JP3692615B2 - Multi-function printer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a tandem color printing apparatus using an electrophotographic system.
[0002]
[Prior art]
First, a tandem color printing apparatus using an electrophotographic system will be described. The first generation of color copying machines using the electrophotographic system uses the frame sequential printing system. This is a system that uses one xerographic engine, which wraps paper around a transfer drum and prints black, yellow, magenta, and cyan for each rotation to achieve full color printing. . However, since four colors are printed by rotating the transfer drum four times, it is not suitable for high-speed processing.
[0003]
For this reason, as represented by DocuColor (trademark) of Fuji Xerox Co., Ltd., a color copier using a tandem method for the purpose of speeding up has recently been put on the market. This is a system that uses four xerographic engines responsible for black, yellow, magenta, and cyan colors. The four xerographic engines are arranged in series on a transfer belt for paper feeding, and high-speed printing is realized by sequentially printing four colors according to the paper feeding. In a color copier using such a tandem system, the four xerographic engines start printing with a certain time difference due to their respective intervals. For this reason, the image processing unit is usually provided with a buffer memory for holding the scanned image data and transferring the image data of each color to the xerographic engine while compensating for the time difference of printing. .
[0004]
By the way, in recent years, colorization of documents in offices has progressed, and the use of color copiers and color printers has become common. In particular, in a relatively small office environment where efficient use of space is desired, it is expected that the demand for a multifunction printing apparatus having both functions of a copying machine and a printer will increase. A method for providing a multi-function printing apparatus that can be used as a printer by providing an interface unit for an external device in a color copier has been studied and proposed.
[0005]
An example of this is disclosed in JP-A-5-153384. This will be described below. Various image processing is performed inside the color copying machine. In other words, the scanner reads the original image with the RGB color system, converts it to the L * a * b * color system, performs compression, color conversion, etc., and then temporarily stores it in the temporary storage unit, and then the xerographic engine for each color The L * a * b data is converted into any one of the CMYK color signals of the CMYK color system and output at the timing requested by. At this time, in this prior art, by knowing in advance the color signal of the image data from the printer control unit, the image data from the external device is input to the copier system at an appropriate position according to the type of the color signal. ing.
[0006]
Japanese Patent Laid-Open No. 6-86032 discloses an example in which image information generated by a computer is converted into intermediate format data, and then image data is generated by a printer output control unit. This will be described below. Documents and charts requested by the user for printing are expanded into intermediate format data and stored in the intermediate format data storage unit. The intermediate format data is composed of color data encoded for each image type and command data for integrating the plurality of color data and decoding them into one page of image data. The printer output control unit transfers the intermediate format data from the intermediate format data storage unit and analyzes the command data by the control unit. At the same time, the printer output control unit outputs a plurality of color data encoded for each image type according to the output of the control unit. The image data is combined by the image data combining unit, and one color is output in accordance with a control signal from the printing apparatus. When a color document is printed using a frame sequential color copying machine, this process is repeated four times to perform multicolor printing. When a tandem color copier is used, four printer output control units are used.
[0007]
However, when the multi-function printing apparatus is configured by the method disclosed in Japanese Patent Application Laid-Open No. 5-153384, the color signal output from the printer output control unit is CMYK, so the input of image data compensates for the printing time difference. This is performed after the temporary storage unit for doing this. For this reason, it is necessary to compensate for this time difference on the printer output control unit side, and there is a problem that a circuit related thereto is required in the printer output control unit.
[0008]
Further, when a tandem multi-function printing apparatus is configured using four printer output control units disclosed in Japanese Patent Application Laid-Open No. 6-86032, the same command data is used for each color. However, there is a problem that each printer output control unit needs to have a control unit.
[0009]
[Problems to be solved by the invention]
The present invention has been made in view of such a conventional problem, and enables image data output from a printer output control unit to be input to a preceding stage of a temporary storage unit. As a result, printer output control is performed. An object of the present invention is to eliminate the need for a circuit for compensating for the printing time difference on the unit side, and to simplify the circuit of the printer output control unit.
