JP2009012477A - Image formation device, image formation method, and memory medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform band developing process to always become timing enabling to continuously form an image, even if in a band in which the developing process time is not in time for an image forming process is included in any band, and to form the image in high through-put. <P>SOLUTION: A CPU 309 analyzes print data received by a host interface unit 302 to optimize a band developing schedule based on the developing process time previously predicted in the case of forming an image formed based on image data generated at a band unit on a recording medium through an intermediate transfer element. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image forming apparatus, an image forming method, and a storage medium. More specifically, the present invention relates to an image forming apparatus, an image forming method, and a storage medium suitable for preventing color misregistration in a printer such as a color laser beam printer. .

  In recent years, page printers such as laser beam printers have been rapidly developed. Recently, many page printers capable of outputting color images have been proposed and commercialized. A color laser beam printer forms a full-color image by superimposing four colors of toner (Y: yellow, M: magenta, C: cyan, K: black) by a known electrophotographic process. Proposed.

  Among them, for example, as shown in FIG. 23, a latent image on a photosensitive drum is formed into a toner image, the toner image is once transferred to an intermediate transfer member, and four color toner images are superimposed on the intermediate transfer member. The intermediate transfer method, in which toner images for four colors are transferred onto a sheet at a time and fixed to form an image, has an intermediate transfer member that is physically fixed. It has the advantage of easily preventing color misregistration of the four colors.

  In addition, the toner image can be transferred to the paper only once, so that the paper path can be made straight and can be easily transferred to a medium difficult to be attached to the transfer drum such as OHP or cardboard. I have.

  24A and 24B are diagrams showing the relationship between the intermediate transfer member and the paper size in the image processing apparatus shown in FIG. 23. FIG. 24A corresponds to the case where an image is formed on the entire surface of the intermediate transfer member, and FIG. This corresponds to the case where an image is formed on a part of the intermediate transfer member.

  As shown in FIGS. 24A and 24B, in the intermediate transfer type image forming method, an intermediate transfer body having a corresponding maximum sheet size is necessary, and when image formation is performed in units of one page. However, there is a problem that the maximum number of printed sheets per minute cannot be made larger than the maximum sheet size for any size of printing.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus, an image forming method, and a storage medium that can maximize the printing throughput of an intermediate transfer method.

  To achieve the above object, according to the present invention, an image forming unit capable of forming an image of a plurality of pages based on print data received from an external device in an image forming area, and an intermediate based on the print data. Prediction means for calculating, for each page, prediction information for predicting development processing time for developing data into a bitmap image, and band development processing time based on the prediction information calculated by the prediction means. After completing the development of the band not in time for the image forming process speed in the first forming mode for outputting a signal for requesting image formation, and after outputting the signal for requesting image formation, the processing time of the band development is Image formation is performed by switching to the second formation mode in which development of a band that does not meet the image forming process speed in the forming unit is started. And having a control means.

  As described above, according to the invention of the present invention, the image forming unit capable of forming a plurality of pages of images based on the print data received from the external device in the image forming area, and the intermediate data based on the print data. Predicting means for calculating prediction information for predicting the development processing time for developing into a bitmap image for each page, and forming one page image on the image forming means based on the prediction information calculated by the predicting means And a first control unit that causes the image forming unit to switch between a second forming mode for forming an image of a plurality of pages and to perform image formation. From the processing time, the image forming unit forms an image for two pages at a time, or forms an image for each page, and the image forming page matches the complexity of the print data. And dynamically changing the di- number, it is possible to greatly improve the total throughput.

  Further, according to the present invention, the control means can perform the first forming mode or the second forming mode depending on whether the image forming mode at the switching timing is the first forming mode or the second forming mode. Since the image formation mode is switched to the image formation mode, an image formation mode suitable for the image formation mode of the preceding page is selected, and an appropriate image formation mode is easily selected.

  In addition, according to the present invention, the image forming apparatus further includes a storage unit capable of storing the intermediate data obtained by analyzing the print data received from the external apparatus for a plurality of pages, and the control unit continuously forms an image. When intermediate data of at least two pages or more capable of being stored is stored in the storage means, the second forming mode is switched, so that the print throughput can be improved without waste.

