JP5105970B2 - Image forming apparatus and control method - Google Patents

Description

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

  Conventionally, a page printer as an image printing apparatus is connected to a host computer having a printer driver via a network, a USB interface, or the like, as shown in FIG. The page printer has a controller unit and an engine unit. The controller unit converts intermediate output data generated from printing source data by a device such as a host computer into output image data suitable for output. On the other hand, the engine unit acquires the output image data output from the controller unit, and outputs the image to a medium such as paper.

  Generation of intermediate output data suitable for the controller unit is generally performed by software called a printer driver. Further, the controller unit converts the intermediate output data into output image data suitable for the engine unit, and outputs the output image data to the engine unit as a video signal in synchronization with an image transfer permission signal from the engine unit.

  The engine unit controls and drives the electrophotographic process, and outputs the input video signal as an image on a medium such as paper. For electrophotographic process type color printers, a high-speed printing method based on parallel processing called an inline method has been proposed and put into practical use. In the in-line method, the photosensitive drums for four colors are arranged in a row, and the printing process of each color is overlapped to shorten the printing time.

  FIG. 4 shows the output data output timing of the inline method, where a is a page synchronization signal, and b to e are transfer timings of the print data. As shown in FIG. 4, in an inline type electrophotographic printer, it is necessary to transfer the print data of each color almost simultaneously in synchronization with the page synchronization signal.

  FIG. 2 is a block diagram illustrating a controller configuration example of a general inline printer. A CPU 201, a ROM 202, an external i / f unit 203, a page memory 204, a 4-channel DMAC 205, an image output unit 260, and the like are connected to a system bus 207. Further, the image output unit 260 is connected to the printer engine 280.

  The intermediate output data generated by the host computer is received by the external i / f unit 203, converted into compressed data that can be hardware processed by the CPU 201, and then stored in the page memory 204. When storage of compressed data necessary for output is completed, the DMAC 205 for four channels is activated by an instruction from the CPU 21, and the stored compressed data for four colors is transferred from the page memory 204 to the image output unit 260.

  The image output unit 260 includes decoder units 261a to 261d, temporary storage buffer memories 262a to 262d, and an engine i / f unit 263. The decoder units 261a to 261d convert the compressed data into an output image data format suitable for the engine i / f unit 263. The engine i / f unit 263 is connected to the printer engine 280 and outputs image data as a video signal.

  In recent years, with an increase in resolution and speed of a printer engine, it is required to increase the transmission speed of the video signal. However, since the video signal output from the engine i / f unit 263 is an analog signal output directly to the exposure unit, there is a limit to speeding up. On the other hand, with recent advances in serial data transfer technology, a technology capable of serially transferring image data at high speed using a high-speed serial transfer technology has been proposed (for example, see Patent Document 1 or Patent Document 2). ).

JP 2002-321407 A JP 2005-301673 A

  As described above, in an in-line color image forming apparatus, it is necessary to transfer data by overlapping four colors of cyan, magenta, yellow, and black. However, when four-color image data is transmitted in a time-sharing manner using one-channel serial data transfer means, the transfer of the color data may not be in time for the speed required by the printer engine. In such a case, there arises a problem that normal printing is not performed.

  Therefore, it is possible to avoid this problem by providing high-speed serial transfer means for each color. However, for this purpose, a plurality of serial transfer units are required, which increases the cost of the image forming apparatus.

  In addition, a page memory is provided in the second image processing means, and it is possible to avoid problems such as normal printing not being performed by transferring one page of data in advance. However, according to this method, since it is necessary to provide an expensive page memory, the cost of the image forming apparatus is also increased.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to realize high-reliability image data transfer at low cost by using a high-speed serial data transfer means.

An image forming apparatus according to the present invention corresponds to each of a plurality of image forming units that execute printing synchronously, a plurality of first storage units that hold image data transferred from an image memory, and the plurality of first units. A plurality of image data transferred in a serial format from a control unit having a transfer unit that transfers a plurality of image data held in one storage unit in a time-division manner in a serial format, and the plurality of image forming units an image forming apparatus for outputting by a distributing means for distributing a plurality of image data transferred by said transfer means, a plurality of second storage means corresponding to each of said image forming means, the plurality by said distributing means the image data stored in the second storage means, and having a conversion means for converting a control signal for controlling the image forming means.

