JPH10294834A - Control method for image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize efficient allocation while dealing with conditions attended with various states such as buffer compression, double side printing and jamming in the case of memory allocation dynamically in the device whose operating mode is selected depending on print data. SOLUTION: In various operating modes, (1) only a frame buffer is used, (2) the frame buffer and a compression buffer are used, and (3) a band buffer, a compression band buffer by a prescribed page number, and an intermediate buffer are used. Image forming conditions are (1), a must condition, where simultaneous processing of image drawing and image transfer are possible at least and pages for both sides are reserved in the case of double side printing, and (2), a want condition, where prescribed pages are recovered on the occurrence of jamming. An operating mode that allocates memory map by required pages is selected depending on a maximum capacity of available memories for image forming depending on the conditions above.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling an image forming apparatus capable of selecting an appropriate memory allocation and an operation mode for image formation in accordance with print data, and more particularly to a method for controlling an image memory for image formation. The present invention relates to a method for controlling an image forming apparatus capable of performing efficient memory map allocation and selecting an operation mode in relation to the memory map allocation.

[0002]

2. Description of the Related Art Conventionally, an image forming apparatus has been developed in which several operation modes can be selected in order to form an optimum image according to print data. In such an image forming apparatus, in a normal case, for example, for print data with a small number of print pages, the operation is performed in a frame mode,
When rendering an image for one page, the rendering process is performed directly and directly on the frame buffer. For print data with a large number of print pages, the first page is printed. The eyes operate in the frame mode, the second and subsequent pages operate in the band mode, and switch between the drawing process of dividing the image area for one page and drawing in the band buffer, and selecting the operation mode. The control for forming the image is performed.

In this type of image forming apparatus,
If the number of mounted image memories is small, that is, if the image area to be drawn in accordance with the print data is larger than the image area provided by the mounted image memory, one page of the print data is similarly used. Will be operated in the band mode. In this band mode operation, an image area for one page is divided into image areas each composed of a plurality of bands, and a bit map memory is provided for each band area from the print data corresponding to the image area of each divided band. To deploy to
The image is developed and the drawing process is performed.

In this type of image forming apparatus,
Various proposals have been made to improve performance in response to performance degradation due to small memory capacity. For example, as proposed in Japanese Patent Application Laid-Open No. 3-93562, a technique for separately securing band buffers for drawing and printing, and switching between these to enable parallel processing of drawing and transfer, JP-A-4-
As disclosed in Japanese Patent Publication No. 364587, there is a technique for drawing for the next page while opening a band buffer after transferring and outputting image data.

In the "printing apparatus" described in Japanese Patent Application Laid-Open No. 6-305202, in order to increase the printing speed in a printing apparatus having an intermediate code memory, the printing capacity is increased according to the memory capacity of the image data memory section. It has been proposed to select an optimal image development control method by using the above method. According to this technique, the memory capacity of the image data memory unit is detected by the memory capacity detecting means, and the capacity of the image data memory is set by the memory setting means according to the output result. Change the deployment method. As a result, when a predetermined amount of image data of the print page is output from the image data memory unit in the continuous printing process, the image data of the next page is read from the intermediate code memory and developed into the image data memory. The printing speed is increased. At the same time, the image development waiting time when an error such as a jam occurs is reduced.

[0006]

However, in the techniques proposed in these publications, for example, memory allocation such as an intermediate code section and an image data section is dynamically allocated at power-on, and an operation mode is selected. However, in that case, when allocating the memory capacity available for the drawing process to the band buffer, the frame buffer here,
One image forming condition such as "perform parallel processing of drawing and transfer" or "perform parallel processing of opening and drawing band buffer" as a condition for determining the allocation of each memory map such as a band buffer. Is just taking into account.

This is based on the amount of memory available at power-on, and calculates how many fixed-size page buffers (memory capacity for one page) can be secured by calculating
If only one band can be secured, the band mode is set. If only one band can be secured, the single page mode is set. For this reason, it does not correspond to the case where the page buffer is used after image compression, and image forming conditions such as "parallel processing of drawing and transfer" and "parallel processing of opening and drawing of band buffer" are considered. Not what it is. In addition to the above, the image forming conditions include, for example, "that two-sided pages can be held when double-sided printing is specified", "at least n pages can be recovered when a jam occurs", and That a work area to be used can be secured ", and there are various other things depending on the request of the print engine.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a memory which efficiently uses an image memory for image formation according to image formation conditions. It is another object of the present invention to provide a control method of an image forming apparatus for performing map assignment and selecting an operation mode in relation to memory map assignment.

[0009]

In order to achieve the above object, a control method of an image forming apparatus according to the present invention has a first feature (the invention described in claim 1) corresponding to a print mode. In an image forming apparatus capable of selecting an operation mode for appropriate image formation, the operation mode includes a first mode using only a frame buffer, a second mode using a frame buffer and a compressed frame buffer, a band buffer, and a predetermined number of pages. There is an operation mode of a third mode using a minute band buffer and an intermediate buffer. The first image forming conditions to be satisfied must be at least a first condition capable of simultaneous and parallel processing of drawing and transfer, and at the time of double-sided printing designation. A second condition for securing pages for both sides is given. As a second image forming condition to be satisfied as much as possible, a jam occurs. In this case, when a third condition that allows recovery for a predetermined number of pages is given, a required page is set according to the first image forming condition and the second image forming condition according to the maximum amount of memory available for image formation. The operation mode in which the memory map can be allocated for each minute is selected.

