JP2000335020A - Image forming apparatus and control method thereof - Google Patents

Abstract

(57) [Problem] To improve the printing efficiency in a printing method for transferring a toner image to an intermediate transfer member. When transferring an image one page at a time to a transfer drum and printing it, a time T6 is required until printing of two pages is completed, and the image of two pages is simultaneously transferred to the transfer drum and printed. In this case, time T2 is required for two pages. Therefore, after the image data of one page is generated, the data amount of the next page is determined by the external device. If the data amount is equal to or less than the predetermined amount, the page can be generated in a time period of T6−T2 = T7 or less, and two pages are formed. Specify the mode. Otherwise, specify the one-page formation mode. As a result, printing is performed in the mode in which printing of two pages is the earliest.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image forming apparatus for forming an image developed with toner or the like on an intermediate transfer member and transferring the image to a print medium to form an image, and a control method therefor.

[0002]

2. Description of the Related Art In recent years, page printers, mainly laser beam printers, have been rapidly developed. More recently, many page printers capable of outputting a color image have been proposed and commercialized. The color laser beam printer has four color toners (Y: yellow, M: magenta,
(C: cyan, K: black) A full-color image is formed by superimposing each color by an electrophotographic process, and various processes have been proposed.

In the intermediate transfer system shown in FIG. 17, a latent image on a photosensitive drum is formed as a toner image, the toner image is temporarily transferred to an intermediate transfer member, and four color toner images are formed on the intermediate transfer member. After the superimposition, toner images of four colors are transferred and fixed on the paper at a time to form an image. Since the positional relationship between the intermediate transfer member and the photosensitive drum is fixed,
The intermediate transfer method has an advantage that it is easier to prevent color misregistration than a method of transferring one color on a sheet at a time.

[0004]

However, as shown in FIG. 18, in the image forming method of the intermediate transfer system,
An intermediate transfer body with a corresponding maximum paper size is required,
When an image is formed in units of one page, the number of prints per unit time is constant regardless of the size of the image to be formed. That is, even if the size is smaller than the maximum paper size, the printing speed cannot be increased.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem. When a plurality of pages can be formed on an intermediate transfer member, an image for a plurality of pages is formed on the intermediate transfer member, thereby reducing An object of the present invention is to provide an image forming apparatus in which the number of printed sheets is increased and productivity is improved, and a control method thereof.

Further, the image forming apparatus according to the present invention is capable of forming a plurality of pages within a predetermined time when printing page data to be printed first from the engine idling state (hereinafter referred to as "first print"). It is an object of the present invention to increase the efficiency of the printing process by forming an image for a plurality of pages on an intermediate transfer body and transferring the image to a print medium.

[0007]

To achieve the above object, the present invention has the following arrangement. That is, an image forming unit capable of forming images of a plurality of pages in an image forming area, a first image forming mode in which image formation in the image forming area is performed one page at a time, and an image forming mode in the image forming area. Mode selecting means for selecting any one of the second image forming modes for performing a plurality of pages each, and control means for controlling the image forming means so as to form an image in the image forming mode selected by the mode selecting means. Prepare.

[0008] More preferably, the mode selecting means includes:
The image forming mode is selected for each page.

[0009] More preferably, the mode selecting means includes:
The image forming mode is selected for each print job.

[0010] More preferably, the mode selecting means includes:
The image forming mode is selected in accordance with the control data transmitted together with the print data from the external device.

[0011] More preferably, said mode selection means comprises:
When the image data of the Nth page is prepared and the image data of the pages other than the Nth page is not prepared,
Within a predetermined time after the image data of the page is prepared,
When the image data of the +1 page can be prepared, the second image forming mode is selected, and the control unit performs image formation on the image forming area by performing two pages each of the Nth page and the (N + 1) th page. The image forming unit is controlled.

[0012] More preferably, said mode selection means comprises:
Even if image data of the Nth page is prepared and image data other than the Nth page is not prepared, if there is no subsequent print data, the first data is output without waiting for a predetermined time.
Is selected.

More preferably, the image forming means forms a color image in which images of a plurality of component colors are superimposed on the intermediate transfer body as the image forming area.

According to the above configuration, it is possible to maximize the printing throughput of the intermediate transfer system, and it is possible to provide a color laser beam printer that achieves both the effect of preventing color misregistration and the printing quality and speed.

Further, the printing in the plural page forming mode can be efficiently performed by the instruction from the external device, and the total printing time of the plural pages can be reduced. In addition, by the processing of the control software running on the external device, the user is not conscious, that is, even when printing single page data, a plurality of pages (jobs and documents)
, It is possible to always provide the maximum printing throughput.

[0016]

FIG. 1 shows the configuration of a system including a color laser printer according to the present embodiment.

<Configuration of Printer System> In FIG. 1, reference numeral 101 denotes an external device such as a host computer;
Is a color laser beam printer to which the present embodiment is applied.

The color laser beam printer 102 is
By actually forming a latent image on the photosensitive drum for each dot data of each color of Y, M, C, and Bk, Y, M,
An engine unit 103 for printing by superimposing and thermally fixing four colors of C and Bk, connected to the engine unit 103, and code data sent from the external device 101;
A controller 104 that receives image data (RGB, YMCK), generates page information composed of dot data of each of Y, M, C, and Bk based on the data, and transmits the dot data to the engine 103 sequentially. Consists of
An operator (user) can specify a predetermined operation of the color laser beam printer 102 by operating the panel unit 105.

The controller 104 and the engine 103
Are connected by a predetermined video interface, and information is exchanged by serial communication of command / status in 8-bit units.

FIG. 2 is a schematic sectional view of the engine unit 103 of the color laser beam printer according to the present embodiment.

In FIG. 1, reference numeral 201 denotes a sheet as a recording medium, and 202 denotes a sheet cassette for holding the sheet 201. Reference numeral 203 denotes a cassette paper feed clutch, which separates only the top sheet of the paper 201 placed on the paper cassette 202, and connects the leading end of the paper separated by a driving unit (not shown) to the paper feed roller 204. Transport to the position. The cassette paper feed clutch 203 rotates intermittently each time paper is fed, and feeds one sheet of paper corresponding to one rotation. When the paper is conveyed by the paper feed clutch 203, the paper feed roller 204 rotates while lightly pressing the paper 201 and conveys the paper 201. Reference numeral 222 denotes a paper tray, and 221 denotes a manual paper feed clutch, which not only feeds paper from the paper cassette 202 but also enables manual paper feed from the paper feed tray 222 one by one.

