JPH06305203A - Image forming device - Google Patents

Abstract

PURPOSE:To shorten unavailable print queue time and consequently obtain efficient printing and suppress the development of error by a method wherein the number of bands, in which page data are expanded, can be changed to the minimum number of bands, which allows no error to develop, before the page data are transferred to an image forming section for convenience of page to be printed. CONSTITUTION:The image region for one page is divided in a plurality of bands. Display list for each band is stored in a memory B3 so as to obtain the total information amount in each band from the memory B3 and then store in a page expanding memory C5. By means of the information in the page expanding memory 5 and the condition for determining the number of bands to expand before the transferring of page data to the image forming section 16 in a memory D17, the minimum number of bands to be expanded is calculated. Thus, the determination of the number of bands to be expanded before the transferring of page data, for convenience of page to be printed, to the image forming section 16 can be possible.

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 in which the number of bands initially developed is changed according to the condition of pages to be printed.

[0002]

2. Description of the Related Art FIG. 13 is a block diagram showing a configuration of a conventional image forming apparatus, which is composed of an image processing section 7 and an image forming section.
Composed of 16. Image processing units 7 and 6 are cables A and
B, 2, 3 and 5 are memories A, B and C, and 4 is a CPU for controlling the overall operation of the image processing unit 7. Also,
The image forming unit 16 includes a laser scanning unit (LSU) 8; a mirror 9; a photoconductor 10; a developing device 11;
Is a paper cassette, 13 is a paper, 14 is a transfer device, and 15 is a fixing device.

In this conventional image forming apparatus, a data expansion method for transferring the data to the image forming unit 16 after expanding the page data to be actually printed by three bands in the image processing unit 7 into three bands is illustrated. It will be explained using 14.

A means for storing image information of one minute by dividing one page into several parts is called a band buffer BF (see FIG. 14), and one having one band of data for each horizontal scanning (raster) is a display list. Although the DL (see FIG. 14) is conventionally used in a band buffer printer, when data is printed, the data transferred from the host computer to the image processing unit 7 via the cable A1 is stored in the memory A.
Once stored in 2.

Based on the data stored in the memory A2, a display list DL for each band (see FIG. 14) is stored in the memory B3.
Create). Regardless of the condition of the printed page,
The page data PD to be actually printed is expanded from the display list DL in the memory B3 to the page expansion memory C5 for three bands (see FIG. 14). When the expansion of the page data PD is completed, the image forming unit 16 is passed via the cable B6.
Send a print signal to and check if the printer is ready to print. At the same time, page data to be actually printed from the display list DL in the memory B3 to the fourth band is started to be created. When printing is possible, the image forming unit 16 is a photosensitive member.
10. Turn on the motor such as LSU8 and prepare for laser emission.

Next, it is checked whether the vertical synchronizing signal for starting printing is output to the image processing unit 7. When the vertical synchronizing signal is turned on, the image processing unit 7 takes out page data from the page expansion memory C5 and sends it to the image forming unit 16.
The image forming unit 16 uses a laser light having a laser power corresponding to the transferred page data from the LSU 8 to a mirror 9
The latent image is formed by irradiating the surface of the photoconductor 10 through the light and exposing it. Next, development is performed in the developing device 11 to visualize the latent image, and a visible image is generated on the photoconductor 10.
The paper 13 is fed from the paper cassette 12 at the timing of 13 and the image is transferred onto the paper by the transfer device 14. Next, the image is fixed on the paper by the fixing device 15, it is checked whether the paper is discharged, each motor is turned off, and the printing is completed.

[0007]

In such a conventional image forming apparatus, the image processing section, as shown in FIG. 14, counts the page data PD to be actually printed regardless of the condition of the page to be printed. Band (constant), band buffer B
Since the page data was started to be transferred to the image forming section after being created in F, and at the same time the expansion to the next band was started, the data is not transferred to the image forming section until the page data for several bands is completely expanded, and printing is performed. Waiting time occurs and printing efficiency is poor.

Further, since the number of bands to be expanded at the beginning is constant, when the amount of data in the first few bands is small and the amount of data in the remaining bands is large, the display list D is displayed.
The expansion from L to the page data PD on the band buffer BF may catch up with the transfer from the page data to the image forming unit, which may cause an error.

The present invention has been made to solve the above problems, and an object of the present invention is to change the number of bands to be initially developed depending on the condition of a page to be printed.

[0010]

In order to achieve the above-mentioned object, the present invention divides an image area for one page into a plurality of bands, and connects information applied for each horizontal scanning,
Further, a list information storage means for storing a display list having the total amount of information for one horizontal scanning at the head, a band information storage means for obtaining and storing the total amount of information in each band from the list information storage means, and image formation A condition storing means for storing the condition of the number of bands to be developed before transferring the information to the unit, and based on the band information storing means and the condition storing means, first, the number of bands for developing the page data is set. It is characterized by changing.