As a second feature (the second aspect of the present invention), the priority order of the operation modes is determined based on the first mode of only the frame buffer, the second mode of the frame buffer and the compressed frame buffer, the band buffer, and the predetermined mode. The third mode of the band buffer and the intermediate buffer for the number of pages is set in order, and a predetermined memory amount calculation rule is applied only to the first image forming condition for each operation mode to calculate a necessary memory amount. A memory map is assigned and an operation mode is selected from the required memory amount based on the maximum amount of usable memory and the priority set between the operation modes.

As a third feature (an invention according to claim 3), the priority order of the operation modes is determined by a first mode of only a frame buffer, a second mode of a frame buffer and a compressed frame buffer, a band buffer, The third mode of the band buffer and the intermediate buffer for the number of pages is set in order, and a predetermined memory amount calculation rule is applied only to the first image forming condition for each operation mode to calculate a necessary memory amount. From the set required memory amount, a temporary allocation of a memory map and a temporary selection of an operation mode are performed based on the maximum amount of usable memory and the priority set between the operation modes. If the priority of the selected operation mode is lowered, the amount of memory required to satisfy the first image forming condition is reduced, and the second image forming condition is reduced. If made to be more satisfied,
The order of the operation modes is lowered, and the operation mode and the memory allocation method are corrected and finally determined.

According to the control method of the image forming apparatus having the above-described characteristics, some given image forming conditions are:
The first image forming condition (hereinafter, referred to as a must image forming condition) which must be satisfied and the second image forming condition (hereinafter, referred to as a want image forming condition) which should be satisfied as much as possible are given, and these conditions are followed. Thus, the allocation of the memory map and the selection of the operation mode are performed.

In this case, first, for each operation mode that can be selected as the operation mode of the image forming apparatus,
According to a predetermined memory amount calculation rule, the amount of memory required to satisfy the must image forming condition is calculated, and the priority set between the maximum amount of usable memory and the operation mode is calculated from the calculated amount of memory. Based on the order, allocation of a memory map and selection of an operation mode are performed.

In addition, according to a predetermined memory amount calculation rule for each operation mode, the amount of memory required to satisfy the must image forming condition is calculated, and the maximum amount of usable memory is calculated from the calculated required memory amount. The temporary assignment of the memory map and the temporary selection of the operation mode are performed based on the priority set between the operation mode and the operation mode. Next, if the order of the tentatively determined operation modes is lowered, the amount of memory required to satisfy the must image forming condition is reduced, and if the want image forming condition is more satisfied, the order of the operation mode is changed. Try to correct the operation mode and memory allocation method.

[0015] Accordingly, the must image forming conditions and wa
Even if the memory amount is increased or decreased while simultaneously considering the nt image forming conditions, the memory map can be optimally allocated according to the available memory capacity at that time, and the operation mode can be selected. For this reason, the memory use efficiency can be improved, and the throughput of the entire system can be improved.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG.
FIG. 1 is a diagram illustrating an overall configuration of an image forming apparatus that implements the present invention in one embodiment. FIG. 2 is a diagram for explaining the operation of the document reading mechanism in the image forming apparatus without using the automatic document feeder. 1 and 2, 1 is an automatic document feeder, 2 is a document, 3 is a document set tray, 4 is a document transport roller, 5 is a document discharge tray, 6 is a platen glass, 7 is a light source, 8 is a mirror, 9 Is a selfoc lens,
Reference numeral 10 denotes a one-dimensional image sensor comprising a CCD, 11 denotes a photosensitive drum, 12 denotes a cleaning unit, 13 denotes a charging unit, 14 denotes a laser beam scanner unit, 15
Denotes a developing unit, 16 transfer units, 17 a fixing unit, 18 a paper supply unit, and 19 a paper discharge tray.

In the case of reading an original by the automatic original feeder 1, as shown in FIG. 1, an original scanning mechanism unit integrally formed of a light source 7 and a mirror 8 is provided with a platen glass 6
It is moved and fixed to the reading position A on the left side of FIG. Then, the original 2 set on the original set tray 3
Is discharged to the document discharge tray 5 by the document conveying roller 4 so as to pass through the document reading position A. At this time, the reflected light of the document 2 when the document 2 passes through the reading position A changes its optical path by a plurality of mirrors 8 and reaches a selfoc lens 9, through which a one-dimensional image sensor constituted by a CCD is formed. The image data is input to the device 10, and the document image is optically read. The optical signal of the read document image is output as an electric signal.

The electrophotographic process section of the main body for forming an image of the read document image is arranged so as to surround the photosensitive drum 11 so that a cleaning unit 12, a charging unit 13, a laser beam scanner unit 14, a developing unit 15, The transfer unit 16 and the fixing unit 17 are arranged, and constitute a mechanism of an electrophotographic process of the image forming apparatus.

The paper supplied from the paper supply unit 18 is transported by a transport roller, passes through the transport path of the paper, and passes through the transfer unit 16 to form an image from the photosensitive drum 11. The toner image is transferred, passes through the fixing unit 17, and is fixed to the toner image.

On the other hand, when reading a document placed on the platen glass 6, as shown in FIG. 2, a document scanning mechanism unit integrally constituted by a light source 7 and a mirror 8 is provided.
By moving in parallel from the reading position B on the left side of the platen glass 6 toward the reading position C on the right side, the reflected light on the original surface on the platen glass 6
The light path is changed to reach the SELFOC lens 9, through which the light is input to the CCD one-dimensional image sensor 10, and the original image is optically read. The optical signal of the read document image is output as an electric signal.

