JP2007011108A - Image forming apparatus and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform continuous printing at a comparatively high speed by shortening intervals between conveyed sheets without requiring special setting. <P>SOLUTION: The image forming apparatus once writes image data into a delay memory in order to adjust the timing of forming images onto sheets conveyed in sequence, then reads the data, and outputs the image data to the image forming means. The image forming apparatus includes: a scanning direction interval retaining means by which the main-scanning direction image data intervals and sub-scanning direction image data intervals, at which images are sequentially formed by the image forming means, are retained for each page; a writing means; a reading means for reading the corresponding image data written in the delay memory; a page specifying means for making a determination so that the effective interval of a specific operation is assigned to only a specific page; and an image processing means by which specific processing is performed for image data output from the delay memory for the page specified by the page specifying means. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus, an image forming method, and the like that have a plurality of color photosensitive drums and perform color printing.

  Conventionally, a so-called 1D printer having one photosensitive drum and a so-called 4D printer (tandem printer) having a plurality of photosensitive drums are widely known as electrophotographic color printers.

  In a 1D printer, four colors of yellow (Y), magenta (M), cyan (C), and black (K) are obtained by rotating a medium called an intermediate transfer member or a transfer drum on which paper is pasted four times. Image formation.

  On the other hand, in the 4D printer, since the photosensitive drums for each of the four colors exist independently, it is possible to form images for four colors at a time. Therefore, when the paper moving speed is the same, a 4D printer can usually achieve a printing speed four times that of the 1D printer. However, in the 4D printer, a plurality of photosensitive drums are arranged at predetermined intervals, respectively, and image processing is performed on each color image signal of red (R), green (G), and blue (B) read by a scanner or the like. After the conversion to four colors YMCK, it is necessary to delay the image signal by the interval between the photosensitive drums of the respective colors. Therefore, a delay memory for delaying the image signal is required.

  On the other hand, when the paper moving speed is the same, in order to increase the printing speed, it is necessary to shorten the so-called paper interval, which is the interval between the paper during printing.

  An apparatus called an MFP (Multi Function Peripheral) is required to output image data of various apparatuses such as a scanner, PDL, and FAX from a printer. In order to improve the productivity of the entire apparatus, it is required to continuously output image data of different image sizes from these various apparatuses from the printer.

However, in the case of the conventional 4D printer, when controlling the delay memory for the photosensitive drum interval, it corresponds to the length of the main scanning effective section signal corresponding to the main scanning direction length of the image data and the length in the sub scanning direction. If only one set of the length of the sub-scanning effective section signal is held and the paper size (image size) is different, image forming operations of different image sizes cannot be performed simultaneously on the photosensitive drums of the respective colors, and the paper gap However, the output speed could be improved by the method described in Patent Document 1, for example.
JP 2003-111748 A

  However, when a plurality of data of different image sizes are continuously received in the delay memory control circuit, it is not possible to change only the processing of a specific page. Could not add a specific treatment.

  FIG. 17 is a diagram showing the relationship between the photosensitive drum and the image size. In the figure, reference numerals 1701 and 1702 denote photosensitive drums having different development colors. Reference numeral 1703 denotes an output image of the first page. Reference numerals 1704 and 1705 denote output images on the second page. d is the interval between the photosensitive drums 1701 and 1702, and i is the interval between the output image of the first page and the output image of the second page.

  In FIG. 6A, the output image sizes of the first page and the second page are the same, and therefore can be output by a conventional 4D printer. On the other hand, since the output image sizes of the first page and the second page are different in FIG. 5B, the conventional 4D printer cannot output the paper with the space between them being reduced. In this case, the interval i between the output images of the first page and the second page needs to be larger than the interval d between the photosensitive drums. Since the 4D printer has four photosensitive drums, the interval between the photosensitive drums located at both ends is three times d, and in the conventional 4D printer, the output image interval i needs to be larger than three times d. There is.

  Therefore, according to the present invention, when controlling the delay memory for the photosensitive drum interval in the 4D printer, the length of the main scanning direction and the length of the sub-scanning scanning direction for a plurality of pages are managed, and the conveyance is performed without performing any special setting. Image forming apparatus and image forming method capable of shortening the interval between sheets to be printed, and further providing a means for switching the processing of specific pages on the printer side rather than the delay memory control circuit, thereby enabling continuous printing at higher speed The purpose is to do.

  In order to achieve the above object, the image forming apparatus of the present invention has, as its first configuration, temporarily storing image data in a delay memory in order to match the timing at which an image is formed on sheets sequentially conveyed to the image forming means. In the image forming apparatus that reads the image data from the delay memory and outputs the image data to the image forming unit, the main scanning direction section and the sub-scanning direction section of the image data in which images are sequentially formed by the image forming unit Scanning direction interval length holding means for holding a plurality of lengths per page, and the corresponding image data in the delay memory based on the lengths of the main scanning direction interval and sub-scanning direction interval held per page And writing means for writing to the delay memory based on the lengths of the main scanning direction section and the sub scanning direction section held for each page. Reading means for reading out image data, page designating means for determining an effective section of a specific operation only for a specific page, and output of output image data of a page designated by the page designating means from the delay memory, An image processing means for performing a specific process is provided.