[0010]
[Means for Solving the Problems]
According to the present invention, in order to achieve such an object, a printing unit that includes a plurality of printing units and realizes multicolor printing by printing different colors with the plurality of printing units, and temporarily stores image data. Image data storage means for storing and reading out to the plurality of printing units at different timings, and reading the original image and inputting it as image data to a multi-function printing apparatus that performs color matching of the multicolor printing based on the timing And color data encoded by image type, and command data for integrating these multiple color data and decoding them into page-by-page image data. Means for developing the intermediate format data to be configured, and converting the intermediate format data into image data. Image data switching means for selectively inputting image data obtained by reading the original image and image data obtained by converting the intermediate format data and outputting the image data to the image data storage means And so on.
[0011]
In this configuration, when the image data is generated from the intermediate format data for printing, the generated image data is stored in the image data storage unit via the image data switching unit in the same manner as the image data obtained by reading the original image. Therefore, the output timing for each printing unit can be realized when the image data is read from the image data storage means. That is, a printer control device (or the above-described printer output control unit that forms part of the printer control device and generates image data from intermediate format data) to compensate for the printing time difference between a plurality of (for example, four) printing units. It is not necessary to provide a plurality of control units and output image data of a plurality of colors independently for each color. For this reason, the circuit of the printer control device can be simplified.
[0012]
In this configuration, the image data storage means may have a capacity capable of storing an image for at least one page.
[0013]
Further, the image data storage means has a capacity required to compensate for the time difference between the data output time to the printing unit that performs printing first and the data output time to each of the other printing units. You may make it have about each printing unit.
[0014]
Alternatively, the intermediate format data may be compressed, and the intermediate format data may be combined with image data after being decompressed. In this case, the intermediate format data is color data compressed and encoded for each image type, and command data for integrating these multiple color data and decoding them into one page of image data. Can do.
[0015]
Further, according to the present invention, in order to achieve the above-described object, a printing unit that includes a plurality of printing units and realizes multicolor printing by printing different colors with the plurality of printing units; Image data storage means for temporarily storing and reading to the plurality of printing units at different timings, image data switching means for reading the original image and inputting it as image data, image data obtained by reading the original image, and others Image information generated by a computer is stored in a printer control device used in a printing apparatus having means for selectively inputting image data from the image data source and outputting the image data to the image data storage means. Separately encoded color data and these multiple color data are integrated and decoded into page-by-page image data Means for developing the intermediate format data as command data, intermediate format data storage means for storing the intermediate format data, and the intermediate format data from the intermediate format data storage means. A transfer unit for transferring, a single control unit for analyzing the command data in the transferred intermediate format data, and a plurality of encoded for each type of the image in the transferred intermediate format data And a plurality of image data synthesizing units for synthesizing the color data by the output of the control unit and simultaneously outputting the image data of a plurality of colors to the image data switching means.
[0016]
In this configuration, a plurality of (for example, four) image data combining units are controlled by using a single control unit in the printer control apparatus, so that the printer control apparatus simultaneously transmits a plurality of colors (for example, four colors) of image data. can do. Therefore, when the above-described printing apparatus is used as a color printer, the image data can be input to the preceding stage of the image data storage means for temporary storage, as in the case of using as a color copying machine. As a result, in order to compensate for the printing time difference between the plurality of printing units, there is no need to provide four control units on the printer control device side and output image data of a plurality of colors independently for each color. For this reason, the circuit of the printer control device can be simplified.
[0017]
Further, according to the present invention, in order to achieve the above-described object, a printing unit that includes a plurality of printing units and realizes multicolor printing by printing different colors with the plurality of printing units; Image data storage means for temporarily storing the image data and reading the data to the plurality of printing units at different timings. The original image is read and input as image data to a printing apparatus that performs color matching of the multicolor printing based on the timings. And means for selectively inputting image data obtained by reading the original image and image data from another image data source and outputting the image data to the image data storage means.