FIG. 3 is a block diagram illustrating the configuration of the control unit of the image forming apparatus. 3, reference numeral 20 denotes a control processor (CPU), 21 denotes a console panel, 22 denotes an automatic document feeder control unit, 23 denotes a document size / direction detection unit, 24 denotes a motor driver circuit, 25 denotes a driving motor,
6, a program memory (ROM); 27, a work memory (RAM); 28, an image information processing unit; 29, an electrophotographic process control unit;
A direction detection unit 32 is a paper presence / absence detection unit.

The control processor 20 performs overall control including control processing and image processing by various mechanisms in the image forming apparatus. For this reason, a control program for performing a control operation by the control processor (CPU) 20 is stored in the program memory (ROM) 26. The work memory (RAM) 27 is a work memory used when performing an image forming process including a control process by a control program and an image process.

The work memory 27 used as an image memory is constituted by a random access memory (RAM), and corresponds to each operation mode when executing an image forming process according to each operation mode. A memory area is provided as a working memory, for example, as a frame buffer memory, as a compressed frame buffer memory, as a band buffer memory, as a compressed band buffer memory, and as an intermediate buffer memory. As will be described later, the memory area of the work memory 27 is allocated as an image memory for expanding and storing image data of a plurality of pages, and the image forming process is executed according to each operation mode.

The console panel 21 is an operation section for the operator to give various instructions to the image forming apparatus.
There are provided various instruction buttons for designating the type of copy, designating the number of copies, and giving a start instruction, and a display unit for displaying a message for guiding the operation thereof. The console panel 21 allows the operator to give an instruction to, for example, collate and copy a plurality of copies of a plurality of documents. The document to be copied is set in the automatic document feeder (1: FIG. 1). The automatic document feeder
It is controlled by the automatic document feeder control unit 22. In this case, the document size / direction detection unit 23 detects the size and direction of the document conveyed from the automatic document feeder.

The drive motor 25 functions as a power source for moving the original scanning mechanism (the light source 7 and the mirror 8) described in FIGS. 1 and 2 in parallel. Although not shown, a plurality of drive motors for the power source are provided,
These drive motors function as a power source for rotating and driving the photosensitive drum in the electrophotographic process unit, and as a power source for feeding and discharging originals and printing paper. The drive of the drive motor 25 is controlled by a motor driver circuit 24.

The electrophotographic process control section 29 is provided with the electrophotographic process section (photosensitive drum 1) described with reference to FIG.
1, cleaning unit 12, charging unit 13, laser beam scanner unit 14, developing unit 15,
It is a control unit of the transfer unit 16 and the fixing unit 17). Since the control operation of the electrophotographic process by the control unit is well known, the description is omitted here. In connection with the operation of the electrophotographic process by the electrophotographic process control unit 29, the paper feed control unit 30 performs control for transporting the paper supplied from the paper supply unit 18 to the paper discharge tray 19, and in this case, The paper size / direction detection unit 31 detects the size and direction of the paper accommodated in the paper supply unit 18, and the paper presence / absence detection unit 32 detects the presence / absence of paper. Since these operations are well known, a description thereof will be omitted.

The image information processing unit 28 performs general image information processing in the image forming apparatus, such as scaling processing such as enlargement / reduction of a document image and page alignment when copying a plurality of copies of a plurality of pages. A data processing unit that performs such data processing. In this image information processing, in order to perform the drawing processing at high speed, according to the installed memory capacity, an optimum memory is allocated among the available memory capacities, and the operation mode is selected. Do.

FIG. 4 is a diagram for explaining the configuration of a main part of a processing module for performing memory allocation and operation mode selection processing in the image information processing unit. FIG. 5 is a diagram for explaining memory allocation and operation mode selection processing. It is. Description will be made with reference to these figures.

In FIG. 4, reference numeral 21 denotes a console panel,
41 is an available memory amount detection unit, 42 is an operation mode selection unit, 43 is a memory allocation processing unit, and 44 is an image formation condition specification unit.

The available memory detection unit 41 detects the available memory capacity in a print job. This is because, when the image forming apparatus has a facsimile function, the available memory capacity fluctuates due to the facsimile function. Is detected. The detected data of the usable memory capacity is supplied to the operation mode selection unit 42 and the memory allocation processing unit 43, and as described later, the memory allocation processing unit 43 outputs the selected operation mode from the available memory area. According to the above, memory allocation (memory map creation) for each page is performed.

The image forming condition designating section 44 corresponds to a print job in the copy mode instructed by the console panel 21 and sets image forming conditions in that case to several images given by a preset control table. The operation mode selection unit 42 is divided into a must image formation condition that must be satisfied by the formation conditions and a want image formation condition that must be satisfied as much as possible. The must image forming condition and wan specified by the control table here
The t image forming conditions include, for example, “that two-sided pages can be held when double-sided printing is specified”, “at least n pages can be recovered when a jam occurs”, and “the work area that is temporarily expanded when the compression buffer is transferred”. That can be secured. " There are various conditions according to the print engine, and these conditions are given as data in the control table.

