JP2009056595A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To carry out printing while avoiding memory overflow in a method not attended with unpredictable data degradation due to irreversible compression at the occurrence of memory overflow in an image forming apparatus. <P>SOLUTION: This image forming apparatus takes a method of ensuring a memory quantity by an overflow reducing mode of carrying out printing without performing compression/expansion processing of image data at the occurrence of memory overflow, or takes a method of ensuring the memory quantity by reducing the degree of color tone or gradient of print data to be generated to reduce the quantity of bit map data. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  When a memory overflow occurs in an image forming apparatus, the amount of data memory is reduced by reducing the color tone or gradation of image conversion, or data compression / decompression processing is avoided, so that there is a margin in memory. The present invention relates to a technique that enables printing without causing a memory overflow.

  In a low-cost image processing apparatus, the CPU performance and memory capacity are limited to some extent. For example, when printing a complex image (an image that burdens image processing) is executed, it is more than expected before printing is completed. There is a problem that it takes time, or a memory overflow occurs due to a shortage of the worst memory, resulting in a problem that a user's desired image cannot be obtained.

  As a conventional technique, in order to avoid the occurrence of an unprintable state due to memory overflow, intermediate code information for one page received from the host when the amount of intermediate code information to be converted exceeds the reserved area There is a method of securing a free area by irreversible compression processing (see Patent Document 1).

  Also, the problem that memory overflow occurs in the frame buffer compression process is to create print frame data for each primary color from the color image data for monitor display of the host machine, and perform irreversible compression on the print data in the order shown in the weight table. There is a method to solve by performing (refer to Patent Document 2).

  However, any of the above methods causes unpredictable image degradation due to lossy compression processing. There is no method for allowing the user to select a process for reducing the amount of image data.

Japanese Patent Laid-Open No. 11-320980 JP-A-9-277620

  The problem to be solved is that when a memory overflow occurs in the image forming apparatus, the memory overflow cannot be avoided without performing irreversible compression processing.

  An image forming apparatus according to the present invention includes an intermediate language conversion unit that converts image data into intermediate language data, a bitmap conversion unit that converts the intermediate language data into bitmap data, and a memory unit that compresses the bitmap data A data compression unit for storing the data, a compressed data decompression unit for decompressing the bitmap data compressed by the data compression unit into bitmap data, and printing the image upon receiving the transfer of the decompressed bitmap data An image forming apparatus including a print engine unit, wherein a data processing selection unit that enables selection of transfer of the bitmap data from the bitmap conversion unit to the print engine unit is provided. .

  The image forming apparatus of the present invention also receives an intermediate language conversion unit that converts image data into intermediate language data, a bitmap conversion unit that converts the intermediate language data into bitmap data, and transfer of the bitmap data. An image forming apparatus including a print engine unit that prints an image, wherein the intermediate language conversion unit or the bitmap conversion unit selects a process for reducing the tone and gradation of the bitmap data. The main feature is that a selection unit is provided.

  An image forming apparatus according to the present invention includes an intermediate language conversion unit that converts image data into intermediate language data, a bitmap conversion unit that converts the intermediate language data into bitmap data, and a memory unit that compresses the bitmap data A data compression unit for storing the data, a compressed data decompression unit for decompressing the bitmap data compressed by the data compression unit into bitmap data, and printing the image upon receiving the transfer of the decompressed bitmap data An image forming apparatus including a print engine unit, wherein a data processing selection unit that enables selection of transfer of the bitmap data from the bitmap conversion unit to the print engine unit is provided. Therefore, when a memory overflow occurs in the image forming apparatus, the bitmap data is not subjected to data compression / decompression processing. For printing by transferring the bit map data generated by the data converting unit to the printing engine unit, it has become possible to complete the printing without causing a memory overflow out is a margin in the memory capacity.

  The image forming apparatus of the present invention also receives an intermediate language conversion unit that converts image data into intermediate language data, a bitmap conversion unit that converts the intermediate language data into bitmap data, and transfer of the bitmap data. An image forming apparatus including a print engine unit that prints an image, wherein the intermediate language conversion unit or the bitmap conversion unit selects a process for reducing the tone and gradation of the bitmap data. Since the main feature is that the selection unit is provided, when a memory overflow occurs in the image forming apparatus, printing is performed by reducing the amount of image data at the time of data conversion. Printing can be completed without causing an overflow.