209 is a photosensitive drum, 208 is a drum cartridge including a photosensitive drum, 210 is a Bk: black toner developing device, 211 is a Y: yellow toner developing device, 21
Reference numeral 2 denotes an M: magenta toner developing device, 213 denotes a C: cyan toner developing device, and 214 denotes a YMC developing device support portion. The developing device support portion 214 rotates and conveys the developing device of the desired color toner to a position where the developing device can be developed on the photosensitive drum 209. Reference numeral 216 denotes a scanner unit including a laser driver (not shown). The laser driver forms an image on the photosensitive drum 209 while turning on / off a semiconductor laser (not shown) according to dot data sent from the printer controller 104. A latent image is formed on a main scanning line by scanning in the main scanning direction. 205 is an intermediate transfer drum. The intermediate transfer drum 205 rotates at a predetermined speed during printing, and
9 is transferred.

The latent image on the photosensitive drum 209 is visualized as a toner image by a predetermined color toner developing unit among the developing units 210, 211, 212, and 213 in parallel with the formation.
Further, the toner image is transferred onto the intermediate transfer drum 205 rotating in parallel, and a toner image of one page size is formed on the intermediate transfer drum 205. In the case of the mono-color (single-color) mode, a one-page toner image of one color (hereinafter, referred to as a plane) is formed on the intermediate transfer drum. In the full color mode, the developing devices 210, 211, 212, 213 are provided on the intermediate transfer drum.
Are superposed and formed.

Reference numeral 224 denotes a secondary transfer roller.
1 is charged between the intermediate transfer drum 205 and the secondary transfer roller 214, and the toner image on the intermediate transfer drum 205 is transferred onto the interposed paper 201 (secondary transfer).
Let it.

Reference numeral 215 denotes a fixing heater for heating and fixing the toner image on the sheet 201, and 216 and 216 'denote fixing rollers. The sheet 201 is further conveyed after receiving the secondary transfer, and the toner image is heated and fixed by the fixing rollers 218 and 218 ′.
9, the paper is discharged to the paper discharge tray 220.

Color laser beam printer 1 of this embodiment
In step 02, the processes of latent image formation and transfer are performed in the order of yellow, magenta, cyan, and black.

Each of the yellow toner developing device 210, the magenta toner developing device 211, the cyan toner developing device 212, and the black toner developing device 213 is a cassette type housing, and can be detached from the main body. Therefore, hereinafter, 210 is referred to as a Y cartridge, 211 as an M cartridge, 212 as a C cartridge, and 213 as a K cartridge.

Reference numeral 221 denotes a reverse re-feeding unit.
Reference numerals 22, 223, and 224 are conveying rollers. The engine unit 103 can select the discharge tray 220 and the reverse re-feed unit 221 as the transport destination of the sheet 201 after the fixing. This specification is performed by the controller unit 104 by the serial communication. Paper 201
Is transported once in the direction of the transport roller 222 when it enters the reversing re-feed unit. When a sensor (not shown) detects the trailing edge of the sheet, the engine unit 103 reverses the rotation of the conveying roller 222 and feeds the sheet 20 to the conveying rollers 223 and 224.
1 is transported. If a double-sided paper re-feed unit is designated as the paper feed port, the paper is re-fed to the transport roller 204 in a state where the paper surface is reversed, so that the double-sided printing can be performed through the above printing process.

As described above, the engine unit 10 of this embodiment
Reference numeral 3 realizes full-color printing and mono-color printing by forming one page of toner image on the intermediate transfer drum 205. Therefore, the outer peripheral length of the intermediate transfer drum 205 is
There is a length longer than the long side of the maximum printable paper size. For this reason, in order to shorten the conveyance interval of the paper and improve the printing throughput, a toner image of two pages is formed on the intermediate transfer drum 205 on the paper having a paper length equal to or less than a half of the maximum paper length. A mode for continuously printing two pages by feeding paper continuously is provided. Hereinafter, the above 2
Continuous printing of pages is called two-page forming mode, and normal printing is one-page forming mode (or normal printing mode).
Called. In the present embodiment, the maximum paper size is twice or more the size of the A4 size horizontal feed, and continuous printing of the above two pages is possible during the A4 horizontal feed.

<Image Forming Timing> FIGS. 3 and 4 are timing charts of interface signals showing printing protocols between the printer engine unit 103 and the controller unit 104 of the color laser beam printer of the present embodiment.

In FIG. 3, PRNT is a signal for requesting the controller 104 to start printing, TOP is a timing signal for requesting the controller 104 to send image data (video signal) to the engine 103, and VDO is image data. , One page is transmitted from the controller unit 104 in synchronization with a clock signal (not shown). Engine part 1
In step 03, when a TRUE of the PRNT signal is detected, the printing operation is started, and the TOP signal is set to TRUE for a predetermined period to the controller 104. The controller 104 is TO
When the TRUE of the P signal is detected, the VDO signal for one page is transmitted in synchronization with the detection. The engine unit 103 forms an image according to the VDO signal.

FIG. 3 is a timing chart of the mono color mode.

In the one page formation mode, the engine unit 103 responds to the PRNT signal of the controller unit 104 by
One TOP signal is issued. In the two-page formation mode, the PRNT signal from the controller 104 is
Issue the TOP signal twice. The controller unit 104
After preparation for printing two pages, the PRNT signal is
The image data of the first page is transmitted in synchronization with the first TOP signal from the engine unit 103, and the image data of the second page is transmitted in synchronization with the next TOP signal.

FIG. 4 is a timing chart of the full color mode.

In the one page forming mode, the engine unit 103 responds to the PRNT signal of the controller unit 104 by
TO for four colors of yellow, magenta, cyan and black
Issues a P signal. In the two-page formation mode, the PRNT signal from the controller unit 104 responds to Y1 (first yellow page), Y2 (second yellow page), M
1, M2, C1, C2, K1, K2 TOP 8 times in total
Issue a signal. After preparation for printing two pages, the controller unit 104 sets the PRNT signal to TRUE, and synchronizes the first page of yellow image data with the next TOP signal in synchronization with the first TOP signal from the engine unit 103. Synchronously, the second page yellow image data, similarly the first page magenta, the second page magenta, 1
Cyan of the second page, cyan of the second page, black of the first page, and black of the second page are transmitted.

The change between the one-page formation mode and the two-page formation mode is performed by the controller unit 104 and the engine unit 103.
The serial communication instruction is sent to the device.

