JP2000280543A - Imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an imaging apparatus for transferring a color image data at high rate in which print processing efficiency is enhanced by shortening the time required for transferring the image data from an image memory to a transfer buffer. SOLUTION: When print data are transferred from an image memory 10 to a transfer circuit for black 11B, a transfer circuit for yellow 11Y, a transfer circuit for cyan 11C, and a transfer circuit for magenta 11M, respectively, a transfer order buffer 36 is used. When a space region is present in the transfer circuit of some color, the color of that is set in the transfer order buffer 36 if the data of a color being transferred next is ready and the color of data ready for transfer is set at next order of the transfer order buffer. Print data is transferred according to the order set in the transfer order buffer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image forming apparatus for speeding up a transfer process of color image data.

[0002]

2. Description of the Related Art Recently, with the spread of computers and word processors, there has been an increasing demand for faster printers. For example, in a tandem head type color printer, two transfer buffers are provided between the image memory and the printing unit for each color data of magenta (M), cyan (C), yellow (Y), and black (B). It has a double buffer configuration. This is because the image data is always stored in one of the two transfer buffers, and while the image data stored in this transfer buffer is being transferred to the printing unit, the other transfer buffer is in the other transfer buffer. , The next image data is transferred from the image memory.
When the transfer from one transfer buffer to the printing unit is completed, the transfer is switched to the other transfer buffer, and the next image memory is transferred from the transfer buffer to the printing unit. By repeating such processing alternately in the two transfer buffers, the printing unit can receive the image data without a standby time, and the transfer time can be shortened.

FIG. 12 is a schematic block diagram of transfer hardware for performing such transfer processing. In the figure,
The transfer hardware includes an image memory 10, a transfer circuit 11,
A printing unit 52 is provided. The transfer circuit 11 includes two transfer buffers 53 (5) for each color data of magenta (M), cyan (C), yellow (Y), and black (B).
3M, 53C, 53Y, 53B), 54 (54M, 54
C, 54Y, 54B). Then, the image data is transferred from the image memory 10 to the printing unit 52 by using the two transfer buffers 53 and 54 alternately for each color.

[0004] The printing unit 52 includes a printer controller 3 and a printer engine 4. The printer controller 3 controls the printer engine 4 and transmits image data transferred from the transfer circuit 11 to the print head of the printer engine 4.

FIG. 13 is a transfer flowchart by the transfer hardware shown in FIG. The figure shows that each transfer buffer 53 (53M, 53C, 53C) is transferred from the image memory 10.
Y, 53B), 54 (54M, 54C, 54Y, 54)
B) shows the processing operation when transferring image data. In this example, the transfer processing is performed in the order of magenta (M), cyan (C), yellow (Y), and black (B).

First, in the transfer buffer of magenta (M), one transfer buffer (for example, M transfer buffer 5)
3M) to determine whether image data is being transferred to the printer controller 3 of the printing unit 52 and whether the other transfer buffer (for example, the M transfer buffer 54M) is empty (step S111). . The process of checking whether or not the image data in the transfer buffer is being transferred and whether or not the transfer buffer is empty is hereinafter referred to as preprocessing.

This pre-processing is performed, and the above-described step S11 is performed.
When the condition of 1 is satisfied (Yes in step S111),
The image data is transferred from the image memory 10 to the empty transfer buffer of magenta (M) (step S112). Thereafter, in the transfer processing of cyan (C), yellow (Y), and black (B), the processing of steps S113 to S118 is performed similarly to the transfer processing of magenta (M) described above.

After that, when each of the processes in steps S111 to S118 is completed, it is determined whether or not the transfer buffer is free (step S119). If there is a free transfer buffer, the process returns to step S111 to return to step S111. If there is no free space, the process ends.

The processes in steps S111 to S118 are continued until the transfer buffer becomes empty.

[0010]

However, as a precondition for performing such processing, image data for four colors of magenta (M), cyan (C), yellow (Y), and black (B) is used. The total time required to transfer from the image memory 10 to each transfer buffer is MCYB
Needs to be shorter than the total time required to transfer the image data for the four colors from each transfer buffer to the printer controller 4. If the total transfer time from the image memory 10 to the transfer buffer is longer, the printer controller 4 cannot immediately obtain the image data from the transfer buffer, causing a waiting time.