  Further, when the image forming unit forms an image, reading of the image data of the previous page from the delay memory and writing of the image data of the next page to the delay memory are performed in parallel, and page designation is performed at an arbitrary timing. It is characterized in that the confirmation of the presence or absence of an interrupt is performed between pages.

  Furthermore, the image forming unit includes a plurality of photosensitive drums, and the sheet is conveyed at an interval shorter than an interval at which the photosensitive drums are arranged.

  In addition, the image forming method of the present invention writes image data once in the delay memory and then stores the image data from the delay memory in order to synchronize the timing of image formation on the sheets sequentially conveyed to the image forming means. In the image forming method of reading and outputting to the image forming unit, a step of holding a plurality of lengths in the main scanning direction section and sub-scanning direction section of image data in which images are sequentially formed by the image forming unit in units of pages; Writing the corresponding image data into the delay memory based on the lengths of the main scanning direction section and the sub-scanning direction section held in the page unit, and the main scanning direction section held in the page unit, and A step of reading the corresponding image data written in the delay memory based on the length of the sub-scanning direction section, and the specific operation at the end of the page Check whether interrupt for, if, when an interrupt is present is characterized by a step of changing the image data processing of only the page.

  According to the present invention, when controlling the delay memory corresponding to the photosensitive drum interval in the 4D printer, by managing the main scanning direction length and the sub scanning direction length for a plurality of pages, no special setting is performed. The gap between the papers can be shortened. Also, by specifying the operation for a specific page, productivity can be improved without reducing the printer speed.

  Embodiments of an image forming apparatus and an image forming method of the present invention will be described with reference to the drawings. The image forming apparatus according to the present embodiment is applied to an MFP (Multi Function peripheral).

  FIG. 1 is a diagram illustrating a configuration of an image forming system according to an embodiment. A computer 102 is a server connected to the network 101. The computers 103a and 103b are clients connected to the network 101 as well. Although not shown, many other clients are connected. Hereinafter, these clients are represented as a client 103 or a computer 103 as a representative.

  In addition, an MFP (Multi Function Peripheral) 104 is connected to the network 101. The MFP 104 is a color 4-drum MFP that can scan and print in full color. Although not shown, the network 101 is also connected to other devices such as an MFP, a scanner, a printer, and a FAX.

  Here, in the computer 103, application software for executing so-called DTP (Desk Top Publishing) is operated, and various documents and figures are created and edited. The computer 103 converts the created document / figure into PDL (Page Description Language), sends it to the MFP 104 via the network 101, and prints it out.

  The MFP 104 has communication means capable of exchanging information with the computers 102 and 103 via the network 101, and sequentially notifies the information and state of the MFP 104 to the computers 102 and 103 side. Furthermore, the computers 102 and 103 have utility software that operates in response to the information, and the MFP 104 is managed by the computers 102 and 103.

[Configuration of MFP 104]
FIG. 2 is a diagram illustrating the configuration of the MFP 104. The MFP 104 has a four-drum type full-color printer. The MFP 104 uses a scanner unit 201 that reads an image, a scanner IP unit 202 that performs image processing on the scanned image data, a FAX unit 203 that transmits and receives an image using a telephone line typified by a facsimile, and the network. A network interface card (NIC) unit 204 that exchanges image data and device information, and a PDL unit 205 that develops a page description language (PDL) sent from the computer 103 into an image signal. Depending on how the MFP 104 is used, the core unit 206 temporarily stores an image signal and determines a route.

  The image data output from the core unit 206 is subjected to image processing by the printer IP unit 207 and then sent to the printer unit 209 for image formation. When the sheet printed out by the printer unit 209 is sent to the finisher unit 210, sheet sorting processing and sheet finishing processing are performed.

  In addition, the display unit 211 is used for so-called preview for confirming the contents of an image without printing out the image or confirming the state of the image before printing out.

[Configuration of Scanner Unit 201]
FIG. 3 is a diagram illustrating the configuration of the scanner unit 201. In the figure, reference numeral 301 denotes an original table glass on which an original 302 to be read is placed. The original 302 is irradiated by an illumination lamp 303, and the reflected light passes through mirrors 304, 305 and 306, and is imaged on the CCD 308 by a lens 307. The first mirror unit 310 including the mirror 304 and the illumination lamp 303 moves the entire surface of the original 302 by moving the mirror 304 at a speed v and moving the second mirror unit 311 including the mirrors 305 and 306 at a speed 1 / 2v. Scan. The first mirror unit 310 and the second mirror unit 311 are driven by a motor 309.

[Configuration of Scanner IP Unit 202]
FIG. 4 is a diagram showing the configuration of the scanner IP unit 202. The optical signal input to the scanner IP unit 202 is converted into an electrical signal by the CCD sensor 308. This CCD sensor 308 is an RGB 3-line color sensor, and is converted into 8-bit digital image signals RO, GO, and BO for each color signal by an A / D converter (A / D converter) 401 as RGB image signals. .

  Thereafter, the shading correction circuit 402 performs known shading correction using the read signal of the reference white plate for each color. Furthermore, since the color line sensors constituting the CCD sensor 308 are arranged at a predetermined distance from each other, the line delay adjustment circuit (line interpolation unit) 403 corrects the spatial deviation in the sub-scanning direction.

