the requested data is not in a plurality of image data buffers Reads the data for the size of the image data buffer and stores it in multiple image data buffers according to the pre-read first-out rule. Those having means, and output means for outputting the data related to the request to the requesting means.

  If this configuration is adopted, since the number of image data buffers equal to or larger than the total number of image lines in a plurality of image data printed side by side in the carriage driving direction is used, a plurality of image data buffers to be used are used. It is possible to expect an optimal printing time reduction effect according to the image data.

  In the printer according to any one of the above-described inventions according to the present invention, in addition to the configuration of each of the above-described inventions, the reading unit may store data corresponding to the size of the image data buffer so that the requested data comes first. Is to read.

  If this configuration is adopted, more data to be used in subsequent printing is prefetched in the image data buffer. As a result, for example, the image data is divided according to the size of the image data buffer, and the number of times of reading the image data is reduced and the printing time is more effectively shortened than when the image data is read for each divided unit. be able to.

  In the printer according to any one of the above aspects of the present invention, in addition to the configuration of each of the above aspects, the image data is encoded image data, and the requesting unit encodes the encoded image data. The number of image data buffers or the upper limit value thereof is determined based on the number of pixels on one side that can be decoded by the decoder.

  By adopting this configuration, when decoding the encoded image data, it is possible to secure the number of image data buffers corresponding to the decoding.

  In the printer according to any one of the above aspects of the present invention, in addition to the configuration of each of the above aspects, the image data is encoded image data, and the requesting unit encodes the encoded image data. The number of image data buffers or the upper limit value thereof is determined based on the number of pixels on one side decodable by the decoder and the aspect ratio of the image of the image data.

  By adopting this configuration, when decoding the encoded image data, it is possible to secure the number of image data buffers corresponding to the decoding.

  In the printer according to any one of the above-described inventions according to the present invention, in addition to the configuration of each of the inventions described above, the forming unit continuously arranges the image direction and the image data corresponding to the carriage driving direction at the time of printing. It operates only when the direction of the row of the image to be shifted is shifted by 90 degrees or 270 degrees.

  An image printing system according to the present invention includes an image supply device having a semiconductor memory and first communication means, and a printer according to any one of the above-described inventions having second communication means for communicating with the first communication means. The semiconductor memory stores the image data, and the reading means of the printer reads the image data from the semiconductor memory via the first and second communication means.

  If this configuration is adopted, the image data related to printing transmitted from the first communication means of the image supply device to the second communication means of the printer is the number of lines of the image data related to the printing or a plurality of image data. It is stored in a plurality of image data buffers corresponding to the total number of rows. As a result, if this configuration is adopted, image data having a data amount larger than the memory size or images based on a plurality of image data whose total data amount is larger than the memory size may be rotated and printed. However, the printing time can be effectively shortened.

  A printing method according to the present invention is a printing method for reading image data in which data is arranged for each row having a height corresponding to a predetermined number of pixels, and printing the image, in accordance with the printing order of the images. If the data corresponding to the request is not in a plurality of image data buffers, data corresponding to the size of the image data buffer including the data related to the request is read and the image data in the image data is read. The image data buffer includes at least the same number of lines as the number of lines in accordance with the pre-read first-out rule, and the step of outputting the data related to the request to the request source.

  In this method, image data related to printing is stored in a plurality of image data buffers having the same number as or more than the number of lines of the image, and in response to a data request, data is received from the plurality of image data buffers. Is output. Therefore, if this configuration is adopted, even when an image based on image data having a data amount larger than the size of a plurality of image data buffers is rotated and printed, the printing time can be effectively shortened. .

  Another printing method according to the present invention is a printing method that reads a plurality of image data in which data is arranged for each row having a height corresponding to a predetermined number of pixels, and prints the images side by side in the carriage driving direction. In accordance with the print order of the images, the step of requesting data corresponding to the print area, and if the data related to the request is not in a plurality of image data buffers, the size of the image data buffer including the data related to the request A step of reading the data and storing the data according to a pre-read first-out rule in at least the same number of image data buffers as the total number of image lines in the plurality of image data, and outputting the data related to the request to the request source , Has.

  In this method, a plurality of image data relating to printing is stored in a plurality of image data buffers having the same number as the total number of lines of the plurality of images or more than the total number of lines. Data is output from a plurality of image data buffers. Therefore, by adopting this configuration, even when an image based on a plurality of image data having a total data amount larger than the size of the plurality of image data buffers is rotated and printed, the printing time is effectively shortened. be able to.

  Hereinafter, a printer, an image printing system, and a printing method according to embodiments of the present invention will be described with reference to the drawings. The image printing system will be described by taking a direct printing system as an example. The printing method will be described as a part of the operation of the printer.

Embodiment 1 FIG.
FIG. 1 is a diagram showing a direct printing system according to Embodiment 1 of the present invention. The direct printing system includes a digital still camera (DSC: Digital Still Camera) 1 as an image supply device and a printer 2. The DSC 1 and the printer 2 are connected by a USB cable 3.

  FIG. 2 is a block diagram showing a hardware configuration of the DSC 1 in FIG. The DSC 1 includes a central processing unit (CPU) 11 that executes a program, a flash memory 12 that stores the program, an I / O (Input / Output) port 13, and a system bus 14 that connects these. Have.

  In the I / O port 13 of the DSC 1, a CCD (Charge Coupled Device) 15 as an imaging device, a card reader 16 as an external memory connection device, a liquid crystal monitor 17 as a display device, and an input device 18 as an input device. Are connected to a USB communication I / F (interface) 19 as a first communication means.

  The CCD 15 has a light receiving part. The light receiving unit has a plurality of light receiving elements. The plurality of light receiving elements are arranged in the light receiving portion side by side in the vertical direction and the horizontal direction so that the whole is substantially rectangular. Each light receiving element outputs a level signal corresponding to the amount of received light. The CCD 15 generates the same number of pixel data as the light receiving elements based on the level signals output from the plurality of light receiving elements. Further, the CCD 15 outputs the generated plurality of pixel data as one image data.

  The card reader 16 has an insertion part. A semiconductor memory 20 formed in a card shape can be inserted into the insertion portion. Examples of the semiconductor memory 20 formed in a card shape include a flash memory. Then, the card reader 16 writes data to the semiconductor memory 20 inserted in the insertion unit, and reads data from the semiconductor memory 20 inserted in the insertion unit.

  The liquid crystal monitor 17 has a display unit. The liquid crystal monitor 17 displays an image based on the display data on the display unit based on the display data.

  The input device 18 has a plurality of input keys and a touch panel. The input device 18 outputs input data corresponding to the input key pushed by the user. The input device 18 outputs input data corresponding to the position pressed by the user of the touch panel.

  The USB communication I / F 19 has a USB connector. A USB cable 3 is connected to the USB connector. When a signal is input from the USB connector, the USB communication I / F 19 extracts data from the signal. The USB communication I / F 19 generates a signal based on the data to be transmitted, and outputs this signal to the USB connector.

  FIG. 3 is a diagram showing the stored contents of the flash memory 12 in FIG. The flash memory 12 of the DSC 1 stores an EXIF (Exchangeable Image File Format) image data generation program 21, a print instruction data generation program 22, an image data transmission program 23, and a communication control program group. The DSC 1 communication control program group includes a USB mass storage class program 24.

  The EXIF image data generation program 21 is executed by the central processing unit 11 to realize an EXIF image data generation unit. The EXIF image data generation unit generates image data in JPEG (Joint Photographic Coding Experts Group) format by compressing the image data output from the CCD 15, and EXIF image data obtained by adding an EXIF header or thumbnail image data to the image data. And outputs this EXIF image data to the card reader 16. The EXIF header can include the number of pixels in the vertical direction and the number of pixels in the horizontal direction, shooting conditions, and the like.

  The print instruction data generation program 22 is executed by the central processing unit 11 to realize a print instruction data generation unit. The print instruction data generation unit displays an image selection screen and a print condition selection screen on the liquid crystal monitor 17. The print instruction data generation unit generates print instruction data. The print instruction data includes a print instruction for printing the image selected based on the image selection screen under the print conditions selected based on the print condition selection screen.

  The image data transmission program 23 is executed by the central processing unit 11 to realize an image data transmission unit as a transmission unit. When a file of image data to be transmitted and a data position extracted from the file are designated, the image data transmission unit extracts data at the data position of the file. Further, the image data transmission unit outputs the extracted data.

  The image data file has a certain amount of data. The data position of this file is a value indicating the order of certain bits when counted from the first bit of this image file. For example, when 10 kbytes are designated as the data position, the image data transmitting unit extracts data having a predetermined length of 10 kbytes from the first bit of the file.