FIG. 5 is a diagram showing that the two-page forming mode is effective for the throughput. In the figure, T1 is an image forming interval in the two-page forming mode,
T2 is the image forming interval in the one-page mode. In the one-page formation mode, the issue interval of the TOP signal is the same T2 regardless of the size in both the A4 landscape feed and the maximum paper size. Therefore, if the maximum throughput is expressed by the number of prints per minute, the same is obtained for both the maximum size and the minimum size. On the other hand, when the two-page formation mode is used, the TOP signal issuance interval becomes T1 as shown in the figure, and the number of printed sheets per minute is doubled.

If the engine section 103 of this embodiment does not detect TRUE of the PRNT signal from the TOP signal of the previous page within a predetermined time, it lowers the laser scanning and the heating voltage of the fixing unit and shifts to the idling state. Since printing of the first page from the idling state cannot be started until the rotation of the scanner motor for laser scanning (not shown) is completed and the temperature of the fixing unit is raised, the controller unit 104 transmits the PRNT signal as much as possible. Control is performed to maintain the throughput by setting to TRUE within a predetermined time.

FIG. 6 is a timing chart for continuous printing in the two-page forming mode and the one-page forming mode.
In the figure, T3 is PRNT after the TOP signal of a certain page becomes TRUE in the one-page formation mode.
It represents the time during which the throughput can be maintained until the signal becomes TRUE. That is, unless the PRNT signal is set to TRUE within T3 from the immediately preceding TOP signal, the state shifts to the idling state.

In T4, in the two-page formation mode, P is set after the TOP signal of a certain page becomes TRUE.
Until it detects that the RNT signal has become TRUE,
This indicates the time during which throughput can be maintained. In other words, in the two-page formation mode, T
If the PRNT signal is not set to TRUE within four, the state shifts to the idling state. As shown in the figure, in the two-page formation mode, the TOP signal issuance interval is shorter than that in the one-page formation mode, so that the time T4 is shorter than the time T3. That is, the relationship of T4 <T3 holds.

FIG. 7 is a timing chart comparing the time required for printing two pages in the one page formation mode and the two page formation mode. In the figure, T1 and T2 are the periods of the TOP signal in each of the two-page formation mode and the one-page formation mode, as in FIG.
The time required for printing two pages is T5 in the two-page formation mode and T6 in the one-page formation mode based on the initial TOP signal generation time, and the difference between T5 and T6 is represented by T7. That is, T6 = T5 + T7. Also, 1
In the period T2 of the TOP signal in the page formation mode, 2
In the page formation mode, two pages of images are formed, so that T5 = T2.

When pages of the same size are formed on a plurality of transfer drums, the outer circumference of the intermediate transfer drum needs to be at least twice as long as the length of one page in the transport direction.
T1 <= T2 / 2. When the cycle of the TOP signal in the two-page formation mode is set to exactly half the cycle of the TOP signal in the one-page formation mode, T
1 = T2 / 2.

When the same image is formed in the one-page mode, the formation of the second page is completed when the intermediate transfer drum has rotated half a turn after the start of the image formation.
Therefore, T7 = T5 / 2 = T2 / 2 = T1.
For example, if the engine is capable of printing 16 sheets of A4 size per minute in the two-page formation mode, T7 = T1 =
60/16 = 3.75 seconds.

As shown in FIG. 7, since T6 = T5 + T7, when printing an image of two pages, the printing start time in the two-page formation mode is delayed by the time T7 from the printing start time in the one-page formation mode. However, the time when printing is completed is the same time. That is, when T1 = T2 / 2 in the two-page formation mode, the printing start time is set to T with respect to the printing start time in the one-page formation mode.
Even if 7 = T1, the printing is completed at the same time.

When printing one page of data, the total printing time can be shortened as the time to start printing in the one-page formation mode after the image data of the page is generated. On the other hand, when printing two pages of data, the time from generation of the PRNT signal to completion of image formation is shorter by T7 in the two-page formation mode than in the one-page formation mode. Therefore, if the generation of the next page is completed within the time T7 or less from the generation of the first page, printing is performed in the two-page formation mode thereafter, so that the total printing time is shorter than the time for printing two pages in the one-page formation mode. Can be shortened. In the case of using the two-page formation mode, printing of a plurality of pages is a repetition of printing of two pages. As described above, the printing start timing for minimizing the total printing time differs between the data of one page and the data of a plurality of pages.

For this reason, the print control program operating on the external device according to the present embodiment generates print data for each job, and detects the total number of pages and the print data size of each page for each job. If a subsequent page exists and its print data size is equal to or smaller than a predetermined size, that is, if the printer has a data size capable of generating image data within time T7, an instruction of a two-page forming mode is given to the page. I do. To this end, the external device may be informed in advance of the image data generation capability of the printer (for example, the amount of processing data per unit time), or may be informed of the predetermined data size itself.

Further, the controller 104 of the present embodiment
Printing is performed by switching between a one-page formation mode and a two-page formation mode in accordance with a mode instruction specified in page units from an external device. In addition. This instruction can be performed on a job-by-job basis. In this case, for all the pages in the job, the above-mentioned condition, that is, the time required to generate the image data formed as the second page in the two-page formation mode is a predetermined time (in this example, If it is within T7), the print job is instructed to be processed in the two-page formation mode.

By controlling as described above, the printing system according to the present embodiment can be implemented without making the user aware.
Whether printing single page data or printing multiple pages (jobs or documents), it is possible to always provide the maximum printing throughput.

<Configuration of Printer Controller> FIG.
FIG. 2 is a block diagram of a controller unit 104 according to the present embodiment.

In FIG. 3, reference numeral 301 denotes a panel interface unit which receives various settings and instructions from the panel unit 105 through data communication with the panel unit 105. 302 is an external device 10 such as a host computer.
A host interface unit 306 is an input / output unit for signals to / from the printer engine 1. An engine interface unit 306 is an input / output unit for signals to / from the printer engine unit 103. Communication control with the communication unit 105 is performed.
Reference numeral 303 denotes an image data generator which generates bitmap data for actual printing based on control code data sent from the external device 101; 305, an image memory for storing image data; and 309, the entire printer controller 103. CPU 304 controls CPU 309
307 is a ROM for storing control codes of
Is a RAM for temporary storage. An EEPROM 310 is a nonvolatile memory unit. 308 is DM
The A control unit transfers bit map data in the image memory to the engine interface unit 306 according to an instruction from the CPU 309. Reference numeral 311 denotes a system bus having an address bus and a data bus. Panel interface section 301, host interface section 302, image data generation section 303, ROM 304, image memory 30
5. Engine interface unit 306, RAM30
7, DMA control unit 308, CPU 309 and EEPROM
Each of the M310s is connected to the system bus 311 and can access all functional units on the system bus 311.