[0018]
Even in this configuration, when the printer control device is used to achieve multiple functions, a plurality of control units are provided in the printer control device in order to compensate for a printing time difference between a plurality of (for example, four) printing units. It is not necessary to output the image data separately for each color. For this reason, the circuit of the printer control device can be simplified.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[Example 1]
FIG. 1 is a block diagram showing Embodiment 1 of the image processing system of the present invention. In the figure, 1 is a host computer that creates a document or chart described in a page description language such as PostScript (trademark of Adobe Systems Inc.), 2 is an interpreter of the page description language, and generates image data. A printer controller to be transferred to the printing apparatus, 3 is a local area network (hereinafter referred to as LAN) such as Ethernet (trademark) or FDDI connecting the host computer and the printer controller, and 11 is used to input image data to be copied. A scanner 12 for converting RGB images read by the scanner into CMYK, an RGB / CMYK converter 13, and an image data input side (scanner 11 side) and a printer controller 2 side as image data input destinations. An image data switching means for switching, 14 is a plurality of image data First storage means for compensating for the time difference transferred to the character device, 15 to 18 are printing devices for printing YMCK image data, and 21 is a document written in a page description language, which is encoded into intermediate format data (described later) Intermediate format data generation means 22, 22 is a network I / F for connecting the printer controller 2 to the LAN, 23 is second storage means for temporarily storing the generated intermediate format data, and 24 is a second storage The printer output control means 29 synthesizes the intermediate format / data stored in the storage means 23 to generate image data and transfers it to the image data switching means 13, 29 is the intermediate format / data generation means 21, and the second storage means 23. A bus connecting the printer output control means 24.
[0020]
An outline of the operation of the multi-function printing apparatus according to the present embodiment will be described separately for a color copying machine and a color printer.
[0021]
When this multipurpose printing apparatus is used as a color copying machine, the image data switching means 13 designates the scanner 11 as an input destination of image data. Image data read in RGB from the scanner 11 is converted to L * a * b * after correction depending on the device of the input gradation. Then, black is generated and finally converted to CMYK depending on the device characteristics of the printing apparatuses 15 to 18. These are performed by the RGB / CMYK color converter 12. The CMYK image data is transferred to the first storage unit 14 via the image data switching unit 13 while synchronizing four colors in parallel. These color conversion and transfer are performed in real time in accordance with the operation of the scanner 11.
[0022]
In a tandem type color copying machine using a plurality of printing devices 15 to 18, a deviation occurs in the printing start time of each color as described above. The first storage means 14 compensates for this. In this embodiment, the first storage means 14 has a capacity capable of storing image data for at least one page. At this time, the first storage unit 14 temporarily stores the image data for one page, and then transfers the image data to the printing devices 15 to 18 in response to the image data request signals from the respective printing devices 15 to 18. When printing for the requested number of sheets is completed, the image data stored in the first storage unit 14 is deleted, and the next image data input waiting state is entered. The above is the flow of processing when this multifunction printer is used as a color copying machine.
[0023]
On the other hand, when this multifunction printing apparatus is used as a printer, the image data switching means 13 designates the printer output control means 24 as an input destination of image data. When the host computer 1 connected to the printer controller 2 via the LAN 3 issues a print instruction for a document or chart written in the page description language, this data is transferred to the intermediate format of the printer controller 2 via the LAN 3. It is transferred to the data generation means 21. The intermediate format data generation means 13 performs the parsing of the page description language and the coordinate conversion of the vector data, then encodes the intermediate format data and stores it in the second storage means 23. When the storage is completed, a system control unit (not shown) transmits a print start instruction to the four printing devices 15 to 18.
[0024]
The printers 15 to 18 perform initialization such as registration and heat up, while the printer output control unit 24 starts to transfer intermediate format data from the second storage unit 23.
[0025]
When the printers 15 to 18 are ready for printing, they send control signals such as page sync, line sync, and byte clock to the printer output control means 24. The printer output control means 24 simultaneously outputs image data of four colors in parallel according to this control signal and intermediate format data.