FIG. 14 is a diagram showing a time chart of the transfer processing shown in FIG. In the figure, 60M, 6
0C, 60Y, and 60B indicate the preprocessing time for each color of MCYB. Also, 61M, 61C, 61Y, 61
B indicates a transfer time for transferring from the image memory 10 for each color of magenta (M), cyan (C), yellow (Y), and black (B) to the transfer buffer.

Conventionally, the time required for transferring image data for four colors of MCYB from the image memory to the transfer buffer (the total time of the pre-processing time 60 and the transfer time 61 in FIG. 1) is equal to the image data for four colors of MCYB. In the transfer buffer to the printer controller 4.

However, recently, the transfer speed from the transfer buffer to the printer controller 4 has been increased,
Due to high resolution and multi-valued, as shown in the figure,
MCYB from transfer buffer to printer controller 4
In some cases, the transfer time 62 of image data for four colors is shorter. As a result, the printer controller 4
The image data could not be immediately received from the transfer buffer, and the printing process was delayed accordingly.

From the above, as shown in FIG.
It is necessary to keep the total time of the pre-processing 60 for four colors of MCYB within the time 63. Here, time 63 is
This is a time obtained by subtracting the time required to transfer image data for four colors of MCYK from the image memory to the transfer buffer from the transfer time 62.

An object of the present invention is to solve the above-mentioned problem, and an object of the present invention is to shorten a processing time for transferring image data from an image memory to a transfer buffer and improve a printing processing efficiency.

[0016]

According to an aspect of the present invention, there is provided an image processing apparatus, comprising: two transfer buffers for each color data; and alternately using the two transfer buffers.
In an image forming apparatus for transferring print data from an image memory to a printing unit, a transfer order storing means for storing a transfer order for transferring print data of each color to the transfer buffer; and a transfer order stored in the transfer order storage means. Print data reading means for reading print data from an image memory in accordance with the print data and alternately writing the print data in the two transfer buffers; and a print processing means for performing a print process in accordance with the print data written in the transfer buffers. This can be achieved by providing a device.

According to an aspect of the present invention, there is provided a transfer order storage means. The transfer order storage means can be constituted by, for example, a buffer or a register for storing the transfer order. Is set, and the print data is read from the image memory and supplied to the transfer buffer in the set order, whereby the print data is automatically written to the transfer buffer.

Therefore, the print data can be efficiently and quickly transferred without performing the preprocessing for each color as in the related art. According to a second aspect of the present invention, in the first aspect, for example, the transfer order of each color is set in advance in the transfer order storage means.

For example, by registering the transfer order in the initial transfer order storage means in advance, the print data is automatically written in the transfer buffer, and the print data can be transferred quickly.

According to a third aspect of the present invention, in the first aspect of the present invention, the transfer order storage means sets, for example, a color having an empty area in the transfer buffer in the transfer order storage means and is ready for transfer. The next color is set in the transfer order storage means on condition that the transfer order is present.

That is, when an empty area occurs in the transfer buffer, the print data corresponding to the color is set in the next transfer order, and the preparation for the transfer of the print data of the next color is determined. If so, the colors are set in the next transfer order.

With this configuration, the transfer order can be set in the transfer order storage means at an early stage, and the print data can be transferred at high speed without performing the conventional preprocessing.

According to a fourth aspect of the present invention, in the first aspect of the invention, the transfer order storage means does not continuously set, for example, the same color in the transfer order storage means. With this configuration, after the print data of the previous color is always transmitted, the print data of the next color is supplied, and the increase in the transfer time due to the continuous output of the same color print data is reduced. Can be prevented.

[0024]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an overall configuration diagram of an image forming apparatus according to an embodiment of the present invention. The image forming apparatus used in the description of the present embodiment is a tandem type color printer. In FIG. 1, a color printer 1 includes an I / F (interface) controller 2,
The printer includes a printer controller 3 and a printer engine 4.

