JP2000343768A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid inability of printing due to overrun error without increasing a capacity of a memory. SOLUTION: This image forming apparatus comprises a PDL interpreter 1 for generating a band by analyzing input data, an intermediate language list memory 2 for storing the band, a band complexity judging means 3 for storing the judged result of the complexity of the band into the intermediate language list memory 2, and an intermediate language rasterizer 4 for developing raster data in a band buffer 5 by predicting a band that may generate an overrun error from the band generated by the PDL interpreter 1. The apparatus further comprises an engine output means 6 for outputting, to a print engine section, an engine process control signal for synthesizing the raster data of the band buffer 5 with the raster data of the band which is already subjected to a developing operation by executing the developing operation of the raster data of the band having the overrun error.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus for controlling a continuous Wrathler output device such as a laser printer using a band buffer memory.

[0002]

2. Description of the Related Art Conventionally, printers based on various principles have been proposed as output terminals such as personal computers and workstations. In particular, a color laser beam printer (hereinafter, referred to as “C-LBP”) using an electrophotographic process and a laser exposure technique has a high advantage in recording speed and printing quality.

In general, a C-LBP includes an image forming apparatus for generating output image data from input data and a print engine unit. Here, in the print engine unit, the resolution tends to be improved in order to improve the print quality. On the other hand, in an image forming apparatus,
The necessity of transferring output image data to a high-resolution print engine unit tends to increase the capacity of a memory for storing image data. Therefore, these factors cause an increase in the cost of the entire apparatus, and the C-LB
This has hindered the spread of P.

As means for solving this problem, a so-called band buffer type image forming apparatus has been proposed.

FIG. 7 is a block diagram showing a conventional band buffer type image forming apparatus.

In FIG. 7, an image forming apparatus includes a PDL interpreter 1 for analyzing a page description language (hereinafter, referred to as “PDL”) such as a postscript, an intermediate language list memory 2 for storing drawing objects, and an intermediate language list memory. 2, a band complexity determining means 3 for determining the complexity of the band by searching the band 2 and storing the determination result in a determination result storage position in the intermediate language list memory 2, a black (K) in the intermediate language list memory 2 The band in which an overrun error is expected to occur in the plane is image-expanded in the band buffer 5 by the image decompression means 15, and the raster data in the intermediate language rasterizer 4 and the band buffer 5 stored in the intermediate language list memory 2 by the image compression means 14. The engine output means 6 is provided for output.

According to such an image forming apparatus, the PDL
The interpreter 1 analyzes the PDL and stores the drawing objects associated with the band determined from the position in the page to be printed in the intermediate language list memory 2 in a list structure.

After the intermediate language list for one page is created, the band complexity determining means 3 outputs the intermediate language list memory 2
And determines the complexity of the band based on the type and number of objects in the band, and sequentially stores the determination results in the determination result storage position in the intermediate language list memory 2.

When the complexity determination for all the bands in one page is completed, the intermediate language rasterizer 4 executes the rendering of the image image to the band buffer 5
Whether or not there is a band in which an overrun error is expected to occur for the black (K) plane in the intermediate language list memory 2 is determined based on the information of the determination result storage position in the intermediate language list memory 2. If there is a complicated band, the band is expanded into an image in the band buffer 5, and the image is compressed and stored in the intermediate language list memory 2 using the image compressing means 14.

When the same processing is completed for all the bands and all the color planes in one page, the intermediate language rasterizer 4 starts developing the data in the band buffer 5 and
When the image development of one band is completed, the output of the raster data by the engine output means 6 is started.

In the image forming apparatus having such a conventional configuration, when a complicated drawing request is present in a partial area in a page, a complex band is image-developed before the print engine section is started, and the print engine is started. The overrun error is prevented by adjusting the image data generation time to the image data output time determined by the unit.

[0012]

However, the conventional image forming apparatus as described above requires a memory for developing an image of a complicated band before starting the print engine unit.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus capable of avoiding printing failure due to an overrun error without increasing the memory capacity.

[0014]

In order to solve this problem, an image forming apparatus according to the present invention comprises: an interpreter for analyzing input data to generate a band; a band memory for storing the band; Band complexity determining means for storing a degree determination result in a band memory, rasterizing means for predicting a band in which an overrun error will occur from the band generated by the interpreter means and developing raster data in a band buffer, and a band buffer And output means for outputting to the print engine unit an engine process control signal for developing the raster data and the raster data of the band of the overrun error and combining the raster data with the raster data of the band already developed. .