[0026]
The image data output from the printer output control means 24 passes through the image data switching means 13 and then temporarily stored in the first storage means 14 and after compensating for the printing start time difference in each of the printing devices 15-18. It is transferred to the printing devices 15-18. Since the operation after the image data switching means 13 is the same as that when the multifunction printing apparatus is used as a color copying machine, the description thereof is omitted.
[0027]
In contrast to the embodiment, in the case of the conventional example as shown in FIG. 2, control signals such as page sync, line sync and byte clock sent from the printers 15 to 18 to the printer controller 2 are sent to the printers 15 to 18. To the printer output control means 25-28. This is because each printer output control means 25-28 needs to compensate for a shift in printing start time of each printing device 15-18, so that one control unit can control four image data synthesis units (described later). This is because it cannot be done. In the first embodiment shown in FIG. 1, it is only necessary to transmit a control signal to the printer output control means 24 only from the printing apparatus (K in this case) that starts printing first. This is because compensation for the deviation of the printing start time of each of the printing devices 15 to 18 is performed by the first storage means 14 in the preceding stage of the printing devices 15 to 18. In this way, the circuit of the printer output control means 24 can be simplified. In FIG. 2, portions corresponding to those in FIG. 1 are denoted by corresponding reference numerals, and detailed description thereof is omitted.
[0028]
Next, details of the processing until conversion from the page description language to the intermediate format data when the multi-function printing apparatus is used as a printer will be described.
[0029]
Page description languages such as PostScript (trademark of Adobe Systems Inc.) and Interpress (trademark of Xerox Corporation) for printing use a device-independent coordinate system that does not depend on the printer, and character information and graphics Information is mainly described as vector data. Since the printing device cannot directly interpret these data, it must be converted into raster data (bit map data) in a format that the printing device can understand before being transferred to the printing device.
[0030]
FIG. 3 is a diagram showing processing until data written in the page description language is expanded into intermediate format data. In FIG. 1 and FIG. 3, the page description language transferred from the host computer 1 to the printer controller 2 is passed to the intermediate format data generation means 21. In the intermediate format / data generating means 21, lexical analysis is first performed by an interpreter (not shown) and transferred to an imager (not shown). The imager unit performs appropriate processing for each object such as character data, graphic data, and image data. In other words, for character data, the coordinates of each point of the vector font are represented in a device-dependent coordinate system, and for graphic data, the curve represented by a Bezier curve is approximated by a straight line, and rotation is performed. It is the role of the imager unit to perform, end point processing, and color conversion and resolution conversion for sample images.
[0031]
Each object interpreted by the imager unit is inserted and stored in a page unit list called an object list. The object list is a list of all objects described in the page description language. However, depending on the vertical relationship between objects, an object may be completely under another object, and not all objects are printed on paper. Therefore, it is necessary to extract only the object (or part of it) that appears on the paper from the object list. The process for this is called a smoothing process. In the smoothing process, all objects belonging to the same scan line are examined, and the highest level object at each point is collected and listed. This list is called a run list. If the run list thus generated is developed into raster data and transferred to the printers 15 to 18, desired data can be printed.
[0032]
However, storing a document to be printed as raster data requires a huge memory depending on the resolution of the printing apparatus. For example, when the resolution of the printing apparatus is 600 dpi (dots per inch: the number of dots per inch), raster data for A3 paper size requires a large amount of memory of about 265 megabytes. For this reason, in order to reduce the cost required for the memory, it is important to reduce the amount of data by performing some kind of compression.
[0033]
FIG. 4 shows the concept of the object-specific compression method based on Japanese Patent Laid-Open No. 6-86032. Documents and diagrams written in a page description language can be broadly divided into character data consisting of fonts, graphics data created with graphics / graph creation software, scanned image data obtained by scanning photographs, etc. Can be classified into three objects. In this method, the run list obtained by the imager and the subsequent smoothing process is encoded for each object using an optimum method to generate intermediate format data. The intermediate format data is decoded in real time using hardware and converted into image data before being transferred to the printers 15 to 18 side. The encoding method for each object is as follows.