The I / F controller 2 further includes a CPU 6,
ROM7, DMAC (Direct Memory Access)
8, RAM 9, image memory 10, transfer order buffer 36,
And a transfer circuit 11, which receives print data transmitted from a PC (personal computer) 5 and converts the print data into image data for each color of cyan (C), magenta (M), yellow (Y), and black (B). And outputs it to the printer controller 3. The transfer circuit 11 is provided for each color of the black transfer circuit 11B, the yellow transfer circuit 11Y, the cyan transfer circuit 11C, and the magenta transfer circuit 11M.

The CPU 6 performs overall control of the I / F controller 2 and also performs initialization processing of the printer controller 3. The image memory 10 stores one image for each color of magenta (M), cyan (C), yellow (Y), and black (B).
The image data for one page is stored, and the DMAC 8 is driven by the control signal of the CPU 6 to transfer the image data for one line to the transfer circuits 11B, 11Y, 11C, 11C for each color.
Output to M. In this case, the DMAC 8 controls transfer of one line of image data from the image memory 10 to each transfer circuit 11 without being individually controlled by the CPU 6.

The transfer circuits 11 B, 11 Y, 11 C, and 11 M that have received the image data for one line transfer the image data for one line to the printer controller 3. At this time, the printer controller 3 sends a busy signal 33 (33) to each transfer circuit 11 in accordance with the processing status of each image forming unit 13 of the printer engine 4 described later.
M, 33C, 33Y, 33B) or an acknowledgment signal 34 (34M, 34C, 34Y, 34B). Each transfer circuit 11 receives these signals, and the received signals are acknowledged signals 34 (34M, 34C, 3C).
4Y, 34B), one line of image data is transferred to the printer controller 3, and if the received signal is a busy signal 33 (33M, 33C, 33Y, 33B), the image data transfer is not performed. Not performed. After transferring the image data to the printer engine 4, each transfer circuit 11 notifies the CPU 6 that the transfer has been completed.

On the other hand, the transfer order buffer 36 stores the order of image data output from the image memory 10 to each transfer circuit 11. In this example, the CPU 6 controls output of image data from the image memory 10 to each transfer circuit 11 in accordance with the transfer order stored in the transfer order buffer 36. RO
M7 stores various control programs and the like executed by the CPU 6, and the RAM 9 stores data and the like required in the process of the CPU 6 executing the programs.

Next, the printer engine 4 performs paper supply /
It comprises a transport mechanism 12, a plurality of image forming unit sections 13, and a fixing device 14. The paper supply / transport mechanism 12 includes a paper feed cassette 16 in which paper P is loaded and stored, and a paper transport system 15. Further, the paper transport system 15 carries out the paper P from the paper feed cassette 16, transports the paper P in the direction of the arrow 17, and feeds the paper P so that the paper position matches the toner image. Standby roll 18
a, standby sensor 3 for detecting that it has reached the position of 18b
5, drive rolls 19 and 20 driven by a motor (not shown), and a transport belt 21 rotated by the drive rolls 19 and 20.

The paper P carried out from the paper supply cassette 16 in the direction of arrow 17 is sent to standby rolls 18a and 18b, and travels on the conveyor belt 21 at a timing coincident with a toner image formed on a photosensitive drum described later. Moving.

While the paper P moves on the conveyor belt 21,
Each image forming unit 2 is provided on the sheet P on the transport belt 21.
The toner of each color is transferred by 2, 23, 24, and 25, and color transfer is performed on the paper P. Then, the fixing device 1
The sheet P is subjected to a heat fixing process, and the sheet P is carried out of the apparatus.

As described above, the image forming unit section 13
The image forming unit includes four image forming units 22 to 25 of cyan (C), magenta (M), yellow (Y), and black (B), which are arranged in this order. Cyan (C), magenta (M), and yellow (Y) are image forming units 22 to 24 that perform color printing by subtractive color mixture, and black (B) image forming unit 25 is an image forming unit that is used for monochrome printing. It is.

Each of the image forming units 22 to 25 has exactly the same configuration except for the (color of) the developer contained in the developing container, and includes a charger, an LED head, a developing device, and the like near the peripheral surface of the photosensitive drum. This is a configuration in which transfer units are sequentially arranged.