In accordance with the data from the image forming condition designating section 44, the operation mode selecting section 42 first secures a necessary amount of memory in accordance with the must image forming condition and the want image forming condition. Operation modes (the first mode using only the frame buffer,
In each of the second mode using the frame buffer and the compressed frame buffer and the third mode using the band buffer, the compressed band buffer and the intermediate buffer for a predetermined number of pages), first, the must image formation is performed in accordance with the predetermined memory amount calculation rule. The amount of memory required to satisfy the condition is calculated, and the priority set between the maximum amount of usable memory and the operation mode (first mode, second mode, third mode) is calculated from the calculated amount of memory. The operation mode of each page is selected based on the priority in the order of the mode).

That is, first, the first mode using only uncompressed frames is selected, and a memory amount for the required number of pages is secured. In the selection of the first mode, if it is not possible to secure the required amount of memory for the number of pages, the second mode using uncompressed frames and compressed frames is selected,
Secure enough memory for the required number of pages. If the required amount of memory cannot be secured by selecting the second mode, the third mode using the band non-compression, the band compression, and the intermediate buffer is selected. When the operation mode is selected, the memory allocation processing unit 43 performs memory allocation for each page from the available memory area according to the amount of memory required in the operation mode.

As described above, the amount of memory necessary to satisfy the must image forming condition is calculated according to the predetermined memory amount calculation rule for each operation mode, and the available memory is calculated based on the calculated required memory amount. The memory map is allocated and the operation mode is selected based on the priority set between the maximum amount and the operation mode.

In this case, as shown in FIG. 5, if the order of the selected operation mode is lowered, for example, if the mode is changed from the first mode to the second mode, the amount of memory necessary to satisfy the must image forming condition is reduced. If the number decreases and further the wan image forming condition is satisfied, the order of the operation mode is lowered, and the operation mode and the memory allocation are corrected. The memory allocation processing unit 43 allocates memory to each page from the available memory area according to the corrected operation mode.

Thus, the conditions for forming the must image and the wa
In consideration of the nt image forming conditions, the memory map can be optimally allocated according to the available memory capacity at that time, and the corresponding operation mode can be selected. Therefore, even if the amount of memory is increased or decreased, the memory use efficiency can be increased in accordance with the available memory capacity at that time, and the throughput of the entire system is improved.

Next, a specific example will be described for an operation example in the case where the operation mode selection and the memory allocation processing are performed. The must image forming conditions here include a first condition of “simultaneous parallel processing of drawing and transfer”,
The second condition of “the pages for both sides can be held when the duplex printing is designated (the transfer when the duplex is designated, the faces must be transferred to the print engine after the front and back sides are aligned)” is given. As the wan image forming condition, a third condition of “can recover five sheets (10 pages when double-sided printing is designated) when a jam occurs” is given. The operation modes include a first mode using only a frame buffer as a page memory, a second mode using a frame buffer and a compressed frame buffer, and a third mode using a band buffer, a compressed band buffer for a predetermined number of pages, and an intermediate buffer. It is assumed that the operation can be performed by switching among the three operation modes described above, and that priorities are assigned in this order when selecting the operation mode.

Here, in order to avoid complicating the description and to make it easy to understand, the size of the paper will be A4 only and the required memory capacity will be described in a specific example. If the paper size is changed to B4 or B5, the memory capacity required for the drawing process for one page also changes. FIG. 6 is a diagram illustrating a memory amount of a unit allocated as a frame buffer, a compressed frame buffer, a band buffer, a compressed band buffer for one page, and an intermediate buffer when the paper size is A4.

Therefore, in this case, as shown in FIG. 6, the size of the buffer (frame buffer) required to hold the frame of one page is 4 MB, and
The size of the buffer (compressed frame buffer) required to compress and hold the page frame buffer is 1M
B, the size per band buffer in banding is 0.5 MB (the number of band divisions per page is 8), and a buffer necessary for compressing and holding eight band buffers for one page Size is 1M
B, and the size of the intermediate buffer required for banding is 2 MB. Here, it is assumed that the available memory detection unit 41 has detected 11 MB as the maximum amount of available memory under the control of a system control unit (not shown). In this image information processing, the time required for compressing / expanding / transferring the frame buffer or band buffer is sufficiently shorter than the time required for drawing in the frame buffer or band buffer.

At this time, in order to operate in the first mode while satisfying the two must image forming conditions (the first condition and the second condition), as shown in FIG.
You need a frame buffer for the page. That is,
Since the frame buffer for one page is 4 MB, a 12 MB memory is required in this case. The operation of each frame buffer is as shown in FIG.

FIG. 8 is a flowchart for explaining the operation in the first mode. The operation in the first mode will be described with reference to FIG. In this case, the three frame buffers of the first frame buffer, the second frame buffer, and the third frame buffer are used, and the drawing process and the transfer process are performed simultaneously, and the two-sided printing is performed continuously. First, in step 80, the front surface 1 is drawn in the first frame buffer according to the print data, and then, in step 81, the back surface 1 is drawn in the second frame buffer. As a result, the front side and the back side are aligned, and transfer can be started (second condition). Therefore, in step 82, the front side 1 drawn from the first frame buffer (to the print engine side)
Forward. In the meantime, in step 83, the front surface 2 is drawn in the third frame buffer. That is, the processing of step 82 and the processing of step 83 are performed simultaneously (first condition).

Next, in step 84, the back side 1 drawn from the second frame buffer is transferred. When the transfer of the front side 1 from the first frame buffer is completed in the processing of the previous step 82, the first frame buffer is in an empty state. Draw back side 2 in buffer. Subsequently, in step 86, the front surface 3 is drawn in the second frame buffer. At this time, in step 87, the front surface 2 drawn from the third frame buffer is transferred.