[0034]
Although character data uses a small number of colors, it is data that requires resolution. Therefore, contour information is saved using binary bit map data (referred to as mask data), and color information of two colors of character color / background color (referred to as constant color data). Can be expressed using. At this time, the character data can be compressed to about 1/32 compared to the raster image data of 8 bits for each color. In addition, since graphics data often has a constant value of several hundred to several thousand pixels, a high compression rate is obtained by run-length compression using color information (constant color data) and its continuous information. be able to. In the case of scan image data, the resolution is 200 to 400 dpi, and the same pixel value is rarely continuous, so the scan image data is encoded without being compressed.
[0035]
In this way, by adding command data for decompression to data encoded for each object to obtain intermediate format data, it is possible to decompress the original image data. At this time, in a document with a small amount of scan image data, a high compression ratio of 1/10 to 1/30 is obtained, and the second storage means 23 has a memory corresponding to one page of image data. In some cases, intermediate format data for 10 to 30 pages can be temporarily stored.
[0036]
FIG. 5 shows an example of such intermediate format data. Intermediate format data indicates command data for integrating encoded data for each object, mask data representing bit map information of character data, and color data used as an index during run length compression It consists of sample color data in which constant color data and scan image data are arranged in a dot-sequential manner.
[0037]
FIG. 6 shows an example of command data. The command data is composed of 2-byte codes each divided from A to E. A indicates which color register (described later) of the image data synthesis unit 45 (FIG. 9) is loaded with constant color data. When 00, load color register 0; when 01, load color register 1; when 10, load color register 2; when 11, do not load a new constant color. B indicates which color register is selected by the multiplexer A (drawing color, which will be described later) of the image data synthesis unit 45. 00 selects color register 0, 01 selects color register 1, 10 selects color register 2, and 11 is undefined here. C indicates which color register is selected by the multiplexer B (background color, which will be described later) of the image data synthesis unit 45. 00 indicates that color register 0 is selected, 01 indicates that color register 1 is selected, 10 indicates that color register 2 is selected, and 11 indicates that a sample channel is selected. D indicates whether to use mask data. 0 indicates that the multiplexer used for output referring to the mask data is A or B, and 1 indicates that the multiplexer used for output without referring to the mask data is A. E is a count. It indicates how many pixels this command data is valid.
[0038]
FIG. 7 shows an example of mask data. 0 indicates that the multiplexer A (drawing color) is selected, and 1 indicates that the multiplexer B (background color) is selected. The mask data is referenced only when the command data is D = 0. Therefore, the mask data length in one page of intermediate format data is equal to the sum of the counts (E) of command data in which D = 0.
[0039]
FIG. 8 shows an example of the configuration of constant color / sample color data. Both the constant color and the sample color are expressed in a format in which four colors of KYMC components represented by 256 tones are sequentially arranged. If the constant color and the sample color are arranged dot-sequentially in this way, the KYMC value of each color can be read simultaneously by reading 4 bytes at a time, which is convenient for the tandem method. Since the constant color data is loaded into the color register when the command data is A ≠ 11, the number of constant color data is equal to the number of command data. The sample color data is read by the count number E when the command data is C = 11. Therefore, the number of sample color data is equal to the sum of the command data count (E) where C = 11.
[0040]
Next, the operation of the printer output control means 24, particularly the details of the control unit 44 and the image data synthesis unit 45 will be described with reference to FIG.
[0041]
FIG. 9 shows a hardware configuration of the printer output control means 24. The printer output control means 24 takes in the intermediate format data from the second storage means 23 and distributes the data to an appropriate channel among the command channel, mask channel, constant color channel, and sample color channel. A transfer unit 41 that analyzes the command data, sends a signal for controlling the image data synthesis unit 45, takes in data divided by object such as constant color, sample color, and so on from the control unit 44 And an image data synthesis unit 45 that synthesizes image data based on the above information.