The control code for controlling the CPU 309 is constituted by an OS that performs time-division control in units of load modules called tasks by a system clock (not shown) and a plurality of load modules (tasks) that operate in units of functions. And

<Image Forming Procedure in Printer> FIG. 9
FIG. 5 is a diagram illustrating a data flow according to the present embodiment. The analysis development task, page operation task, and engine monitoring task in the figure are tasks having the CPU 304 as an entity as described above, and are logically operated in parallel.

FIG. 10 shows the structure of the page table in FIG. The page table 1001 is a table for logically recognizing each page in the CPU 304. The page table 1001 exists as a continuous area in a control information storage area (not shown) of the RAM 307 and is acquired by a page management function unit (not shown). Controlled release. “Page number” in FIG. 10 is an ID for uniquely identifying a page. The “raster pointer” is a head pointer of an area for one page in the image memory 305,
At the time of power-on initialization, a corresponding area (not shown) in the image memory 305 is divided for each page and linked here. The “status flag” is an area for storing a flag indicating the status of the page. As shown in FIG. 10, the “release flag”, the “decompression end flag”, the “print start flag”, and the “discharge end flag”
including. The “page forming mode” takes one of the values of “one page forming mode” and “two page forming mode”. Note that the “two-page formation wait time” is not used in this embodiment.

The data flow of FIG. 9 will be described below.

Print data (control code, PDL, etc.) input from the external device 101 is stored in the host interface unit 302 in a predetermined block unit. When the analysis and development task 901 detects data in the host I / F unit 302, it acquires a page table. Then, the data is analyzed in units of one block, and image formation information (PDL drawing command, character code, etc.) is analyzed by the image data generator 3.
03 (not shown in FIG. 4) or the CPU 30
4 itself develops the image and stores it in the area indicated by the “raster pointer” in the page table.

Control information (such as the number of copies, paper feed selection, etc.) for the printer is stored in a page table. As one of the control information, "page forming mode"
The external device 101 designates “page formation mode” as a PDL command.

After the analysis and development of one page of data is completed, the development end flag is set to TRUE and the data is attached to a page queue having a FIFO structure.

The page operation task 902 simultaneously monitors the status flags of all pages in the page queue and changes the transport procedure according to the status to implement printing.

From the page operation task 902, the engine I /
The page that has been sent to the F-section 306 and for which image formation has been started has its print start flag set. For a page on which printing has been completed by the printer engine unit 103 and the print paper has been discharged, the discharge end flag is set.

The page operation task 902 starts printing for a page whose page formation mode is the two-page formation mode, after waiting for the generation of the subsequent page to be completed.

The page table for which the discharge end flag is set to TRUE is taken out of the page queue and returned to the page management function unit. The engine monitoring task 903 is executed by the printer engine unit 10 via the engine I / F unit 306.
3 and a predetermined period, and when a factor that changes the state of the page occurs, the state flag of the page is updated.

FIG. 11 is a control flowchart of the page operation task 902 characterizing this embodiment.

When the page operation task 902 is started when the power is turned on (step S1), it monitors the page queue at a predetermined cycle. "Expansion end flag = O" in the page queue
N "and" print start flag = OFF ", that is, it is determined whether there is a page N in a state where the generation of the image data has been completed but the printing has not been started yet (step S).
2). When its presence is detected, the next page, page N
+1 and the development end flag are determined (step S
3). If the page N + 1 exists, the printing procedure is executed in the two-page forming mode by combining the pages N and N + 1 (step S4), and the process returns to step S2. In step S4, printing is performed in the two-page forming mode as described with reference to FIGS.

On the other hand, in step S3, page N + 1
Is not completed, it is determined whether the page formation mode of the page N is the “two-page formation mode” (step S5). If so, the process returns to step S3.

If it is determined in step S5 that the page formation mode of page N is "one page formation mode", page N is printed in one page formation mode (step S6), and the process returns to step S2.

FIG. 12 is a control flowchart of the print execution routine.

In the print execution routine, the page formation mode is notified to the engine unit 103 (step S12), and the PRN is executed.
The T signal is set to TRUE (step S13), and the process waits until the TOP signal becomes TRUE (step S1).
4). When the TRUE of the TOP signal is detected, the DMA controller 308 and the engine interface 306 are activated to start the image transfer (step S15). Further, the time at that time is stored as the final print start time (step S16), and the process ends. The engine unit transfers the toner image formed on the photosensitive drum to the intermediate transfer drum,
Further, a TOP signal is generated at an appropriate timing so that it is transferred to a correct position on the conveyed sheet. For this purpose, for example, an optical or mechanical sensor detects that the intermediate transfer drum has reached a predetermined rotational phase, and generates a TOP signal.
Start transfer. As a predetermined rotation phase, one position may be provided for every 360 degrees of rotation of the intermediate transfer drum in the one-page formation mode, and one place for every 180 degrees of rotation of the intermediate transfer drum in the two-page formation mode.

By operating the printer as described above,
When the two-page formation mode is instructed from an external host or the like, printing is executed in the two-page formation mode in accordance with the instruction.

<Control Procedure in External Device> FIG.
FIG. 2 is a block diagram illustrating a configuration of a control system of the external device 101 according to the embodiment.

In FIG. 13, reference numeral 110 denotes the external device 101.
Is a system control unit, 120 is a display unit, 121 is an operation unit, and 122 is a storage unit such as a hard disk.

Reference numeral 119 denotes a system bus, which includes an address bus and a data bus, and connects each unit of the system control unit 110. Hereinafter, devices connected to the system bus 119 will be described.

Reference numeral 111 denotes a DMA controller (DMAC), which controls data block transfer between devices connected to the internal bus. A ROM 112 is used by being logically divided into a program area for storing control codes and the like of the CPU 113 and a font area for storing character font data. A CPU 113 controls each device connected to a system bus. Reference numeral 114 denotes a RAM which is used as a main storage memory of the CPU 113 or a device connected to the system bus 120 as a work area. 115 is an operation control unit (KEYC)
And the operation unit 121 via a predetermined interface.
Receive instructions from. 116 is a printer communication control unit (P
RNC), and transmits and receives data to and from the color laser beam printer 102 according to a predetermined protocol. 117
Is a device control unit (DEVC), and in this embodiment, sends and receives data to and from the storage unit 122 through a predetermined bus interface. A display control unit (PNLC) 118 controls display of the display unit 120 via a predetermined interface.