Here, the four image forming units 22 to 2
Image forming unit 2 for magenta (M)
2 will be described as an example. The peripheral surface of the photoconductor drum 26 is made of, for example, an organic photoconductive material, and the charger 27 and the LED head 2 are disposed near the peripheral surface of the photoconductor drum 26.
8. Developing roll 29 '(developing device 29) and transfer device 30
Are sequentially arranged. The photoreceptor drum 26 rotates in the direction of the arrow 31, and first charges the peripheral surface of the photoreceptor drum 26 uniformly by applying a charge from the charger 27. Next, LED
An electrostatic latent image is formed on the peripheral surface of the photosensitive drum 26 by optical writing based on print information from the head 28, and a toner image is formed by a developing process using a developing roll 29 '. At this time, the toner image formed on the peripheral surface of the photosensitive drum 26 is made of magenta (M) toner stored in the developing container 29. The toner image formed on the peripheral surface of the photosensitive drum 26 in this manner reaches the position of the transfer device 30 with the rotation of the photosensitive drum 26 in the direction of the arrow 31, and is transferred onto the transport belt 21 by the transfer device 30. The image is transferred onto the paper P being conveyed.

FIG. 2 is a schematic block diagram of transfer hardware according to one embodiment of the present invention. Note that, in the figure, the transfer circuits 11M, 11C, 11Y, and 11B are collectively described as one. The numbers used in the description of FIG. 2 are the same as the numbers used in FIG.

The CPU 6 controls the transfer buffers 53 (53M, 53C, 53Y, 53B), 54 (5
4M, 54C, 54Y, 54B), the transfer order of the image data to be stored in the transfer order buffer 36 is determined. Based on the transfer order stored in the transfer order buffer 36, the CPU 6 transfers the image data in the image memory to each transfer order buffer. The other configuration is the same as the configuration shown in FIG.

FIG. 3 is a diagram showing a flowchart for transferring image data from the image memory to the printer controller via the transfer buffer. The transfer process for each color of magenta (M), cyan (C), yellow (Y), and black (B) is the same, and therefore, the transfer process for one color is shown in FIG. This transfer process includes three processes: a transfer preparation process, a transfer process, and a transfer end process.

In the transfer preparation processing, when the printing paper reaches the position of the standby rolls 18a and 18b, the standby sensor 35
However, when this is detected, the CPU 6 notifies the CPU 6 that the printing paper has reached the standby position (step S301). In response to this, the CPU 6 makes transfer settings for the printer controller 4. First, image data is previously transferred from the image memory to the two transfer buffers 0 and 1 (step S303).
To S306).

Next, in the in-transfer processing, when the paper reaches the transfer position (step S307), the image data is transferred from the transfer buffer 0 to the printer controller 4, and when the processing is completed, the fact is notified to the CPU 6. Notification is made (step S308). The CPU 6 receives this,
The data transfer setting process is performed for the transfer buffer 0 (step S310), and the image data is transferred to the transfer buffer 0 (step S310).

On the other hand, when the image data is transferred from the transfer buffer 1 to the printer controller 4 and the processing is completed, the fact is notified to the CPU 6 (step S31).
1). In response to this, the CPU 6 performs a data transfer setting process on the transfer buffer 1 (step S312).
Data is transferred to the transfer buffer 1 (step S
313).

Thereafter, the image is transferred from the image memory to the printer controller by repeating such processing alternately in the transfer buffers 0 and 1. In the transfer end processing, the CPU 6 sets the transfer of the last image data to the transfer buffer 1 (or 0) and notifies the printer controller of the transfer end (step S31).
8). Then, the image data is transferred to the transfer buffer 1 (step S319), and the image data is transferred from the transfer buffers 0 and 1 to the printer controller (steps S320 and 321), and the transfer process ends.

Hereinafter, the present example will be described in different cases. In this example, the printing process is performed in accordance with the transfer order set in the transfer order buffer as described above. I do. <At the start of transfer of first sheet> First, the processing at the start of transfer of the first sheet will be described.

