JP3029154B2 - Image forming device - Google Patents

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 such as a page printer.

[0002]

2. Description of the Related Art Hitherto, page printers have often not been provided with a function for generating an image of a very large size. In addition, the capacity of the storage unit for generating an image has only the maximum outputable image size of one page. In addition, even if the page size of such a page printer can be changed, the maximum image size that can be output is relatively small. Used to be.

[0003]

However, if the image has only the storage capacity for one page of the image, the image expansion processing of the next page cannot be performed until the output of the image is completed.
In a high-speed printing machine such as a multifunction machine of a copying machine and a page printer, the printing speed cannot be sufficiently utilized in many cases. In addition, such a multifunction peripheral often has a relatively large maximum output image size. On the other hand, the size of an image frequently output by a user is often less than half of the size, and in such a case, there is a problem that the memory use efficiency is reduced.

[0004] It is an object of the present invention to provide a memory controller.
Memory control with simple control without complicating the configuration.
Controller read operation and page description language data
Parallel processing of image data processing such as data expansion processing
To improve overall throughput
It is another object of the present invention to provide a functional image forming apparatus. Also book
Another object of the invention is to further generate large size images
For image forming devices that can output,
When generating and outputting small images, split the image memory
If one area is waiting for output, expand it to the other.
It is possible to improve the overall through put
An object of the present invention is to provide an image forming apparatus.

[Means and actions for solving the problems] Achieving the above object
The image forming apparatus according to the present invention has a predetermined size.
Memory capable of storing image data of
Processing means for processing image data to be processed; and
The image data of each area is provided corresponding to each predetermined area.
At least two for generating an address signal for reading
And a memory controller of any of the above areas
Selectively disconnecting one from the bus with the processing means,
The image data of the separated area corresponds to that area
In parallel with the read operation by the memory controller,
The processing means can execute processing of image data in other areas.
It is characterized by having done. Preferably, it is smaller than a predetermined size.
When forming images of multiple pages,
Selectively disconnect one from the bus with the processing means
Then, the image data of the page in the separated area
Read by the memory controller corresponding to the area
Sometimes, the processing means processes the image data of the next page.
Is performed using another area. Ma
Preferably, the processing means is output from a higher-level device.
The page description data into image data
To be stored. According to the invention, at least two memories
A controller is provided for each predetermined area of the memory,
Any one of the regions can be selectively used with the processing means.
Image data of the separated area separated from the bus
Read by the memory controller corresponding to the area
In parallel with the outputting operation, the processing means outputs image data of another area.
Data processing can be executed.
With simple control without complicating the configuration of
Read operation by recontroller and page description language
Parallel processing of image data processing such as data expansion processing
It becomes possible. Further, in an image forming apparatus capable of outputting a relatively large size, a large storage capacity for generating an image is used, and depending on the size of an image to be generated, a storage unit is divided and used for generation and output. Thus, the problems described above can be solved.

[0005]

FIG. 1 is an overall view of a digital copying machine 1000 to which an embodiment of the present invention is applied. Normally, the digital copying machine 1000 has a configuration in which density data can be expressed in multiple values for each pixel in order to output an image read by the image reader section 31 with high quality. An example in which the present invention is implemented as a multi-valued printer by using this will be described. In this embodiment, an external device 23 is connected to use the copier 1000 as a printer.

Documents loaded on the document feeder 1 are 1
The sheets are sequentially conveyed onto the glass surface of the document table 2. When the document is conveyed, the lamp 3 of the scanner is turned on, and the scanner unit 4 moves to irradiate and scan the document. The reflected light of the original passes through a lens 8 via mirrors 5, 6, and 7,
After that, it is input to the image sensor unit 9. Each of the above components constitutes the image reader unit 31.

[0007] As shown in FIG.
The output image signal from 1 is processed by an image signal control circuit 32 controlled by the CPU 30 and reaches the printer unit 33. The signal input to the printer unit 33 controls the laser beam by the exposure control unit 10 (FIG. 1) and irradiates the photoconductor 11 as an optical signal. The latent image formed on the photoreceptor by the irradiation light is developed by the developing device 13. The transfer paper is conveyed from the transfer paper stacking units 14 and 15 in synchronization with the formation timing of the latent image, and the developed image is transferred in the transfer unit 16. The transferred image is fixed on the transfer sheet by the fixing unit 17, and then discharged from the sheet discharging unit 18 to the outside of the apparatus. Reference numeral 20 denotes an intermediate tray used for double-sided printing, and reference numeral 19 denotes a switching flapper for switching between sheet discharge and sheet conveyance to the intermediate tray 20.

Next, a configuration in which the printer unit 33 of the copying machine outputs multi-value density data will be described. The copying machine according to the present embodiment modulates a signal for controlling a laser beam used as an exposure unit for operating one line at a time to change an irradiation area on a photoconductor, thereby performing area gradation for each pixel. The density can be changed.