  The USB mass storage class program 24 is executed by the central processing unit 11 to realize a USB mass storage class. In the USB mass storage class, data can be bulk transferred between a host and a device. In the present embodiment, a SCSI subclass is used as the subclass.

  FIG. 4 is a block diagram showing functions realized at the time of imaging in the DSC 1 of FIG. As shown in FIG. 4, the EXIF image data generation unit 31 is realized in the DSC 1 at the time of imaging.

  The CCD 15 outputs imaging data to the EXIF image data generation unit 31. The EXIF image data generation unit 31 compresses the imaged data using the JPEG method to generate EXIF image data. The card reader 16 assigns a predetermined file name to the EXIF image data and writes the EXIF image data into the semiconductor memory 20. The card reader 16 adds different file names to the plurality of EXIF image files 32 so that the files 32 of the plurality of EXIF image data in the semiconductor memory 20 can be distinguished from each other.

  FIG. 5 is an explanatory diagram of compression processing by the EXIF image data generation unit 31 in FIG. FIG. 5A is a diagram illustrating an arrangement of a plurality of pixels in an image. As shown in FIG. 5A, the image of the imaged data output from the CCD 15 will be described as constituting a horizontally-long rectangular image having a larger number of pixels in the horizontal direction than the number of pixels in the vertical direction.

  When such imaging data is input, the EXIF image data generation unit 31 calculates 8 × 8 pixels as one block and calculates a spatial frequency for each block, as shown in FIG. 5B. Note that the number of pixels per block is not limited to 8 × 8, and may be 16 × 16, for example.

  Further, as shown in FIG. 5B, the EXIF image data generation unit 31 sequentially starts from the row of the upper block in the drawing along the long side of the horizontally long image, and in the same block row. The spatial frequency of the block is calculated in order from the left block. FIG. 5B is a diagram showing the arrangement of blocks on the image.

  Then, as shown in FIG. 5B, when the spatial frequency is calculated for all the blocks of m rows and n columns (m and n are integers of 1 or more), the EXIF image data generation unit 31 calculates the total spatial frequency data. The spatial frequency data is thinned out so that the amount is equal to or less than the predetermined data amount. The EXIF image data generation unit 31 repeats this data thinning process until the total amount of data in JPEG format is equal to or less than a predetermined amount. Through the above encoding process, the EXIF image data generation unit 31 generates JPEG data having a data amount equal to or less than a predetermined data amount. Note that the data amount of a plurality of blocks in JPEG format data is not uniform.

  FIG. 5C is a diagram showing the data arrangement of each block on the EXIF image data. EXIF header data is stored at the beginning of the EXIF image data. After the EXIF header, a plurality of blocks of data are stored in the encoding order. That is, the data of the upper left block (1) of the image follows the EXIF header. The data of the block (1) at the upper left of the image is followed by the data of the block (2) right next to the block. Following the data in the rightmost block (n) in the top block row of the image, the data in the leftmost block (n + 1) in the second block row from the top of the image follows. At the end of the plurality of block data, the data of the lower right block (m × n) of the image comes. After the plurality of blocks, EOF (End Of File) data indicating the end of data of the file is stored.

  When the imaging data is compressed in the JPEG format and the compressed image data is stored in the semiconductor memory 20, the number of image lines in the image is the number of block lines.

  FIG. 6 is a block diagram showing a hardware configuration of the printer 2 in FIG. The printer 2 includes a central processing unit 41, a memory 42 used when the central processing unit 41 executes a program, a storage unit 43 that stores the program, an I / O port 44, and a system bus 45 that connects them. And have.

  A USB communication I / F 46 as a second communication unit and a printing device 47 are connected to the I / O port 44 of the printer 2. The USB communication I / F 46 of the printer 2 has the same function as that of the USB communication I / F 19 of the DSC 1, and the description thereof is omitted. However, the USB communication I / F 46 of the printer 2 functions as a USB host, and the USB communication I / F 19 of the DSC 1 functions as a USB device.

  FIG. 7 is a transparent perspective view showing the internal mechanism of the printer 2 in FIG. The printing device 47 includes a paper feed tray 51, a paper feed roller 52, a transport roller pair 53, a paper discharge tray 54, a carriage 55, and a carriage holding member 56. The paper feed roller 52, the conveyance roller pair 53, the carriage holding member 56, and the carriage 55 are disposed inside the housing 57 of the printer 2.

  The paper 58 is placed on the paper feed tray 51. The paper feed roller 52 nips the paper 58 on the paper feed tray 51 and sends the top paper 58 in the paper feed tray 51 toward the paper discharge tray 54. The conveyance roller pair 53 further feeds the paper 58 sent out from the paper feed tray 51 in the direction of the paper discharge tray 54. As a result, the sheets 58 placed on the sheet feed tray 51 are conveyed one by one from the sheet feed tray 51 to the sheet discharge tray 54 and are discharged to the sheet discharge tray 54.

  The carriage holding member 56 is formed in a long bar shape. The carriage holding member 56 is positioned so that its longitudinal direction is substantially parallel to the extending direction of the conveyance roller pair 53 above the conveyance path of the paper 58 between the conveyance roller pair 53 and the paper discharge tray 54. Arranged. The carriage 55 is movably attached to the carriage holding member 56. As a result, the carriage 55 can move in the extending direction of the conveyance roller pair 53.

  The carriage 55 has an ink tank and a plurality of nozzles. The nozzle discharges ink in the ink tank. The plurality of nozzles are formed side by side along a direction perpendicular to the moving direction of the carriage 55. The plurality of nozzles may be arranged in a plurality of rows.

  The printing device 47 having such a configuration rotates the conveyance roller pair 53 based on the print control data, and conveys the paper 58 to a position (printing position) facing the carriage 55. Further, the printing device 47 ejects ink from predetermined nozzles while moving the carriage 55 based on the printing control data. When ink for one printing line is ejected onto the carriage 55, the printing device 47 rotates the pair of conveying rollers 53 to feed the paper 58 for the printing line. Further, the printing device 47 ejects ink from a predetermined nozzle while moving the carriage 55 based on the next printing control data. In this way, by alternately repeating the ink ejection control from the carriage 55 for each print line and the paper 58 feed for each print line, the printing device 47 can print an image based on the print control data on the surface of the paper 58. Form.

  When the ink ejection onto the paper 58 is completed, the printing device 47 rotates the transport roller pair 53 and discharges the paper 58 from the printing position to the paper discharge tray 54. As a result, the paper 58 on which an image based on the print control data is formed is discharged to the paper discharge tray 54.

  FIG. 8 is a diagram showing the stored contents of the storage unit 43 in FIG. The storage unit 43 of the printer 2 stores a print instruction data interpretation program 61, a cache system program 62, a decoder program 63, a print control data generation program 64, and a communication control program group. The communication control program group of the printer 2 has a USB mass storage class program 65. FIG. 9 is a block diagram showing functions implemented in the direct printing system of FIG. By executing the various programs shown in FIG. 8, various functions on the printer 2 side in FIG. 9 are realized.

  The USB mass storage class program 65 is executed by the central processing unit 41 to realize the USB mass storage class 95. In the first embodiment, a SCSI subclass is used as a subclass.

  The print instruction data interpretation program 61 is executed by the central processing unit 41 to realize the print instruction data interpretation unit 91. The print instruction data interpretation unit 91 interprets the print instruction data, and causes the printer 2 to execute the printing process designated by the print instruction data.

  The cache system program 62 is executed by the central processing unit 41 to realize a cache system 92 as a reading unit and an output unit. The cache system 92 generates a cache memory 71 in the memory 42. The cache memory 71 has a predetermined number of cache buffers 72 as a predetermined number of image data buffers. Each cache buffer 72 is associated with information indicating the range of the file name (file ID) and data position of the stored data, and information on the cached order (for example, time).

  FIG. 10 is a diagram showing a configuration of the cache memory 71 generated in the memory 42 in FIG. The cache memory 71 in FIG. 10 has P cache buffers 72. Each cache buffer 72 is generated as an area for storing data corresponding to the size.

  Note that the number P of the cache buffers 72 is a predetermined large value corresponding to the upper limit value of the printable image data size. For example, in the case of image data in EXIF (JPEG) format in which the number of vertical and horizontal pixels of a block is h, the number of pixels that can be decoded by the decoder 93 (the number of pixels on one side of the image) is α, and the aspect ratio of the image is 3: 4. Then, P is an integer obtained by rounding up the decimal point of the value (α × 3/4) / h (= α / h × 3/4). Alternatively, assuming the case of 4up, for example, in the case of EXIF (JPEG) format image data in which the number of vertical and horizontal pixels of the block is h, the number of pixels that can be decoded by the decoder 93 (the number of pixels on one side of the image) is α. When the aspect ratio of the image is 3: 4, P is an integer obtained by rounding up the value (α × 3/4) / h × 2 (= α / h × 3/2) after the decimal point.