[0011]

According to the present invention, the image area for one page is divided into a plurality of bands, the information (image or text) on one horizontal scan (raster) is connected, and the one horizontal line is attached to the head. Create a display list for each band that has the total amount of information of scanning (raster). The total amount of information for each band is calculated from the created display list, and the total amount of information obtained and the preset condition for the number of bands to be developed before transferring the page data to the image forming unit are used. Determine the number of bands to be expanded before transferring page data to. From the above, efficient printing can be performed.

That is, depending on the condition of the page to be printed,
Since the number of bands to be expanded before transferring page data to the image forming unit can be changed to the minimum number of bands that does not cause an error, wasteful print waiting time can be omitted and efficient printing can be obtained. Also, the occurrence of errors can be suppressed.

[0013]

1 is a block diagram showing the configuration of an image forming apparatus according to an embodiment of the present invention. In FIG. 1, 17 and 18 are memories D and E, and other blocks having the same functions as those in FIG. 13 are designated by the same reference numerals, and the description thereof will be omitted.

2 and 3 are views for explaining the printing operation of FIG. 1, and FIGS. 4 to 12 are flowcharts of the printing operation of FIG. 1, each step being represented by S.

First, as shown in the flow chart of FIG. 4, input data (command, image image, etc.) from a host computer (not shown) is taken into the image processing unit 7 in the image forming apparatus main body via the cable A1. (Step 1), it is temporarily stored in the memory A2 (Step 2). Next, the CPU 4 connects the information (image text) that is applied to one horizontal scanning (raster) from the data taken in the memory A2, and the total information amount of that one horizontal scanning (raster) is added to the head. Display list DL (Figure 2)
Is created and stored in the memory B3 (step 3). The total amount of information for each band is obtained from the display list DL stored in the memory B3.

Here, as shown in the following (Table 1), the total information amount of the first band of the display list DL is A, the total information amount of the second band is B, the total information amount of the third band is C, Fourth
The total information amount of the band is set to D, and the total information amount of the fifth band is set to E, which is stored in the page expansion memory C5 as an information amount storage block 19 (step 4). The state of this storage is shown in FIG.

[0017]

[Table 1]

Next, the CPU 4 uses the page expansion memory C5.
The total amount of information stored in each band and the information in the memory D17, that is, the page data is expanded from the display list DL to the memory E18 (band buffer BF) before the page data is transferred to the image forming unit 16. The conditional expression shown in the following (Table 2) for determining the number of bands and the display list DL shown in FIG. 3 to the memory E18 (band buffer BF)
A decompression speed α for decompressing page data and a transfer rate β for transferring the page data to the image forming unit 16 are stored.

[0019]

[Table 2]

Based on this (Table 2), the data transferred from the host computer is expanded from the display list in the memory B3 to the band buffer BF of the memory E18 before the page data is transferred to the image forming section 16. The CPU 4 determines whether or not the condition that the number of bands to be stored is 1 is satisfied (step 5). If the condition is satisfied, the process proceeds to step 9 in FIG. 6, and if the condition is not satisfied, the number of bands is 2
It is determined whether or not a certain condition is satisfied (step 6).

If the condition is satisfied, the process proceeds to step 13 in FIG. 7. If the condition is not satisfied, it is determined in step 7 in FIG. 5 whether the condition that the number of bands is 3 is satisfied, and the condition is satisfied. If so, the process proceeds to step 17 in FIG. 8. If the condition is not satisfied, it is determined in step 8 in FIG. 5 whether the condition that the number of bands is 4 is satisfied, and if so, the process proceeds to step 21 in FIG. If not, go to step 25 in FIG.

In step 9 of FIG. 6, the image forming unit 16
If the number of bands to be expanded from the display list DL shown in FIG. 3 to the band buffer BF of the memory E18 before transferring the page data to 1 is one band from the display list in the memory B3 to the memory E18, Expand the page data that is actually printed. When the expansion is completed, a print signal is sent to the image forming unit 16 via the cable B6 (step 10), and it is confirmed whether the printer is in a printable state (step 11). At the same time, the development to the second band is started (step 12).

Further, in step 13 of FIG. 7, before the page data is transferred to the image forming section 16, the band buffer B of the memory E18 is changed from the display list DL shown in FIG.
If the number of bands to be expanded to F is 2, memory B3
2 bands from the display list in memory to memory E18,
Expand the page data that is actually printed. Then, when the expansion is completed, the image forming unit 16 is passed through the cable B6.
A print signal is sent to (step 14), and it is confirmed whether the printer is ready for printing (step 15). At the same time, the expansion to the third band is started (step 16).