  According to the present invention, serial data transfer means can be used efficiently by transferring image data for each color in accordance with the order of image formation. As a result, it is possible to realize image data transfer without providing a 4-channel serial data transfer means or a page memory in the engine, and to perform highly reliable image data transfer with an inexpensive configuration. Also, by using the serial data transfer means, it is possible to realize highly reliable data transfer without using analog data transfer from the controller to the printer engine.

(First embodiment)
Embodiments according to the present invention will be described below in detail with reference to the accompanying drawings.
FIG. 1 is a block diagram illustrating a functional configuration example of the color image forming apparatus according to the present exemplary embodiment.
The system according to this embodiment is divided into a controller unit 1 that is a first image processing unit and a printer engine unit 3 that is a second image processing unit. Image data is serially transferred using high-speed serial data transfer means 2 provided between the controller unit 1 and the printer engine unit 3. In this embodiment, transfer of image data of four colors of cyan, yellow, magenta, and black is performed using the serial data transfer unit 2 of one channel.

  The CPU 11 controls the entire apparatus and generates image data that can be output to the printer engine unit 3 from print data received from the external interface 13. The ROM 12 stores processing procedures (programs) processed by the CPU 11, font data, and the like.

  The external interface 13 is a LAN interface such as Ethernet (registered trademark) or an I / O interface such as USB, IEEE1284, or IEEE1394, and receives image data from a host device (host computer). The image memory 14 temporarily stores image data for one page or one band generated by the CPU 11. At this time, in order to save memory capacity, the CPU 11 can compress the image data and store the compressed data.

  The image data output unit 15 transfers image data from the image memory 14 for each color, and outputs the image data to the printer engine unit 3. The printer engine unit 3 is an inline laser beam printer, and requires simultaneous transfer of image data of a plurality of colors.

  Next, the internal configuration of the image data output unit 15 will be described. Reference numerals 19 to 22 denote FIFO (First In First Out) memories (first storage means) for each color, and image data for each color stored in the image memory 14 is transferred by the DMA access control unit 18. The multiplexer 23 is for selecting data stored in the FIFO memories 19 to 22 of the first to fourth stations and transferring them to the printer engine unit 3 using the serial data transfer means 2.

  The serializer 17 converts the parallel data input from the FIFO memories 19 to 22 into serial data and performs high-speed serial data transfer at 600 Mbps to 1 Gbps.

  The multiplexer 23 includes means for generating a packet for each color from the data stored in the FIFO memories 19 to 22 and counting the number of packets transferred to the serializer 17. Further, the multiplexer 23 arbitrates transfer of image data from the FIFO memories 19 to 22 based on the number of transferred packets.

  Next, the configuration of the printer engine unit 3 will be described. The deserializer 31 converts the serial data transferred by the serial data transfer means 2 into parallel data. The demultiplexer 32 distributes the parallel image data to the FIFO memories (second storage means) 33 to 36 for the color and transfers them. The FIFO memories 33 to 36 for each color store image data and transfer the data to the image processing units 37 to 40.

  The image processing units 37 to 40 for each color perform image processing such as γ correction and halftone processing. In addition, the image processing units 37 to 40 include a lookup table, and can perform appropriate image processing according to the print image by changing the γ table and the halftone table. Further, image processing corresponding to the characteristics of the printer engine unit 3 can be performed by changing the lookup table based on feedback from various sensors of the engine (not shown).

  The video signal conversion units 41 to 44 convert the image data transferred from the image processing units 37 to 40 into video signals for controlling the laser lighting, and control the lasers of the scanner units 45 to 48. The video signal conversion units 41 to 44 control the exposure timing based on the horizontal synchronization signals from the scanner units 45 to 48.

  The scanner units 45 to 48 control the lighting of the laser by the video signal to expose a photosensitive drum (not shown), and output a horizontal synchronization signal to the video signal conversion units 41 to 44.