[0042]
FIG. 10 shows a hardware configuration of the control unit 44. The control unit 44 distributes the command data from A to E for each data, the load information monitoring unit 52 for sending a constant color transfer request signal based on the data of A, and the data of C. Based on the sample monitor 53 for sending the sample color transfer request signal, the counter 54 for counting the byte clock of the control signal until the E value of the command data is reached, the command data B, C, D The register 55 temporarily holds the value of.
[0043]
FIG. 11 shows a hardware configuration of the image data synthesis unit 45. The image data composition unit 45 outputs three color registers 61 to 63 for holding constant color data, and two multiplexers (A and B) 64 and 65 for selecting a color register for drawing color and background color. It comprises a multiplexer (C) 66 that selects which multiplexer is used as a color.
[0044]
When the command / data stored in the second storage means 23 is transferred to the control unit 44 by the transfer unit 41, first, it is decomposed into data A to E by the command distribution unit 51 and distributed to appropriate channels. . A is data indicating which color register is loaded with a new sample color. This data is transmitted to the load information monitoring unit 52 and the image data synthesizing unit 45 at the first byte clock in the count in which the command data is valid. The load information monitoring unit 52 checks whether a new constant color load is requested in A, and if there is a request, sends a constant color transfer request signal to the transfer unit 41. Since A needs only to be executed once per command / data, it is not necessary to hold A's data using a register. B and C are data indicating which color register is selected by each of the multiplexers A and B. This data is transmitted to the four image data synthesis units 45 in synchronization with the byte clock. Since this data needs to be valid for the count number indicated by E of the command data, this information is held using the register 55. D is data indicating whether the command data requires mask data. When the mask data is necessary, the control unit 44 transmits a mask data transfer request signal to the transfer unit 41. If mask data is not needed, do nothing. Since this data also needs to be valid for the count number indicated by E in the command data, this information is held using a register. E is data indicating how many counts the command data is valid. The byte clock is counted by the count number, and when the value is reached, the control unit 44 transmits a command / data transfer request signal to the transfer unit 41.
[0045]
Next, the operation of each image data synthesis unit 45 that receives signals from these control units 44 will be described. First, when the constant color load is indicated by the signal A coming from the control unit 44, the control unit 44 transmits a constant color transfer request signal to the transfer unit 41. Therefore, the image data synthesis unit 45 may load the constant color data sent from the transfer unit 41 into the color register designated by the A signal. The color registers designated by the B signal and the C signal are designated by the multiplexers A and B. Then, the F signal is checked, and if the mask data is valid, the multiplexer is designated according to the F signal. When the mask data is invalid, the multiplexer A is designated. Then, the image data is transmitted in synchronization with the byte clock. Since each image data synthesis unit 45 is output in synchronization with the same byte clock, it is guaranteed that the image data output from the four image data synthesis units 45 are synchronized in parallel.
[0046]
[Example 2]
Next, a second embodiment of the present invention will be described. In this embodiment, the first storage unit 14 has a capacity necessary for compensating for the time difference between the printing device that performs printing first and each printing device for each printing device 15 to 18. It is.
[0047]
FIG. 12 shows the first storage means 14 in the second embodiment. Here, it is assumed that the printing devices 15 to 18 in charge of the colors of KYMC are arranged at intervals of L1, L2, and L3, respectively. At this time, the image data size existing between the print start times of the K and Y printing devices 15 and 16 is L1 * l * D bytes. Here, l is the length of the paper in the scanning direction, and D is the printing resolution. Similarly, the image data size existing between the print start times of the K and M printing devices 15 and 17 is (L1 + L2) * l * D bytes, and the print start times of the K and C printing devices 15 and 18 are the same. The image data size existing during the shift is (L1 + L2 + L3) * l * D bytes. Therefore, in order to compensate for the difference in printing start time of the printing devices 15 to 18, a buffer having a size capable of storing these image data is arranged in front of each printing device 16 to 18, and the transfer of the image data is delayed. You can do that.