The CPU 113 is, for example, a ROM 112
RAM 115 based on the font data stored in
The outline font is expanded (rasterized) to the display information area set above, and the PNLC 118 is executed.
WYSIWYG in the display unit 120 via
Is possible.

That is, the CPU 113 can control the display and non-display of various windows and buttons registered in advance.

The CPU 113 can receive an instruction from a key or the like of the operation unit 121 as a command or data via the KEYC 115.

Using these functions, the CPU 113 can change the display on the display unit 120 according to the situation, and can execute various processes in response to an instruction from the operator.

The control code for controlling the CPU 113 includes an OS for performing time-division control in units of load modules called tasks or processes by a system clock (not shown) and a plurality of load modules (tasks) operating in units of functions. Shall be performed. In the present embodiment, control by a task configuration will be described as an example. However, as long as the functions of the present invention can be executed, the present invention can be applied to other control methods of the CPU.

The configuration of the external device of this embodiment is an example,
The present invention can be applied to a device capable of recognizing the total number of pages and the data amount of print data, for example, a computer such as a general personal computer.

FIG. 14 is a data flow diagram for explaining the operation of the control software according to the present embodiment that operates on the external device 101. As described above, each software operates as a process on the operation system.

In FIG. 14, the application software is a generalization of a word processor, a spreadsheet, a graphic drawing program, and the like. Page description data 1 is
A page description language distributed as a print data expression format in the external device 101 is shown. The page description data 2 is
A page description language, which is distributed as a print data expression format in the controller unit 104, is assumed to be a data format including the layout information. The layout data indicates additional print information such as the number of copies. The panel window represents a logical panel that is graphically displayed on the display unit 120 and can be operated with a mouse, a keyboard, or the like of the operation unit 121. The spool area is an area configured in a file system provided by the operation system, and is physically stored in the RAM 114 or the storage unit 122.

The control software includes a data converter and a print controller 1
41. The data conversion unit receives the page description data 1 and the layout information from the application software, further receives the layout data from the panel window, and stores it in the spool area while converting the data in job units and page units as necessary. Print control unit 141
Monitors the spool area and confirms the job and the page, and sends the print data to the printing apparatus 102 via the PRNC 116 not shown in FIG.

FIG. 15 is a diagram simply illustrating the job management table (job table) and page management table (page table) stored in the spool area.
(A) shows a table when the page formation mode is specified for each page, and (B) shows a table when the page formation mode is specified for each job.

In FIG. 15A, the job management table 151a has “data size” indicating the table size, “total number of pages” belonging to the job, and a pointer “page management table 152a of the first page belonging to the job”. First page table "is stored.

In the page management table 152a, "data size" indicating the size of print data of a page, a pointer "next page table" to the page management table of the next page, one page formation mode or two page formation mode are designated. The “formation mode” is stored.

On the other hand, in FIG. 15B, the formation mode is
It is included in the job management table 151b instead of the page management table 152b.

FIG. 16 is a control flowchart of the print control unit 141 which characterizes this embodiment.

The print controller 141 determines whether there is a page N in the spool (step S31), and when the page N is confirmed, determines whether the next page N + 1 exists (step S32). If it exists, it is determined whether the data size of the page N + 1 is equal to or smaller than a predetermined size (TSIZE) (step S33). The data is transmitted (step S35), and the process returns to step S31.

On the other hand, if it is determined in step S32 that the next page N + 1 does not exist, or if it is determined in step S33 that the data size of page N + 1 is equal to or larger than TSIZE, one page formation mode is designated for page N. To send data to the printing device (step S35),
It returns to step S31.

The value of TSIZE in step S33 is determined by the time required to expand the print data of the size TSIZE by the printer, the time T7 in FIG.
It is decided to be. As a result, printing in the two-page formation mode is limited to the case where printing is completed earlier than printing in the one-page printing mode.

By controlling as described above, whether or not printing can be performed in the two-page forming mode by the external device, and if possible, image forming can be completed earlier in the one-page forming mode or the two-page forming mode. The image forming mode is instructed to the printing apparatus according to the determination result. The printing device executes printing in the image forming mode according to the instruction. Therefore, print output can be completed earlier. This makes it possible to maximize the throughput of an electrophotographic printing apparatus that forms a plurality of pages of toner images before transferring the toner images to paper.

Further, it is possible to always provide the maximum print throughput regardless of whether the user prints single page data or prints a plurality of pages (job or document) without the user's awareness.

The present invention includes a case where the page formation mode is changed according to only the total number of pages of the print data or only the data amount.

If print data can be stored in a storage unit such as a hard disk in the printing apparatus or a memory in units of jobs and the total number of prints can be determined, the same function as that of the present invention can be applied to the printing apparatus stand-alone. Can be realized.

The configuration of the printer according to the present invention is effective in an electrophotographic printing apparatus for forming a plurality of pages of toner images before transferring the toner images to paper. Therefore, it is effective for a mono-color laser beam printer as long as the image forming apparatus is of the above-described type.

[Second Embodiment] As a second embodiment, before printing of page data to be printed first from the engine idling state (hereinafter referred to as "first print"), generation of a succeeding page is predetermined. A printer that performs time weighting (hereinafter referred to as “two-page forming weight”) will be described. The configuration of this printer is the same as that of the device of the first embodiment, but the control procedure by the controller is different from that of the first embodiment. In the first embodiment, the controller unit of the printer executes the two-page formation wait at the time of the first print, thereby executing printing in the two-page formation mode, thereby reducing the total printing time of the two pages.

The data flow in this embodiment is the same as that shown in FIG. 9 as in the first embodiment, except that “two page formation wait time” is included as an entry in the page table and “page formation mode”. It differs from the first embodiment in that the contents are different. That is, in the present embodiment, the wait time set from the external device or the operation panel of the printer is set to the “2 page formation wait time” in FIG.
Set by 1. The “two-page formation wait time” stores a designated time in seconds. The “two page formation wait time” is specified and set as a PDL command from the external device 101, for example.

As the “page formation mode”, “1”
There are “page forming mode”, “first page of two-page forming mode”, and “second page of two-page forming mode”.

The flow of FIG. 9 in the present embodiment is as follows.

