JP2005283904A - Image forming apparatus and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable a printing device to effectively use decoders, which decode print data, regardless of the length of paper used for printing. <P>SOLUTION: From a receiver buffer 6, a piece of Y even data, a piece of Y odd data, a piece of M even data and a piece of M odd data, all of which are compressed print data, are transferred to and decoded by decoders 501, 502, 503, and 504, respectively. The pieces of video data recovered are sequentially outputted to a video I/F 510 via FIFOs 505 to 508 and a selector 509. Thereafter, likewise, a piece of C even data, a piece of C odd data, a piece of K even data and a piece of K odd data are transferred to the decoders 501, 502, 503, and 504, respectively, which have finished the processes, and they are successively outputted to the video I/F 510. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus and an image forming method.

  2. Description of the Related Art Conventionally, an image forming apparatus such as a laser beam printer is known that includes an image forming unit such as a photosensitive drum (image carrier) for each color of toner (recording agent) to be used. For example, in an apparatus for forming an image on a sheet (recording medium) using four types of toners of cyan (C), magenta (M), yellow (Y), and black (K), a conveyance path for conveying the sheet is used. Four image forming units are provided along. Also, in an image forming apparatus, print data sent from a host device (external device) is often received by a reception buffer as compressed data and restored using a decoder for use. In this case, an image forming apparatus having an image forming unit for each toner color to be used as described above uses a plurality of decoders for decoding processing in order to supply print data in synchronization with the image forming operation by these units. In general, this is performed in parallel for each type of toner.

  FIG. 1 is a diagram showing the structure of a decoding process of a printer according to a conventional example, in particular. As shown in FIG. 1, print data for each color in a compressed state transferred from a personal computer (PC) 1 as a host device is stored in a reception buffer 6 under the control of a CPU 7. When there is a print data transfer request from a printer engine configured by the image forming unit or the like, the control unit 50 of the controller 5 receives the print data for each color stored in the reception buffer 6 and corresponds to the decoders 51Y and 51M. , 51C and 51K, respectively. In these decoders, the compressed print data is restored and sent to the corresponding FIFOs 52Y, 52M, 52C, and 52K in the subsequent stages. This FIFO synchronizes with the engine side and is output to the engine as video signals Video1 to Video4, respectively. In other words, conventionally, the number of decoders for restoring (converting) compressed print data in the printer controller is decoded to be the same as the number of image forming units that form an image on paper with a plurality of color toner images. Processing was performed in parallel for each color (for example, see Patent Document 1).

JP 2003-330631 A

  However, in the configuration related to the conventional decoding process described above, at least one of the decoders provided for each color is used in relation to the length L of the paper used for image formation and the arrangement interval D of the plurality of image forming units. There is a problem that the decoder is not used effectively as a result.

  FIGS. 2A and 2B are diagrams for explaining this problem, and are diagrams schematically showing the relationship between the arrangement interval D of the image forming units (photosensitive drums in each color) and the length L of the paper. is there. In FIG. 2, Ly, Lm, Lc, and Lk indicate laser beams emitted from a semiconductor laser (not shown) based on image data output from Video1, Video2, Video3, and Video4, respectively. As shown in FIG. 1A, when image formation is performed on four sheets of a long sheet of paper at the same time, there is a period in which the video signals Video1 to Video4 shown in FIG. 1 are simultaneously output. . Accordingly, the decoders 51Y, 51M, 51C, and 51K have a period during which decoding processing is performed simultaneously.

  On the other hand, as shown in FIG. 2B, in the case where there are two drums for forming an image simultaneously on one sheet with a short sheet length L, for example, there are four decoders 51Y. , 51M, 51C, 51K, two decoders are used simultaneously. In this case, there are times when the two decoders are not used, and as a result, the decoders are not used effectively.

  The present invention has been made to solve this problem. The object of the present invention is to convert received data of a predetermined color into image data by performing conversion processing of received data of a predetermined color into image data. An object of the present invention is to provide an image forming apparatus capable of speeding up conversion processing.

  Therefore, in the present invention, in an image forming apparatus that forms a color image by superimposing a plurality of color images on the paper by a plurality of image forming units arranged along a paper conveyance path, a plurality of images received from an external device Storage means for storing received data relating to color, a plurality of data processing means provided corresponding to the plurality of image forming units, and converting the received data into image data used in the image forming unit; Control means for controlling transfer of the received data from the storage means to the data processing means, and the control means transfers the received data for a predetermined color to any one of the plurality of data processing means. A first control mode for controlling to perform, and a second control mode for controlling to transfer the received data relating to the predetermined color to the two or more data processing means. Characterized in that it has.