  In the image forming apparatus, when a memory overflow occurs, in order to suppress the occurrence of the memory overflow without irreversible compression processing of the image data, the user can select the reduction of the color tone or the gradation or the image data It was solved by selecting a method that does not perform compression / decompression processing.

[Constitution]
FIG. 1 is a functional block diagram of an image forming apparatus according to an embodiment of the present invention.

  The image forming apparatus 101 includes an intermediate language conversion unit 111, a bitmap conversion unit 113, a data compression unit 115, a compressed data decompression unit 117, a print engine unit 119, an input unit 121, a communication unit 123, a control unit 125, a memory unit 127, A band buffer memory 129 and a bus 131 are provided.

  The image forming apparatus 101 is connected to the terminal device 201 via the communication unit 123.

  The intermediate language conversion unit 111 converts printable data (usually PDL; data written in a page description language) transmitted from the terminal device 201 into intermediate language data for each band (DL in the present embodiment; display list). To do.

  The bitmap conversion unit 113 converts the intermediate language data (DL) converted by the intermediate language conversion unit 111 into bitmap data understood by the print engine.

  The data compression unit 115 compresses the bitmap data and stores it in the memory unit 127.

  The compressed data decompression unit 117 decompresses the data compressed by the data compression unit 115 to the original bitmap data. The decompressed bitmap data is transferred to a band buffer memory 129 described later.

  The print engine unit 119 performs printing by transferring the bitmap data from the band buffer memory 129.

  The input unit 121 receives input of printable data from the terminal device 201 and input of how to perform processing when a memory overflow occurs. The input may be a method of receiving the selection input from the terminal device 201 via the communication unit 123 or an input from an input panel provided in the image forming apparatus main body included in the input unit. May be.

  The communication unit 123 has a network interface and is responsible for communication with the terminal device 201 that is an external device.

  The control unit 125 (data processing selection unit) has a CPU and a peripheral control circuit to control the entire image forming apparatus, and selects a method for avoiding the memory overflow when a memory overflow occurs. Present to the user. Then, the selection is received via the input unit 121, and the intermediate language conversion unit 111, the bitmap conversion unit 113, the data compression unit 115, the compressed data expansion unit 117, and the print engine unit 119 perform processing according to the selection. Control.

  The memory unit 127 includes a semiconductor memory and a rotating magnetic disk device, and holds programs and data for causing the image forming apparatus 101 to function.

  The band buffer memory 129 is a part of a semiconductor memory area in the memory unit 127, and holds band bitmap data for printing in the area. A band is a unit for performing image processing in which one page of print data is divided by a predetermined number of dots in the running direction of the rotary drum. As the band buffer memory, a memory for two bands is usually prepared, and one side performs reading while one side performs writing.

  The above functional units can exchange data with each other via a bus 131.

  A scanner unit and a FAX transmission / reception unit provided in a normal image forming apparatus are omitted because they are not related to the essence of the present invention.

[Description of Intermediate Language DL (Display List)]
Next, DL (display list), which is an intermediate language between printable data (usually PDL; page description language) and bitmap data, will be described.

  Handling one page of image information at a time increases the amount of data, and the print engine does not print one page of data at a time, but the rotating drum rotates and sequentially processes the data. The image information of the page is divided into a plurality of band information having a fixed height and processed.

  The PDL (page description language) transmitted from the terminal device 201 to the image forming apparatus 101 is converted into a DL (display list) for each band. One band information is composed of a plurality of DLs, and the number of DLs of each band varies depending on the content of the band image.

  The converted DL data has a data structure connected by a linked list as shown in FIG.

  Next, FIG. 3 shows a process for developing an intermediate language DL bitmap image.

  DL is categorized according to its properties. Specifically, control system (CALL / SET etc.), vector system (VECTOR_RECTANGLE etc.), color / pattern system (SET_ROP / SET_PATTERN etc.), image system (BLT_RECTANGLE / MAP_IMAGEMASK etc.) ), A command such as a plane operation system (such as SET_DESTINATION). Each DL is a collection of such commands necessary for drawing processing (bitmap image development processing) in the band buffer memory.