The flowchart shown in FIG. 4 is a flowchart for explaining the transfer order setting operation at the start of the transfer of the first sheet. FIG. 5 shows a data configuration set in the transfer order buffer 36 in this case.

At the start of the first first sheet, as shown in FIG. 5, the transfer order storage areas "1" to "8" of the transfer order buffer 36 store magenta (M), cyan (C), Yellow (Y) and black (B) color information are sequentially stored. That is, initially, the transfer order buffer 36
In the transfer order storage area “1”, magenta (M) is set first, and in the next transfer order storage area “2”, cyan (C) is set, and the next transfer order storage area “3” is set. Is set to yellow (Y), and the transfer order storage area "4" is set to black (B).

Further, magenta (M) is set again in the next transfer order storage area "5", and thereafter, cyan (C) and transfer order storage area "7" are set in the transfer order storage area "6" in the same manner as described above. "Is set to yellow (Y), and the transfer order storage area" 8 "is set to black (B).

In the setting process described above, specifically, as shown in the flowchart of FIG. 4, the CPU 6 determines the start of the transfer of the first sheet (step (hereinafter referred to as ST) 1 is YES), and then stores the transfer order first. Magenta (M) is set in area "1" (ST2). Next, cyan (C) is set in the transfer order storage area "1" (ST3), and yellow (Y),
Black (B), magenta (M), cyan (C),
The settings of yellow (Y) and black (B) are made in the transfer order storage areas “2” to “8”.

Therefore, when the printing process is performed in accordance with the transfer order buffer 36 in which the above settings are registered, the transfer circuit 1
In each of the transfer buffers 53 and 54, print data is automatically written from the image memory. That is, first, the data of magenta (M) set in the transfer order storage area “1” is read from the image memory 10 and the M transfer buffer 0
(M transfer buffer 53M). Next, the cyan (C) data set in the transfer order storage area “2” is read from the image memory 10 and the C transfer buffer 0 is read.
(Transfer buffer 53C). Next, the yellow (Y) data set in the transfer order storage area “3” is read out from the image memory 10 and is read from the Y transfer buffer 0.
The data is written to the transfer buffer 53Y, and the black (B) data set in the transfer order storage area “4” is read from the image memory 10 and written to the B transfer buffer 0 (the transfer buffer 53B).

Next, the magenta (M) data set in the transfer order storage area "5" is written into the M transfer buffer 1 (M transfer buffer 54M), and the cyan set in the transfer order storage area "6". The data of (C) is written to the C transfer buffer 1 (transfer buffer 54C), and the yellow (Y) data set in the transfer order storage area “7” is written to the Y transfer buffer 1 (transfer buffer 54Y). Finally, the black (B) data set in the transfer order storage area “8” is transferred to the B transfer buffer 1 (the transfer buffer 5).
4B).

Thereafter, the data in each transfer buffer 53 or 54 is stored in the printer controller (PR) 3 as described above.
The data is automatically written into the transfer buffer 53 or 54 which has been output to the empty area according to the order registered in the transfer order buffer 36 described above.

With this configuration, the initial time 1
In the case of the transfer process for the first sheet, data is automatically stored in the image memory 1
0 is supplied to the transfer buffers 53 and 54, so that the time for preprocessing can be omitted. <At the time of normal transfer> Next, when the printing process is continued and the state of the initial printing is changed to the state of the continuous printing (the state of the normal transfer), the following processing is performed.

The flowchart shown in FIG. 6 is a flowchart for explaining a transfer order setting operation at the time of normal transfer. FIG. 7 shows a data configuration set in the transfer order buffer 36 in this case.

At the time of normal transfer, for example, when the N transfer buffer becomes empty, an interrupt process for performing the process shown in FIG. 6 is started. First, N is set in the transfer order buffer (ST10). That is, the N colors that have become free areas are set in the transfer order buffer 36.

Next, it is determined whether the color corresponding to N + 1 is in the transfer preparation state (ST11), and if it is in the transfer preparation state (ST11: YES), the color corresponding to N + 1 is set in the transfer order buffer 36 (ST11). ST12). On the other hand, if it is not in the transfer preparation state (NO in ST11), the above-described interrupt processing ends (ST13).