[0048]
In the case of the first storage unit 14 shown in FIG. 12, the first storage unit cannot store image data for one page. Therefore, when printing a plurality of sheets, the scanner 11 is only for the number of printed sheets. The document needs to be scanned. Instead, there is an advantage that the first storage means 14 can be made smaller compared to the case where the first storage means 14 has a capacity for one page.
[0049]
The operation of the multi-function printing apparatus in the present embodiment is the same as that in the first embodiment except for the configuration of the first storage unit 14 and the operation related thereto.
[0050]
[Example 3]
Next, a second embodiment of the present invention will be described. In this embodiment, the intermediate format data is encoded in a compressed form, and the printer output control means 24 decompresses the intermediate format data encoded in a compressed form, and synthesizes it with the image data to print it. The data is transferred to the 15-18 side.
[0051]
In this embodiment, when generating the intermediate format data, the sample color is subjected to fixed-length block compression for each sub-scan line corresponding to the block size in the sub-scan direction. This is done for each color. The fixed-length block compression processing technique used in the present embodiment is called a GBTC (Generalized Block Truncation Coding) type coding system. Details are described in, for example, the 1990 National Conference of the Institute of Electronics, Information and Communication Engineers, D-254 (1990). A feature of this technique is that an image is divided into blocks of a certain size, and the image data is encoded with respect to three components of an average level of the block, a gradation width index within the block, and a quantization level for each pixel. In this embodiment, dedicated hardware is used in which one block is 4 × 4 pixels and the compression rate (fixed) is 3/8.
[0052]
FIG. 13 shows the configuration of sample data when this fixed-length block compression processing technique is used. In the figure, sample0-2 (K) is the second byte data of the 0th block of K color. If fixed-length block compression is used, the block lengths are equal to each color, so that data of each color can be arranged in block order in the order of CMYK, for example, for each byte. This arrangement is convenient when simultaneously extracting CMYK sample / color data.
[0053]
FIG. 14 shows the printer output control means 24 when this fixed-length block compression processing technique is used. In the figure, reference numeral 71 denotes a decoding unit for decoding compressed sample data. The transfer unit 41 extracts the sample data of the number of blocks corresponding to 4 scan lines from the second storage unit 23 and transfers the sample data to the decoding unit 71. The decoding unit 71 expands this into 4 × 4 blocks, and temporarily holds them in a buffer for 4 scan lines. Then, according to the sample color transfer request signal sent from the control unit, the sample color data is transferred to the image data synthesis unit 45. It is assumed that the decoding unit 71 can obtain the data throughput required by the image data synthesis unit 45.
[0054]
The operation of the multi-function printing apparatus in this embodiment is the same as that in the first and second embodiments except that the sample data is subjected to a fixed-length compression process and is decompressed by the decoding unit 71. The details are omitted here.
[0055]
As described above, according to the method described in the above embodiments, the first storage unit 14 used to compensate for the difference in the printing time is suitably used in the multi-function printing apparatus, thereby controlling the printer output. The means 24 can be simplified.
[0056]
In addition, this invention is not limited to the above-mentioned Example, A various change is possible in the range which does not deviate from the meaning. For example, the present invention can be applied not only to an image forming apparatus using an electrophotographic process but also to other recording apparatuses such as an ink jet recording apparatus and a thermal transfer recording apparatus.
[0057]
【The invention's effect】
As described above, according to the present invention, the image data generated in the printer output control unit based on the image information created by the computer is input to the preceding stage of the image data storage means for temporary storage. On the printer output control unit side, a circuit for compensating for the printing time difference is not necessary, and the circuit of the printer output control unit can be simplified.
[Brief description of the drawings]
FIG. 1 is a block diagram for explaining an overall printing system configuration according to a first embodiment of the invention.
FIG. 2 is a block diagram for explaining a configuration of a conventional printing system.