  In addition, when there is a data output request from the decoder 93, the cache system 92 first checks whether or not the data related to the acquisition request is stored in the cache memory 71. When data related to the acquisition request is stored in the cache memory 71, the cache system 92 reads the data from the cache memory 71 and outputs the data.

  When the data related to the acquisition request is not stored in the cache memory 71, the cache system 92 transmits the number of bytes equal to the size of one cache buffer 72 so that the data related to the acquisition request is at the head. Generate a request. In this transmission request, the file name (or file ID) of the data to be cached is also specified.

  When the cache system 92 receives the requested data, the cache system 92 selects a free cache buffer 72 and stores the received data in the selected cache buffer 72. If there is no free cache buffer 72, the cache system 92 selects the cache buffer 72 cached earliest and stores the received data in the selected cache buffer 72. The cache memory 71 is updated by a FIFO (First In First Out) method. In addition, the cache system 92 acquires data related to the output request from the cache buffer 72 storing the new data or from the USB host 95 and outputs the data to the decoder 93.

  The decoder program 63 shown in FIG. 8 is executed by the central processing unit 41, thereby realizing a decoder 93 as a request unit that requests data according to the printing order of images. The decoder 93 decodes the EXIF image data and generates raw (RAW) image data. In the image data after decoding, the data of each pixel is divided into data independent from each other as data. Examples of the image data in which the data is divided for each pixel include bitmap image data and TIFF (Tagged Image File Format) image data.

  The print control data generation program 64 is executed by the central processing unit 41 to realize the print control data generation unit 94. The print control data generation unit 94 generates print control data for controlling the carriage 55 and the conveyance roller pair 53 of the print device 47 based on the image data in which the data is divided for each pixel and the print layout information. .

  Next, the operation of the direct printing system having the above configuration will be described.

  The USB communication I / F 19 of the DSC 1 and the USB communication I / F 46 of the printer 2 are connected by the USB cable 3. In DSC 1, a print instruction data generation unit 81, an image data transmission unit 82, and a USB mass storage class 83 are realized. In the printer 2, a print instruction data interpretation unit 91, a cache system 92, a decoder 93, a print control data generation unit 94, and a USB mass storage class 95 are realized. The cache system 92 generates a cache memory 71.

  The USB communication I / F 46 of the printer 2 transmits a USB descriptor transmission request to the USB communication I / F 19 of the DSC 1.

  The USB communication I / F 19 outputs the descriptor of DSC 1 in response to the descriptor transmission request. The descriptor of DSC 1 is transmitted to the USB communication I / F 46 of the printer 2. The USB communication I / F 46 of the printer 2 generates a communication buffer called an end point based on the received descriptor of the DSC 1. This endpoint includes what the USB mass storage classes 83 and 95 use to bulk transfer data. Thus, the USB configuration process is completed.

  First, the print instruction data generation unit 81 reads the file name list of the EXIF image file 32 stored in the semiconductor memory 20 from the semiconductor memory 20, and selects the EXIF image file 32 to which the file name list is assigned. Are displayed on the liquid crystal monitor 17. Thereby, the selection screen of the selection screen of the EXIF image file 32 is displayed on the liquid crystal monitor 17. Note that the print instruction data generation unit 81 may read a thumbnail image instead of a file name, and cause the liquid crystal monitor 17 to display an image selection screen of the EXIF image file 32 to which the thumbnail image is assigned.

  The user operates the input key or the touch panel to select a file name from the list of file names displayed on the liquid crystal monitor 17. In response to this selection operation, the input device 18 generates input data. The print instruction data generation unit 81 selects a file name based on the input data. When the user performs an operation of selecting a plurality of file names, the print instruction data generation unit 81 selects the plurality of file names.

  After selecting an image, the print instruction data generation unit 81 causes the liquid crystal monitor 17 to display a print condition selection screen. The input device 18 generates input data in response to a user operation. Based on this input data, the print instruction data generation unit 81 selects a print condition. The printing conditions include, for example, the print quality of the image (high quality, standard, etc.), the type of paper 58 (A4, B5, L size, etc.), the layout of the image printed on one paper 58 (1up, 2up, etc.). 4 up).

  When the image and the printing conditions are selected, the print instruction data generation unit 81 generates print instruction data.

  After generating the print instruction data, the print instruction data generation unit 81 transmits the generated print instruction data to the printer 2 by the USB mass storage class 83.

  When receiving the print instruction data, the USB mass storage class 95 of the printer 2 outputs the print instruction data to the print instruction data interpretation unit 91. Note that this print instruction data may be transmitted using a method similar to that disclosed in Japanese Patent Laid-Open No. 2003-256154, for example.

  FIG. 11 is a flowchart showing the operation of the print instruction data interpretation unit 91 in FIG.

  When the print instruction data is input, the print instruction data interpretation unit 91 starts control of the print process designated by the print instruction data (step S1). Specifically, the print instruction data interpretation unit 91 first extracts a file name (or file ID) from the print instruction data, and generates acquisition request data for image size information of the file such as the file name.

  This image size information acquisition request data is transferred from the SCSI host 97 to the USB mass storage class 95 of the printer 2 and transferred to the USB mass storage class 83 of the DSC 1 by the USB mass storage class 95 of the printer 2. The USB mass storage class 83 of the DSC 1 outputs this image size information acquisition request data to the image data transmission unit 82.

  When receiving the image size information acquisition request data, the image data transmission unit 82 extracts a file name included in the acquisition request data. Further, the image data transmission unit 82 reads the number of pixels in the vertical direction and the number of pixels in the horizontal direction from the EXIF header of the file 32 of the file name, and the number of pixels in the vertical direction and the number of pixels in the horizontal direction of the image. The information of is output.

  Information on the number of pixels in the vertical direction and the number of pixels in the horizontal direction of the image is transmitted to the printer 2 by the USB mass storage class 83 of the DSC 1 and is input to the print instruction data interpretation unit 91 by the USB mass storage class 95 of the printer 2. The

  When information on the number of pixels in the vertical direction and the number of pixels in the horizontal direction of the image is input, the print instruction data interpretation unit 91, based on the layout information included in the print instruction data and the number of pixels in the vertical and horizontal directions, It is determined whether the image needs to be rotated (step S2).

  When information on the number of pixels in the vertical direction and the number of pixels in the horizontal direction is input, the print instruction data interpretation unit 91, based on the layout information included in the print instruction data and the number of pixels in the vertical and horizontal directions, It is determined whether the image is rotated and printed (step S2).

  For example, when the carriage scanning direction is parallel to the short side of the paper 58 and the print layout is 1 up or 4 up, the print instruction data interpretation unit 91 is used when the number of pixels in the vertical direction of the image is smaller than the number of pixels in the horizontal direction. Is determined to rotate the image, and when the number of pixels in the vertical direction of the image is equal to or greater than the number of pixels in the horizontal direction, the print instruction data interpretation unit 91 determines not to rotate the image.

  Further, for example, when the carriage scanning direction is parallel to the short side of the paper 58 and the print layout is 2 up or 8 up, the print instruction data is obtained when the number of pixels in the vertical direction of the image is equal to or less than the number of pixels in the horizontal direction. The interpretation unit 91 determines that the image is not rotated, and when the number of pixels in the vertical direction of the image is larger than the number of pixels in the horizontal direction, the print instruction data interpretation unit 91 determines to rotate the image.

  FIG. 12 is a diagram for explaining the number of pixels of an image. As shown in FIG. 12A, the number of horizontal pixels of an image is the number of pixels on one side (that is, a block row) along the encoding direction, and the number of vertical pixels of the image is one side (vertical to the encoding direction ( That is, the number of pixels in the block row).

  When it is determined that the image is to be rotated, as shown in FIG. 12B, the direction on the image 201 corresponding to the scanning direction of the carriage (that is, the line direction to be printed at one time) and the encoding direction of the image data. Are vertical.

  If it is determined that it is not necessary to rotate the image, the print instruction data interpretation unit 91 designates a file name and outputs an instruction to decode the EXIF image data included in the file 32 of the file name to the decoder 93 ( Step S3). That is, the print instruction data interpretation unit 91 outputs an instruction to perform decoding processing to the decoder 93 without rotating the image.