  In the configuration described above, the CPU 11 receives data sent from the host computer via the external interface 13, generates image data in a format that can be output to the printer engine unit 3, and stores the image data in the image memory 14. When image data of a predetermined amount (a page or a band of a predetermined size) is generated, the CPU 11 notifies the printer engine unit 3 of a print start instruction via an engine interface circuit (not shown). In response to the print start instruction, the printer engine unit 3 starts a printing operation and outputs a vertical synchronization signal indicating the transfer timing of the image data.

  The engine interface circuit notifies the CPU 11 of the data transfer timing of each color from the vertical synchronization signal received from the printer engine unit 3. As a result, the CPU 11 activates a DMA controller (not shown) in the DMA access control unit 18 for the color to be transferred to the printer engine unit 3 to transfer image data.

  Image data stored in the FIFO memories 19 to 22 by the DMA controller is controlled by the multiplexer 23 and transferred to the printer engine unit 3. At that time, the multiplexer 23 forms a packet for each FIFO memory and transfers the data in the FIFO memories 19 to 22 to the serializer 17.

FIG. 5 is a flowchart showing an example of an operation procedure of the multiplexer 23 in the present embodiment. The operation of the multiplexer 23 will be described with reference to FIG.
In FIG. 5, n1 is the number of data of the image data of the first image forming means necessary for exposing the time from the exposure start time of the first image forming means to the exposure start time of the second image forming means. It is.

  n2 is the number of data of the image data of the second image forming means necessary for exposing the time from the exposure start time of the second image forming means to the exposure start time of the third image forming means. n3 is the number of data of the image data of the third image forming means necessary for exposing the time from the exposure start time of the third image forming means to the exposure start time of the fourth image forming means. m1 is the number of data satisfying 0 <m1 ≦ n1 (m1 is n1 or less). For example, m1 = n1 / 2. m2 is the number of data satisfying 0 <m2 ≦ n2 (m2 is n2 or less). For example, m2 = n2 / 3. m3 is the number of data satisfying 0 <m3 ≦ n3 (m3 is n3 or less). For example, m3 = n3 / 4.

  The multiplexer 23 checks whether there is a transfer request in the FIFO memories 19 to 22 (step S1). If there is no transfer request as a result of this confirmation, the process waits as it is. On the other hand, if there is a transfer request as a result of the confirmation in step S1, it is confirmed whether or not there are a plurality of FIFO memories having a transfer request (step S2). If the result of this confirmation is that there is one FIFO memory requesting transfer, access to the serializer 17 is permitted to this FIFO memory (step S3). On the other hand, if there are a plurality of data transfers as a result of the confirmation in step S3, the process proceeds to step S4.

  Next, it is determined whether or not the number of transmitted packets of the first station is less than or equal to m1 (step S4). If the result of this determination is m1 or less, the transfer request from the FIFO memory 19 of the first station is prioritized and the data in the FIFO memory 19 of the first station is transferred (step S5).

  On the other hand, if the number of transferred data in the first station is larger than m1 as a result of the determination in step S4, the number of transferred packets in the first station and the second station is confirmed to determine whether the condition is satisfied. (Step S6). The condition at this time is that the number of transferred data in the first station is n1 + m2 or less and the number of transferred data in the second station is m2 or less.

  If the condition is satisfied as a result of this determination, the data of the first and second stations are transferred in round robin (step S7). On the other hand, if the result of determination in step S6 does not satisfy the condition, the number of transferred data of the first, second, and third stations is confirmed to determine whether the condition is satisfied (step S8). The condition at this time is that the number of transferred data in the first station is n1 + n2 + m3 or less, the number of transferred data in the second station is n2 + m3 or less, and the number of transferred data in the third station is m3 or less.

  If the condition is satisfied as a result of this determination, the data of the first, second, and third stations are transferred in round robin (step S9). On the other hand, if the condition is not satisfied as a result of the determination in step S8, the data of all stations are transferred in round robin (step S10).

  As described above, according to the present embodiment, when transferring image data of each color, it is possible to change and determine the priority of image data transfer in the corresponding FIFO memory according to the number of data transferred by serial data transfer. It becomes. As a result, the serial data transfer means can be used in the order of data required by the engine control unit, and data transfer can be performed efficiently.