  An image forming method for printing on paper using a plurality of types of recording agents, the decoder for decoding print data corresponding to each of the plurality of types of recording agents, wherein at least the recording agent A number of decoders corresponding to the number of types, and means for forming an image on a sheet based on print data decoded by the decoder, comprising image forming means corresponding to each of the plurality of recording agents. The print data of a plurality of predetermined recording agents in each of the plurality of types of recording agents is subjected to decoding processing divided using a plurality of decoders, and the plurality of decoders for the print data of the predetermined plurality of recording agents Each of them has a step of performing decoding processing in a time-sharing manner with each other.

  According to the present invention, it is possible to provide an image forming apparatus capable of speeding up conversion processing of received data by performing conversion processing of received data of a predetermined color into image data by a plurality of data processing means. it can.

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

  FIG. 3 is a block diagram showing a schematic configuration of the printer according to the embodiment of the present invention.

  As shown in FIG. 3, a printer 2 as an image forming apparatus forms an image based on print data sent from a host apparatus 1 such as a personal computer (PC). The print data sent from the host device 1 is, for example, data in a format in which image data in bitmap format is compressed, and the printer 2 performs a conversion process by a decoder to restore the compressed image data.

  The printer 2 includes an electrophotographic engine unit 4 using a laser beam. This engine unit 4 applies four types of toners of yellow (Y), magenta (M), cyan (C), and black (K). Correspondingly, four image forming units 401 to 404 each having photosensitive drums 201 to 204 are provided.

  The printer 2 also includes a controller unit 3 that performs overall control of the printer 2. The controller unit 3 controls the arithmetic processing of the ASIC 5 that performs arithmetic processing on print data and signals, the print data from the host device 1 and stores the compressed print data, and the ASIC 5. The CPU 7 is configured as an information processing apparatus that performs overall control of the printer, such as processing of print data and operation of the engine unit 4. The ASIC 5 includes four decoders 501 to 504 and four FIFO buffers 505 to 508 corresponding to the four image forming units 401 to 404 of the engine unit 4, and a plurality of video data (image data) as described later. A selector 509 for switching a transfer destination to which of the image forming units 401 to 404 is to be transferred. The reception buffer 6 is configured by a DRAM that can store print data of each color of Y, M, C, and K by dividing the print data into a plurality of areas.

  As will be described later, the data transferred from the host device 1 is once stored in the reception buffer 6 separately for each color area. This received data is read from each area (Yeven, Meven, Ceven, Keven, Yodd, Modd, Codd, Kodd) of the receiving buffer 6 in response to a request from the engine unit 4 and restored by the decoder of the ASIC 5. Converted to video data. The video data transferred from the decoders 501 to 504 to the FIFO buffers 505 to 508 is sent to the image forming units 401 to 404 of the engine unit 4 to form an image on a sheet. Here, the transfer destination of the print data of a predetermined color (for example, yellow) stored in the reception buffer 6 is provided corresponding to the image forming unit (for example, the yellow image formation unit 401) corresponding to the predetermined color. A decoder (for example, decoder 501) may be selected, or a plurality of decoders (for example, decoders 501 and 502) may be selected as transfer destinations of print data of a predetermined color (for example, yellow). The CPU 7 gives these instructions to the ASIC 5.

  Several embodiments of the present invention based on the configuration described above will be described below.

(First embodiment)
In the first embodiment of the present invention, as shown in FIG. 2B, the paper length L used for printing in a printer having four image forming units is simultaneously formed by two image forming units. However, when the length is such that image formation is not performed simultaneously by three image forming units, that is, when the interval between the image forming units is D, the length L of the printing paper is 2D or less and greater than D. In this case, the configuration effectively uses four decoders.

  FIG. 4 is a block diagram showing a detailed configuration of the ASIC 5 according to the first embodiment of the present invention.

In FIG. 4, the host device 1 obtains the number of image forming units to be used simultaneously based on the relationship between the distance D, which is information on the image forming units obtained from the printer 2, and the length L of the paper used for printing. FIG. 2 shows a part of the printer 2 that forms a toner image on a sheet by an electrophotographic method. The image forming units 401 to 404 for each color provided from the upstream to the downstream in the transport direction are shown in FIG. , Photosensitive drums 201 to 204 as image carriers carrying toner as a recording agent, a laser light exposure unit (not shown) for forming an electrostatic latent image corresponding to video data on each photosensitive drum, Developing units 205 to 208 for developing the electrostatic latent image formed on the photosensitive drum with toner are provided.
In the present embodiment, the control mode is set to the first control mode when the length L of the printing paper is greater than 2D (first case) and when the length is 2D or less and greater than D (second case). The mode is different from the second control mode.