  If it is determined that the image needs to be rotated, the print instruction data interpretation unit 91 designates the file name (or file ID), and the EXIF image data image included in the file 32 such as the file name. An instruction to decode while rotating is output to the decoder 93 (step S4).

  FIG. 13 is a flowchart showing the operation of the decoder 93 in FIG. FIG. 14 is a flowchart showing the operation of the cache system 92 in FIG.

  First, the decoder 93 determines whether or not an instruction to rotate the image is included in the decode instruction from the print instruction data interpretation unit 91 (step S11).

  If the instruction to rotate the image is not included, the decoder 93 starts reading the EXIF image data (step S12). Specifically, the decoder 93 designates a file name and outputs an instruction to output data for one word from the head of the file to the cache system 92.

  When an instruction to output data for one word from the head of the file is input, the cache system 92 determines whether or not the data for one word related to the instruction is stored in the cache memory 71 (step). S31). When the EXIF image file 32 having the designated file name is read for the first time, the data of the file is not read into the cache memory 71. Therefore, the cache system 92 determines that the data for one word related to the instruction is not stored in the cache memory 71.

  When the data for one word related to the instruction is not stored in the cache memory 71, the cache system 92 generates a data transmission request (step S32). This data transmission request includes the file name associated with the request and the range of the data position of the data to be read (for example, a combination of the data position of the first byte and the data position of the last byte of the range of the read data position) It is. In the first data transmission request, the first byte of the file is designated as the first byte of the data to be read, and the byte corresponding to the size of the cache buffer 72 is designated as the last byte.

  After the data transmission request is output from the cache system 92, the USB mass storage class 95 of the printer 2, the USB communication I / F 46 of the printer 2, the USB communication I / F 19 of DSC1, and the USB mass storage class 83 of DSC1 are output. To the image data transmitting unit 82.

  When a data transmission request is input, the image data transmission unit 82 reads data relating to the request from the semiconductor memory 20. Based on the request for the first data, the image data transmission unit 82 reads data from the first byte of the EXIF image file 32 having the designated file name to a byte corresponding to the size of the cache buffer 72.

  After the data read into the image data transmission unit 82 is output from the image data transmission unit 82, the USB mass storage class 83 of DSC 1, the USB communication I / F 19 of DSC 1, the USB communication I / F 46 of printer 2, and the printer 2 Is sent to the cache system 92 via the USB mass storage class 95.

  When the requested data is input, the cache system 92 writes the data in the free cache buffer 72 (step S33). The cache system 92 also stores information indicating the file name of the data stored in the cache buffer 72 and the range of the stored data position, and cache time information. If there is no free cache buffer 72, the cache system 92 selects the cache buffer 72 that cached the data earliest and overwrites the received data in the selected cache buffer 72.

  Then, the cache system 92 outputs the data to the decoder 93 (step S34).

  When the data for one word requested to the cache system 92 is input from the cache system 92, as shown in FIG. 13, the decoder 93 completes the reading of all the data for one block by the input of the data. It is determined whether or not it has been done (step S13). The decoder 93 then repeatedly outputs an output request for the next one word of data to the cache system 92 until all the data for one JPEG encoded block has been read.

  Each time a data output request for one word is input from the decoder 93, the cache system 92 compares information indicating the data range of the cache buffer 72 with the position of the requested data, and relates to the request. It is determined whether or not the data is in the cache memory 71 (step S31). Further, when there is data in the cache memory 71, the cache system 92 reads and outputs the data from the cache memory 71 (step S34), and when there is no data in the cache memory 71, new data is received from the DSC 1. Acquired (steps S32 and S33), and outputs data related to the request (step S34).

  When the reading of all the data for one block is completed, the decoder 93 performs a decoding process for the block (step S14). The decoder 93 outputs the decoded pixel data for each pixel to the print control data generation unit 94. Note that the decoding process may be performed collectively for a predetermined number of blocks instead of for each block.

  When the decoding process is completed, the decoder 93 determines whether all the EXIF image data of the file designated by the print instruction data interpretation unit 91 has been read (step S15). When the decoder 93 has read all the EXIF image data of the designated file, the decoder 93 ends the decoding process.

  Whether or not all the EXIF image data of the file has been read may be determined based on whether or not the EOF data added at the end of the file has been read.

  If reading of all the EXIF image data of the designated file has not been completed, the decoder 93 resumes the data reading process for each word from the first bit of the next block (step S16).

  When determining that all the data for one block has been read, the decoder 93 determines the byte next to the last byte of the last read data as the first byte of the next block.

  Through the above processing, all the EXIF image data of the file designated by the print instruction data interpretation unit 91 to the decoder 93 is converted into pixel data for each pixel and output to the print control data generation unit 94.

  The print control data generation unit 94 holds pixel data input for each block. Then, when the pixel data for at least one print line (that is, at least one carriage scan) has been prepared, the print control data generation unit 94 generates print control data based on the pixel data for the one print line. The printing device 47 performs printing processing for at least one line on the paper 58 using the print control data.

  The print control data generation unit 94 repeats the print control data generation process based on the pixel data for one print line for all pixel data. As a result, an image based on the EXIF image data of the file designated by the print instruction data interpretation unit 91 in the decoder 93 is formed on the paper 58 discharged to the paper discharge tray 54 with a predetermined layout. Further, the image is formed in a posture in which the longitudinal direction of the image is the paper feeding direction of the paper 58.

  By the way, when the data reading in units of words by the decoder 93 advances and the data requested by the decoder 93 is no longer in the cache buffer 72, the cache system 92 newly acquires data for one cache buffer 72 from the DSC1. To do. Further, the cache system 92 stores the data newly acquired from the DSC 1 in the free cache buffer 72 or in the cache buffer 72 having the oldest update time when there is no free cache buffer 72. Further, the cache system 92 reads out the data requested by the decoder 93 from the newly acquired data and outputs the data to the decoder 93.

  As described above, the data cached in the cache memory 71 is updated as the data reading in units of words by the decoder 93 proceeds. Further, the data cached first is erased by the data cached later.

  FIG. 15 is a diagram illustrating an example of a state change of the cache memory 71 when the image is not rotated. FIG. 15A shows the data structure of EXIF image data read into the cache memory 71. FIG. 15B is a diagram showing an example of the storage state of the cache memory 71 immediately after starting decoding in the case of decoding without rotating the image. FIG. 15C is a diagram illustrating an example of a storage state of the cache memory 71 when decoding is completed in the case where decoding is performed without rotating an image.

  When decoding without rotating the image, the EXIF image data is sequentially read from the top of the cache memory 71 as illustrated in FIG. When there is no more free cache buffer 72, the cache buffer 72 that stores old data is overwritten with newly read data in order.

  Therefore, when printing the EXIF image data without rotating it, the cache system 92 caches the EXIF image data in order from the top in increments of the size of the cache buffer 72. Each byte of the EXIF image data is read into the cache memory 71 once.

  Returning to FIG. 13 and FIG. 14, when the instruction to rotate the image is included in the decode instruction from the print instruction data interpretation unit 91, the decoder 93 prescans the EXIF image data instructed to be decoded. Start (step S17).

  In the pre-scan, the decoder 93 designates a file name, outputs a data reading instruction in units of one word to the cache system 92, and reads EXIF image data in order from the top to the end. When the data requested from the decoder 93 is in the cache memory 71, the cache system 92 reads the data from the cache memory 71 and outputs the data to the decoder 93 (step S34), and the data requested from the decoder 93 is cached. If it is not in the memory 71, the data including the data is read from the DSC 1 into the cache buffer 72 (steps S32 and S33), and the one-word data is output to the decoder 93 (step S34).

  When data of one word is input from the cache system 92, the decoder 93 determines whether or not the data is the first byte of the block line. The first byte of the block row is the first byte of the block located at the left end of the block row in the image.

  When the data input from the cache system 92 is the first byte of the block row, the decoder 93 reads the data position of the first byte in the EXIF image data, that is, how many bytes from the first bit of the EXIF image data. It memorizes whether it is data.

  The decoder 93 repeats data acquisition in word units until the end of the EXIF image data. After repeating the data acquisition in units of words until the end of the EXIF image data, the decoder 93 stores the data positions of the first bytes of all the block rows of the image included in the EXIF image data. The data position of the first byte of each block row is stored in each pointer buffer.

  When the above prescan process is completed, the decoder 93 starts reading for decoding the EXIF image data (step S18). First, the decoder 93 starts reading data in units of words from the first byte of the uppermost block row of the image (that is, one block closest to the beginning of the image data). The cache system 92 outputs the data requested by the decoder 93 to the decoder 93 while caching the data as necessary. In the present embodiment, the top of the image refers to the image portion of the first portion of the image data, and the left of the image refers to the side on which the image of the first block of the image data is placed.