  In this embodiment, the serial data transfer rate is set to 600 Mbps to 1 Gbps, but is not limited to these transfer rates. Further, since the printer engine unit 3 includes the FIFO memories 33 to 36, it is possible to start the transfer of image data at the same time that the controller unit 1 issues a print start instruction without waiting for the engine vertical synchronization signal. . In the above description, the number of data is counted and used for setting priority. However, when serially transferring data in units of packets, the number of packets may be counted and used for setting priority. In that case, the same control can be performed by the same control method.

(Second Embodiment)
FIG. 6 is a block diagram illustrating a functional configuration example of the color image forming apparatus according to the present embodiment. Parts having the same functions as those in the configuration of the first embodiment are given the same numbers. Further, the description of the parts described in the first embodiment is omitted. The details of the present embodiment will be described below with reference to FIG.

  The FIFO memories 33 to 36 of the printer engine unit 3 output the remaining amount of data to the demultiplexer 32. Then, the demultiplexer 32 transfers the remaining data amount of each of the FIFO memories 33 to 36 to the serializer 49 by round robin. The serializer 49 transfers and notifies the remaining data in the FIFO memories 33 to 36 to the deserializer 24 of the controller unit 1 through the serial data transfer means 50. Further, the multiplexer 23 can sequentially know the remaining amount of data in the FIFO memories 33 to 36 of the printer engine unit 3 based on the information from the deserializer 24.

  FIG. 7 is a diagram illustrating an example of setting the priority level of the multiplexer 23 with respect to the remaining amount of data stored in the FIFO memory. For example, when the amount of data stored in the kth (k is 1 to 4) color FIFO memory is less than the threshold value 1 (1/4), the priority level of the kth color is set to level 0. When the remaining data amount is not less than threshold 1 (1/4) and less than threshold 2 (1/2), level 1 is set. When the remaining data amount is equal to or greater than the threshold 2 (1/2), the level 2 is set. Such a threshold value can be freely set according to data transfer capability or the like. Here, the priority level is level 0> level 1> level 2, and level 0 has the highest priority.

FIG. 8 is a flowchart illustrating an example of an operation procedure of the multiplexer 23 in the present embodiment.
First, the multiplexer 23 checks whether or not there is a data transfer request from the FIFO memories 19 to 22 (step S81). If there is no transfer request as a result of this confirmation, the process waits as it is. On the other hand, if there is a data transfer request as a result of the confirmation in step S81, it is confirmed whether there are a plurality of requested FIFO memories (step S82). If there is one FIFO memory requesting data transfer, data transfer to the serializer 17 is permitted to this FIFO memory (step S83).

  On the other hand, if there is a plurality of FIFO memories requesting data transfer as a result of the confirmation in step S82, a data transfer request with the highest priority level is issued from the priority levels of the FIFO memories 33 to 36 of each color of the printer engine unit 3. It is confirmed whether or not there is (step S84). If there is one data request with the highest priority level as a result of this confirmation, the data transfer request for the FIFO memory with the color with the highest priority level is permitted (step S85). On the other hand, as a result of the confirmation in step S84, if there are a plurality of data transfer requests at the highest priority level, the process proceeds to step S86.

  Note that the right to use the serializer is evenly given by the round robin method or the like. For example, a counter (wait counter) that counts the number of waiting times is prepared for each FIFO memory, and the wait counter is incremented when data transfer is not permitted even though the counter has the highest priority level. That is, when there are a plurality of data transfer requests at the highest priority level, the multiplexer 23 permits the FIFO memory having a large wait counter value to transfer data to the serializer.

  In step S86, data transfer is permitted to the FIFO memory having a large number of waiting times. Here, the wait counter of the FIFO memory permitted to transfer data is reset, and the wait counter of the FIFO memory not permitted to transfer data is incremented. Through the above operation, the image data in the FIFO memory that is permitted to transfer data is transferred to the printer engine unit 3 via the serializer 17.