That is, in the second case, a maximum of two image forming units simultaneously use video data (in FIG. 2B, a Y image forming unit and an M image forming unit). In this case, the host apparatus 1 uses the four decoders 501 to 504 for the print data of Y, M, C, and K so that all of the four decoders 501 to 504 are simultaneously used via the control unit 500. Assign usage. That is, in the state shown in FIG. 2B, the C print data and the K print data do not need to be converted by the decoder, so the Y print data is converted using two decoders 501 and 502. , M data is assigned to be converted using decoders 503 and 504. The Y print data is all converted by the decoders 501 and 502, and the C print data is assigned to use the same decoders 501 and 502 as the Y print data. Further, the K data is assigned to use the same decoders 503 and 504 as the M data. After the above allocation process, the host device 1 compresses the image data of each color for each color and transfers the compressed image data to the reception buffer 6. At that time, the bandwidth (number of lines) to be compressed is compressed in accordance with the capacity (number of lines) of each of the FIFO buffers 505 to 508. For example, when the capacity of the FIFO buffer is 10 lines, the unit to be compressed by the host device 1 is 10 lines as 1 band. Then, these are transferred to the printer 2 as an even band and an odd band.
On the other hand, in the first case, that is, when the length of the printing paper is greater than 2D, the decoder 501 is used for Y print data, the decoder 502 is used for M print data, the decoder 503 is used for C print data, and K A decoder 504 is assigned to each print data.

  FIG. 5 is a diagram showing the allocation of print data storage areas in the reception buffer 6. FIG. 5A shows the allocation of the reception buffer 6 in the first case, and FIG. The allocation of the reception buffer 6 in the case of 2 is shown.

  As shown in FIG. 5B, the reception buffer 6 in the second case stores the transferred print data of each color in an area obtained by dividing the even band and odd band. As a result, the reception buffer is divided into eight. Further, as shown in FIG. 5A, the reception buffer 6 in the first case stores the print data divided into four areas for each color.

  As described above, after the reception of the print data from the host apparatus 1 is completed, first, according to the arrangement order of the image forming units 401 to 404 (FIG. 4) along the sheet conveyance path shown in FIG. , Y and M compressed print data are transferred from the reception buffer 6 to the four decoders 501 to 504 in the order of the even band and odd band, respectively. The Y even band data is the decoder 501 and the Y odd band data is In the decoder 502, the M even band data is decoded by the decoder 503, and the M odd band data is decoded by the decoder 504. Then, the restored print data (video data) is input to the corresponding FIFO buffers 505 to 508, and the video I is sequentially transmitted via the selector 509 in synchronization with the sequential image formation by the Y and M drums in the engine unit 4. / F510.

  Further, the C and K compressed print data are transferred from the reception buffer 6 to the four decoders 501 to 504 in the order of the even band and odd band, respectively, to the decoder that has finished processing in synchronization with this output. The even band data is decoded by the decoder 501, the odd band data of C by the decoder 502, the even band data of K by the decoder 503, and the odd band data of K by the decoder 504. Then, the restored print data (video data) is input to the corresponding FIFO buffers 505 to 508, and sequentially video I / O via the selector 509 in synchronization with the sequential image formation by the C and K drums in the engine unit 4. It is output to F510.

  FIG. 6 is a timing chart showing the output timing of the video data output as described above.

  As shown in the figure, the video I / F 510 outputs the video data from the FIFO buffers 505 and 506 to Video1 (Y) between t0 and t1 by switching the output destination by the selector 509. Next, during t1 to t2, the video data from the FIFO buffers 505 and 506 is output to Video1 (Y), and the video data from the FIFO buffers 507 and 508 is output to Video2 (M). Next, during t2 to t3, the video data from the FIFO buffers 507 and 508 is output to Video2 (M), and the video data from the FIFO buffers 505 and 506 is output to Video3 (C). Further, during t3 to t4, the video data from the FIFO buffers 505 and 506 is output to Video3 (C), and the video data from the FIFO buffers 507 and 508 is output to Video4 (K). Thereafter, the video data from the FIFO buffers 507 and 508 is further output to Video4 (K).

  With the output of the video data at the above timing, the engine unit 4 moves the sheet of length L as shown in FIG. 2B while Y, M, C, and K are conveyed in the direction of the arrow in the figure. The drums (image forming units) perform image formation in this order.