Print data (control code, PDL, etc.) input from the external device 101 is stored in the host interface unit 302 in a predetermined block unit. When the analysis and development task 901 detects data in the host I / F unit 302, it acquires a page table. Then, the data is analyzed in units of one block, and image formation information (PDL drawing command, character code, etc.) is analyzed by the image data generator 3.
03 (not shown in FIG. 4) or the CPU 30
4 itself develops the image and stores it in the area indicated by the “raster pointer” in the page table.

Control information (such as the number of copies, paper feed selection, etc.) for the printer is stored in a page table. One of the control information is “two-page formation wait time”, and the external device 101 specifies “two-page formation wait time” as a PDL command.

After the data of one page has been analyzed and developed, the development end flag is set to TRUE and the data is attached to a page queue having a FIFO structure.

The page operation task 902 simultaneously monitors the status flags of all pages in the page queue and changes the transport procedure according to the status to realize printing. On this occasion,
When the page operation task confirms the presence of only one page in the page queue, the subsequent page formation waits for the “two page formation wait time”.

The page operation task 902 sends the engine I /
The page that has been sent to the F-section 306 and for which image formation has been started has its print start flag set. For a page on which printing has been completed by the printer engine unit 103 and the print paper has been discharged, the discharge end flag is set.

The page table whose discharge end flag is TRUE is taken out of the page queue and returned to the page management function unit. The engine monitoring task 903 is executed by the printer engine unit 10 via the engine I / F unit 306.
3 and a predetermined period, and when a factor that changes the state of the page occurs, the state flag of the page is updated.

FIG. 19 is a control flowchart of the page operation task 902 characterizing this embodiment.

When activated at power-on (step S1), the page operation task 902 monitors the page queue at a predetermined cycle. "Expansion end flag = O" in the page queue
N "and" print start flag = OFF ", that is, it is determined whether there is a page N in a state where the generation of the image data has been completed but the printing has not been started yet (step S).
2). When its presence is detected, the next page, page N
+1 and the development end flag are determined (step S
3). If the page N + 1 exists, the printing procedure is executed in the two-page forming mode by combining the pages N and N + 1 (step S4), and the process returns to step S2. In step S4, printing is performed in the two-page forming mode as described with reference to FIGS.

On the other hand, in step S3, page N + 1
Is not completed, it is determined whether a page other than the page N exists in the page queue (step S).
7). If it does not exist, it is determined that it is the first print, and if it exists, it is determined that it is not the first print. If it is determined in step S7 that page N is not the first print, a print routine is executed to print page N in the one-page formation mode (step S6), and the process returns to step S2. With this loop, the continuous printing state of the engine unit 103 is maintained.

If there is no page other than page N in the page queue, page N is determined to be the first print by engine unit 103. in this case,
"2 page formation wait time designation" in the page table
, It is determined whether or not the designated wait time has elapsed (step S8).
A print routine is executed so as to print in the page formation mode (step S6), and the process returns to step S2. If the designated wait time has not elapsed, the process returns to step S3.

As described above, if the development of the page N + 1 is completed within the wait time designated at the time of the first print, printing is performed in the two-page formation mode, and under other conditions, printing is performed in the one-page formation mode.

FIG. 20 is a control flowchart of the wait time elapse processing in step S6 in FIG. In the figure, WFLG, NOWT, WAITT, UPT are RAM
307 is a value stored in a predetermined area.

WFLG is a flag indicating whether or not the next page (the (N + 1) th page) is in a wait state, and if ON, indicates that the apparatus is in a wait state. NOWT indicates the current time, WAITT indicates "two page formation wait time designation" set in the page table, and UPT indicates the time-up time of the wait.

In FIG. 20, the current time is read from the timer or the like into the NOWT (step S20). Next, WFL
G is tested (step S21), and if it is OFF, an initial setting for measuring the elapse of a predetermined time is performed. For this purpose, first, the specified wait time WAITT is added to the read current time NOWT and the time is set to the time-up time UPT (step S22). Further, the flag W
FLG is set to ON (step S23), and "NO"
Is returned as a return value (step S24).

On the other hand, in step S21, the flag WF
If LG is ON, since the measurement of the elapse of the wait time has already been started, the current time NOWT is compared with the time-up time UPT (step S25). If the current time has not passed the time-up time, the process ends with “NO” as a return value (step S24). NOWT is U
If PT has elapsed, it is determined that the wait time has expired, and "YES" is returned as the return value, and the process ends (step S2).
6).

Note that the print execution routine is the same as that of the first embodiment shown in FIG. 12, and a description thereof will be omitted.

By configuring and controlling the printer in this manner, it is possible to maximize the throughput of an electrophotographic printing apparatus that forms a plurality of pages of toner images before transferring the toner images onto paper. .

Further, whether printing single page data or printing multiple pages (jobs or documents), it is possible to provide the maximum printing throughput in accordance with the operation of the user.

Further, by allowing the operator to set the time for the two-page formation wait, the operator can determine the wait time so as to minimize the average time required for printing two pages.

By controlling as described above, the color laser printer 102 of the present embodiment adjusts the balance between the printing time of single page data and the printing time of a plurality of pages (called a job) according to the operator's request. It can be set.

In this embodiment, the storage location of “designation of wait time for two pages” may be anywhere. That is, “designation of wait time for two pages” is stored in the RAM 307,
For example, by storing in accordance with the designation from the operation panel of the printer or the like and referring to the area in step S22 of FIG. 20, "designation of two-page formation wait time" is designated as the printer state or set value. It is possible to do.

When a plurality of pages are handled as one job (or document), "designation of wait time for forming two pages" is stored in the job table, and FIG.
By referring to the area in S22, it is possible to specify "two-page formation wait time designation" as a set value for each job or each document.

"2 page formation wait time designation"
May be specified in any manner. In other words, here, the description has been made as a specification in the job control language
Even in the case of designation by the panel unit 105, the page operation task can perform the same operation by storing it in the area corresponding to the above-mentioned "designation of two page formation wait time".

[Third Embodiment] In the second embodiment,
In the case of the first print, the generation of the image data for two pages is always waited for the designated wait time. However, if there is no data for the second page, this waiting merely delays the printout and is meaningless. Therefore, the printer of the third embodiment is
Even if it is the first print, the generation of the image for two pages is not waited for unconditionally, but only for the data of the following page.

FIG. 21 is a diagram showing a data flow at the time of image formation in this embodiment. First embodiment and second embodiment
Compared with FIG. 9 showing the data flow in the embodiment, the page operation task 902 differs from the host interface unit 302 and the analysis development task 901 in that the presence / absence of data is introduced. The other points are the same as those of the first and second embodiments.