Further, in step 17 of FIG. 8 described above, before the page data is transferred to the image forming section 16, the band buffer B of the memory E18 is changed from the display list DL shown in FIG.
If the number of bands to be expanded to F is 3, the memory B3
From the display list inside to memory E18 for 3 bands,
Expand the page data that is actually printed. Then, when the expansion is completed, the image forming unit 16 is passed through the cable B6.
A print signal is sent to (step 18), and it is confirmed whether the printer is ready for printing (step 19). At the same time, the development of the fourth band is started (step 20).

Further, in step 21 of FIG. 9 described above, before the page data is transferred to the image forming section 16, the band buffer B of the memory E18 is displayed from the display list DL shown in FIG.
If the number of bands expanded to F is 4, memory B3
4 bands from display list in memory to memory E18,
Expand the page data that is actually printed. Then, when the expansion is completed, the image forming unit 16 is passed through the cable B6.
A print signal is sent to (step 22) and it is confirmed whether the printer is ready for printing (step 23). At the same time, the development of the fifth band is started (step 24).

Further, in step 25 of FIG. 10, before the page data is transferred to the image forming section 16, the band buffer B of the memory E18 is displayed from the display list DL shown in FIG.
If the condition that the number of bands to be expanded to F is 1, 2, 3, 4 is not satisfied, the page data actually printed is expanded from the display list in the memory B3 to the memory E18 by one page. When the expansion is completed, the print signal is sent to the image forming unit 16 via the cable B6.
(Step 26), it is confirmed whether the printer is ready for printing (Step 27).

When printing is possible, the image forming unit 16 turns on the motors of the photoconductor 10, the LSU 8 and the like to prepare for laser emission and the like as shown in FIG. 11 (step 28). Next, it is checked whether the vertical synchronizing signal for starting printing is output to the image processing unit 7 (step 29). When the vertical synchronizing signal is turned on, the image processing unit 7 extracts the page data from the band buffer BF of the memory E18, and the image forming unit 16
To (step 30).

Then, as shown in FIG. 12, a laser beam having a laser power corresponding to the transferred data is irradiated from the LSU 8 onto the photoconductor 10 via the mirror 9 and is exposed to form a latent image. (Step 31). Next, development is performed in the developing device 11, the latent image is visualized, and a visible image is generated on the photoconductor 10 (step 32). Next, the paper is fed from the cassette 12 at the timing when the visible image is placed on the paper 13,
The transfer device 14 transfers the image onto the paper 13 (step 33). Then, the fixing device 15 fixes the image on the paper 13 (step 34). Next, it is checked whether or not the paper is discharged (step 35), the image forming unit 16 turns off each motor, and the printing is finished (step 36).

[0029]

As described above, according to the image forming apparatus of the present invention, the number of bands to be developed before the page data is transferred to the image forming unit is set to the minimum number of bands that does not cause an error depending on the condition of the page to be printed. Since it can be changed to, the useless printing waiting time can be omitted, efficient printing can be obtained, and the occurrence of errors can be suppressed.

[Brief description of drawings]

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

FIG. 2 is a diagram illustrating the printing operation of FIG.

FIG. 3 is a diagram illustrating the printing operation of FIG.

FIG. 4 is a flowchart of the printing operation of FIG.

5 is a flowchart of the printing operation of FIG.

FIG. 6 is a flowchart of the printing operation of FIG.

FIG. 7 is a flowchart of the printing operation of FIG.

8 is a flowchart of the printing operation of FIG.

9 is a flowchart of the printing operation of FIG.

10 is a flowchart of the printing operation of FIG.

11 is a flowchart of the printing operation of FIG.

FIG. 12 is a flowchart of the printing operation of FIG.

FIG. 13 is a block diagram showing a configuration of a conventional image forming apparatus.

FIG. 14 is a diagram showing a method of expanding the data of FIG.

[Explanation of symbols]

1 ... Cable A, 2 ... Memory A, 3 ... Memory B,
4 ... CPU, 5 ... Memory C, 6 ... Cable B, 7
... image processing unit, 8 ... laser scanning unit (LSU), 9 ... mirror, 10 ... photoconductor, 11 ... developing device, 12 ... paper cassette, 13 ... paper, 14 ... transfer device, 15 ... fixing device, 16 ... Image forming unit, 17 ... Memory D, 18 ... Memory E (buffer memory), 19 ... Information amount storage block.

Claims (1)

[Claims] 1. An image area for one page is divided into a plurality of bands, information hanging for each horizontal scanning is concatenated, and a display list having the total information amount of the horizontal scanning is stored in the head. The list information storage means, the band information storage means for obtaining and storing the total amount of information in each band from the list information storage means, and the condition of the number of bands to be developed before the information is transferred to the image forming unit. An image forming apparatus, comprising: a condition storage unit for storing, wherein the number of bands in which page data is first expanded is changed based on the band information storage unit and the condition storage unit.