  The input masking unit 404 converts the reading color space determined by the spectral characteristics of the R, G, and B filters of the CCD sensor 308 into the NTSC standard color space. The sensitivity characteristic of the CCD sensor 308 and the spectral characteristics of the illumination lamp A 3 × 3 matrix operation using constants unique to the apparatus in consideration of various characteristics such as the above is performed, and the input (RO, GO, BO) signal is converted into a standard (R, G, B) signal.

  Further, the luminance / density conversion unit (LOG conversion unit) 405 is configured by a look-up table (LUT) RAM, and is converted so that RGB luminance signals become C1, M1, and Y1 density signals. The image signal is sent to the core unit 206.

[Configuration of NIC unit 204]
FIG. 5 is a diagram showing the configuration of the NIC unit 204 and the PDL unit 205. The NIC unit 204 has an interface function with respect to the network 101. For example, an Ethernet (registered trademark) cable such as 10Base-T or 100Base-TX is used to obtain information from the outside, or to send information to the outside. Play a role.

  When obtaining information from the outside, first, the information signal is voltage-converted by the transformer unit 501 and sent to the LAN controller unit 502. The LAN controller unit 502 includes a first buffer memory (not shown) therein, and after determining whether the information is necessary information, the second buffer memory (not shown). Then, a signal is output to the PDL unit 205.

  When providing information to the outside, the LAN controller unit 502 adds necessary information to the data sent from the PDL unit 205 and outputs the data to the network 101 via the transformer unit 501.

[Configuration of PDL Unit 205]
As shown in FIG. 5, in the PDL unit 205, image data created by application software running on the computer 103 is composed of documents, figures, photographs, etc., and character codes, figure codes, raster image data, etc., respectively. It consists of a combination of image description elements. This is a so-called PDL (Page Description Language), which is typified by Adobe's PostScript (registered trademark) language.

  The PDL unit 205 performs conversion processing from PDL data to raster image data. First, PDL data sent from the NIC unit 204 is temporarily stored in a large-capacity memory 504 such as a hard disk (HDD) by the CPU unit 503, and managed and saved for each job.

  The CPU unit 503 performs rasterized image processing called RIP (Raster Image Processing) as necessary, and develops PDL data into a raster image. The developed raster image data is stored for each job in a memory 505 that can be accessed at high speed, such as DRAM, for each color component of CMYK, and is stored in the core unit 206 by the CPU unit 503 according to the status of the printer unit 209. Sent.

[Configuration of Core Unit 206]
FIG. 6 is a diagram showing the configuration of the core unit 206. The bus selector unit 601 of the core unit 206 plays a role of traffic control in the MFP 104. That is, the bus selector unit 601 switches the bus according to various functions in the MFP 104 such as a copying function, a network scan, a network printer, a facsimile transmission / reception, or a display display.

The bus switching pattern for executing each function is shown below.
Copy function: scanner 201 → core 206 → printer 209
Network scan: scanner 201 → core 206 → NIC unit 204
Network printer: NIC unit 204 → core 206 → printer 209
Facsimile transmission function: scanner 201 → core 206 → FAX unit 203
Facsimile reception function: FAX unit 203 → core 206 → printer 209
Display display function: scanner 201, FAX unit 203 or NIC unit 204 → core 206 → display 211

  Next, the image data output from the bus selector unit 601 is sent to the printer unit 209 (PWM unit 208) or the compression unit 602, the memory unit 603 including a large capacity memory such as a hard disk (HDD), and the decompression unit 604. It is sent to the display unit 211.

  The compression method used in the compression unit 602 may be a general method such as JPEG, JBIG, or ZIP. The compressed image data is managed for each job and stored together with additional data such as a file name, a creator, a creation date and time, and a file size.

  Furthermore, a personal box function can be supported by providing a job number and password and storing them together. This is a function for temporarily storing data or for allowing only a specific person to print out (read from the HDD). When an instruction to print out a job stored in the memory unit 603 is given, after authentication by a password, the image data is called from the memory unit 603, and the decompression unit 604 performs image decompression and rasterization. When the image is returned, it is sent to the printer IP unit 207.

[Configuration of Printer IP Unit 207]
FIG. 7 is a diagram illustrating the configuration of the printer IP unit 207. In the figure, reference numeral 701 denotes an output masking / UCR circuit, which corrects C1, M1, Y1 signals to C, M, Y, K signals, which are toner colors of the image forming apparatus, and outputs them.

  Reference numeral 702 denotes a gamma correction (conversion) unit. The gamma correction unit 702 uses a look-up table (LUT) RAM in which C, M, Y, and K signals take into account the color characteristics of toner to output an image. Converted to C, M, Y, K data. Reference numeral 703 denotes a spatial filter, and edge enhancement or smoothing is performed by the spatial filter 703.

  A drum delay unit 704 includes a memory necessary for delaying the photosensitive drum for each color. The image signal delayed for each color by the drum delay unit 704 is sent to the PWM unit 208.

[Configuration of PWM unit 208]
FIG. 8 is a diagram showing the configuration and operation of the PWM unit 208. The multivalued image data separated into four colors of yellow (Y), magenta (M), cyan (C), and black (K) output from the printer IP unit 207 passes through each PWM unit 208 and is converted into an image. It is formed.

  In the figure, reference numeral 801 denotes a triangular wave generator. Reference numeral 802 denotes a D / A converter (D / A conversion unit) that converts an input digital image signal into an analog signal. The output signal “a” from the triangular wave generator 801 and the output signal “b” from the D / A converter 802 are compared in magnitude by the comparator 803 and sent to the laser driver 804 as an output signal c. Here, the CMYK output signals c are converted into laser beams by the CMYK laser oscillators 805, respectively.