That is, when the page operation task 901 confirms that there is only one page in the page queue, that is, determines that the print is the first print, the host interface unit 302 receives print data from the external device 101. Inquire if it is. Further, it inquires of the analysis and development task 901 whether image data of a subsequent page is being formed. In either case, the subsequent page formation is waited for the “two page formation wait time” specified in the page table.

FIG. 22 is a control flowchart of the page operation task 902 characterizing this embodiment.

When activated at power-on (step S1), the page operation task 902 monitors the page queue at a predetermined cycle. "Expansion end flag = O" in the page queue
N ”and“ print start flag = OFF ”, that is, it is determined whether there is a page N in a state where the generation of image data has been completed but printing has not been started yet (step S).
2). When its presence is detected, the next page, page N
+1 and the development end flag are determined (step S
3). If the page N + 1 exists, the printing procedure is executed in the two-page forming mode by combining the pages N and N + 1 (step S4), and the process returns to step S2. In step S4, printing is performed in the two-page forming mode as described with reference to FIGS.

On the other hand, in step S3, page N + 1
Is not completed, it is determined whether a page other than the page N exists in the page queue (step S).
7). If it does not exist, it is determined that it is the first print, and if it exists, it is determined that it is not the first print. If it is determined in step S7 that page N is not the first print, a print routine is executed to print page N in the one-page formation mode (step S6), and the process returns to step S2. With this loop, the continuous printing state of the engine unit 103 is maintained.

If there is no page other than page N in the page queue, page N is determined to be the first print by engine unit 103. in this case,
It is determined whether print data from the external device 101 has been received by the host interface unit 301 or whether a subsequent page is being formed by the analysis and development task 901 (step S9). If any, it is determined whether or not the designated wait time has elapsed by referring to “designation of wait time for two pages” in the page table (step S8). A printing routine is executed so as to perform printing in the formation mode (step S6), and the process returns to step S2. If the designated wait time has not elapsed, the process returns to step S3.

As described above, if the development of the page N + 1 is completed within the wait time designated at the time of the first print, printing is performed in the two-page formation mode, and under other conditions, printing is performed in the one-page formation mode.

By configuring and controlling in this manner, the delay in image formation due to waiting for the generation of image data for two pages despite the fact that only one page of data is prepared at the time of first printing is achieved. , Second
The disadvantages in the embodiment can be improved.

Therefore, it is possible to maximize the throughput of an electrophotographic printing apparatus that forms a plurality of pages of toner images before transferring the toner images to paper.

Further, whether printing single page data or printing multiple pages (jobs or documents), it is possible to provide the maximum printing throughput according to the operation of the user.

[0133]

[Other Embodiments] The present invention can be applied to a system composed of a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), and can be applied to a single device (for example, a copying machine). Machine, facsimile machine, etc.).

The object of the present invention is to realize the functions of the above-described embodiment by using FIGS. 11 and 12, FIGS. 19 and 20, and FIGS.
A storage medium (or recording medium) storing the program code of FIG. 0 and FIG. 12 or FIG. It is also achieved by reading and executing code. In this case, the program code itself read from the storage medium implements the functions of the above-described embodiment, and the storage medium storing the program code constitutes the present invention. By executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but also an operating system (OS) running on the computer based on the instructions of the program code. This also includes a case where some or all of the actual processing is performed and the functions of the above-described embodiments are realized by the processing.

Further, after the program code read from the storage medium is written into the memory provided in the function expansion card inserted into the computer or the function expansion unit connected to the computer, the program code is read based on the instruction of the program code. , The CPU provided in the function expansion card or the function expansion unit performs part or all of the actual processing,
The case where the function of the above-described embodiment is realized by the processing is also included.

[0136]

According to the above arrangement, it is possible to obtain the maximum printing efficiency when an image is formed by transferring a plurality of pages to an intermediate transfer member. For this reason, it is possible to achieve both print quality and printing efficiency of the intermediate transfer method.

Further, when page data to be printed first from the engine idling state, that is, when a plurality of pages can be formed within a predetermined time at the time of first printing, images for a plurality of pages are formed on the intermediate transfer member. By transferring it to a print medium, the printing process can be made more efficient.

Further, when data of a plurality of pages is not prepared, an image is printed without waiting for a plurality of pages to be formed within a predetermined time. As a result, wasteful waiting time can be eliminated and more efficient printing can be realized.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an overall configuration of a system including a printer to which the present invention is applied.

FIG. 2 is a diagram illustrating a configuration of a printer engine to which the present invention is applied.

FIG. 3 is a diagram illustrating an interface between a printer engine and a controller to which the present invention is applied;

FIG. 4 is a diagram for explaining an interface between a printer engine and a controller to which the present invention is applied;

FIG. 5 is a diagram for explaining an interface between a printer engine and a controller to which the present invention is applied;

FIG. 6 is a diagram for explaining an interface between a controller and an engine of a printer to which the present invention is applied;

FIG. 7 is a diagram for explaining an interface between a printer engine and a controller to which the present invention is applied;

FIG. 8 is a block diagram illustrating an electrical configuration of a printer controller to which the present invention is applied.

FIG. 9 is a diagram for explaining a data flow and a control flow in the embodiment.

FIG. 10 is a diagram illustrating a logical map configuration of a memory according to the embodiment.

FIG. 11 is a diagram illustrating an operation of a CPU 309 according to the first embodiment.

FIG. 12 is a diagram for explaining an operation of a CPU 309 in the first to third embodiments.

FIG. 13 is a block diagram illustrating an electrical configuration of an external device according to the embodiment.

FIG. 14 is a diagram for explaining a data flow and a control flow in the first and second embodiments.

FIG. 15 is a diagram for explaining a logical map configuration of a memory in the embodiment.

FIG. 16 is a diagram for explaining the operation of the CPU 113 in the embodiment.

FIG. 17 is a diagram for explaining a conventional example.

FIG. 18 is a diagram for explaining a problem of a conventional example.

FIG. 19 is a diagram for explaining an operation of a CPU 309 according to the second embodiment.

FIG. 20 is a diagram for explaining the operation of a CPU 309 in the second and third embodiments.

FIG. 21 is a diagram for explaining a data flow and a control flow in the third embodiment.

FIG. 22 is a diagram for explaining an operation of a CPU 309 according to the third embodiment.