  As described above, according to the present embodiment, when the image formation timing in the engine unit is not simultaneous with four colors but may be simultaneous with two colors, the two colors at the timing of image formation are The print data can be decoded using two decoders, and four decoders can be used effectively. As a result, for example, not only data transfer will not be in time and there will be less trouble with printing, but also the data that has a poor compression rate and the decoding speed will not be in time, the decoding speed will apparently double. It is possible to perform printing corresponding to such data.

  FIG. 7 is a flowchart showing processing related to printing according to the present embodiment described above.

  Note that the process in FIG. 7 is a process executed by the controller unit 3.

  In step S <b> 701, the controller unit 3 sends information related to the configuration of the printer 2 to the host device 1. This information includes the size (storage capacity) of the reception buffer 6, the arrangement interval D of the image forming units 401 to 404, the size (storage capacity) of the FIFO buffer, and the like. The arrangement interval D is an interval between positions where the sheet and the photosensitive drum are in contact with each other, and indicates the distance between T1 and T2, between T2 and T3, and between T3 and T4 in FIG.

  In step S <b> 702, the controller unit 3 sets from the host device 1 settings related to area division of the reception buffer 6 based on the above information and to which of a plurality of decoders the print data of a predetermined color should be transferred. Information and setting information about switching of the selector 509 are received, and settings corresponding to the information are performed.

  In step S702, the controller unit 3 converts the received print data for a plurality of colors into Y even, Y odd, M even, and the like, as described above with reference to FIG. 5B. The received buffer 6 is divided into eight areas of M odd, C even, C odd, K even, and K odd.

  In step S703, the controller unit 3 assigns the received data to the reception buffer 6 based on the reception buffer allocation information received from the host apparatus 1 in step S702. It is determined whether the assignment is greater than (2nd case) or greater than 2D (first case). That is, if the allocation is in the first case, the controller unit 3 determines that the control mode is the first control mode and proceeds to step S704. If the allocation is in the second case, the controller unit 3 determines that the allocation is in the second control mode and proceeds to step S706. Proceed to

  First, the operation of step S704 and step S705, which are the first control mode, will be described.

  In step S704, the controller unit 3 transfers Y print data to the decoder 501, M print data to the decoder 502, C print data to the decoder 503, and K print data to the decoder 504.

  In step S705, the controller unit 3 outputs all of the Y, M, C, and K video data to the image forming units 401 to 404 and finishes the formation of the toner image on the paper, and then finishes the image formation on the paper. Judge that.

Next, the operation in steps S706 to S711, which is the second control mode, will be described.
In step S706, as described above, the controller unit 3 sets the Y odd data to the decoder 501, the Y even data to the decoder 502, the M even data to the decoder 503, and the M odd data to the decoder 503 as described above. The odd data is set to be assigned to the decoder 504, respectively.

  Similarly, as described above, the selector switching is performed by setting the output of the FIFO buffer 505 to Video1 (Y), the output of the FIFO buffer 506 to Video1 (Y), the output of the FIFO buffer 507 to Video2 (M), and the FIFO. The output of the buffer 508 is set to be output to Video2 (M).

  Therefore, the controller unit 3 controls to transfer Yeven to the decoder 501, transfer Yodd to the decoder 502, transfer Meven to the decoder 503, and transfer Mod to the decoder 504.

  It should be noted that the decoder 501 converts the Even image data as video data to the image forming unit 401 that forms the Y image through the FIFO buffer 505 while restoring the Even received data in response to a request from the engine unit 4. Output. Similarly to the decoder 501, the decoder 502 outputs the Yodd image data as video data to the image forming unit 401 that forms the Y image. Note that the controller unit 3 outputs a predetermined number of rows from the FIFO buffer 505 so that image data (band data) output from the two decoders 501 and 502 is output to the image forming unit 401 as one image data. After outputting image data corresponding to the number of lines (the number of lines constituting one band data), control is performed so that image data for a predetermined number of lines is output from the FIFO buffer 506.

  In step S707, the controller unit 3 determines whether all of the Y image data is output to the image forming unit 401 and the Y image formation is completed. When the controller unit 3 determines the end, the process proceeds to step S708, and the setting of C print data is changed so that C odd data is assigned to the decoder 501 and C even data is assigned to the decoder 502. The selector 509 is switched when the output of Y image data from the FIFO buffers 505 and 506 is finished. The output of the FIFO buffer 505 is Video3 (C), and the output of the FIFO buffer 506 is Video3 (C). Change settings to output to.