When the printing process is started, the bitmap conversion unit 113 sequentially interprets the DLs one by one in units of bands and converts them into bitmaps in synchronization with the printing engine feeding and transporting. The image image is recorded in the band buffer memory 129, and the recorded bitmap image is sequentially transferred to the print engine to be printed. (When compression / decompression processing is omitted)
In the image forming apparatus, since the print engine unit 119 performs development processing while rotating at a constant rotation speed, the intermediate language conversion process and the bitmap conversion, which are the previous processes, are performed at the data speed processed by the print engine unit 119. If the process cannot catch up, an error occurs in which there is no data to be processed by the print engine and the process stops. This error is called print overrun.

  In order to avoid the print overrun error, particularly in a color image forming apparatus, a bitmap image for one page can be stored once and then transferred to the print engine. In this case, since the amount of the bitmap data image for one page is very large, there is a problem that securing the memory for holding all of them leads to an increase in the cost of the apparatus. However, since the bitmap image data has a very high data compression ratio because it has a large number of repeated portions of data of the same pattern in general, the bitmap data for one page is compressed for each band. When the compressed storage for one page is completed, the compressed data is decompressed for each band, transferred to the band buffer memory, and further transferred to the print engine for printing. .

  This method makes it possible to prevent a print overrun without securing a memory amount for one page of bitmap data.

  However, the time required for intermediate language conversion and bitmap conversion in the image forming apparatus has also been shortened due to the speeding up of the CPU, and the data is sequentially transferred to the band buffer memory without performing compression / decompression processing after the bitmap conversion. Even if transfer to all print engines and print processing are continuously performed, it has become possible to perform processing without causing a print overrun.

  In the embodiment of the present invention, the control unit 125 (data processing selection unit) can select a method for performing printing by performing conventional compression / decompression in the image forming apparatus and a method for performing printing without performing compression / decompression. It is.

  As a selection method is to be a method of selecting by which method the take or user preset, also the memory overflow occurs when printing was conducted in the way of performing the conventional compression and decompression, the user A method for notifying the fact and selecting whether or not to proceed with the process without compression / decompression by an input from the input unit is also possible. Further, the control unit 125 may predict the occurrence of a memory overflow from the print data and the usage status of the memory unit 127, and if the occurrence is predicted, the process may proceed without performing the compression / decompression as described above.

  Also, when a memory overflow occurs or is predicted, the data amount is reduced by selecting the reduction of the color tone or the reduction of the gradation of the image data, and the memory overflow is avoided at the time of the re-processing. A method can also be selected.

  The method for securing the amount of memory without performing the above compression / decompression, the method for securing the amount of memory by reducing the color tone, and the method for securing the amount of memory by reducing the gradation can be set independently. All of them may be set at the same time, and either one or two methods can be selected.

[flowchart]
The flow of the printing operation and the memory overflow avoidance operation will be described with reference to the flowchart on the terminal device 201 (PC: Personal Computer) side in FIG. 4 and the flowchart on the image forming apparatus side in FIG.

  First, the operation is started from the terminal device 201 in FIG.

  S11: On the terminal device 201 (PC: Personal Computer) side, printable data (generally PDL; page description language; print data written in page description language) is generated and transmitted to the image forming apparatus to be printed. I do. Here, the operation shifts to the P terminal in FIG.

  S13: The image forming apparatus 101 receives the printable data, analyzes the print data, and gives an instruction for color reduction (reduction in color tone) or gradation reduction (reduction in tone level) during PJL (Print Job Language). Whether or not is included. If it is included, the operation proceeds to S14. If not included, the operation proceeds to S15.

  S14: When converting the print data to the intermediate language conversion unit 111, settings are made so as to follow the instruction (reduction in color tone or reduction in gradation) analyzed in S13.

  S15: The image forming apparatus 101 receives the printable data, analyzes the print data, and reduces the memory amount by performing the memory overflow reduction mode (print processing without compression / decompression) during PJL (Print Job Language). Judgment is made as to whether or not a secure method is set. If the memory overflow reduction mode is set, the operation proceeds to S31. If it is not set, the operation proceeds to S16.

  S16: The intermediate language conversion unit 111 converts the PDL (page description language) data into a DL (display list. The converted data is stored in the memory unit 127. In this case, the reduction in color tone or the level in S14 is stored. If there is an instruction to reduce the furniture, data is generated according to the instruction.