Claims (18)

[Claims] An image forming unit configured to form an image of a plurality of pages in an image forming area; a first image forming mode for forming an image in the image forming area one page at a time; A mode selection unit for selecting any one of a second image formation mode for performing image formation by a plurality of pages, and a control for controlling the image formation unit to form an image in the image formation mode selected by the mode selection unit And an image forming apparatus. 2. The image forming apparatus according to claim 1, wherein the mode selection unit selects an image forming mode on a page basis. 3. The image forming apparatus according to claim 1, wherein the mode selecting unit selects an image forming mode for each print job.
An image forming apparatus according to claim 1. 4. The image forming apparatus according to claim 1, wherein said mode selecting means selects an image forming mode in accordance with control data transmitted together with print data from an external device. 5. The image processing apparatus according to claim 1, wherein the mode selection unit is configured to, after the image data of the N-th page is prepared and the image data of the N-th page is not prepared, be prepared after the image data of the N-th page is prepared. When the image data of the (N + 1) th page can be prepared within a predetermined time, the second image forming mode is selected, and the control means performs the image formation in the image forming area on the (N) th page and the (N + 1) th page, respectively. The image forming apparatus according to claim 1, wherein the image forming unit is controlled to perform the image forming operation every two pages. 6. The mode selection unit according to claim 1, wherein the image data of the Nth page is prepared, and even if image data other than the Nth page is not prepared, if there is no subsequent print data, the predetermined time elapses. The image forming apparatus according to claim 5, wherein the first image forming mode is selected without waiting. 7. The image forming apparatus according to claim 1, wherein the image forming unit forms a color image in which images of a plurality of element colors are superimposed on the intermediate transfer body that is the image forming area. . 8. A first image formation mode in which image formation in an image formation area is performed one page at a time in accordance with designation, and a second image formation in which image formation in the image formation area is performed by a plurality of pages each An image forming control apparatus for performing printing by an image forming apparatus that forms an image in any one of modes, wherein the print data to be printed by the image forming apparatus has at least two pages, and the amount of the print data is Determining means for determining whether the size is within a predetermined size; if the result of the determination by the determining means is true, the second image forming mode is designated to pass print data to the image forming apparatus; An image forming control apparatus, comprising: a mode specifying unit that specifies a first image forming mode and transfers print data to the image forming apparatus. 9. An image forming system including an image forming apparatus and a host apparatus for performing printing using the image forming apparatus, wherein the host apparatus has at least two pages of print data to be printed by the image forming apparatus. Determining means for determining whether the amount of print data is within a predetermined size; and, if the determination result by the determination means is true, specifying the second image forming mode and forming the print data in the image forming mode. A mode designating unit for passing the print data to the image forming apparatus by designating the first image forming mode, and forming the image on the plurality of pages in the image forming area. Possible image forming means, a first image forming mode in which image formation in the image forming area is performed one page each, and an image forming mode in the image forming area. Mode selection means for selecting any of the second image formation modes for performing page by page, and control means for controlling the image formation means to form an image in the image formation mode selected by the mode selection means. An image forming system comprising: 10. A method for controlling an image forming apparatus having an image forming means for forming an image on an intermediate transfer member and transferring the image to a print medium to form an image, comprising: And a second image forming mode in which the image transfer to the intermediate transfer body and the transfer to the print medium are performed by a plurality of pages, respectively. A control method for an image forming apparatus, comprising: a mode selection step of selecting; and a control step of controlling the image forming unit so as to form an image in the image formation mode selected by the mode selection step. 11. The method according to claim 10, wherein in the mode selecting step, an image forming mode is selected for each page.
3. The method for controlling an image forming apparatus according to claim 1. 12. The method according to claim 10, wherein the mode selecting step selects an image forming mode for each print job. 13. The method according to claim 10, wherein said mode selecting step selects an image forming mode in accordance with control data transmitted together with print data from an external device. 14. The method according to claim 1, wherein in the mode selecting step, when the image data of the Nth page is prepared and no image data other than the Nth page is prepared, the image data of the Nth page is prepared. When the image data of the (N + 1) th page can be prepared within a predetermined time, the second image forming mode is selected, and the control step performs the image forming on the intermediate transfer body and the transfer on the print medium in the Nth page, respectively. Page and N +
The method according to claim 10, wherein the image forming unit is controlled so as to perform two pages per page. 15. The method according to claim 1, wherein, even if image data of the N-th page is prepared and image data other than the N-th page is not prepared, a predetermined time elapses if there is no subsequent print data. The method according to claim 14, wherein the first image forming mode is selected without waiting. 16. A first image forming mode in which image formation on an intermediate transfer body and transfer to a print medium are performed one page at a time in accordance with designation, and image formation on the intermediate transfer body and transfer to a print medium. The second to transfer multiple pages each
A method of controlling an image forming apparatus that performs printing by an image forming apparatus that forms an image in any one of the image forming modes, wherein the print data printed by the image forming apparatus has at least two pages, and A determination step of determining whether the amount of print data is within a predetermined size, and if the result of the determination in the determination step is true, pass the print data to the image forming apparatus by specifying the second image forming mode; Otherwise, there is provided a mode designating step of designating the first image forming mode and passing print data to the image forming apparatus. 17. A storage medium for storing a computer program for controlling an image forming apparatus that forms an image on an intermediate transfer body and transfers the image to a print medium to form an image, the computer comprising: A first image forming mode in which image formation on the intermediate transfer body and transfer to the print medium are performed one page each, and a second image formation mode in which image formation on the intermediate transfer body and transfer to the print medium are performed a plurality of pages each. A computer program for realizing mode selection means for selecting one of the image forming modes and control means for controlling the image forming means to form an image in the image formation mode selected by the mode selection means is stored. Computer readable storage medium. 18. A first image forming mode in which image formation on an intermediate transfer body and transfer to a print medium are performed one page at a time in accordance with designation, image formation on the intermediate transfer body, and transfer to a print medium. The second to transfer a plurality of pages each
A storage medium storing a computer program for causing an image forming apparatus that forms an image in any one of the image forming modes to perform printing, wherein at least two pages of print data to be printed by the image forming apparatus by the computer are provided. Determining means for determining whether or not the print data amount is within a predetermined size, and if the result of the determination by the determining means is true, the second image forming mode is designated and the print data is A computer-readable storage medium storing a computer program for realizing a mode designating unit for passing the print data to the image forming apparatus by passing the print data to the image forming apparatus and otherwise designating the first image forming mode.