FIG. 3 is a view for explaining a portion for generating a signal for modulating a laser beam from an image signal input to the printer section. The density data of the image input to the printer unit 33 is a digital value. This value is calculated as D / A for each pixel.
When input to the converter 41, it is converted to an analog value and input to the comparator 42. From the triangular wave generator 40, a triangular wave used for comparison with an image signal is input to a comparator 42. FIG. 4 shows a relationship between two signals input to the comparator 42 and a signal output from the comparator 42 as an exposure control signal.
Shown in The exposure signal is output as a pulse width modulation signal (PWM) corresponding to the level of the image signal. If the irradiation time of the laser beam for each pixel in one scanning line is controlled in accordance with this exposure signal, the irradiation area for each pixel can be changed, so that area gradation can be realized.

Next, the binary image generation / storage device 34 shown in FIG. 2 will be described. Binary image generation / storage device 3 shown in FIG.
Reference numeral 4 denotes image data that is stored in the housing of the external device 23 and expands image data based on data according to a page description language sent from a computer. The page description language here is a language system for expressing image data for each screen output by a page printer or the like in a command format. The interface 53 is used for input / output with a computer. When the CPU 50 receives the page description language data transmitted through this, the CPU 50
The memory controller 5 interprets the contents and
The binary image data is developed on the image memory 52 via the line 1.

The image thus developed and the image read by the image reader section 31 are stored in the disk drive 24.
, Or can be displayed on the display device 22, but is normally output by the printer unit 33. That is, when the development of the image data is completed, the CPU 50 communicates with the CPU 30 of the copying machine 1000 via the communication line 54 and prepares to transmit the image data via the image bus 55. When transmitting image data to the copier 1000,
Image data is converted through a binary / multi-value converter 56 and an enlargement / reduction circuit 57 in the figure. Binary to multi-level converter 56
Then, the binary of the image data expanded on the image memory 52 is assigned to the maximum value and the minimum value of the multi-value data, and the multi-value data is output. If the image memory 52 has a function of expanding multi-value data, the binary / multi-value converter 56 is omitted. The enlargement / reduction circuit 57 converts the received multi-value data in the main scanning direction and the sub scanning direction by the following algorithm.

Referring to FIG. 6, a case will be described in which the main scanning pixels are enlarged to x / (xy)%. In the case of the same magnification, there is no problem because the actual output position in FIG. 6 and the actual pixel position of the original image data correspond to each other. However, when enlarging, it is considered that an image signal is input at a virtual pixel position. . If the image data at this position is output to the actual output position, the image is enlarged, so the image density at the virtual pixel position is interpolated from the density value of the image signal input at the actual reading position based on the following formula. Predict.

T2 = {R1 · y + R2 · (xy)} / x In the case of sub-scanning, the present algorithm may be applied to each scanning line.

Normally, the content of an image described in a page description language targets a resolution corresponding to a dedicated page printer. As an example, the copier can output 400 dots of pixels per inch, and outputs data of 240 dots per inch according to a page description language compatible with a page printer.
It is assumed that the data has been sent to the storage device 34. The CPU 50 develops image data corresponding to 240 dpi in the image memory 52. When transferring the expanded data to the printer unit 33 of the copying machine 1000, the expansion / reduction circuit 57

[0015]

[Outside 1] Set the data to enlarge at the magnification of. As described above, the image data is converted into multi-value data by the binary / multi-value converter 56, and thereafter, is enlarged at the magnification set by the enlargement / reduction circuit and transferred to the copying machine 1000. Copier 10
00 outputs the transferred image data at 4000 dpi.

Next, an example in which the above-described page description language does not depend on the resolution will be described. Being independent of the resolution means that the binary image generation / storage device 34 can expand the transmitted page description language data in accordance with the specified resolution.
In particular, when the image data described in the page description language is data in a vector format, it is possible to cope with any resolution by expanding the data according to a constant depending on the resolution. However, in the configuration in which the CPU 50 develops the image in the image memory 52 as in the present embodiment, the higher the resolution, the longer the time required for the development. However, since binary / multi-value conversion and scaling can all be performed in real time, if the image is developed at a lower resolution within a range that does not significantly affect image quality, actual image data is output from the copying machine 1000. It is possible to considerably shorten the time until the completion. Comparing the development time with the area ratio, 400d
At pi and 240 dpi,

[0017]

[Outside 2] The effect is enormous because there is a difference of nearly three times.

FIG. 7 shows an example of a flow chart when a low-resolution development is selected from a computer connected to the interface 53.