  S17: The bitmap conversion unit 113 converts the DL generated in the previous step into bitmap data. The converted data is stored in the memory unit 127. The conversion source DL is erased from the memory unit 127.

  S19: The data compression unit 115 compresses the bitmap data and stores it in the memory unit 127. The bitmap data that is the conversion source is deleted from the memory unit 127.

  S21: It is determined whether or not the data conversion performed for each band in S16, S17, and S19 is completed for one page and the compressed bitmap data for one page is stored in the memory. If the bitmap data for one page is finished, the operation proceeds to S23. If not completed yet, the process returns to S16 and repeats the data conversion in units of bands.

  S23: Since bitmap data for one page has been completed, the compressed data decompression unit 117 decompresses the bitmap data compressed for each band.

  S25: The bitmap data restored by the decompression process is transferred to the band buffer memory 129.

  S 27: The bitmap data transferred to the band buffer memory 129 is transferred to the print engine unit 119.

  S29: The print engine unit 119 prints the transferred bitmap data.

  The processes from S23 to S25 are sequentially performed in parallel for each band, and printing for one page is performed. When the processing up to S29 is completed, the operation shifts to the Q terminal in the flowchart of FIG.

  S31: If the memory overflow reduction mode is selected, the processing from S31 is started. This process converts PDL (page description language) data into DL (display list; intermediate language) data as in S16.

  S33: Convert DL to bitmap data. This is the same processing as S17.

  S35: Here, the bitmap data generated without performing the compression process is transferred to the band buffer memory. This process is the same as S25.

  S37: The bitmap data transferred to the band buffer memory is transferred to the print engine unit 119. This process is the same as S27.

  S39: The print engine unit 119 prints the transferred bitmap data. This process is the same as S29.

  The processes from S31 to S39 are sequentially performed in parallel for each band, and printing for one page is performed. When the processing up to S39 is completed, the operation shifts to the Q terminal in the flowchart of FIG.

  S40: When an error such as a memory overflow or print overrun occurs during the processing from S13 to S39, an interrupt process starts, and the printing operation cannot be continued any more, so an error code indicating the cause of the error is shown in FIG. The operation is shifted to the Q terminal in the flowchart of B).

  Next, the operation on the terminal device 201 side starting from the Q terminal in FIG. 4B will be described.

  S41: It is determined whether an error (memory overflow, print overrun) has occurred in the image forming apparatus. If no error has occurred, it is determined that printing has been performed normally, and the operation ends normally in S43. If an error has occurred, the operation proceeds to S45.

  S45: An error avoidance operation is set. Select “Cancel” to cancel the printing operation, reduce the color tone (for example, change the color printing to monochrome printing), or reduce the tone level (for example, 4 bpp (bit per pixel) is changed to 2 bpp (bit per pixel)). change to bit per pixel).

  S47: It is determined whether or not the selection in S45 is cancel. If cancelled, printing is not performed and the operation ends in S49. If not cancelled, the operation proceeds to S51.

  S51: It is determined whether or not the selection in S45 is a reduction in color tone. If so, the operation proceeds to S53. Otherwise, the operation proceeds to S55.

  S53: An instruction to reduce the color tone is added to PJL (Print Job Language).

  S55: It is determined whether or not the selection in S45 is a reduction in gradation. If so, the operation proceeds to S57. Otherwise, the operation proceeds to S59.

  S57: An instruction to reduce the gradation is added to PJL (Print Job Language).

  S59: It is determined whether or not the selection in S45 is the setting of the memory overflow reduction mode. If so, the operation proceeds to S61. Otherwise, the operation proceeds to S63.

  S61: An instruction to execute the memory overflow reduction mode is added to PJL (Print Job Language).

  S63: If there is an instruction added in S53, S57, S61, the instruction is added, and if not, a normal print instruction is given to the image forming apparatus.

  Next, the operation shifts to the P terminal in the flowchart of FIG. 5 on the image forming apparatus side.

  Through the above series of operations, data that could not be printed due to a memory overflow once can be printed with the memory amount secured by the avoidance method described above.

  In this flowchart, only a loop for each band related to data for one page is shown. In actual print data, a single job includes a plurality of pages. In this case, processing for one page is repeated. Since loops for a plurality of pages are not related to the essence of the present invention, they are omitted here.