Then, in step 87, when the transfer of the surface 2 drawn from the third frame buffer is completed,
Next, at step 88, the third
The back surface 3 is drawn in the frame buffer. At this time, the back surface 2 is transferred from the first frame buffer in step 89 in a process simultaneous with step 88. Hereinafter, similarly, the transfer process of the front surface 3 and the back surface 3 and the subsequent drawing process of the front surface 4 and the back surface 4 are performed.

As described above, in the first mode, the three frame buffers of the first frame buffer, the second frame buffer, and the third frame buffer are used, and the simultaneous processing of the drawing processing and the transfer processing is performed. Then, printing on both sides is performed.

Similarly, when operating in the second mode,
Although a part of the compressed frame buffer is used instead of the frame buffer, in this case, the operation is performed while satisfying the two must image forming conditions (the first condition and the second condition). Therefore, two frame buffers, a first frame buffer and a second frame buffer, and one compressed frame buffer for transfer are required. That is, in this case, as shown in FIG. 9, the frame buffer for two pages is 8 MB, and
Since the compressed frame buffer for a page is 1 MB,
9MB of memory is required. The operation in this case is as shown in FIG.

FIG. 10 is a flowchart for explaining the operation in the second mode. The operation in the second mode will be described with reference to FIG. In this case, as described above, the first
Using two frame buffers, a frame buffer and a second frame buffer, and one compression frame buffer, simultaneous processing of drawing processing and transfer processing is performed, and printing on both sides is performed continuously. That is, first, in step 101, the front side 1 is drawn in the first frame buffer according to the print data, and then, in step 102, the back side 1 is drawn in the second frame buffer. Simultaneously with the operation in step 102, in step 103, the front surface 1 drawn in the first frame buffer is compressed into a compression frame buffer. By this processing, the front side and the back side are aligned, and transfer can be started (second condition). In the next step 104, the front side 1 is expanded from the compressed frame buffer and transferred (to the print engine side).
Subsequently, in step 105, the rear surface 1 drawn from the second frame buffer is transferred.

Next, in the processing of the previous step 103, the first
When the front surface 1 is compressed from the frame buffer into the compression frame buffer, the first frame buffer becomes empty, and in the next step 106, the front surface 2 is drawn in the first frame buffer. Subsequently, in step 107, the surface 1 drawn in the first frame buffer is compressed into the compressed frame buffer, and
, The back surface 2 is drawn in the second frame buffer.
By this processing, the front side and the back side are aligned, and transfer can be started (second condition).
The surface 2 is decompressed and transferred from the compressed frame buffer.
Subsequently, in step 110, the back surface 2 drawn from the second frame buffer is transferred. Hereinafter, similarly,
The drawing process and the transfer process of the front surface 3 and the back surface 3 are continued.

As described above, in the second mode, drawing processing is performed using the first frame buffer and the second frame buffer, and transfer processing is performed using the compressed frame buffer. As a result, the transfer is started after the front and rear surfaces are aligned, and the drawing process and the transfer process are performed simultaneously, so that the above-described must drawing condition is satisfied and continuous printing on both sides is performed.

Similarly, when the usable memory capacity is small, the operation is performed in the third mode. In this case, however, as shown in FIG. In order to operate while satisfying (the first condition and the second condition), one intermediate buffer, two band buffers, and a compressed band buffer for three pages are used. As a result, the transfer is started after the front side and the back side are aligned, the simultaneous processing of the drawing processing and the transfer processing is performed, and the printing of both sides is performed continuously. In this case, 3 MB is used as a compression band buffer for three pages.
Is allocated, 1 MB is allocated as two band buffers, and 2 MB is allocated as one intermediate buffer, so that a total of 6 MB of memory is required. The operation in this case is as shown in FIGS.

FIG. 12 is a first flowchart for explaining the operation in the third mode, and FIG. 13 is a second flowchart for explaining the operation in the third mode. The operation in the third mode will be described with reference to these drawings. In this case, in the image formation for one page, the drawing process for one page is performed by the drawing process eight times for each (1/8) screen by the band mode operation.

When the process is started in the third operation mode, first, in step 121, the first (1/8) portion of the front surface 1 is drawn in the first band buffer. Next, in step 122, a second (1/8) portion of surface 1 is drawn in the second band buffer. At the same time, in step 123, the first (1/8) portion of surface 1 in the first band buffer is compressed into the first compressed band buffer. Next, in step 124,
Draw a third (1/8) portion of surface 1 in the first band buffer. At the same time, in step 125,
The second (1/1) of surface 1 in the second band buffer
8) Compress the part into a first compression band buffer. Similarly, the first band buffer and the second band buffer are alternately used to sequentially draw (（) portions of the surface 1, and these drawn portions are stored in the first compressed band buffer. Then, the drawing of the front surface 1 for one page is completed by the drawing processing eight times.

That is, the processing so far (not shown)
In the first band buffer, the seventh (1/8) of the surface 1
After drawing the portion, next, in step 126, the eighth (1/8) of the surface 1 is stored in the second band buffer.
The portion is drawn, and the drawing process of the front surface 1 is completed. Also,
Simultaneously with the processing in step 126, in step 127, the seventh (1/8) portion of the surface 1 in the first band buffer is compressed into the first compression band buffer. Then, in the drawing process, in order to start drawing on the back surface 1, in the next step 128, the first (１ ／) portion of the back surface 1 is drawn on the first band buffer.
At the same time, in step 129, the last eighth (1/8) portion of surface 1 in the second band buffer is compressed into the first compressed band buffer. This allows
The formation of the print image on the front surface 1 is completed in the compression band buffer.