With respect to the above configuration, an operation characteristic of the present invention will be described with reference to a flowchart of FIG. The copying machine 1000 of this embodiment can output up to A3 size paper. For this reason, the capacity of the image memory 52 is required to be at least (297 mm × 240 dpi / 25.4 mm / inch) × (420 mm × 240 dpi / 25.4 mm / inch) /8=1.4 MByte as the capacity at 240 dpi. In this embodiment, page description language data is received from a computer (steps s1, s2), and the size of an image to be generated is determined (step s3).
When outputting to an image of A 4 size, so sufficient 0.7MByte half this, the image memory 5
2 is divided into two areas 52a and 52b for use (step s4). Assuming that the output order of the developed image is not changed, the image is output when the development is completed on the divided image memory, but if one (for example, 52a) is being output, the process proceeds from step s5 to step s7, where the entire system is output. Because it is in a waiting state, use this time for 5
The development of the image of the next page is started in step 2b (step s8). After the output of the image of 52a is completed, the image data of the next page is developed on 52a during the output standby time after the image development of 52b is completed (step s9). Further, when developing an image of B4 or A3 size, the image memory 52 is used.
The whole is occupied by one image. In order to perform such processing, the memory controller 5 shown in FIG.
It is desirable that the controller 1 be composed of two equivalent controllers in order to facilitate control. This is because, when the image memory 52 is divided into two and used, two controllers are assigned to each of the memory areas 52a and 52b obtained by dividing the memory controller.

That is, the memory controller 52 generates, for example, an address signal when outputting image data from the RAM 52. If the memory controller 52 corresponds to a predetermined memory area, the memory controller 52 can be easily constituted by a gate array or the like. it can. When the CPU 50 instructs the memory controller corresponding to the area 52a in advance, the bus connected to the area 52a is disconnected from the CPU 50, and thereafter, the memory controller corresponding to the area 52a and the CPU 50 are connected in parallel. A completely different operation can be performed.

As described above, according to this embodiment,
Even during output of the image signal of the previous page (during operation of one of the memory controllers), image development by the CPU 50 can be started (steps s6 and s8), and after output of the previous page is completed (step s10). The output of the image (the operation of the other memory controller) can be performed (step s12) while performing processing such as zooming (step s11).

As another embodiment of the present invention, a plurality of memory controllers and CPUs for controlling the image memory may be provided.

In this case, the configuration of the CPU C5 shown in FIG.
It becomes a form that incorporates two 0s. The flowchart is the same as that in FIG. 8, but the development and output can be made faster than in the first embodiment because the development on the divided image memories can be performed in parallel.

When an image is developed using the entire image memory, an appropriate development can be performed by prohibiting the development by one of the CPUs.

[0025]

As described above , according to the present invention,
At least two memory controllers are configured
Provided corresponding to each area, select one of the above areas
Alternatively, disconnect from the bus with the processing means and disconnect
Of the image data of the specified area
In parallel with the read operation by the controller,
The column enabled processing of image data in other areas.
So, without complicating the configuration of the memory controller,
Read by memory controller with easy control
Operation and image data such as page description language data expansion processing
Data processing can be performed in parallel,
-It is possible to improve the put. In an image forming apparatus capable of generating and outputting a large-sized image,
When generating and outputting an image smaller than the predetermined size,
By dividing the image memory and expanding one area when the other area is in the output standby state to the other, it is possible to improve the overall throughput.

[Brief description of the drawings]

FIG. 1 is an overall view of an image forming apparatus applied to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating the inside of the image forming apparatus.

FIG. 3 is a block diagram illustrating an exposure signal generation circuit.

FIG. 4 is a diagram illustrating signal waveforms when an exposure signal is generated.

FIG. 5 is a block diagram of a binary image generation / storage device.

FIG. 6 is an explanatory diagram of an enlarging algorithm.

FIG. 7 is a flowchart of resolution selection.

FIG. 8 is a flow chart in which an image memory is divided and used.

[Explanation of symbols]

 Reference Signs List 23 external device 30 CPU 31 image reader unit 32 image signal control circuit 33 printer unit 34 binary image generation / storage device 40 triangular wave generator 41 D / A converter 42 comparator 50 CPU 51 memory controller 52 image memory 53 interface 54 Communication Line 55 Image Bus 56 Binary / Multi-Valued Converter 57 Magnification / Reduction Circuit 1000 Image Forming Apparatus Main Body

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-254516 (JP, A) JP-A-2-194977 (JP, A) JP-A-60-220771 (JP, A) JP-A-63-254 173120 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41J 5/30 B41J 21/00 G06F 3/12 H04N 1/21

Claims (3)

(57) [Claims] And 1. A capable of storing image data of a predetermined size memory, a processing means for processing the image data that is stored in the memory, provided for each predetermined area of the memory, image data of each area and at least two memory controllers for generating an address signal for reading, said disconnect from the bus and selectively the processing means any one of the areas, the disconnected region image data of, in parallel with the operation Shi read out that by the memory controller <br/> corresponding to the area, the processing means the image forming apparatus is characterized in that a can execute the processing of image data in the other region . 2. An image of a plurality of pages smaller than a predetermined size.
When forming an image, selectively use any one of the above regions.
And separated from the bus with the processing means.
The memo corresponding to the area in the image data of the page of the area
In parallel with the read operation by the recontroller,
The processing means uses the other area to process the next page of image data.
2. The image according to claim 1, wherein the image is executed by using
Forming equipment. 3. The processing means outputs from a higher-level device.
The page description data into image data
3. The image according to claim 1, wherein the image is stored in
Image forming device.