  In this flowchart, an operation example in which an error avoidance operation is set after an error has occurred once in S45 is shown, but an error avoidance operation may be set in advance before a print instruction in S11.

  Further, the control unit 125 (data processing selection unit) determines whether or not a memory overflow is predicted from the print data and the memory state of the image forming apparatus, and avoids an error when a memory overflow is predicted. An operation may be performed or an error avoidance operation setting selection operation may be performed.

  In this flowchart, an example of an operation in which the user selects an error avoidance operation after an error has occurred once in S45 is shown. However, when a memory overflow occurs, the memory overflow reduction mode is automatically selected and compression / decompression processing is performed. It is also possible to retry printing in a method that does not perform the above.

[Effect of Example]
According to the embodiment of the present invention, when the memory overflow occurs in the image forming apparatus, the memory amount can be secured by adopting the memory overflow reduction mode in which the compression / decompression processing of the bitmap data is not performed, and the print data is deteriorated. It became possible to print without letting.

  In addition, by reducing the amount of bitmap data by reducing the color tone and the gradation, the memory amount is secured and the occurrence of memory overflow is avoided.

  Based on the data processing selection result input through the input unit 121 of the image forming apparatus 101, it is possible to select what processing is to be performed.

[Others]
The color reduction (reduction in color tone) includes converting a color image into a monochrome image.

  In the embodiment of the present invention, the tone reduction and the gradation reduction are performed by the intermediate language conversion unit 111, but may be performed by the bitmap conversion unit 113.

1 is a functional block diagram of an image forming apparatus (first embodiment). FIG. (Example 1) which is explanatory drawing of the internal structure of page information. (Example 1) which is explanatory drawing of the bitmap image expansion | deployment process of a display list (DL). 5 is a flowchart on the terminal device (PC) side (first embodiment). 3 is a flowchart on the image forming apparatus side (first embodiment).

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Image forming apparatus 111 Intermediate language conversion part 113 Bitmap conversion part 115 Data compression part 117 Compressed data expansion part 119 Print engine part 121 Input part 125 Control part (data processing selection part)
201 terminal device

Claims (6)

An intermediate language conversion unit for converting image data into intermediate language data;
A bitmap converter for converting the intermediate language data into bitmap data;
A data compression unit for compressing the bitmap data and storing it in a memory unit;
A compressed data decompression unit for decompressing the bitmap data compressed by the data compression unit into bitmap data;
An image forming apparatus including a print engine unit that receives the transfer of the decompressed bitmap data and prints an image;
An image forming apparatus comprising: a data processing selection unit that enables selection of transfer of the bitmap data from the bitmap conversion unit to the print engine unit. The image forming apparatus according to claim 1,
It has an input unit that accepts user input,
The data processing selection unit transfers the bitmap data to the print engine unit after the compression / decompression processing in the data compression unit and the compressed data decompression unit, or the data processing selection unit and the compressed data decompression unit An image forming apparatus, wherein whether to transfer to the print engine unit after conversion by the bitmap conversion unit without performing compression / decompression processing can be set by an input from the input unit. The image forming apparatus according to claim 1, wherein
The data processing selection unit transfers the bitmap data to the print engine unit after the compression / decompression process in the data compression unit and the compressed data decompression unit based on the state of the remaining storage capacity of the memory unit, or An image forming apparatus that selects whether to transfer to the print engine unit after conversion by the bitmap conversion unit without performing compression / decompression processing by the data compression unit and the compressed data expansion unit. An intermediate language conversion unit for converting image data into intermediate language data;
A bitmap converter for converting the intermediate language data into bitmap data;
An image forming apparatus including a print engine unit that receives the transfer of the bitmap data and prints an image;
An image forming apparatus comprising: a data processing selection unit that selects at least one of a color tone reduction process or a gradation reduction process of the bitmap data in the intermediate language conversion unit or the bitmap conversion unit . The image forming apparatus according to claim 4,
It has an input unit that accepts user input,
The image processing apparatus, wherein the data processing selection unit can set selection of at least one of color tone reduction processing or gradation reduction processing of the bitmap data by input from the input unit. The image forming apparatus according to claim 4, wherein:
The data processing selection unit accepts selection of at least one of color tone reduction processing and gradation reduction processing of the bitmap data based on the state of the remaining storage capacity of the memory unit at the input unit. An image forming apparatus.

Images