At this time, the drawing processing (step 128) of the next back side 1 has already started, and in the next step 130, the second (1/8) of the back side 1 is stored in the second band buffer.
Draw a part. At the same time, in step 131, the first (1/8) portion of the back surface 1 that has been drawn in the first band buffer is compressed into the second compression band buffer. Similarly, the first band buffer and the second band buffer are alternately used, and the (1/8) portion of the back surface 1 is sequentially drawn, and these drawn portions are stored in the second compressed band buffer. Then, the drawing of the back surface 1 for one page is completed by eight drawing processes (steps 132, 133, and 135). Also,
At this time, drawing of the first (1/8) portion of the next surface 2 has already started (step 134).

In this manner, (1/1 /
8) When the drawing process for each part is performed, drawing of the front surface 1 is completed in the first compression band buffer, and drawing of the back surface 1 is completed in the second compression band buffer, the drawn compressed print image is decompressed. Then, a process of transferring the data to the print engine is performed.

This will be described with reference to the flowchart of FIG. In step 141, after drawing the surface 1 and compressing it to the first compression band buffer in the band mode operation as described above, then in step 142, the band mode operation is performed similarly. Then, the back side 1 is drawn and compressed to the second compression band buffer. As a result, the front side and the back side are aligned, and transfer can be started (second condition). Next, in step 143, the front side 1 is expanded from the first compression band buffer and transferred (to the print engine side). I do. At this time, the next drawing process is started at the same time, and in step 144, the front surface 2 is drawn and compressed into the third compression band buffer.

Next, in step 145, the back side 1 is decompressed from the second compression band buffer and transferred (to the print engine side). At this time, the previous step 14
Since the first compression band buffer becomes empty in the processing of step 3, the next drawing processing is started at the same time, and step 146 is executed.
, The back surface 2 is drawn and compressed into a first compression band buffer.

Then, in the next step 147, the front surface 3 is drawn and compressed into the second compression band buffer.
At this time, at the same time, in step 148, the surface 2 is expanded and transferred from the third compression band buffer. In this process, the third compression band buffer becomes empty. In the next step 149, the back surface 3 is drawn and compressed into the third compression band buffer. At this time, at the same time, in step 150, the back surface 2 on which drawing has already been completed is expanded and transferred.

As described above, in the operation in the third mode, the drawing process is a drawing process for each divided region of the drawing process of one page by the band mode operation. When the process is started, the drawing process and the transfer process are performed at the same time, and printing on both sides satisfying the above-described must drawing forming condition is performed.

As described above, the operation mode selection unit here selects an operation mode that satisfies at least the must image forming condition and performs the process. Since the selection condition is given separately for the must image formation condition and the wait image formation condition, the remaining memory amount after allocating the necessary memory amount under the must image formation condition is further determined from the available memory amount. In order to further satisfy the wan image forming condition, the modification can be made to correct the selection of the operation mode and correct the memory allocation.

Next, such an embodiment will be described as a second embodiment. FIG. 14 is a diagram illustrating a process of selecting the operation mode by comparing the required memory capacity in each of the first mode, the second mode, and the third mode. FIG. 15 is a diagram illustrating a configuration of a main part of a processing module that performs memory allocation and operation mode selection processing in the image information processing unit according to the second embodiment. Description will be made with reference to these figures. In FIG.
151 is a memory amount calculation unit, 152 is an operation mode determination unit,
153 is a memory map determining unit for the must image forming conditions,
Reference numeral 154 denotes a memory map determining unit for the wan image forming condition.

The memory amount calculator 151 first calculates a memory amount necessary for operating in each operation mode while satisfying some given must image forming conditions.
Therefore, the memory amount calculation unit 151 is provided with the data of the must image formation condition 151a, some switchable operation modes 151b, and the memory amount calculation rules 151c, and operates in each mode according to these data. The required memory amount for performing the calculation is calculated. Specifically, the memory amount calculation unit 151 determines the amount of memory required to operate in the first mode, the second mode, and the third mode while satisfying the two must image forming conditions described above, as described above. ,
It is calculated as 12 MB, 9 MB, and 6 MB, respectively.
The calculated required memory amount 152a in each operation mode is:
The operation mode determination unit 152 is provided.

On the other hand, the operation mode determination section 152 is provided with data of the maximum amount 152b of available memory from the system control side, and the operation mode determination section 152 selects an operation mode based on these data. To decide.

To explain this with a specific numerical example, as shown in FIG. 14, when 11 MB is given as data of the maximum amount 152b of available memory from the system control side, the operation mode is changed to the first mode. Then the required memory amount is 12
It is inoperable only in the second mode having a required memory amount of 9 MB and the third mode having a required memory amount of 6 MB. The operation modes are prioritized in the order of the first mode, the second mode, and the third mode. Therefore, as the operation mode in this case, the operation mode having the highest priority among the operable operation modes is eventually used. Decide on two modes.

When the operation mode here is determined to be the second mode, the memory map determination unit 153 for the must image forming condition incorporated as a subsystem in the operation mode determination unit 152 operates in the second mode. Using the required memory amount of 9 MB, the memory map of the memory area is allocated.