[0015] This makes it possible to avoid printing due to an overrun error without increasing the memory capacity.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention according to claim 1 of the present invention provides an interpreter for analyzing input data to generate a band, a band memory for storing a band, and a band memory for determining a band complexity. Band complexity determining means stored in the memory; rasterizing means for predicting a band in which an overrun error will occur from the band generated by the interpreter means to expand raster data in a band buffer; raster data in the band buffer and overrun error Output means for outputting to the print engine unit an engine process control signal for developing raster data of the band and combining the raster data of the band already developed with the raster data of the band, thereby increasing the memory capacity. To avoid possible printing due to overrun error It has the effect that it becomes possible.

According to a second aspect of the present invention, there is provided an image forming apparatus according to the first aspect, wherein the overrun error recovery processing can be set to be enabled or disabled.
When the overrun error recovery processing is invalid, there is an effect that it is possible to switch from the band buffer system to the page memory system by installing an additional memory.

According to a third aspect of the present invention, in the first or second aspect of the invention, the print engine unit forms a composite toner image of a plurality of colors on the intermediate transfer belt by a plurality of processes. This is an image forming device that is an engine unit or a print engine unit that forms a composite toner image of multiple colors on the intermediate transfer belt in one process, and avoids printing due to overrun errors without increasing memory capacity. Has the effect that it becomes possible to

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. In these drawings, the same members are denoted by the same reference numerals, and duplicate description is omitted.

(Embodiment 1) FIG. 1 is a block diagram showing an image forming apparatus according to Embodiment 1 of the present invention, and FIG.
FIG. 3 is a schematic diagram showing a mechanism of a print engine unit for forming CMY color toner images in four processes, FIG. 3 is a timing chart of the print engine unit in FIG. 2 during normal operation,
FIG. 4 is a timing chart when an overrun error occurs in the print engine unit of FIG.

As shown in FIG. 1, an image forming apparatus according to the present embodiment analyzes a PDL, which is input data, to generate a band, which is an intermediate code, and a PDL interpreter (interpreter means) 1, and an intermediate for storing the band. A language list memory (band memory) 2, a band complexity determining means 3 for storing the determination result of the band complexity in the intermediate language list memory 2, a band in which an overrun error occurs is predicted from the band generated by the PDL interpreter 1. An intermediate language rasterizer (rasterizing means) 4 for expanding raster data in a band buffer 5 and a band buffer 5
Engine output means (output means) 6 for outputting to the print engine unit an engine process control signal for developing the raster data and the raster data of the band of the overrun error and synthesizing the raster data of the band already developed. I have.

According to such an image forming apparatus, the PDL
The interpreter 1 analyzes the PDL and stores the drawing objects associated with the band determined from the position in the page to be printed in the intermediate language list memory 2 in a list structure.

After the intermediate language list for one page is created, the band complexity determining means 3 outputs the intermediate language list memory 2
And determines the complexity of the band based on the type and number of objects in the band, and sequentially stores the determination results in the determination result storage position in the intermediate language list memory 2.

When the complexity determination is completed for all the bands in one page, the intermediate language rasterizer 4 determines that there is a band in the intermediate language list memory 2 where an overrun error is expected to occur, for example, for a black (K) plane. Whether to perform the determination is determined based on the information on the storage position of the determination result in the intermediate language list memory 2, and this is notified to the engine output means 6. Then, development of the black (K) plane image image into the band buffer 5 is started.

The engine output means 6 includes a band buffer 5
Is transferred to the print engine unit as raster data.

Such processing is performed for cyan (C),
Magenta (M) and yellow (Y) are sequentially performed.

FIG. 2 shows a mechanism of a print engine unit for forming KCMY color toner images by four processes.

As shown, the print engine unit comprises:
A photoreceptor belt 8 on which a latent image is formed by a light beam 7 emitted based on raster data from the image forming apparatus is rotatably tuned by three rollers.

A black developing device for developing a black toner image, a cyan developing device for developing a cyan toner image, a magenta developing device for developing a magenta toner image, There are provided four developing units 9 of a yellow developing unit for developing the toner image of FIG.

These developing devices 9 are urged in a direction away from the photoreceptor belt 8, and contact / separation cams 10 are provided respectively.
Is pressed by the photoreceptor belt 8. Then, the latent image is visualized by the toner supplied from the developing unit 9 that is pressed, and a toner image is formed on the photosensitive belt 8.