Next, a specific example of the above processing will be described with reference to FIG. The state shown in FIG. 7A shows the transfer order set in the transfer order buffer 36 before the above-described interrupt processing is started. In this state, for example, when the transfer buffer (N transfer buffer) of magenta (M) becomes empty, an interrupt process is started, and the empty magenta (M) is set in the transfer order buffer 36 first. (ST10). By this setting processing, the setting state of the transfer order buffer 36 becomes the state of FIG. 7B.

Next, it is determined whether the color (black (B)) corresponding to N + 1 is ready for transfer (ST11).
If it is in the transfer preparation state (YES in ST11), black (B) is set in the transfer order buffer 36 (ST12).
By this setting processing, the setting state of the transfer order buffer 36 becomes the state shown in FIG.

With such a configuration, when the transfer buffer 53 or 54 corresponding to the previous color becomes empty, the transfer preparation state of the next color is determined. Since the transfer order is registered in the forward buffer 36, data can be buffered more efficiently and quickly than in the case of determining the empty state of the transfer buffer corresponding to each color as in the conventional example.

In the above example, when the magenta (M) becomes empty, the transfer preparation state of the black (B) is judged.
6, the transfer order of black (B) is set. For example, when cyan (C) becomes empty, the transfer preparation state of yellow (Y) is determined, and when yellow (Y) becomes empty. The transfer preparation state of magenta (M) is determined, the transfer preparation state of cyan (C) is determined when black (B) is empty, and the transfer order of the corresponding color is immediately set if the transfer preparation state is cyan. Is what you do.

The flowchart shown in FIG. 8 shows that the image memory 10 transfers data from the transfer buffer 53 to the transfer buffer 53 in accordance with the transfer order data set in the transfer order buffer 36 as described above.
The process of transferring the print data to 54 will be described. That is, it is determined whether N of the transfer order buffer 36 is set (ST14), and if it is set, the N is read from the transfer order buffer 36 (ST15), and the N transfer buffer is set (ST16).

For example, if N is magenta (M) as shown in FIG. 7, the data is read from the transfer order buffer 36, and the print data read from the image memory 10 is transferred to the M transfer buffer 0 or 1 (M (Transfer buffer 53M or 54M). In the example described above, the transfer order data of black (B) set in the transfer order buffer 36 is further read, and the print data of black (B) read from the image memory 10 is transferred to the B transfer buffer 0 or 1.
(B transfer buffer 53B or 54B). still,
The same processing can be performed for other colors. <At the time of continuous transfer> Next, at the time of continuous transfer will be described. The process at the time of the continuous transfer is a transfer process in a case where the printing process of a plurality of sheets is continuously performed, and FIGS. 9 and 10 show a data configuration set in the transfer order buffer 36 in this case.

This example explains the processing operation of the transfer order buffer 36 during continuous transfer.
The setting process of black (B) is performed from the state of (a),
If a free area is created in the B transfer buffer after the state shown in FIG. 9B, the M transfer buffer 0 is set in the area of the next transfer order buffer 36 in the same manner as described above (FIG. 9).
(State of (c)).

Thereafter, as shown in FIG.
When an empty area is created in the B transfer buffer from the state (a) (state (b) in the figure), the next color of the M color corresponding to the next color, magenta (M), is transferred to the transfer order buffer 36 next. The M transfer buffer 1 is set in the forward area (set (state of FIG. 10C)).

With this configuration, magenta (M) is always set after the transfer order of black (B), and M transfer buffer 0 (53M) and M transfer buffer 1 (54M) alternate. Data that is selected and of the same color is not continuously supplied from the image memory 10 to the transfer buffer. This is not limited to magenta (M),
The same applies to cyan (C), yellow (Y), and black (B).

With this configuration, the data transfer from the image memory 10 to the transfer buffer can be efficiently performed, and high-speed print data transfer processing can be performed. As described above, in this example, the transfer order buffer 36 is provided,
In this transfer order buffer 36, a transfer order in which data of the same color is not continuous can be set without fail, efficient transfer processing is performed, and high-speed transfer is enabled.