At this point, the available memory amount is 11M
9 MB is subtracted from B, leaving 2 MB. The remaining memory is used to satisfy some given want image forming conditions. In this case, as described above, for example, if "want recovery for 5 sheets (10 pages when double-sided printing is specified) when a jam occurs" is given as the wan image forming condition, that is, "10 pages Can save data for minutes "
This is given as an nt image forming condition.

In order to store one page of data by using the remaining memory, 1 MB is required even if the data is compressed. Therefore, two pages of data can be stored with the memory of 2 MB. Therefore, in this case, similarly, the wa included in the operation mode determination unit 152 as a subsystem
The memory map determining unit 154 for the nt image formation condition allocates a memory map of the memory area so that the remaining memory amount of 2 MB can be used, for example, as a compression frame buffer.

As a result, in accordance with the must image forming conditions, together with the data for three pages secured in the second mode determined, a total of five pages (2.5 sheets, but 2 (Equivalent data). That is, when a jam occurs, two sheets can be recovered.

As described above, in consideration of the given image forming conditions and the desired image forming conditions, the optimum memory map is allocated and the operation mode is selected using the given available memory amount. it can.

By the way, as described above, the given mu
Considering the st image forming condition and the wan image forming condition,
When the optimum memory map is allocated and the operation mode is selected, in the above-described second embodiment, first, an operation mode and memory allocation for satisfying a given must image forming condition are performed, and then, The remaining memory amount satisfies the want image forming condition as much as possible and allocates a memory map using the given available memory amount. In consideration of both of the conditions, the present invention can be modified so that an optimal memory map can be allocated and an operation mode can be selected using a given available memory amount. An embodiment in this case will be described as a third embodiment.

In the third embodiment, as in the case of the above-described second embodiment, first, the first of the usable operation modes while satisfying the given must image forming condition is satisfied.
The amount of memory required to operate in the mode, the second mode, and the third mode is calculated. In this case, the maximum amount of memory that can be used, must image forming conditions,
If the image forming conditions and the like are the same as in the second embodiment, the first image is satisfied while satisfying the must image forming conditions.
The amounts of memory required to operate in the mode, the second mode, and the third mode are 12 MB, 9 MB, and 6 MB, respectively.
And the calculated required memory amount in each operation mode is provided to the operation mode determination unit 152.

The calculated 12 MB, 9 MB, and 6 MB of the required memory amount in each operation mode are compared with the maximum usable memory amount of 11 MB. Is temporarily determined as the second mode having the highest priority among the operable operation modes. Subsequently, when memory allocation is performed using the remaining memory amount of 2 MB so as to satisfy the want image forming condition, the operation mode determination unit 152 performs a correction process as follows.

That is, in this case, as described in the second embodiment, data can be held only for five pages (two sheets) as it is. Therefore, the priority of the provisionally determined operation mode is reduced. For example, if the operation mode is changed from the second mode to the third mode, the given mu
As described above, the amount of memory required to satisfy the st image forming condition is reduced to 6 MB, and the remaining amount of memory available for the want image forming condition is increased to 5 MB.
If there is a memory capacity of 5 MB, data of 5 pages can be stored by compression. Therefore, the third
A total of eight pages (four pages) of data can be stored together with the three pages of data already secured in the operation mode. In other words, when the operation mode and the memory allocation are changed in this way, when a jam occurs, the four-sided printing is performed.
It is possible to recover the number of sheets, and it becomes possible to more satisfy the wan image forming conditions.

Therefore, the operation mode determining section 152 changes the operation mode to the third mode, and in response to this, mu
The memory map determination unit 153 for the st image forming condition
Using a required memory amount of 6 MB for operating in the mode, a memory map is allocated to the memory area, and w
The memory map determining unit 154 for the ant image forming conditions allocates a memory map to the memory area so that the remaining memory amount of 5 MB can be used as, for example, a compression frame buffer.

As described above, in the third embodiment, the operation mode is corrected to the operation mode 3 and the final decision is made. In this way, the given mode is given in consideration of the given must image forming condition and the want image forming condition. It is possible to allocate a memory map and select an operation mode optimal for an available memory amount.

Although both the second and third embodiments have been described with reference to a case in which there is only one want image forming condition, when there are a plurality of want image forming conditions, the plurality of want image forming conditions are used. Weighting is performed on each forming condition, and the operation mode and the allocation of the memory map can be determined in consideration of the importance of each want image forming condition. Among a plurality of want image forming conditions, a certain wan
If you want to increase the importance of the image forming conditions,
It is only necessary to increase the weight for the t image formation condition, and conversely, to reduce the importance, the weight may be reduced. Also,
When it is desired to consider a plurality of want image forming conditions on average, all the want image formation conditions may have the same weight.

[0076]

As described above, according to the present invention, even if the amount of memory is increased or decreased, the memory at that time is automatically taken into account, considering both the must image forming condition and the want image forming condition at the same time. The memory map can be optimally allocated to the capacity, and the operation mode can be selected. Therefore, according to the present invention, the memory use efficiency can be improved, and the throughput of the entire system can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an overall configuration of an image forming apparatus that implements the present invention in one embodiment.

FIG. 2 is a diagram illustrating an operation of a document reading mechanism in the image forming apparatus that does not rely on an automatic document feeder.

FIG. 3 is a block diagram illustrating a configuration of a control unit of the image forming apparatus.

FIG. 4 is a diagram illustrating a configuration of a main part of a processing module that performs memory allocation and operation mode selection processing in an image information processing unit.