  The laser beam output from the laser oscillator 805 is scanned by the polygon scanner 913 and applied to the respective photosensitive drums 917, 921, 925, and 929.

[Configuration of Printer Unit 209 of MFP 104 (4-Drum Type Printer)]
FIG. 9 is a diagram showing a configuration of the four-drum type color printer unit 209. In the figure, reference numeral 913 denotes a polygon mirror, which receives four laser beams emitted from four semiconductor laser oscillators 805. One of them scans the photosensitive drum 917 through the mirrors 914, 915, and 916, the other scans the photosensitive drum 921 through the mirrors 918, 919, and 920, and the other one scans the photosensitive drum 921. 924, the photosensitive drum 925 is scanned, and the remaining one scans the mirror 926, 927, 928 and the photosensitive drum 929.

  A developing unit 930 supplies yellow (Y) toner, and forms a yellow toner image on the electrostatic latent image formed on the photosensitive drum 917 by laser light. A developing device 931 supplies magenta (M) toner, and forms a magenta toner image on the electrostatic latent image formed on the photosensitive drum 921 by laser light. A developing unit 932 supplies cyan (C) toner, and forms a cyan toner image on the electrostatic latent image formed on the photosensitive drum 925 by laser light. A developing device 933 supplies black (K) toner, and forms a black toner image on the electrostatic latent image formed on the photosensitive drum 929 by laser light. When these four color (Y, M, C, K) toner images are transferred to a sheet, a full-color output image can be obtained.

  The sheet supplied from any one of the sheet cassettes 934 and 935 and the manual feed tray 936 is adsorbed onto the transfer belt 938 via the registration roller 937 and conveyed. In order to synchronize with this sheet feeding timing, toner of each color is developed in advance on the photosensitive drums 917, 921, 925, and 929, and the toner is transferred to the sheet as the sheet is conveyed.

  The sheet on which the toner of each color is transferred is separated and conveyed by the conveyance belt 939, and the toner is fixed to the sheet by the fixing device 940. The sheet that has passed through the fixing device 940 is once guided downward by the flapper 950, and after the trailing edge of the sheet has passed through the flapper 950, the sheet is switched back and discharged. As a result, the sheets are discharged in a face-down state, and the correct order is obtained when printing is performed in order from the first page.

  The four photosensitive drums 917, 921, 925, and 929 are arranged at equal intervals with a distance d. Further, when the sheet is conveyed at a constant speed v by the conveying belt 939, synchronization is taken at this timing, and the four semiconductor laser oscillators 805 are driven.

[Configuration of Display Unit 211]
FIG. 10 is a diagram showing the configuration of the display unit 211. Since the image signal output from the core unit 206 is CMYK data, the inverse LOG conversion unit 1001 needs to convert the image signal into RGB data. In order to match the color characteristics of the display device 1004 such as a CRT, the gamma conversion unit 1002 performs output conversion using a lookup table. The converted image data is once stored in the memory unit 1003 and then displayed on a display device (monitor) 1004 such as a CRT.

  Here, the display unit 211 is used for performing a preview function for confirming an output image in advance, a proof function for verifying whether an output image is definitely intended, or whether printing is necessary. This is to eliminate the waste of the print sheet when checking.

[Configuration of Finisher Unit 210]
FIG. 11 is a diagram illustrating a configuration of the finisher unit 210. The sheet exiting the fixing unit 940 of the printer unit 209 enters the finisher unit 210. The finisher unit 210 is provided with a sample tray 1101 and a stack tray 1102, which are switched according to the type of job and the number of sheets to be discharged, and the sheets are discharged.

  There are two sort methods for sorting. One of them is a bin sorting method that has a plurality of bins and distributes sheets to each bin. The other is a shift sort method that uses an electronic sort function, which will be described later, and shifts bins (or trays) in the back / front direction and distributes output sheets for each job.

  The electronic sort function is called collate. When the above-described core unit 206 has a large-capacity memory, the so-called collate function is used in which the buffered page order and the discharge order are changed using this buffer memory. The electronic sorting function is supported. On the other hand, the group function is a function for sorting by page, while sorting is sorted by job.

  Further, when discharging to the stack tray 1102, it is possible to store the sheets before being discharged for each job and bind them with the stapler 1105 immediately before discharging.

  In addition, a Z-folder 1104 for folding the paper into a Z shape and a puncher 1106 for punching two (or three) holes for files are provided up to the two trays. Each process is performed according to the type of job.

  Further, the saddle stitcher 1107 binds the central portion of the sheet at two places, and then folds the sheet by folding the central portion of the sheet on a roller to perform a process of creating a booklet such as a weekly magazine or a pamphlet. . The sheet created by the saddle stitcher 1107 is discharged to the booklet tray 1108.

  In addition, although not shown, it is possible to add binding by glue (gluing) for bookbinding or cutting for aligning the end surface opposite to the binding side after binding.

  The inserter 1103 sends a sheet set on the tray 1110 to one of the trays 1101, 1102, and 1108 without passing through the printer. As a result, the sheet set on the inserter 1103 can be inserted (inserted) between the sheets fed into the finisher 210.