FIG. 3 is a diagram showing a flow of processing from page description language to intermediate format data.
FIG. 4 is a conceptual diagram of intermediate format data used in the present invention.
FIG. 5 is a configuration diagram of intermediate format data.
FIG. 6 is a conceptual diagram of command data.
FIG. 7 is a configuration diagram of mask data.
FIG. 8 is a configuration diagram of constant color / sample color data.
9 is a configuration diagram of a printer output control means 24. FIG.
10 is a configuration diagram of a control unit 44. FIG.
11 is a configuration diagram of an image data synthesis unit 45. FIG.
FIG. 12 is a diagram illustrating the configuration of first storage means 14 used in Embodiment 2 of the present invention.
FIG. 13 is a configuration diagram of sample data of fixed length compression used in Embodiment 3 of the present invention.
FIG. 14 is a configuration diagram of printer output control means 24 used in Embodiment 3 of the present invention.
[Explanation of symbols]
1 Host computer
2 Printer controller
11 Scanner
13 Image data switching means
14 First storage means
15-18 printing device
21 Intermediate format data generation means
23 Second storage means
24 Printer output control means
41 Forwarding unit
44 Control unit
45 Image data composition unit
71 Decoding part

Claims (6)

A plurality of printing units corresponding to a plurality of printing colors, and printing means for realizing multi-color printing by printing different printing colors by the plurality of printing units; and temporarily storing each image data for each printing color In the multi-function printing apparatus having image data storage means for reading out each image data to the plurality of printing units at different timings and performing color matching of the multicolor printing based on the timings,
Means for reading an original image, performing color conversion and inputting it as image data for each print color;
Intermediate information composed of computer-generated image information, color data encoded by image type, and command data for integrating these multiple color data and decoding them into page-by-page image data Means for developing the format data,
A plurality of image data synthesizer and printer output control means comprising a single control unit corresponding to a plurality of print colors, the plurality of the image data synthesizer to the color data is input both of the single Printer output control means for simultaneously controlling according to the command data by the control unit and outputting each image data for each print color from the intermediate format data at the same timing ;
Each image data for each print color obtained by reading the original image and each image data for each print color generated simultaneously from the intermediate format data are selectively input and output to the image data storage means And a multi-function printing apparatus.   2. The multifunction printing apparatus according to claim 1, wherein the image data storage means has a capacity capable of storing at least one page of images.   The image data storage means stores the capacity required to compensate for the time difference between the data output time to the first printing unit that performs printing and the data output time to each of the other printing units. The multi-function printing apparatus according to claim 1, which is provided for each unit.   4. The multi-function printing according to claim 1, wherein the intermediate format data is in a compressed form, and the intermediate format data is decompressed and then combined with each image data for each print color. apparatus.   5. The intermediate format data includes color data compressed and encoded for each image type, and command data for integrating the plurality of color data and decoding into one page of image data. The multifunction printer described. A plurality of printing units corresponding to a plurality of printing colors, and printing means for realizing multi-color printing by printing different printing colors by the plurality of printing units; and temporarily storing each image data for each printing color Image data storage means for reading to the plurality of printing units at different timings, original image reading means for reading the original image and performing color conversion and inputting it as image data for each print color, and obtained by reading the original image Used in a printing apparatus having image data switching means for selectively inputting each image data for each print color and each image data for each print color from another image data source and outputting the image data to the image data storage means. In the printer control device,
Intermediate information composed of computer-generated image information, color data encoded by image type, and command data for integrating these multiple color data and decoding them into page-by-page image data Means for developing the format data,
Intermediate format data storage means for storing the intermediate format data;
A transfer unit for transferring the intermediate format data from the intermediate format data storage means;
A single control unit for analyzing the command data in the transferred intermediate format data;
The plurality of color data encoded according to the type of the image in the transferred intermediate format data is synthesized by the output of the control unit, and the image data switching means for each print color at the same timing. And a plurality of image data synthesizing units that output to the printer control apparatus.

Images