FIG. 5 is a diagram illustrating memory allocation and operation mode selection processing.

FIG. 6 is a diagram illustrating a memory amount of a unit allocated as a frame buffer, a compressed frame buffer, a band buffer, a compressed band buffer for one page, and an intermediate buffer when the paper size is A4.

FIG. 7 is a diagram illustrating the amount of memory required to operate the operation mode as a first mode.

FIG. 8 is a flowchart illustrating an operation in a first mode.

FIG. 9 is a diagram illustrating the amount of memory required to operate the operation mode as a second mode.

FIG. 10 is a flowchart illustrating an operation in a second mode.

FIG. 11 is a diagram illustrating the amount of memory required to operate the operation mode as a third mode.

FIG. 12 is a first flowchart illustrating an operation in a third mode.

FIG. 13 is a second flowchart illustrating the operation of the third mode.

FIG. 14 is a diagram illustrating a process of selecting an operation mode by comparing a required memory capacity in each of the first mode, the second mode, and the third mode.

FIG. 15 is a diagram illustrating a configuration of a main part of a processing module that performs memory allocation and operation mode selection processing in an image information processing unit according to a second embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Automatic original feeder, 2 ... Original, 3 ... Original set tray, 4 ... Original conveyance roller, 5 ... Original discharge tray, 6 ... Platen glass, 7 ... Light source, 8 ... Mirror, 9 ... Selfoc lens, 10 ... CCD one-dimensional image sensor, 11 photoconductor drum, 12 cleaning unit, 13 charging unit, 14 laser beam scanner unit, 15 developing unit, 16 transfer unit, 1
7: fixing unit, 18: paper supply unit, 19: paper discharge tray, 20: control processor (CPU), 21
... Console panel, 22 ... Automatic document feeder control unit,
23: Document size / direction detector, 24: Motor driver circuit, 25: Drive motor, 26: Program memory (R
OM), 27: Work memory (RAM), 28: Image information processing unit, 29: Electrophotographic process control unit, 30: Feed control unit, 31: Paper size / direction detection unit, 32: Paper presence / absence detection unit, 41 ... Available memory amount detection unit, 42 ... Operation mode selection unit, 43 ... Memory allocation processing unit, 44 ... Image formation condition designation unit, 151 ... Memory amount calculation unit, 152 ...
Operation mode determination unit, 153: memory map determination unit for must image formation conditions, 154: memory map determination unit for want image formation conditions.

Claims (5)

[Claims] 1. An image forming apparatus in which an operation mode for forming an appropriate image can be selected according to a print mode, wherein the operation mode uses a first mode using only a frame buffer, and a frame buffer and a compression frame buffer. There are two operation modes, a second mode, and a third mode using a band buffer, a compression band buffer for a predetermined number of pages, and an intermediate buffer.
A first condition that allows simultaneous and parallel processing of drawing and transfer, and a second condition that ensures pages for both sides when double-sided printing is designated are given. As a second image forming condition that should be satisfied as much as possible, a predetermined page is set when a jam occurs. When a third condition capable of recovering several minutes is given, a memory map for a required page is obtained by the first image forming condition and the second image forming condition according to the maximum amount of memory usable for image formation. A method of controlling an image forming apparatus, wherein the operation mode that can be assigned is selected. 2. The method for controlling an image forming apparatus according to claim 1, wherein the priority order of the operation modes is a first mode of only a frame buffer, a second mode of a frame buffer and a compressed frame buffer, a band buffer, and a predetermined order. The third mode of the third mode of the compression band buffer and the intermediate buffer for the number of pages is set in order, and a predetermined memory amount calculation rule is applied for each operation mode only to the first image forming condition, and a required memory amount is set. And calculating a memory map and selecting an operation mode from the calculated required memory amount based on the maximum amount of available memory and the priority set between the operation modes. A method for controlling an image forming apparatus. 3. The control method for an image forming apparatus according to claim 1, wherein the priority order of the operation modes is a first mode of only a frame buffer, a second mode of a frame buffer and a compressed frame buffer, a band buffer, and a predetermined order. The third mode of the third mode of the compression band buffer and the intermediate buffer for the number of pages is set in order, and a predetermined memory amount calculation rule is applied for each operation mode only to the first image forming condition, and a required memory amount is set. Based on the calculated required memory amount, based on the maximum amount of available memory and the priority set between the operation modes, temporarily allocate a memory map and temporarily select an operation mode, Subsequently, if the priority of the temporarily selected operation mode is lowered, the amount of memory required to satisfy the first image forming condition is reduced, Serial when the second image forming condition is to be more satisfied, dropped order of operation mode, the control method for an image forming apparatus, characterized in that the final decision to modify the operating mode and the memory allocation process. 4. The control method for an image forming apparatus according to claim 2, wherein the operation mode is a first mode in which a memory is allocated only to a frame buffer, and the memory is a frame buffer and a compressed frame. The second assigned to the buffer
Mode and memory are two of a third mode in which a memory is allocated to a band buffer, a compressed band buffer for a predetermined number of pages, and an intermediate buffer. The priority order of the operation modes is the first mode, the second mode, and the third mode. A method for controlling an image forming apparatus, characterized in that the modes are in order. 5. The image forming apparatus according to claim 1, wherein the first image forming condition or the second image forming condition includes a fourth condition capable of temporarily expanding a work area during transfer of a compression buffer. How to control the device.