  It is assumed that sheets are set face-up by the user on the tray 1110 of the inserter 1103, and are fed in order from the uppermost sheet by the pickup roller 1111. Accordingly, the sheet from the inserter 1103 is discharged as it is to the trays 1101 and 1102 and is discharged in a face-down state. When sending to the saddle stitcher 1107, after sending it to the puncher 1106 side, it is switched back and sent to match the face orientation.

[Configuration of Drum Delay Unit 704]
FIG. 12 is a diagram showing an internal configuration of the drum delay unit 704. In the figure, reference numeral 1201 denotes a synchronization control unit. The synchronization control unit 1201 is provided with a main scanning effective section holding unit 1201a and a sub scanning effective section holding unit 1201b. The main scanning effective section holding unit 1201a can hold the length of a main scanning effective section signal henb_in described later for three pages. Similarly, the sub-scan effective section holding unit 1201b can hold the length of a sub-scan effective section signal venb_in described later for three pages. 1202 is a data converter. Reference numeral 1203 denotes an address generation unit. Reference numeral 1204 denotes a RAM control unit. Reference numeral 1205 denotes an SDRAM (synchronous DRAM) as a delay memory.

  The synchronization control unit 1201 receives the following image synchronization signal.

vsync_in = synchronous start signal in the sub-scanning direction venb_in = valid section signal in the sub-scanning direction hsync_in = synchronous start signal in the main scanning direction henb_in = valid section signal in the main scanning direction pvsync_in = sub-scan activation signal phsync_in of the printer Start signal

  Each of these signals becomes active at the L level. Here, the effective interval signal venb_in in the sub-scanning direction and the effective interval signal henb_in in the main scanning direction change for each page according to the input image size. Further, the sub-scan activation signal pvsync_in of the printer and the main scan activation signal phsync_in of the printer are activation signals that request image signals input from the printer, and the input timing differs for each color. Further, the following control signals are output from the synchronization control unit 1201.

count16 = 16 counter signal composed of a 4-bit counter and counting 16 cycles henb_rd = main scanning effective section signal for data reading henb_vo = main scanning effective section signal for data output henb_ref = main scanning effective section signal for refresh control of SDRAM

  These signals are active at the H level except for count 16. Further, the data conversion unit 1202 receives the 4-bit image data data_in from the spatial filter 703, temporarily stores it as 16-bit data for every four pixels, and then uses the synchronization signal from the synchronization control unit 1201 to generate 16-bit data at a predetermined timing. Are transferred to the SDRAM 1205. The transferred image data is written by the SDRAM 1205. Also, 16-bit image data read from the SDRAM 1205 is converted into 4 bits × 4 pixels and output as data_out.

  The address generation unit 1203 generates an address of the SDRAM 1205 based on a control signal from the synchronization control unit 1201. Write addresses and read addresses are generated as addresses, respectively, and a data write sub-scanning effective section signal venb_wr and a data writing main scanning effective section signal henb_wr, which are synchronization signals from the synchronization control unit 1201, are active. At this time, the write address is updated every 16 cycles. Similarly, when the sub-scan effective section signal venb_rd for data read and the main scan effective section signal henb_rd for data reading are active, the read address is updated every 16 cycles.

  Each address is converted into the address format of the SDRAM 1205 and output as an SDRAM address ram_ad and an SDRAM bank address ram_ba.

  The RAM control unit 1204 generates a chip select signal ram_cs, a RAS signal ram_ras, a CAS signal ram_cas, and a write signal ram_we, which are signals necessary for the read / write command control of the SDRAM 1205, based on the control signal from the synchronization control unit 1201. Further, a command control signal necessary for the refresh operation of the SDRAM 1205 is generated in accordance with the main scanning effective section signal henb_ref for refresh control.

[Drum delay unit 704 control timing]
FIG. 13 is a timing chart showing changes in the control signal in the main scanning direction of the drum delay unit 704. As described above, the drum delay unit 704 includes the main scanning effective section holding unit 1201b that stores the length of the main scanning effective section signal henb_in for each page, and can store three pages.

  First, the sub-scan effective section signal venb_in for the first page is input (page0_wr). Further, the image signal data_in is input simultaneously with the main scanning effective section signal henb_in. Data is input for the main scanning effective section (data_valid_p0) of the first page, and 16 clocks are temporarily stored as one block (w0), and are grouped into blocks in units of 16 clocks (w1, w2).

  The temporarily stored image data is output to the SDRAM 1205 as a section ram_data of the write main scanning effective section signal henb_wr, and a plurality of image data is stored in the SDRAM 1205. Here, as described above, the length of the main scanning effective section (data_valid_p0) is stored in the main scanning effective section holding unit 1201b. Similarly, data w3, w4, and w5 of the next line are input and similarly written to the SDRAM 1205.

  Next, when the sub-scan start signal pvsync_in and the main scan start signal phsync_in for the first page are input from the printer (page0_rd), the synchronization control unit 1201 generates a read main scan effective section signal henb_rd. This read main scanning effective section signal henb_rd is generated with the same section as the main scanning effective section (data_valid_p0) stored in the main scanning effective section holding unit 1201a.

  In the read main scanning effective section signal henb_rd, a read operation is performed from the SDRAM 1205 in a section where no write operation is performed, and the 16-bit image data r0 corresponding to the image data w0 is read. The read image data r0 is converted into 4-bit image data by the data converter 1202, and is output as data_out. Similarly, r1 and r2 data are output every 16 clocks.