In step S709, the controller unit 3 determines whether or not the M image data is all output to the image forming unit 402 and the M image formation is completed. When the controller unit 3 determines the end, the controller unit 3 proceeds to step S710, and changes the setting of the K print data so that the odd data of K is assigned to the decoder 503 and the even data of K is assigned to the decoder 504. The selector 509 is switched when the output of M image data from the FIFO buffers 507 and 508 is finished. The output of the FIFO buffer 507 is set to Video4 (K), and the output of the FIFO 508 is set to Video4 (K). Change settings to output. Finally, in step S711, when the controller unit 3 determines that the C and K image formation has been completed, the process ends.

(Second Embodiment)
In the second embodiment of the present invention, as shown in FIG. 8B, when the length L of the sheet is D and the distance between the image forming units (drums) is D, the length is 3D or less and longer than 2D. It relates to how to use the decoder. FIG. 8A is a diagram showing the same state as FIG. 2A, and the description thereof is omitted here.
In the present embodiment, the control mode is set to the third control when the length L of the printing paper is greater than 3D (third case) and when the length is 3D or less and greater than 2D (third case). The mode is different from the fourth control mode. The third control mode is the same control as the first control mode in the first embodiment.

  As shown in FIG. 8B, in the fourth case, the maximum number of image forming units that simultaneously form images on one sheet is three. In this case, the number of decoders and FIFOs used at the same timing is three.

  In the second embodiment, in this case, two decoders and two FIFO buffers are used simultaneously for the two colors Y and K located at both ends in the arrangement of the image forming units of each color shown in FIG. 8B.

  FIG. 9 is a block diagram showing a detailed configuration of the ASIC 5 shown in FIG. 3 according to the second embodiment of the present invention, and is the same diagram as FIG. 4 according to the first embodiment. As shown in the figure, the decoders 501 and 502 and the FIFO buffers 505 and 506 include Y applied to the image forming unit 401 located at the most upstream side in the sheet conveying direction, and the image forming unit 404 located at the most downstream side in the sheet conveying direction. Is used for time division according to the K print data. In response to this, as shown in FIG. 10B, the reception buffer 6 of this embodiment stores the transferred Y and K print data in an area obtained by dividing the even band and odd band. Thus, the Y and K print data are divided into two areas, and the M and C print data each have one area, resulting in a total of six reception buffers. FIG. 4A is a diagram showing a reception buffer (four divisions) in the third control mode.

  In the above configuration, after the reception of the print data from the host device 1 is completed, the image forming units 401 to 404 along the sheet conveyance path shown in FIG. First, the Y even band data is transferred to the decoder 501, the Y odd band data is transferred to the decoder 502, the M band data is transferred to the decoder 503, and the C band data is transferred to the decoder 504. Is done. The restored print data (video data) is input to the corresponding FIFO buffers 505 to 508, and is synchronized with the sequential image formation by the Y and M image forming units 401 and 402 in the engine unit 4. Are sequentially output to the video I / F 510.

  Furthermore, the K even band data is transferred from the reception buffer 6 to the decoder 501 and the K odd band data is transferred to the decoder 502 from the reception buffer 6 to the decoders 501 and 502 which have completed the conversion process in synchronization with this output. Decoding is performed. The restored print data (video data) is input to the corresponding FIFOs 505 and 506, respectively, and is sequentially transmitted to the video I / F 510 via the selector 509 in synchronization with the sequential image formation by the C and K drums in the engine unit 4. Is output.

  FIG. 11 is a timing chart showing the output timing of the video data output as described above.

  As shown in the figure, the video I / F 510 outputs the video data from the FIFO buffers 505 and 506 to Video1 (Y) between t0 and t1 by switching the output destination by the selector 509.

  Next, during t1 to t2, the video data from the FIFO buffers 505 and 506 is output to Video1 (Y), and the respective video data is output from the FIFO buffer 507 to Video2 (M).

  Next, during t2 to t3, the video data from the FIFO buffers 505 and 506 is output to Video1 (Y), the video data from the FIFO 507 is output to Video2 (M), and from the FIFO buffer 507 Video data is output to Video3 (C).

  Further, during the period from t3 to t4, the video data from the FIFO buffer 507 is output to Video2 (M), and the video data from the FIFO buffer 508 is output to Video3 (C).

  Further, during t4 to t5, the video data from the FIFO buffer 507 is output to Video2 (M), the video data from the FIFO buffer 508 is output to Video3 (C), and from the FIFO buffers 505 and 506. Are output to Video4 (K).

  During t5 to t6, the video data from the FIFO buffer 508 is output to Video3 (C), and the video data from the FIFO buffers 505 and 506 is output to Video4 (K).