  As described above, in the present embodiment, when transferring the image data of each color, the data transfer of the FIFO memories 19 to 22 of the corresponding controller unit 1 is performed according to the remaining amount of data stored in the FIFO memories 33 to 36 of the printer engine unit 3. The priority level can be changed dynamically. As a result, the priority level of data transfer can be set high for a specific color with a small remaining amount of data stored in the FIFO memory, and data transfer can be performed preferentially.

(Other embodiments according to the present invention)
Each means constituting the image forming apparatus and each step of the image forming method in the embodiment of the present invention described above can be realized by operating a program stored in a RAM or ROM of a computer. This program and a computer-readable recording medium recording the program are included in the present invention.

  Further, the present invention can be implemented as, for example, a system, apparatus, method, program, or recording medium. Specifically, the present invention may be applied to a system including a plurality of devices. The present invention may be applied to an apparatus composed of a single device.

  The present invention includes a case where a software program (in the embodiment, a program corresponding to the flowcharts shown in FIGS. 5 and 8) for realizing the functions of the above-described embodiments is directly or remotely supplied to a system or apparatus. . This includes the case where the system or the computer of the apparatus is also achieved by reading and executing the supplied program code.

  Accordingly, since the functions of the present invention are implemented by computer, the program code installed in the computer also implements the present invention. In other words, the present invention includes a computer program itself for realizing the functional processing of the present invention.

  In that case, as long as it has the function of a program, it may be in the form of object code, a program executed by an interpreter, script data supplied to the OS, and the like.

  Examples of the recording medium for supplying the program include a flexible disk, a hard disk, an optical disk, and a magneto-optical disk. Further, there are MO, CD-ROM, CD-R, CD-RW, magnetic tape, nonvolatile memory card, ROM, DVD (DVD-ROM, DVD-R) and the like.

  As another program supply method, there is a method of connecting to a homepage on the Internet using a browser of a client computer. The computer program itself of the present invention or a compressed file including an automatic installation function can be downloaded from the homepage by downloading it to a recording medium such as a hard disk.

  It can also be realized by dividing the program code constituting the program of the present invention into a plurality of files and downloading each file from a different homepage. That is, a WWW server that allows a plurality of users to download a program file for realizing the functional processing of the present invention on a computer is also included in the present invention.

  As another method, the program of the present invention is encrypted, stored in a recording medium such as a CD-ROM, distributed to users, and encrypted from a homepage via the Internet to users who have cleared predetermined conditions. Download the key information to be solved. It is also possible to execute the encrypted program by using the key information and install the program on a computer.

  Further, the functions of the above-described embodiments are realized by the computer executing the read program. Furthermore, based on the instructions of the program, an OS or the like running on the computer performs part or all of the actual processing, and the functions of the above-described embodiments can be realized by the processing.

  As another method, the program read from the recording medium is first written in a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer. Then, based on the instructions of the program, the CPU or the like provided in the function expansion board or function expansion unit performs part or all of the actual processing, and the functions of the above-described embodiments are also realized by the processing.

1 is a block diagram illustrating an example of a functional configuration of a color image forming apparatus according to a first embodiment of the present invention. It is a block diagram which shows the example of a controller structure of the conventional inline system printer. It is a figure which shows the structural example of a general printer. FIG. 6 is a diagram illustrating output data output timing of an inline method. It is a flowchart which shows an example of the operation | movement procedure of the multiplexer in the 1st Embodiment of this invention. It is a block diagram which shows the function structural example of the color image forming apparatus in the 2nd Embodiment of this invention. It is a figure which shows the example of a setting of the priority level of the multiplexer 23 with respect to the data remaining amount accumulate | stored in the FIFO memory in 2nd Example of this invention. It is a flowchart which shows an example of the operation | movement procedure of the multiplexer in the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Controller part 2 Serial data transfer means 3 Printer engine part 11 CPU
12 ROM
13 External interface 14 Image memory 16 System bus 17 Serializer 18 DMA access control unit 19-22 FIFO memory 23 Multiplexer 31 Deserializer 32 Demultiplexer 33-36 FIFO memory 37-40 Image processing unit 41-44 Video signal conversion unit 45-48 Scanner Part

Claims (12)