  Next, a case where the sub-scan effective section signal venb_in for the second page is input is shown. Here, a case where the length data_valid_p1 of the main scanning section signal of the second page is different from the length data_valid_p0 of the main scanning section signal of the first page is shown. The image data is input for the main scanning effective section (data_valid_p1) of the second page, and 16 clocks are temporarily stored as one block (wa), and are grouped into blocks in units of 16 clocks (wa, wb). The temporarily stored image data is output to the SDRAM 1205 as a section ram_data of the write main scanning effective section signal henb_wr, and a plurality of image data is stored in the SDRAM 1205. Here, as described above, the length of the main scanning effective section (data_valid_p1) is stored in the main scanning effective section holding unit 1201a.

  When the main scanning activation signal phsync_in is input from the printer, the 16-bit image data r3 corresponding to the image data w3 of the first page is read from the SDRAM 1205, converted into 4-bit image data, and then output as data_out. Similarly, r4 and r5 image data are read out. Here, the main scanning effective section signal henb_rd for reading is output for the length data_valid_p0 of the stored main scanning section signal of the first page.

  Further, when the sub-scan activation signal pvsync_in and the main-scan activation signal phsync_in for the second page are input from the printer (page1_rd), the 16-bit image data ra corresponding to the image data wa for the second page is read from the SDRAM 1205. After conversion to image data, it is output as data_out. Similarly, the image data wb is read out. Here, the main scanning effective section signal henb_rd for reading is output for the length data_valid_p1 of the stored main scanning section signal of the second page.

  In this manner, in this embodiment, the length of the main scanning effective section signal henb_in at the time of writing is stored for three pages (data_valid_p0, data_valid_p1, data_valid_p2), and main scanning for reading corresponding to each page at the time of reading is performed. A valid interval signal henb_rd is generated. As a result, even when the write and read of the SDRAM 1205 of different pages are in the same section, it is possible to operate without any problem without changing the setting in the middle.

[Clock control of drum delay unit 704]
FIG. 14 is a timing chart showing changes in the control signal in units of clocks in the drum delay unit 704. FIG. 14 shows control timing in units of clocks with respect to the timing chart of FIG. In the SDRAM 1205, necessary initial settings and mode settings defined in advance are performed by a circuit (not shown). Here, the CAS latency is set to “3” and the burst mode is set to “4”. Shall.

  First, the 16 counter count 16 output from the synchronization control unit 1201 repeatedly counts from “0” to “15”. When the read main scanning effective section henb_rd is active, the 16 counter performs a read operation from “0” to “7”, and when the writing main scanning effective section henb_wr is active, the 16 counter is “8”. ”To“ 15 ”, the write operation is performed. Further, when the refresh valid section signal henb_ref is active, the refresh operation of the SDRAM 1205 is performed while the 16 counter is “8” to “15”. However, when the write main scanning effective section henb_wr is active, the refresh effective section signal henb_ref is set not to be active.

  When the 16 counter is “0”, the RAM control unit 1204 outputs ram_cs, ram_ras, ram_cas, ram_we control signals and an address generation unit 1203 to transfer the active command ACT defined by the SDRAM specification. From the RAM address signal ram_ad for read data, a signal corresponding to the row address and the ram_ba signal are transferred.

  Next, when the 16 counter is “1”, in order to transfer the read command RDA defined by the SDRAM specification, each signal is output from the RAM control unit 1204 and the read data RAM is transferred from the address generation unit 1203. Of the address signal ram_ad, the signal corresponding to the column address and the ram_ba signal are transferred. When the 16 counter is “4”, the 16-bit RAM data ram_data is output from the SDRAM 1205 as the read data Di0. Subsequently, the 16-bit image data is output continuously with the read data Di1, the read data Di2, and the read data Di3. Is done.

  When the 16 counter is “8”, each signal is output from the RAM control unit 1204 and the RAM address signal ram_ad for write data from the address generation unit 1203 in order to transfer the active command ACT defined in the SDRAM specification. Among them, the signal corresponding to the row address and the ram_ba signal are transferred.

  When the 16 counter is “9”, each signal is output from the RAM control unit 1204 to transfer the write command WRA defined in the SDRAM specification, and the RAM address signal ram_ad for write data from the address generation unit 1203. Among them, the signal corresponding to the column address and the ram_ba signal are transferred. At the same time, 16-bit write data Do0 is output to the SDRAM 1205. Subsequently, 16-bit image data is output to the SDRAM 1205 in succession to the write data Do1, the write data Do2, and the write data Do3. The 16 counter returns to “0”, and the same read operation is performed from the 16 counter “0” to “7”.

  Further, when the 16 counter is “8”, the refresh valid section henb_ref is active, so that each signal is output from the RAM control unit 1204 in order to transfer the refresh command REF defined by the SDRAM specification. Thereafter, when the 16 counter is “12”, the refresh command REF is similarly transferred.

[Sub-scanning control of drum delay unit 704]
15 and 16 are timing charts showing changes in the control signal of the drum delay unit 704 in the sub-scanning direction. Here, lines 0, 1, 2,... Represent the number of lines in the sub-scanning direction. Further, page_wr and page_rd are counters for managing pages at the time of writing and reading, respectively, and count up to 0, 1, 2, 0... For each page. However, in the example of FIG. 15, since the number of pages is 1, the count remains “0”.