  Thereafter, the video data from the FIFO buffers 505 and 506 is further output to Video4 (K).

  With the output of the video data at the above timing, the engine unit 4 moves the sheet of length L as shown in FIG. 8B while Y, M, C, and K are conveyed in the direction of the arrow in the figure. The drums (image forming units) perform image formation in this order.

  As described above, according to the present embodiment, when the image formation timing in the engine unit 4 is not simultaneously in four colors but may be in three colors at the same time, the three image formation timings in the image formation timing are the same. Of the colors, the print data of the two colors in which the image forming unit is arranged at both ends can be decoded using two decoders, respectively, whereby the four decoders can be used effectively. As a result, for example, not only data transfer is not in time and printing is less likely to be disturbed, but even for data whose compression rate is poor and decoding speed is not in time, the decoding speed is apparently 2 for Y and K. Therefore, printing can be performed corresponding to such data.

  FIG. 12 is a flowchart showing processing related to printing according to the present embodiment described above. The process in FIG. 12 is a process executed by the controller unit 3.

  In step S <b> 1201, the controller unit 3 sends information related to the configuration of the printer 2 to the host device 1. This information includes the size (storage capacity) of the reception buffer 6, the arrangement interval D of the image forming units 401 to 404, the size of the FIFO, and the like. The arrangement interval D is an interval between positions where the sheet and the photosensitive drum are in contact with each other, and indicates the distance between T1 and T2, between T2 and T3, and between T3 and T4 in FIG. In step S1202, the controller unit 1 sets, from the host device 1, settings related to area division of the reception buffer 6 and whether to assign to which of a plurality of decoders the print data of a predetermined color should be transferred. Information and setting information about switching of the selector 509 are received, and settings corresponding to the information are performed.

  In step S1202, the controller unit 3 converts the received print data for a plurality of colors into Y even, Y odd, M, C, and Y in this embodiment, as described above with reference to FIG. The area is divided into six areas of K even and K odd and stored in the reception buffer 6.

  In step S1203, the controller unit 3 assigns the received data to the reception buffer 6 based on the reception buffer allocation information received from the host device 1 in step S1202, and the printing paper length L is 2D or less. It is determined whether the assignment is greater than (4th case) or greater than 3D (third case). That is, if the allocation is in the third case, the controller unit 3 determines that the control mode is the third control mode and proceeds to step S1204. If the allocation is in the fourth case, the controller unit 3 determines that the allocation is in the fourth control mode and proceeds to step S1206. Proceed to

First, the operation of step S1204 and step S1205, which is the third control mode, will be described.
In step S1204, the controller unit 3 transfers Y print data to the decoder 501, M print data to the decoder 502, C print data to the decoder 503, and K print data to the decoder 504.
In step S1205, when the controller unit 3 outputs all of the Y, M, C, and K video data to the image forming units 401 to 404 to finish forming the toner image on the paper, the image forming on the paper is finished. Judge that.

Next, the operation in steps S1206 to 1209, which is the fourth control mode, will be described.
In step S1206, as described above, the controller unit 3 sets the Y odd data to the decoder 501, the Y even data to the decoder 502, the M data to the decoder 503, and the C data, as described above. Are assigned to the decoders 504, respectively.

Similarly, as described above, the selector switching setting is such that the output of the FIFO buffer 505 is Video1 (Y), the output of the FIFO buffer 506 is Video1 (Y), the output of the FIFO buffer 507 is Video2 (M), and the FIFO 508 Are set to be output to Video3 (C).
Accordingly, the controller unit 3 controls to transfer Yeven to the decoder 501, transfer Yodd to the decoder 502, transfer M to the decoder 503, and transfer C to the decoder 504.
It should be noted that the decoder 501 converts the Even image data as video data to the image forming unit 401 that forms the Y image through the FIFO buffer 505 while restoring the Even received data in response to a request from the engine unit 4. Output. Note that the controller unit 3 outputs a predetermined number of rows from the FIFO buffer 505 so that image data (band data) output from the two decoders 501 and 502 is output to the image forming unit 401 as one image data. After outputting image data corresponding to the number of lines (the number of lines constituting one band data), control is performed so that image data for a predetermined number of lines is output from the FIFO buffer 506.

  In step S1207, the controller unit 3 determines whether or not the Y image data is all output to the image forming unit 401 and the Y image formation is completed. When the controller unit 3 determines the end, the process proceeds to step S1208, and the settings of the K print data are changed so that the odd data of K is assigned to the decoder 501 and the even data of K is assigned to the decoder 502. The selector 509 is switched when the output of Y image data from the FIFO buffers 505 and 506 is finished. The output of the FIFO buffer 505 is set to Video4 (K), and the output of the FIFO 506 is set to Video4 (K). Change settings to output. Finally, when it is determined in step S1209 that printing has ended, this process ends.