  Further, the decoder 93 determines whether or not reading of all data for one block is completed (step S19), and repeats reading of data in units of words until it is completed.

  When all the data for one block has been read, the decoder 93 stores the data position of the next byte of the data. The decoder 93 overwrites the pointer buffer of this block row with this new data position for this block row (step S20).

  After updating the data position to be stored in the pointer buffer, the decoder 93 decodes the read block (step S21). Further, the decoder 93 outputs pixel data for each pixel generated by the decoding process to the print control data generation unit 94. Note that the decoder 93 may decode a plurality of blocks collectively.

  When the decoding process is completed, the decoder 93 determines whether all the EXIF image data of the file 32 designated by the print instruction data interpretation unit 91 has been decoded (step S22). When the decoder 93 has decoded all the EXIF image data of the designated file, the decoder 93 ends the decoding process.

  If reading of all the EXIF image data of the specified file has not been completed, the decoder 93 further includes one block row of images (ie, one block row necessary for printing by at least one carriage scan). It is determined whether or not the reading of the minute data has been completed (step S23).

  When the decoding process of the upper left block of the image is completed, the EXIF image data is not read for decoding, and the data reading for one block row of the image is not completed. Therefore, the decoder 93 starts the decoding process for the next block row (step S24).

  Specifically, the decoder 93 reads the data position from the pointer buffer corresponding to the second block line from the top of the image, and starts reading data in word units from this data position. Then, after reading the data for one block (step S19), the decoder 93 sets the value of the pointer buffer in the second block line from the top of the image to the data of the data next to the last data in the block. The position is updated (step S20), and the block is decoded (step S21).

  The decoder 93 repeats the decoding process for each block row (steps S19 to S24). When the decoding process is completed for all the blocks in the leftmost block row of the image, the decoder 93 performs the decoding process for the top block row of the image (step S25). At this time, the pointer buffer corresponding to the top block row of the image stores the data position of the byte next to the last byte of the leftmost block of the image. Therefore, the decoder 93 performs the decoding process for the second block from the left of the uppermost block row of the image.

  As described above, the decoder 93 is provided with a pointer buffer for storing the first bit of the block for each block row of the image. When the data of each block is read, the data position stored in the pointer buffer is sequentially updated, Repeat the decoding process for the block rows in order. As a result, the decoder 93 performs the decoding process in order from the block sequence on the left side of the image (that is, the block sequence corresponding to the image to be printed first) to the block sequence on the right side.

  The print control data generation unit 94 holds pixel data input for each block. Then, when the pixel data for at least one print line (that is, at least one carriage scan) has been prepared, the print control data generation unit 94 generates print control data based on the pixel data for the one print line. The printing device 47 performs printing processing for at least one line on the paper 58 using the print control data.

  Further, the print control data generation unit 94 repeatedly performs the generation process of the print control data based on the pixel data for at least one print line for all the pixel data. As a result, an image based on the EXIF image data of the file designated by the print instruction data interpretation unit 91 in the decoder 93 is formed on the paper 58 discharged to the paper discharge tray 54 with a predetermined layout. Further, the image is formed in a posture in which the longitudinal direction of the image is the feeding direction of the paper 58, that is, rotated by 90 degrees or 270 degrees.

  By the way, even when the image is rotated and printed in this way, when the data reading in units of words by the decoder 93 proceeds and the cache buffer 72 has no data requested by the decoder 93, the cache system 92 Acquires new data for the size of the cache buffer 72 from the DSC 1. Further, the cache system 92 stores the data newly acquired from the DSC 1 in the free cache buffer 72 or in the cache buffer 72 having the oldest update time when there is no free cache buffer 72.

  FIG. 16 is a diagram illustrating an example of a state change of the cache memory 71 when an image is rotated. FIG. 16A shows the data structure of EXIF image data read into the cache memory 71. FIG. 16B is a diagram illustrating an example of a storage state of the cache memory 71 at the time when the decoding process for one column is completed when the image is rotated and decoded. FIG. 16C is a diagram illustrating an example of the storage state of the cache memory 71 at the time when the decoding process for two columns of blocks is completed when the image is rotated and decoded.

  Note that the cache system 92 includes P number of cache buffers 72 that are greater than or equal to the number m of block lines of an image. In general, the size of the cache buffer 72 is larger than the data amount of one block. Incidentally, in JPEG image data, the data amount of a block for one column is generally several tens of bytes, or several kilobytes at most.

  Therefore, when decoding the image by rotating it, the decoding of the block for the leftmost column of the image (the block column corresponding to the first image to be printed) is completed as shown in FIG. 16B. Thus, the data of all the blocks in the block column at the left end of the image are cached in the plurality of cache buffers 72 of the cache memory 71. In addition, the data of the block in the second column from the left of the cached image together with the data of the block for the leftmost column of the image remains in the cache memory 71 without being erased. Therefore, in this case, even if the cache system 92 does not cache data from the DSC 1, the decoder 93 can decode the blocks in the second column from the left.

  If the cache memory 71 does not have the data requested from the decoder 93 in the cache memory 71, the cache system 92 stores data having a data amount corresponding to the size of the cache buffer 72 starting from the data, Read from the DSC 1 to the cache buffer 72. In other words, as illustrated in FIG. 16C, when the second block from the left on the top of the image is decoded, the cache system 92 does not cache the data in the block. Only new data is cached. In this cache, the data of the third and subsequent blocks from the left are also cached together.

  In an ideal case where the amount of data in each block in the block column is uniform, the data stored in the cache buffer 72 as many as the number of block rows is cached in order at the same time. Subsequent data will be cached in. In this ideal state, each data is cached in only once, and when the data is read into the decoder 93, it is cached out.

  In an actual case, it is expected that the data amount of each block in the block sequence is rarely uniform, but even in that case, two blocks are provided by providing the cache buffer 72 having the number of block lines or more. The data straddling the line was not stored in the cache buffer 72, and a plurality of blocks belonging to a plurality of block lines corresponding to the same scanning line on printing were imaginary in parallel with the plurality of cache buffers 72. The possibility of becoming a state increases. As a result, the frequency of data cache-out and cache-in again can be reduced, and the cache hit rate in the cache system 92 is increased.

  Further, the cache system 92 designates read data in the minimum unit of data read for DSC1. For this reason, the rate at which data cached in the past and already used for decoding is cached in again is reduced. In the first embodiment, for convenience of explanation, the minimum unit of data read is set to 1 byte unit. However, when a SCSI command is used, the minimum unit of data read is usually 512 bytes or 1024 bytes. Become. Further, since the minimum unit of data read varies depending on the file system and file management protocol to be used, the data amount of the minimum unit of the implemented method may be adopted.

  Next, in order to show the effectiveness of the cache system 92 according to the first embodiment, a comparison with other cache methods will be described.

  FIG. 17 is a diagram showing a change in the state of the cache memory in another cache method. In this method, when the image is rotated, the number P of cache buffers is smaller than the number m of lines in the block of the image. In this method, the cache system divides the EXIF image data for each cache buffer size, and caches the data for each division unit.

  FIG. 17A is a diagram illustrating an example of a storage state of the cache memory at the time when the cache buffer becomes full immediately after starting decoding in the case of decoding by rotating an image. FIG. 17B is a diagram illustrating an example of the storage state of the cache memory at the time when the block is decoded by one column when the image is rotated and decoded.

  When the number of cache buffers P is less than the number m of image block rows and the cache memory capacity is smaller than the image data, as shown in FIG. Can not do it. Therefore, at the time when the block decoding process for one column is completed, as shown in FIG. 17B, the data in the uppermost block row of the image does not remain in the cache memory. Therefore, the cache system must cache data from DSC 1 each time the decoder decodes each block. In addition, since the size of the cache buffer is used as a read unit, a large amount of data is not used even when cached in.

  Compared to the conventional system, that is, the number of cache buffers P is smaller than the number m of image block lines as in the system of FIG. 17, and EXIF image data is cached in units divided by cache buffer size. Thus, the direct printing system according to the first embodiment can significantly reduce the time from the print image selection operation in the DSC 1 to the completion of printing in the printer 2.

  For example, when an image having a length of 3450 pixels and a width of 4600 pixels is converted into block data every 8 × 8 pixels, the number of block rows is 432 (≈3450 / 8 = 431.25). When printing these four images on one sheet 58, the two images are arranged in a direction perpendicular to the sheet 58 feeding direction. At this time, in order to generate one print line, it is necessary to decode 864 (= 432 × 2) blocks.