  Further, venb_rd_cntr0, venb_rd_cntr1, and venb_rd_cntr2 are up / down counters for managing the read / write operations in the sub-scanning direction corresponding to the pages of the counters page_wr and page_rd, respectively. Count down every time.

  For example, the up / down counter venb_rd_cntr2 counts up for each line when page_wr = 2 and venb_in = 0, and counts down for each line when page_rd = 2 and venb_rd_cntr2 is not zero.

  Further, the counters ad_wr and ad_rd each change the write address and the read address for each line, and return to “0” after “9” which is the maximum value of the address.

  FIG. 15 shows a case where the sub-scanning length of the output image is longer than the drum interval. The drum interval is 5 lines and the sub-scanning length of the output image is 16 lines. In the line 0, when the sub-scan effective period signal venb_in and the image data data_in are input, the counter venb_rd_cntr0 counts up for each line when the venb_in = 0 (when the image data is input). The value is counted up to 5.

  Next, when the sub-scan activation signal pvsync_in of the printer is input, the read sub-scan section signal is set to “1”. In addition, although venb_rd_cntr0 is once counted up to a value of 6 on the line 8, since it performs a read operation, it counts down to a value of 5 in the same line.

  Thereafter, since the write operation and the read operation are simultaneously performed up to the line 18, the counter venb_rd_cntr0 counts only the value 6 and the value 5. Further, in line 19, the write operation ends (because no image data is input), and the counter venb_rd_cntr0 counts down to a value of 4 and thereafter counts down to a value of 0 in line 23. In the next line 24 in which the counter venb_rd_cntr0 becomes 0, the read sub-scanning valid section signal venb_rd = 0 is set, and the read operation is completed.

  FIG. 16 shows a case where the length of the image output in the sub-scanning direction is shorter than the drum interval and the length in the sub-scanning direction is different for each page. The drum interval is 7 lines, and the length of the output image in the sub-scanning direction is 1st page 3 lines, 2nd page 6th line, 3rd page 4th line, 4th page 2nd line, 5th page 2nd line.

  The image data of the first page is input from line 1 to line 3, page_wr = 0, and the counter is incremented until the value venb_rd_cntr0 becomes 3. Next, image data of the second page is input from line 6 to line 11 and counted up to page_wr = 1, and counted up until the counter venb_rd_cntr1 becomes 6.

  Also, data read for the first page starts from line 8, page_rd = 0 is set, counter venb_rd_cntr0 counts down thereafter, the value becomes 0 on line 10, and the read sub-scan interval signal venb_rd = 0 on line 11. Thus, the read operation for the first page is stopped. Further, the data read of the second page starts from the line 13 and counts up to page_rd = 1, the counter venb_rd_cntr1 counts down, the value becomes 0 on the line 18, and the read sub-scan interval signal venb_rd = 0 on the line 19 By doing so, the read operation of the second page is stopped.

  Further, the image data of the third page is input from line 14 to line 17 and counted up to page_wr = 2, and counted up until the counter venb_rd_cntr2 becomes 4. Then, the image data of the fourth page is input on the lines 20 and 21, the page_wr = 0 is returned, and the count is incremented until the counter venb_rd_cntr0 becomes 2. Similarly, the write operation and the read operation by data input are repeated.

  In this way, the sub-scan effective section signal venb_in at the time of reading is managed by the three counters (venb_rd_cntr0, venb_rd_cntr1, venb_rd_cntr2), so that the sub-scanning direction length of the image output from the drum interval is shorter, and Even when the length in the sub-scanning direction is different for each page, the operation can be performed without changing the setting for each page.

  The above is the description of the embodiments of the present invention. However, the present invention is not limited to the configurations of these embodiments, and the functions shown in the claims or the functions of the configurations of the embodiments are included. Any configuration that can be achieved is applicable.

  For example, in the above embodiment, the lengths of the main scanning section signal and the sub-scanning section signal for three pages are managed, but the number of pages can be further increased. In this case, even when the drum interval is more than three times the length of the output image in the sub-scanning direction, the operation can be performed without any problem. In other words, it is possible to cope with a large apparatus in which the drum interval is wider, or a case where the output paper is smaller.

  Further, in the above embodiment, all of the control performed on the delay memory based on the length of the main scanning effective section and the length of the sub scanning direction effective section managed in units of pages in the drum delay unit is controlled by hardware. However, at least a part thereof may be performed by software control executed by the CPU.

  Next, using these functions, a page and an operation are designated at an arbitrary timing, and a desired process is performed only on a specific page.

  FIG. 18 is a timing chart when a change is made so that a page ID can be added to the conventional delay memory control circuit. At timing (1), the page ID is set in the hardware simultaneously with other image processing parameters at the start of the page. It is possible to assign an arbitrary ID depending on the bit width of the interface prepared by hardware.

  FIG. 19 shows a hardware sequence including a software interface for changing the output of a specific page in the present invention. First, it is confirmed whether it is time to set image processing parameters or the like for page data (step 1810). Next, when the page can be set, the input of the page ID is accepted (step 1820), and the page ID (4 digits in the example) input by the software is linked with the counter in the drum delay memory circuit ( Step 1830) Operation is possible.