(Other embodiments)
The embodiment described above has been described by taking an example of an electrophotographic printing apparatus using a laser beam, but the present invention can also be applied to an ink jet printing system using ink as a recording agent. Specifically, in a so-called full-line type printing apparatus in which recording heads for each color having nozzle rows corresponding to the width of the paper to be conveyed are arranged along the paper conveyance path, simultaneously with respect to the paper to be conveyed. The use of the decoder can be set according to the number of recording heads that eject ink.

  In each of the above embodiments, the decoder and FIFO are set from the host device, and the print data is set. However, such a setting may be performed by the printing device itself. The printing apparatus itself may supply print data, such as a multi-function printer that includes a reading apparatus and can also execute a copying function.

(Still another embodiment)
As described above, the present invention can be applied to a system composed of a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.) but also to an apparatus composed of a single device (for example, a copying machine, a facsimile machine). May be.

  In addition, the apparatus connected to the various devices or the computer in the system to operate the various devices so as to realize the functions of the embodiments described above with reference to FIG. 6, FIG. 7, FIG. Embodiments implemented by supplying software program codes for realizing the functions of the embodiments and operating the various devices according to the stored programs in the system or apparatus computer (CPU or MPU) are also within the scope of the present invention. included.

  Further, in this case, the program code of the software itself realizes the functions of the above-described embodiments, and the program code itself and means for supplying the program code to the computer, for example, a storage storing the program code The medium constitutes the present invention.

  As a storage medium for storing the program code, for example, a floppy (registered trademark) disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.

  Further, by executing the program code supplied by the computer, not only the functions of the above-described embodiments are realized, but also the OS (operating system) in which the program code is running on the computer, or other application software, etc. It goes without saying that the program code is also included in the embodiment of the present invention even when the functions of the above-described embodiment are realized in cooperation with the embodiment.

  Further, after the supplied program code is stored in a memory provided in a function expansion board of a computer or a function expansion unit connected to the computer, a CPU provided in the function expansion board or the function expansion unit based on an instruction of the program code However, it is needless to say that the present invention also includes a case where the function of the above-described embodiment is realized by performing part or all of the actual processing.

It is a figure which shows the structure of the decoding process of the printer concerning one prior art example especially. (A) And (b) is a figure which shows typically the relationship between the photosensitive drum of each color, and the length of a recording paper. 1 is a block diagram illustrating a schematic configuration of a printer according to an embodiment of the present invention. FIG. 4 is a block diagram showing a detailed configuration of the ASIC 5 shown in FIG. 3 according to the first embodiment of the present invention. (A) And (b) is a figure which shows the conventional receiving buffer and the receiving buffer of 1st Embodiment, respectively. 5 is a timing chart showing video data output timing in the configuration shown in FIG. 4. It is a flowchart which shows the process regarding printing of 1st embodiment of this invention. (A) And (b) is a figure which shows typically the other example of the relationship between the photosensitive drum of each color, and the length of a recording paper. It is a block diagram which shows the detailed structure of ASIC5 concerning 2nd embodiment of this invention especially shown in FIG. (A) And (b) is a figure which shows the conventional receiving buffer and the receiving buffer of 2nd Embodiment, respectively. 10 is a timing chart showing video data output timing in the configuration shown in FIG. 9. It is a flowchart which shows the process regarding printing of 2nd embodiment of this invention.

Explanation of symbols

1 Host computer (PC)
2 Printer 3 Controller 4 Engine part 5 ASIC
6 Receive buffer (RAM)
7 CPU
500 Control unit 501, 502, 503, 504 Decoder 505, 506, 507, 508 FIFO
509 Selector 510 Video I / F

Claims (13)