  In the case where such four images are cached in a 3M-byte cache memory and rotated and printed, compared to the case where only 200 cache buffers each having 15 kbytes are used in the conventional method, the present embodiment With the structure of the cache memory, the time from the selection operation of the print image in the DSC 1 to the completion of printing in the printer 2 can be reduced to about 1/5.

  When the cache memory structure of the present embodiment is realized in the 3 Mbyte cache memory 71, the size of the cache buffer 72 is 3472 (≈3M / 864) bytes.

  Further, in the case where 864 cache buffers 72 are configured in such a 3 Mbyte cache memory 71, when one image based on 4 Mbyte image data is rotated and printed on one sheet 58, 200 caches are stored. Compared with the case where the buffer is configured, the time from the selection operation of the print image in DSC 1 to the completion of printing in the printer 2 can be reduced to about one third.

  As described above, in the direct printing system according to the first embodiment, with the above configuration, the efficiency of the cache memory 71 is improved, and an image based on large image data can be quickly printed even with the cache memory 71 having a small capacity. can do. In the case of the ideal state described above, even when the image is rotated and printed, the number of times of the EXIF image data divided by the size of the cache buffer 72 (remainder) during the decoding process. In the case where there is, the image based on the EXIF image data can be printed only by caching the data from the DSC 1 to the printer 2 by the number of times obtained by adding 1 to the quotient).

  In the first embodiment, the cache system 92 reads data from the semiconductor memory 20 so that the data requested by the decoder 93 is included at the head of the data to be read. For this reason, the cache buffer 72 is prefetched more data used in subsequent printing. As a result, for example, the number of times image data is read can be reduced as compared with a case where image data is divided for each size of the image data buffer 71 and image data is read for each divided unit.

  In the first embodiment, the cache system 92 generates a plurality of cache buffers 72 having the same number as the number of block lines (m) in the image data or more than the number of block lines (m). doing. In addition to this, for example, when images of a plurality of image data are printed side by side in the driving direction of the carriage 55, the cache system 92 is equal to the total number of block lines of the plurality of image data or the block lines thereof. If a plurality of cache buffers 72 having a number larger than the total number of lines are generated, the same effect can be expected.

Embodiment 2. FIG.
In the direct printing system according to the second embodiment of the present invention, the configuration of the cache memory 71 is changed according to the size of the image data. The configuration and operation of the DSC 1 are the same as those of the first embodiment, and the same reference numerals are given and description thereof is omitted. The hardware configuration of the printer 2 is the same as that of the first embodiment, and the same reference numerals are given and the description thereof is omitted.

  FIG. 18 is a diagram illustrating the contents stored in the storage unit 43 in the printer 2 according to the second embodiment of the present invention. FIG. 19 is a block diagram illustrating functions implemented in the direct printing system according to the second embodiment of the present invention. The storage unit 43 of the printer 2 stores a print instruction data interpretation program 101, a cache system program 102, a decoder program 63, a print control data generation program 64, and a communication control program group. The communication control program group of the printer 2 has a USB mass storage class program 65.

  The decoder program 63, the print control data generation program 64, and the USB mass storage class program 65 are the same as those in the first embodiment, and the description thereof will be omitted by attaching the same reference numerals.

  The print instruction data interpretation program 101 is executed by the central processing unit 41 to realize the print instruction data interpretation unit 111. The cache system program 102 is executed by the central processing unit 41 to realize a cache system 112 as a forming unit, a reading unit, and an output unit. The print instruction data interpretation unit 111 and the cache system 112 are basically the same as those in the first embodiment, but as described later, some of the operations when rotating and printing an image are changed. ing.

Next, the operation of the direct printing system having the above configuration will be described.

  In DSC1, a print instruction data generation unit 81, an image data transmission unit 82, and a USB mass storage class 83 are realized. In the printer 2, a print instruction data interpretation unit 111, a cache system 112, a decoder 93, a print control data generation unit 94, and a USB mass storage class 95 are realized. The cache system 112 as a forming unit generates a cache memory 113 as a buffer memory having a predetermined size in the memory 42. The size and number of cache buffers in the cache memory 113 at the time of generation are the same as those of the cache memory 71 of the first embodiment.

  Then, the configuration processing by the USB communication I / F 46 of the printer 2 and the USB communication I / F 19 of the DSC 1 is completed, and the print instruction data is transmitted from the print instruction data generation unit 81 of the DSC 1 to the print instruction data interpretation unit 111. .

  FIG. 20 is a flowchart showing the operation of the print instruction data interpretation unit 111 in FIG.

  When the print instruction data is input, the print instruction data interpretation unit 111 starts control of the print process specified by the print instruction data (step S41). Specifically, the print instruction data interpretation unit 111 first extracts a file name and the like from the print instruction data, the file data amount (file size) of the file name, and the size of the image included in the file Generate data requesting acquisition of information.

  This file data amount and image size information acquisition request data is transmitted to the image data transmission unit 82. When receiving the image size information acquisition request data, the image data transmission unit 82 extracts a file name included in the acquisition request data. Further, the image data transmission unit 82 reads the data amount and the image size information from the file 32 with the file name, and transmits them to the print instruction data interpretation unit 111.

  When receiving the data amount (file size) of the image file 32, the number of vertical pixels and the number of horizontal pixels of the image, the print instruction data interpretation unit 111 determines whether the image needs to be rotated (step S42).

  The print instruction data interpretation unit 111 outputs a first reconfiguration instruction for the cache memory 113 to the cache system 112 when image rotation is not necessary. Upon receiving this reconfiguration instruction, the cache system 112 reduces the number of cache buffers (for example, 200), and makes the capacity of one cache buffer larger than the capacity of the cache buffer of the first embodiment (for example, 15k). Byte) (step S43).

  Thereafter, the image data is decoded by the decoder 93 in the same manner as in the first embodiment (step S3). In this case, since the size of the cache buffer is large, the number of times of exchanging data in the cache buffer is reduced.

  On the other hand, if it is necessary to rotate the image, the print instruction data interpretation unit 111 determines whether the data amount of the image file 32 is equal to or smaller than the size of the cache memory 113 (step S44).

  If the data amount of the image file 32 is less than or equal to the size of the cache memory 113, the print instruction data interpretation unit 111 causes the cache system 112 to issue a first reconfiguration instruction for the cache memory 113 (step S45). Thereafter, the decoder 93 decodes the image data in the order in which the images are rotated (step S4). In this case, the image is rotated, but since all the data of the image file 32 is cached, the hit rate of the cache data is high, and there is no particular problem with this point.

  Further, when the data amount of the image file 32 is larger than the size of the cache memory 113, the stamp difference instruction data interpretation unit 111 outputs a second reconfiguration instruction of the cache memory 113 to the cache system 112. Upon receiving this reconfiguration instruction, the cache system 112 sets the size and number of cache buffers in the same manner as in the first embodiment (step S46). That is, as compared with the case of step S43, the number of cache buffers increases and the size of one cache buffer decreases.

  Thereafter, as in the first embodiment, the decoder 93 decodes the image data in the order in which the images are rotated (step S4). As described above, in the second embodiment, only when the size of the cache memory 113 is smaller than the data amount of the image file 32 and the image needs to be rotated, the cache system 112 and the cache system 112 and The cache memory 113 operates.

  Note that the operation of the print control data generation unit 94 and the printing process on the paper 58 by the printing device 47 are the same as those in the first embodiment, and a description thereof will be omitted.

  As described above, in the second embodiment, only when the size of the cache memory 113 is smaller than the data amount of the image file 32 and the rotation of the layer is necessary, the cache method of the first embodiment is used. In the case where the system 112 and the cache memory 113 operate and more than that, the number of cache buffers is small and the capacity of the cache buffer is increased. As a result, when the size of the cache memory 113 is smaller than the data amount of the image file 32 and image rotation is required, the cache data hit rate can be increased and the printing time can be reduced as in the first embodiment. In other cases, the printing time can be reduced by reducing the number of times data is taken in and out of the cache memory 113.

  In the second embodiment, the cache system 112 generates the same number of cache buffers as the number of block lines (m) in the image data or more than the number of block lines (m). ing. In addition to this, for example, when images of a plurality of image data are printed side by side in the driving direction of the carriage 55, the cache system 112 is equal to the total number of block lines of the plurality of image data or the block lines thereof. If a plurality of cache buffers having a number larger than the total number of lines are generated, the same effect can be expected.