  When the setting is completed, the normal sequence is taken. An image is input (step 1840), and the necessity of image processing is determined at an arbitrary timing (step 1850). If it is desired to add special data to the data in the memory, the page ID as a result of the determination is written in a register (step 1860). This corresponds to (2) in FIG. Further, when data is written, it is checked whether the page read from the memory and the determined page ID are equal between the end of the page and the next page output (step 1870).

If the page ID and the internal counter value are the same, specific data can be added to the image output from the memory (step 1880). ((3) in FIG. 18)
FIG. 20 shows an example of data to be output.

  For example, as shown in the above figure, a specific checker logo is superimposed on the data in the memory to protect confidentiality, or a frequently used logo is registered to operate the counter in the hardware, or the delay memory It is possible to change the pattern according to the page size managed in the control circuit, or change the logo size according to the page size.

1 is a diagram illustrating a configuration of an image forming system in an embodiment. 2 is a diagram illustrating a configuration of an MFP 104. FIG. 2 is a diagram illustrating a configuration of a scanner unit 201. FIG. 2 is a diagram illustrating a configuration of a scanner IP unit 202. FIG. FIG. 2 is a diagram showing the configuration of a NIC unit 204 and a PDL unit 205. FIG. 3 is a diagram illustrating a configuration of a core unit 206. 2 is a diagram illustrating a configuration of a printer IP unit 207. FIG. 3 is a diagram showing the configuration and operation of a PWM unit 208. FIG. 2 is a diagram illustrating a configuration of a 4-drum type color printer unit 209. FIG. 3 is a diagram illustrating a configuration of a display unit 211. FIG. It is a figure which shows the structure of the finisher part. 3 is a diagram illustrating an internal configuration of a drum delay unit 704. FIG. 6 is a timing chart showing changes in a control signal in a main scanning direction of a drum delay unit 704. 6 is a timing chart showing changes in control signals in units of clocks in a drum delay unit 704. 6 is a timing chart showing changes in a control signal in a sub-scanning direction of a drum delay unit 704. 6 is a timing chart showing changes in a control signal in a sub-scanning direction of a drum delay unit 704. It is a figure which shows the relationship between a photosensitive drum and image size. 6 is a timing chart of a drum delay unit 704. 5 is a characteristic flowchart of the present invention in a drum delay unit 704. It is a figure which shows an example of the data made to output in the actual usage example by the new function with respect to the drum delay part 704.

Explanation of symbols

704 Drum delay unit 1201 Synchronization control unit 1201a Main scanning effective section holding section 1201b Sub scanning effective section holding section 1202 Data conversion section 1205 SDRAM

Claims (7)

In order to synchronize the timing at which images are formed on the sheets sequentially conveyed to the image forming means, the image data is once written in the delay memory, and then the image data is read from the delay memory and output to the image forming means. In the forming device,
A scanning direction interval length holding unit that holds a plurality of lengths of a main scanning direction interval and a sub scanning direction interval of image data in which images are sequentially formed by the image forming unit;
Writing means for writing the corresponding image data into the delay memory based on the length of the main scanning direction section and the sub-scanning direction section held in the page unit;
Reading means for reading out the corresponding image data written in the delay memory based on the lengths of the main scanning direction section and the sub scanning direction section held in the page unit;
A page specifying means for determining a valid section of a specific action only on a specific page;
An image forming apparatus comprising: an image processing unit that performs a specific process on output of output image data of a page specified by the page specifying unit from the delay memory.   The image data of the previous page from the delay memory and the writing of the image data of the next page to the delay memory are concurrently performed when the image forming unit forms an image. Image forming apparatus.   When forming an image with the image forming means, apart from reading / writing the image data, the input timing of the page specifying means is performed at an arbitrary timing, and the operation of enabling the page specifying means The image forming apparatus according to claim 1, wherein the image forming apparatus is automatically performed by hardware between pages.   The image forming apparatus according to claim 1, wherein the image forming unit includes a plurality of color photosensitive drums, and the sheet is conveyed at an interval shorter than an interval between both ends of the arranged photosensitive drums. . In order to synchronize the timing at which images are formed on the sheets sequentially conveyed to the image forming means, the image data is temporarily written in the delay memory, and then the image data is read from the delay memory and output to the image forming means. In the forming method,
A step of holding a plurality of lengths in the main scanning direction section and sub-scanning direction section of image data in which images are sequentially formed by the image forming unit;
Writing the corresponding image data in the delay memory based on the length of the main scanning direction section and the sub-scanning direction section held in the page unit;
Reading the corresponding image data written in the delay memory based on the length of the main scanning direction section and the sub scanning direction section held in the page unit;
A page specification process for performing a specific operation;
An image forming method comprising: checking whether or not there is an interrupt for the specific operation at the end of a page, and changing the image data processing for only the page if an interrupt is present.   When forming an image with the image forming means, reading the image data of the previous page from the delay memory and writing the image data of the next page to the delay memory in parallel are performed separately from the image data reading / writing. 6. The image forming method according to claim 5, wherein an input timing of the page designating step is performed at an arbitrary timing, and an operation of enabling the page designating unit is performed between pages.   6. The image forming method according to claim 5, wherein the image forming unit has photosensitive drums of a plurality of colors, and the sheet is conveyed at an interval shorter than an interval between both ends of the arranged photosensitive drums.

Images