The intermediate transfer belt 11 is rotatably tuned by three rollers in contact with the photosensitive belt 8. The intermediate transfer belt 11 is pressed against the photoreceptor belt 8 and rotates in the forward direction with respect to the photoreceptor belt 8, and each color toner image formed on the photoreceptor belt 8 in a total of four processes Are sequentially transferred to the intermediate transfer belt 11 by the pressing force and are superimposed on each other.

The print engine unit is provided with a paper cassette, and the paper stored in the paper cassette is taken out one by one by a pickup roller 12 and conveyed through a paper feed path.

A fixing device 13 is provided on the conveyance path behind the contact position with the intermediate transfer belt 11. Then, when the sheet passes through the fixing device 13, the toner image collectively transferred from the intermediate transfer belt 11 to the sheet is fixed.

Next, the operation of the print engine unit controlled by the image forming apparatus according to the present embodiment will be described with reference to FIGS.

FIG. 3 is a timing chart at the time of normal operation, and FIG. 4 is a timing chart at the time of forming a one-page black image by two transfer processes because a part of the band of the black plane is complicated. is there.

During normal operation, as shown in FIGS. 1 and 2, the image image developed in the band buffer 5 is sent to the print engine unit as raster data by the engine output means 6, and is converted into a light beam 7 by the photoconductor. The light is irradiated onto the belt 8, developed by the developing device 9 driven by the contact / separation cam 10, and then transferred onto the intermediate transfer belt 11. When the transfer of K is completed, the same processing is continuously performed for C, M, and Y, and a combined toner image of four colors of K, C, M, and Y is formed on the intermediate transfer belt 11. . This toner image is picked up by the pickup roller 12.
After being transferred onto a sheet picked up and conveyed by the fixing roller 13, the sheet is fixed by the fixing roller 13.

On the other hand, when overrun error occurrence is predicted,
As shown in the timing chart of FIG. 4, the image image developed in the band buffer 5 is sent to the print engine unit as raster data by the engine output unit 6, but the raster data of the band predicted to cause an overrun error is generated. Becomes a zero signal, and is not irradiated on the photosensitive belt 8 as the light beam 7. Then, only the raster data of the band predicted not to cause an overrun error is developed by the developing device 9 driven by the contact / separation cam 10, and then transferred onto the intermediate transfer belt 11. Once the transfer of K is completed in this way, the raster data of the band for which an overrun error has occurred is assumed to be the toner image already formed on the intermediate transfer belt 11 by the K exposure, development, and transfer processes performed again. Is synthesized.

The operations for C, M, and Y are the same as those in the normal state.
M and Y toner images are formed. The toner image is transferred onto a sheet picked up and conveyed by the pickup roller 12 and then fixed by the fixing roller 13.

As described above, according to this embodiment, when the occurrence of an overrun error is predicted, the raster data of the band of the overrun error is developed again in addition to the normal printing process, and the developed data has already been developed. Since the data is synthesized with the raster data of the band, it is possible to avoid printing due to an overrun error without increasing the memory capacity.

In this case, if the overrun error recovery processing can be set to be enabled or disabled, it is possible to disable the overrun error recovery using an operation panel or the like when an additional memory is installed. Thus, the band complexity determining means 3 is stopped, and the intermediate language rasterizer 4 can develop the image data from the complicated band buffer system to the page memory system. Thus, the output of the raster data by the engine output means 6 is started when all the page images have been generated.

(Embodiment 2) FIG. 5 is a schematic view showing a mechanism of a tandem type print engine unit for forming each color toner image of KCMY in one process, and FIG. 6 is an overrun of the print engine unit of FIG. 6 is a timing chart when an error occurs. In this embodiment, the image forming apparatus is the same as that described in the first embodiment.

As shown in FIG. 5, the print engine unit uses a light beam 7 emitted based on raster data from the image forming apparatus to generate black (K), yellow (Y),
A process unit 19 includes a photosensitive drum on which toner images of magenta (M) and cyan (C) are formed, and a toner image forming member for forming a toner image on the surface of the photosensitive drum. The intermediate transfer belt 17 provided along the photoreceptor drum is adjusted and supported by a plurality of rollers and rotates. Then, the toner images of the respective colors formed by being superimposed on the photosensitive member in one process are collectively transferred to the intermediate transfer belt 17 by the pressing force.

At the lower part of the apparatus, there is provided a paper cassette in which paper is stored. The paper is fed out of the paper cassette one by one to a paper transport path by a feeding roller 18.