Corresponding to each of a plurality of image forming units that execute printing synchronously, a plurality of first storage units that hold image data transferred from an image memory, and a plurality of images that are held by the plurality of first storage units An image forming apparatus that receives a plurality of image data transferred in a serial format from a control unit having a transfer unit that transfers data in a serial format in a time-sharing manner and outputs the image data by the plurality of image forming units. ,
A distribution unit that distributes the plurality of image data transferred by the transfer unit to a plurality of second storage units corresponding to each of the image forming units;
Conversion means for converting the image data stored in said plurality of second memory means, a control signal for controlling the image forming unit by the distributing means,
An image forming apparatus comprising: Before Kiten feed means, said plurality of image forming means transfers the plurality of image data in order based on the order of an image formed from the plurality of first storage means to said plurality of second memory means The image forming apparatus according to claim 1, wherein:   The image forming apparatus according to claim 1, wherein the plurality of image forming units perform exposure printing of a plurality of colors by an inline method.   A plurality of channels corresponding to the plurality of first storage means, and further comprising a DMA transfer means for transferring the image data from the image memory to each of the plurality of first storage means by a direct memory access method. The image forming apparatus according to any one of claims 1 to 3.   5. The image forming apparatus according to claim 1, wherein each of the first and second storage units is configured in a FIFO format. Before Kiten feed means comprises counting means for counting the data that has been transferred to said plurality of second memory means from said plurality of first storage means, before Kiten feed means on the basis of the count value of said counting means 6. The image forming apparatus according to claim 1, wherein the image data held in at least one of the plurality of first storage units is preferentially transferred.   The image forming apparatus according to claim 6, wherein the counting unit counts the number of data transferred in units of packets. Comprising a notification unit that notifies the amount of data held in the second storage means to the front Kiten feeding means,
Before Kiten feeding means based on the amount of data notified by the notification unit, any one of claims 1 to 7, characterized in that forwarding by priority to the small second storage unit amount of data held 2. The image forming apparatus according to item 1. An image forming apparatus having an image forming unit including a plurality of image forming units that execute printing synchronously, and a control unit,
The controller is
A plurality of first storage means corresponding to each of the image forming means and holding image data transferred from the image memory for each color;
A multiplexer for sequentially selecting the plurality of first storage means;
Transfer means for converting and transferring the output of the multiplexer to a serial format;
The image forming unit includes:
A demultiplexer that distributes a plurality of image data transferred by the transfer means to a plurality of second storage means corresponding to each of the image forming means;
Conversion means for converting image data stored for each color in the plurality of second storage means by the distribution means into control signals for controlling the image forming means;
An image forming apparatus comprising: 10. The image according to claim 9, wherein the multiplexer preferentially transfers image data to be transferred to the second storage unit having a small amount of data based on the amount of data held in the second storage unit. 11. Forming equipment. Corresponding to each of a plurality of image forming units that execute printing synchronously, a plurality of first storage units that hold image data transferred from an image memory, and a plurality of images that are held by the plurality of first storage units And a transfer unit that transfers data in a serial format in a time-sharing manner. A control method for an image forming apparatus that receives a plurality of image data transferred in a serial format from a control unit and outputs the data by the plurality of image forming units Because
A transfer step of transmitting a plurality of image data held by the plurality of first storage means in a serial manner in a time-sharing manner;
A distribution step of distributing the plurality of image data transmitted in the transfer step to a plurality of second storage units corresponding to each of the image forming units;
A conversion step of converting the image data stored in the plurality of second storage means in the distribution step into a control signal for controlling the image forming means;
A control method characterized by comprising: An image forming apparatus including a plurality of image forming units that perform printing in synchronization and a control unit, and a control method for an image forming apparatus,
A first storage step of holding image data transferred from the image memory for each color in a plurality of first storage units corresponding to each of the image forming units;
A selection step of sequentially selecting the plurality of first storage means by a multiplexer;
A transfer step of converting and transferring the output of the multiplexer to a serial format,
A distribution step of distributing a plurality of image data transferred in the transfer step by a demultiplexer to a plurality of second storage units corresponding to each of the image forming units;
A conversion step of converting the image data stored for each color in the plurality of second storage units by the sorting step into a control signal for controlling the image forming unit;
A control method characterized by comprising:

Images