In an image forming apparatus for forming a color image by superimposing a plurality of color images on the paper by a plurality of image forming units arranged along a paper transport path,
Storage means for storing received data for a plurality of colors received from an external device;
A plurality of data processing means provided corresponding to the plurality of image forming units, and converting the received data into image data used in the image forming unit;
Control means for controlling transfer of the received data from the storage means to the data processing means,
The control means controls a first control mode for transferring the received data relating to a predetermined color to any one of the plurality of data processing means; and two or more plural receiving data relating to the predetermined color. And a second control mode for controlling transfer to the data processing means. Selecting means for selecting an output destination of the image data from the plurality of data processing means to the plurality of image forming units;
The selection unit transfers the image data output from the data processing unit to one of the plurality of image forming units in the first control mode, and two or more in the second control mode. 2. The output destination of the image data is selected so that two or more pieces of image data output from the data processing unit are transferred to any one of the plurality of image forming units. Image forming apparatus.   The second control mode is a mode in which the received data is alternately transferred to the first data processing means and the second data processing means as band data composed of a plurality of lines. The image forming apparatus described in 1.   The selecting unit selects the first image data output from the first data processing unit and the second image data output from the second data processing unit from any one of the plurality of image forming units. The image forming apparatus according to claim 3, wherein an output destination of the image data is selected so as to be transferred to the printer.   The control unit is in the first control mode when the length of the paper in the conveyance direction formed by the plurality of image forming units is longer than a predetermined length, and the length of the paper in the conveyance direction is the predetermined length. The image forming apparatus according to claim 1, wherein the second control mode is set when the length is shorter than the length. An image forming apparatus that performs printing on paper using a plurality of types of recording agents,
A decoder that decodes print data corresponding to each of the plurality of types of recording agents, the number of decoders corresponding to at least the number of types of the recording agents;
Means for forming an image on a sheet based on the print data decoded by the decoder, the image forming means corresponding to each of the plurality of recording agents;
A plurality of decoders (501 and 502, 503 and 504, or 501) for print data of a predetermined plurality of recording agents (Y and C, or M and K, or Y and K) in the plurality of types of recording agents. 502), and the plurality of decoders (501 and 502, or the print data (Y and C, or M and K, or Y and K) of the predetermined recording agent are divided. 503 and 504, or 501 and 502), each of which performs decoding processing in a time-sharing manner,
An image forming apparatus comprising:   The image forming units of the image forming unit corresponding to each of the plurality of recording agents are respectively arranged along a conveyance path through which the sheet is conveyed, and the decode control unit is a range in which the plurality of image forming units are arranged. The image forming apparatus according to claim 6, wherein the decoding process is controlled based on a predetermined relationship in which a length of the conveyed sheet is shorter than a length along the conveyance path.   For the print data decoded by the plurality of decoders, print data respectively corresponding to the plurality of image forming units is synchronized with the image forming timing of each of the plurality of image forming units for one sheet of paper conveyed. The image forming apparatus according to claim 7, further comprising a supplying synchronization unit.   The image forming apparatus according to claim 8, wherein the synchronization unit includes a FIFO. An image forming method for printing on paper using a plurality of types of recording agents,
A decoder that decodes print data corresponding to each of the plurality of types of recording agent, the number of decoders corresponding to the number of types of the recording agent, and a sheet based on the print data decoded by the decoder An image forming unit corresponding to each of the plurality of recording agents;
A plurality of decoders (501 and 502, 503 and 504, or 501) for print data of a predetermined plurality of recording agents (Y and C, or M and K, or Y and K) in the plurality of types of recording agents. 502), and the plurality of decoders (501 and 502, or the print data (Y and C, or M and K, or Y and K) of the predetermined recording agent are divided. 503 and 504, or 501 and 502), respectively, to perform decoding processing in a time-sharing manner.
An image forming method comprising steps.   The image forming units of the image forming unit corresponding to each of the plurality of recording agents are respectively arranged along a conveyance path through which the sheet is conveyed, and the decode control unit is a range in which the plurality of image forming units are arranged. The image forming method according to claim 10, wherein the decoding process is controlled based on a predetermined relationship in which a length of the conveyed sheet is shorter than a length along the conveyance path.   For the print data decoded by the plurality of decoders, print data respectively corresponding to the plurality of image forming units is synchronized with the image forming timing of each of the plurality of image forming units for one sheet of paper conveyed. The image forming method according to claim 11, further comprising a supplying step. A program for causing an information processing apparatus to execute print information processing for printing on paper using a plurality of types of recording agents,
A decoder that decodes print data corresponding to each of the plurality of types of recording agent, the number of decoders corresponding to the number of types of the recording agent, and a sheet based on the print data decoded by the decoder An image forming unit corresponding to each of the plurality of recording agents;
A plurality of decoders (501 and 502, 503 and 504, or 501) for print data of a predetermined plurality of recording agents (Y and C, or M and K, or Y and K) in the plurality of types of recording agents. 502), and the plurality of decoders (501 and 502, or the print data (Y and C, or M and K, or Y and K) of the predetermined recording agent are divided. 503 and 504, or 501 and 502), respectively, to perform decoding processing in a time-sharing manner.
A program characterized by having a process having steps.

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