FIG. 11 is a diagram for explaining an example in which the transfer time is shortened by the transfer processing according to the present invention. As shown in the figure, the step of performing the pre-processing 60 is eliminated, and the time 61 of transferring data from the image memory 10 to the transfer buffer is sufficiently shorter than the time 62 of transferring data from the transfer buffer to the PR. .

[0065]

According to the aspect of the present invention, since the transfer order is set in the transfer order storage means in advance, the data may be automatically transferred in the transfer order, and the data transfer process is performed efficiently and quickly. be able to.

Therefore, according to the image forming apparatus of the present invention, it is possible to print image data at higher speed.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic block diagram of transfer hardware according to an embodiment of the present invention.

FIG. 3 is a diagram illustrating a flowchart when image data is transferred from an image memory to a printer controller via a transfer buffer.

FIG. 4 is a flowchart illustrating a transfer order setting operation at the start of transfer of a first sheet.

FIG. 5 is a diagram showing a data configuration set in a transfer order buffer.

FIG. 6 is a flowchart illustrating a transfer order setting processing operation during normal transfer.

FIG. 7A shows a transfer order set in a transfer order buffer before interrupt processing is started, and FIG.
The state after the M transfer buffer is set is shown, and (c) shows the state after the B transfer buffer is set.

FIG. 8 is a flowchart illustrating processing for transferring print data from an image memory to a transfer buffer according to data in the transfer order set in the transfer order buffer.

FIG. 9 is a diagram for explaining processing during continuous transfer.

FIG. 10 is a diagram for explaining processing during continuous transfer.

FIG. 11 is a diagram illustrating a process after improvement according to the present example.

FIG. 12 is a diagram illustrating a conventional example.

FIG. 13 is a flowchart illustrating processing of a conventional example.

FIG. 14 is a diagram for explaining processing of a conventional example.

[Explanation of symbols]

Reference Signs List 1 color printer 2 I / F controller 3 printer controller 4 printer engine 6 CPU 7 ROM 8 DMAC 8 9 RAM 10 image memory 11 transfer circuit 11B transfer circuit for black 11Y transfer circuit for yellow 11C transfer circuit for cyan 11M transfer circuit for magenta 12 paper Supply / Conveying Mechanism 13 Image Forming Unit 14 Fixing Device 15 Paper Conveying System 16 Paper Cassette 17 Arrows 18a, 18b Standby Roll 19, 20 Drive Roll 21 Conveying Belt 22-25 Image Forming Unit 26 Photoconductor Drum 27 Charger 28 LED Head 29 'Development roll 29 Developing device 30 Transfer device 36 Transfer order buffer 53 (53M, 53C, 53Y, 53B) Transfer buffer 54 (54M, 54C, 54Y, 54B) Transfer buffer

Continued on front page F term (reference) 2C087 AA15 BA07 BC01 BC02 BC07 BD32 BD41 BD53 5C052 AA11 AA17 CC06 FA03 FA06 FC03 FE01 FE08 GA05 GA07 GC06 GD09 GE04 GF00 5C055 AA14 BA03 BA08 EA02 EA05

Claims (4)

[Claims] 1. An image forming apparatus comprising two transfer buffers for each color data, wherein the two transfer buffers are used alternately to transfer print data from an image memory to a printing unit. Transfer order storage means for storing a transfer order for transferring data to the transfer buffer; print data is read from an image memory in accordance with the transfer order stored in the transfer order storage means; and the print data is alternately stored in the two transfer buffers. An image forming apparatus comprising: a print data writing unit that writes a print data; and a print processing unit that performs a print process according to the print data written in the transfer buffer. 2. The image forming apparatus according to claim 1, wherein a transfer order of each color is set in the transfer order storage unit in advance. 3. The transfer order storage means sets a color having an empty area in the transfer buffer in the transfer order storage means, and stores the next color in the transfer order on condition that transfer is ready. 2. The image forming apparatus according to claim 1, wherein the setting is made in a storage unit. 4. The image forming apparatus according to claim 1, wherein the transfer order storage unit does not continuously set the same color in the transfer order storage unit.