A fixing device 20 is provided on the conveyance path behind the contact position with the intermediate transfer belt 17. Then, as the sheet passes through the fixing device 20, the toner image collectively transferred from the intermediate transfer belt 17 to the sheet is fixed.

In such a print engine section,
At the time of predicting the occurrence of the overrun error, as shown in the timing chart of FIG. 6, the image image developed in the band buffer 5 for each color is sent to the print engine unit as raster data by the engine output unit 6 (FIG. 1). However, the raster data of the band in which an overrun error is predicted to occur becomes a zero signal for all colors, and is not irradiated as a light beam 16 on the photosensitive drum in the process unit 19. Then, the transfer of the KCMY toner image other than the raster data of the band of the overrun error is performed on the intermediate transfer belt 17.

After the transfer is completed in this manner, KCMY exposure, development, and transfer processes are continuously performed on the raster data of the overrun error occurrence prediction band.
The toner images are combined with the toner images of the respective colors already formed on the intermediate transfer belt 17.

Thus, on the intermediate transfer belt 17,
K, C, M, Y of all bands in two process cycles
Is formed.

After being transferred onto the sheet picked up and conveyed by the toner image feeding roller 18 formed as described above, the toner image is fixed by the fixing roller 20.

As described above, according to the present embodiment, when the occurrence of an overrun error is predicted, the raster data of the band of the overrun error is developed again in addition to the normal printing process, and is already developed. Since the data is synthesized with the raster data of the changed band, it is possible to avoid printing due to an overrun error without increasing the memory capacity.

In this case, if the overrun error recovery processing can be set to be enabled or disabled, the overrun error recovery can be disabled by using an operation panel or the like when an additional memory is installed. Thus, the band complexity determining means 3 is stopped, and the intermediate language rasterizer 4 can develop the image data from the complicated band buffer system to the page memory system. Thus, the output of the raster data by the engine output means 6 is started when all the page images have been generated.

In the present embodiment, the print engine is of an electrophotographic type using a laser beam, but is not limited to this.
An ED system, a liquid crystal shutter system, or the like can be applied.

[0052]

As described above, according to the present invention, it is possible to obtain an effective effect that it is possible to avoid printing due to an overrun error without increasing the memory capacity.

If the overrun error recovery processing can be set to be valid or invalid, if the overrun error recovery processing is invalid, it is possible to switch from the band buffer system to the page memory system by installing an additional memory. That is, an effective effect is obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an image forming apparatus according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram showing a mechanism of a print engine unit for forming each color toner image of KCMY by four processes.

FIG. 3 is a timing chart at the time of a normal operation of the print engine unit of FIG. 2;

FIG. 4 is a timing chart when an overrun error occurs in the print engine unit of FIG. 2;

FIG. 5 is a schematic view showing a mechanism of a tandem type print engine unit for forming KCMY color toner images in one process.

FIG. 6 is a timing chart when an overrun error occurs in the print engine unit of FIG. 5;

FIG. 7 is a block diagram showing a conventional band buffer type image forming apparatus.

[Explanation of symbols]

 Reference Signs List 1 PDL interpreter (interpreter means) 2 Intermediate language list memory (band memory) 3 Band complexity determining means 4 Intermediate language rasterizer (rasterizing means) 5 Band buffer 6 Engine output means (output means)

 ──────────────────────────────────────────────────続 き Continued on front page F term (reference) 2C087 AB05 AC08 BC02 BC05 BC07 BD01 BD07 CB03 CB06 DA09 2H030 AD11 5B021 AA01 DD08 LG07 5C074 AA15 BB02 DD16 DD24 EE14 FF20 HH02 HH04 9A001 BB03 HH28 HH31 JJ35 KK

Claims (3)

[Claims] 1. An interpreter for analyzing input data to generate a band, a band memory for storing the band, and a band complexity determining unit for storing a result of determining the complexity of the band in the band memory. Rasterizing means for estimating a band in which an overrun error will occur from the band generated by the interpreter means and developing raster data in a band buffer; Output means for outputting an engine process control signal for synthesizing the raster data of the band which has already been developed to the print engine unit. 2. The image forming apparatus according to claim 1, wherein the overrun error recovery processing can be set to be enabled or disabled. 3. A print engine unit for forming a synthetic toner image of a plurality of colors on an intermediate transfer belt in a plurality of processes, or a synthetic toner of a plurality of colors on an intermediate transfer belt in a single process. 2. A print engine unit for forming an image.
Or the image forming apparatus according to 2.