Embodiment 3 FIG.
In the direct printing system according to the third embodiment of the present invention, the configuration of the cache memory 133 is changed according to the data amount of the image file 32. The configuration and operation of the DSC 1 are the same as those of the first embodiment, and the same reference numerals are given and description thereof is omitted. The hardware configuration of the printer 2 is the same as that of the first embodiment, and the same reference numerals are given and the description thereof is omitted.

  FIG. 21 is a diagram showing the contents stored in the storage unit 43 in the printer 2 according to the third embodiment of the present invention. FIG. 22 is a block diagram showing functions implemented in the direct printing system according to the third embodiment of the present invention. The storage unit 43 of the printer 2 stores a print instruction data interpretation program 121, a cache system program 122, a decoder program 63, a print control data generation program 64, and a communication control program group. The communication control program group of the printer 2 has a USB mass storage class program 65.

  The decoder program 63, the print control data generation program 64, and the USB mass storage class program 65 are the same as those in the first embodiment, and the description thereof will be omitted by attaching the same reference numerals.

  The print instruction data interpretation program 121 is executed by the central processing unit 41 to realize the print instruction data interpretation unit 131. The cache system program 122 is executed by the central processing unit 41 to realize a cache system 132 as a forming unit, a reading unit, and an output unit. The print instruction data interpretation unit 131 and the cache system 132 are basically the same as those in the first embodiment, but as described later, a part of the operation when rotating and printing an image is changed. ing.

  Next, the operation of the direct printing system having the above configuration will be described.

  In DSC1, a print instruction data generation unit 81, an image data transmission unit 82, and a USB mass storage class 83 are realized. In the printer 2, a print instruction data interpretation unit 131, a cache system 132, a decoder 93, a print control data generation unit 94, and a USB mass storage class 95 are realized. The cache system 132 as a forming unit generates a cache memory 133 as a buffer memory having a predetermined size in the memory 42.

  Then, the configuration processing by the USB communication I / F 46 of the printer 2 and the USB communication I / F 19 of the DSC 1 is completed, and the print instruction data is transmitted from the print instruction data generation unit 81 of the DSC 1 to the print instruction data interpretation unit 131. .

  FIG. 23 is a flowchart showing the operation of the print instruction data interpretation unit 131 in FIG.

  When the print instruction data is input, the print instruction data interpretation unit 131 starts control of the printing process designated by the print instruction data (step S1). Specifically, the print instruction data interpretation unit 131 first transmits image size information acquisition request data to the image data transmission unit 82. When receiving the image size information acquisition request data, the image data transmission unit 82 extracts a file name and the like included in the acquisition request data. Further, the image data transmission unit 82 reads the image size information from the file 32 with the file name, and transmits it to the print instruction data interpretation unit 131.

  Upon receiving these pieces of information, the print instruction data interpretation unit 131 needs to rotate the image based on the information about the number of pixels in the vertical direction and the number of pixels in the horizontal direction and the print layout of the image on the paper 58. Whether or not (step S2).

  If it is determined that there is no need to rotate the image, decoding and printing processing is performed as in the first embodiment (step S3).

  On the other hand, when determining that the image needs to be rotated, the print instruction data interpretation unit 131 determines the number of cache buffers in the cache memory 133 and the number of cache buffers in the cache memory 133 based on the information about the number of pixels in the vertical direction of the image and the print layout. The capacity of one cache buffer is calculated (step S51).

  Specifically, for example, when printing without arranging images in a direction perpendicular to the paper feeding direction (for example, in the case of 1 up), the print instruction data interpretation unit 131 sets the number of vertical pixels of the image to 1 block. Divided by the number of vertical pixels (here, 8). Then, the print instruction data interpretation unit 131 calculates the value of the quotient (the value obtained by adding 1 to the quotient when there is a remainder) as the number of cache buffers in the cache memory 133. Note that the capacity of one cache buffer is obtained, for example, by dividing the capacity of the cache memory 133 by the number of cache buffers and rounding off fractions less than the minimum unit of reading.

  In addition, for example, when printing two images side by side in a direction perpendicular to the paper feeding direction (for example, in the case of 4 up), the print instruction data interpretation unit 131 sets the number of vertical pixels of the image to one block. Divide by the number of vertical pixels (here 8). Then, the print instruction data interpretation unit 131 calculates twice the value of the quotient of the calculation result (the value obtained by adding 1 to the quotient when there is a remainder) as the number of cache buffers in the cache memory 133. .

  When p (p is a natural number) images are arranged in a direction perpendicular to the paper feeding direction, p times the calculation result per image is calculated as the number of cache buffers in the cache memory 133. That's fine. When arranging a plurality of images, if the number of pixels of each image is different, the number of cache buffers may be calculated from the sum of the number of vertical pixels of each image.

  Further, the print instruction data interpretation unit 131 outputs the calculated number and capacity information of the cache buffer to the cache system 132.

  When information on the number of cache buffers is input from the print instruction data interpretation unit 131, the cache system 132 as a forming unit causes the number of cache buffers in the cache memory 133 to be the instructed number and capacity. The cache memory 133 is reconfigured.

  Thereafter, as in step S45 of the first embodiment, the image of the EXIF image data is decoded while being rotated, and the image is printed (step S4).

  As described above, in the third embodiment, since the same number of cache buffers as the number of block lines of the image in the image data related to printing is formed and used, the use efficiency of the cache memory 133 can be further increased, and the image It is possible to expect an optimal printing time reduction effect according to the data.

  In the third embodiment, the cache system 132 generates a plurality of cache buffers equal to the number of block lines (m) in the image data or larger than the number of block lines (m). ing. In addition to this, for example, when images of a plurality of image data are printed side by side in the driving direction of the carriage 55, the cache system 132 is equal to the total number of block lines of the plurality of image data or the block lines thereof. If a plurality of cache buffers having a number larger than the total number of lines are generated, the same effect can be expected.

  Each of the above embodiments is a preferred embodiment of the present invention, but the present invention is not limited to this, and various modifications and changes are possible.

  In the above embodiment, when rotating an image, the decoder 93 performs pre-scanning and then starts reading data for decoding. In addition to this, for example, when image optimization processing such as APF (Auto Picture Fine) processing for changing the image quality of an image is performed in the previous stage of decoding processing, in order to generate parameters used for the processing When scanning image data, the data position of the first byte of each block row may be stored in the pointer buffer, and the prescan process by the decoder 93 may be omitted.

  In addition, for example, the decoder 93 reads the data in order from the beginning of the EXIF image data without pre-scanning as in the case where the image is not rotated even when the image is rotated. Start decoding of the leftmost block sequence, and store the data position of the first byte of the second block from the left of each block row in the pointer buffer when decoding the leftmost block sequence of the image. In the decoding process of the second and subsequent block strings from the left, the pointer buffer may be used to perform the reading process for each block row.

  In each of the above embodiments, the EXIF image data is cached for printing processing. In addition to this, for example, the direct printing system may print JPEG image data, bitmap-format image data, and the like. For example, in the case of image data in the bitmap format of a horizontally long image, the number of lines of the image in the image is a pixel line, so if the number of cache buffers equal to or more than the number of pixels in the vertical direction is used, The same effect as in the first embodiment can be obtained. That is, in bitmap format image data and the like, data used in multiple scans of the carriage can be read by one-time data cache, thereby obtaining an effect of shortening the printing time.

  In each of the above embodiments, the image of the EXIF image data in the semiconductor memory 20 inserted in the card reader 16 of the DSC 1 is rotated and printed. In addition, for example, the present invention can be applied to a case where a printer is provided with a card reader and the image of the EXIF image data in the semiconductor memory 20 inserted in the card reader is rotated and printed.

  In each of the above embodiments, the DSC 1 and the printer 2 are connected by USB, but instead, another interface may be adopted. In that case, in addition to a wired interface or a wired communication method, a wireless interface such as Bluetooth (trademark) or infrared communication, or a wired communication method such as a wireless LAN may be used. In addition, although direct printing control commands and responses between the DSC 1 and the printer 2 are performed using the USB mass storage class, PictBridge (trademark) or the like may be used instead. .

  In each of the above embodiments, the image file 32 is stored in the DSC 1, but instead, other electronic devices such as a mobile phone, a music player, and a storage device without a photographing function may be used. In that case, the electronic device is provided with communication means capable of communicating with the printer 2.

  In each of the above-described embodiments, the cache systems 92, 112, 132, the decoder 93, and the print control data generation unit 94 are realized by software. Some or all of these are realized by dedicated hardware. It may be realized.

  In each of the above embodiments, the file size is used as the data amount of the EXIF image data 32, but instead, the data amount excluding the EXIF header of the EXIF image data 32 may be used.

  The present invention can be used, for example, in a direct printing system in which a digital camera and a printer are directly connected and an image based on an image data file stored in the digital camera is printed by the printer.

It is a figure which shows the direct printing system which concerns on Embodiment 1 of this invention. It is a block diagram which shows the hardware constitutions of DSC in FIG. It is a figure which shows the memory content of the flash memory in FIG. It is a block diagram which shows the function implement | achieved at the time of imaging in DSC of FIG. It is explanatory drawing of the compression process by the EXIF image data generation part in FIG. FIG. 2 is a block diagram illustrating a hardware configuration of the printer in FIG. 1. FIG. 2 is a transparent perspective view showing an internal mechanism of the printer in FIG. 1. It is a figure which shows the memory content of the memory | storage part in FIG. It is a block diagram which shows the function implement | achieved by the direct printing system of FIG. It is a figure which shows the structure of the cache memory implement | achieved in the memory in FIG. It is a flowchart which shows operation | movement of the printing instruction data interpretation part in FIG. It is a figure explaining the pixel number of an image. 11 is a flowchart showing an operation of the decoder in FIG. 10. It is a flowchart which shows operation | movement of the cache system in FIG. The figure which shows an example of the state change of the cache memory when not rotating an image. The figure which shows an example of the state change of the cache memory in the case of rotating an image. The figure which shows the comparative example of the state change of the cache memory in another cache system. The figure which shows the memory content of the memory | storage part of the printer of the direct printing system which concerns on Embodiment 2 of this invention. The block diagram which shows the function implement | achieved by the direct printing system which concerns on Embodiment 2 of this invention. FIG. 20 is a flowchart showing an operation of a print instruction data interpretation unit in FIG. 19. FIG. The figure which shows the memory content of the memory | storage part of the printer of the direct printing system which concerns on Embodiment 3 of this invention. FIG. 9 is a block diagram showing functions implemented in a direct printing system according to Embodiment 3 of the present invention. It is a flowchart which shows operation | movement of the printing instruction data interpretation part in FIG.

Explanation of symbols

1 DSC (image supply device), 2 printer, 19 USB communication I / F (first communication means), 20 semiconductor memory, 46 USB communication I / F (second communication means), 55 carriage, 72 cache buffer ( Image data buffer), 82 Image data transmission unit (transmission means), 93 Decoder (request means), 92 Cache system (reading means, output means), 113, 133 Cache memory (buffer memory), 112, 132 Cache system (formation) Means, reading means, output means)

Claims (13)

In a printer that reads image data in which data is arranged for each row having a height of a predetermined number of pixels and prints the image,
At least the same number of image data buffers as the number of image lines in the image data;
Request means for requesting data corresponding to the print area in accordance with the printing order of the images;
When the data related to the request is not in the plurality of image data buffers, the data corresponding to the size of the image data buffer including the data related to the request is read, and the pre-read first-out rule is read into the plurality of image data buffers Reading means for storing according to
Output means for outputting data relating to the request to the request means;
A printer comprising: In a printer that reads image data in which data is arranged for each row having a height of a predetermined number of pixels and prints the image,
A buffer memory having a predetermined size;
When the data amount of the image data is larger than the size of the buffer memory, a first number of image data buffers equal to at least the number of image rows in the image data is formed in the buffer memory, and the image Forming means for forming, in the buffer memory, a second number of image data buffers smaller than the first number when the amount of data is less than or equal to the size of the buffer memory;
Request means for requesting data corresponding to the print area in accordance with the printing order of the images;
When the data related to the request is not in the plurality of image data buffers, the data corresponding to the size of the image data buffer including the data related to the request is read, and the pre-read first-out rule is read into the plurality of image data buffers Reading means for storing according to
Output means for outputting data relating to the request to the request means;
A printer comprising: In a printer that reads image data in which data is arranged for each row having a height of a predetermined number of pixels and prints the image,
A buffer memory having a predetermined size;
Obtaining means for obtaining the number of rows of the image data;
Forming means for forming, in the buffer memory, a plurality of image data buffers having at least the same number as the number of lines based on the number of lines of the communication data acquired by the acquiring means;
Request means for requesting data corresponding to the print area in accordance with the printing order of the images;
When the data related to the request is not in the plurality of image data buffers, the data corresponding to the size of the image data buffer including the data related to the request is read, and the pre-read first-out rule is read into the plurality of image data buffers Reading means for storing according to
Output means for outputting data relating to the request to the request means;
A printer comprising: In a printer that reads a plurality of image data in which data is arranged for each row having a height of a predetermined number of pixels, and prints these images in the carriage drive direction.
At least the same number of image data buffers as the total number of image rows in the plurality of image data;
Request means for requesting data corresponding to the print area in accordance with the print order of the images;
When the data related to the request is not in the plurality of image data buffers, the data corresponding to the size of the image data buffer including the data related to the request is read, and the pre-read first-out rule is read into the plurality of image data buffers. Therefore, the reading means for storing,
Output means for outputting data relating to the request to the request means;
A printer comprising: In a printer that reads a plurality of image data in which data is arranged for each row having a height of a predetermined number of pixels, and arranges and prints these images in the carriage drive direction.
A buffer memory having a predetermined size;
When the total data amount of the plurality of image data is larger than the size of the buffer memory, the first number of image data that is at least equal to the total number of image rows in the plurality of image data is stored in the buffer memory. Forming means for forming a buffer and forming a second number of image data buffers smaller than the first number in the buffer memory when the data amount of the plurality of image data is less than or equal to the size of the buffer memory When,
Request means for requesting data corresponding to the print area in accordance with the printing order of the images;
When the data related to the request is not in the plurality of image data buffers, the data corresponding to the size of the image data buffer including the data related to the request is read, and the pre-read first-out rule is read into the plurality of image data buffers Reading means for storing according to
Output means for outputting data relating to the request to the request means;
A printer comprising: In a printer that reads a plurality of image data in which data is arranged for each row having a height of a predetermined number of pixels, and arranges and prints these images in the carriage drive direction.
A buffer memory having a predetermined size;
Obtaining means for obtaining the number of rows of the image data;
Forming means for forming in the buffer memory at least the same number of image data buffers as the total number of lines based on the number of lines of the image data acquired by the acquiring means;
Request means for requesting data corresponding to the print area in accordance with the printing order of the images;
When the data related to the request is not in the plurality of image data buffers, the data corresponding to the size of the image data buffer including the data related to the request is read, and the pre-read first-out rule is read into the plurality of image data buffers Reading means for storing according to
Output means for outputting data relating to the request to the request means;
A printer comprising:   The printer according to any one of claims 1 to 6, wherein the reading unit reads data corresponding to a size of the image data buffer so that data relating to the request is at the head. . The image data is encoded image data,
The request means is a decoder for decoding the encoded image data;
The number of the image data buffers or the upper limit value thereof is determined based on the number of pixels on one side that can be decoded by the decoder;
The printer according to any one of claims 1 to 6, wherein: The image data is encoded image data,
The request means is a decoder for decoding the encoded image data;
The number of the image data buffers or the upper limit value thereof is determined based on the number of pixels on one side decodable by the decoder and the aspect ratio of the image of the image data,
The printer according to any one of claims 1 to 6, wherein:   The forming unit operates only when an image direction corresponding to a carriage driving direction at the time of printing and a direction of a row of continuously arranged images in the image data are shifted by 90 degrees or 270 degrees. The printer according to any one of claims 2, 3, 5, and 6. An image supply device having a semiconductor memory and a first communication means;
A printer according to any one of claims 1 to 10, comprising a second communication means for communicating with the first communication means,
The semiconductor memory stores image data,
The image printing system, wherein the reading unit of the printer reads image data from the semiconductor memory via the first and second communication units. A printing method for reading image data in which data is arranged for each row having a height of a predetermined number of pixels and printing the image,
Requesting data corresponding to the print area according to the print order of the images;
When the data related to the request is not in the plurality of image data buffers, the data corresponding to the size of the image data buffer including the data related to the request is read, and at least as many as the number of lines of the image in the image data Storing in the image data buffer according to a pre-read first-out rule;
Outputting the data related to the request to the request source;
A printing method characterized by comprising: A printing method for reading a plurality of image data in which data is arranged for each row having a height corresponding to a predetermined number of pixels and printing the images side by side in a carriage driving direction,
Requesting data corresponding to the print area according to the print order of the images;
When the data related to the request is not in the plurality of image data buffers, the data corresponding to the size of the image data buffer including the data related to the request is read, and the total number of image rows in the plurality of image data And storing in at least the same number of image data buffers according to the pre-read-first-out rule;
Outputting the data related to the request to the request source;
A printing method characterized by comprising:

Images