  Further, according to the present invention, the determination unit that determines whether or not the expansion processing time of each band of each page predicted by the prediction unit exceeds a continuous image formation interval for the image forming unit, and the determination by the determination unit Based on the result, a first start mode for starting image formation after starting development of a band whose development processing time for the band is not in time for the image forming process speed set in the image forming means, and image formation is started. And a second control unit that switches between a second start mode for starting development of each band, and when the development processing time of each band does not exceed the continuous image formation interval for the image forming unit. The image formation in the first start mode that can maintain the continuous image formation can be continued, and the image formation can be performed with the highest throughput.

  Further, according to the present invention, the continuous image formation interval is a time from the transfer start timing of image data of a page formed according to the immediately preceding image formation mode to the start of image formation. It is possible to appropriately determine whether the image formation timing is in time.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[1] First Embodiment FIG. 2 is a block diagram showing an overall configuration of a system including a color laser beam printer according to a first embodiment of the present invention. The system including the color laser beam printer according to the first embodiment of the present invention is roughly composed of an external device 101 and a color laser beam printer 102. Further, the color laser beam printer 102 includes an engine unit 103, a controller unit 104, and a panel unit 105.

  The configuration of each of the above parts will be described in detail. The external device 101 is configured as, for example, a host computer or the like, and provides code data, image data (R (red), G (green), B (blue) to the color laser beam printer 102. ), Y (yellow), M (magenta), C (cyan), Bk (black)). The engine unit 103 of the color laser beam printer 102 superimposes four colors Y, M, C, and Bk on the sheet by actually forming a latent image on the photosensitive drum for each dot data of each color Y, M, C, and Bk. Printing is performed by aligning and heat fixing.

  The controller unit 104 of the color laser beam printer 102 is connected to the engine unit 103, receives code data and image data (RGB, YMCBk) sent from the external device 101, and based on these data, Y, M, C , Bk generate page information composed of dot data of each color, and sequentially transmit the dot data to the engine unit 103. The panel unit 105 of the color laser beam printer 102 is used when a predetermined operation is designated to the color laser beam printer 102 by an operator (user) operating it.

  The controller unit 104 and the engine unit 103 in the color laser beam printer 102 are connected by a predetermined video interface, and information exchange is performed by, for example, 8-bit unit command / status serial communication.

  FIG. 3 is a configuration diagram showing the configuration of the engine unit 103 of the color laser beam printer 102 according to the first embodiment of the present invention. The engine unit 103 of the color laser beam printer 102 according to the first embodiment of the present invention includes a paper cassette 202, a cassette paper feed clutch 203, a paper feed roller 204, an intermediate transfer drum 205, a drum cartridge 208, a photosensitive drum 209, Black (Bk) toner developing unit 210, yellow (Y) toner developing unit 211, magenta (M) toner developing unit 212, cyan (C) toner developing unit 213, YMC developing unit support 214, fixing heater 215, scanner unit 216 Reverse refeed unit 234 having a secondary transfer roller 231, fixing rollers 217 and 232, transport rollers 218 and 219, a paper discharge tray 220, a manual paper feed clutch 221, a paper feed table 222, and transport rollers 223, 224 and 233. It is the composition provided with.

  The configuration of each unit will be described in detail together with the operation. The paper cassette 202 holds a paper 201 as a recording medium. The cassette paper feed clutch 203 separates only the uppermost sheet 201 of the paper 201 placed on the paper cassette 202, and the position of the paper feed roller 204 is driven by a driving means (not shown) at the leading end of the separated paper. The cam is conveyed intermittently to rotate each time paper is fed, and one sheet is fed corresponding to one rotation. When a sheet is conveyed by the cassette sheet feeding clutch 203, the sheet feeding roller 204 rotates while lightly pressing the sheet 201 and conveys the sheet 201. The paper feed tray 222 and the manual paper feed clutch 221 enable not only paper feed from the paper cassette 202 but also manual paper feed from the paper feed tray 222 one by one.

  The photosensitive drum 209 mounted on the drum cartridge 208 forms a latent image on the drum surface and is developed. The black toner developing unit 210, the yellow toner developing unit 211, the magenta toner developing unit 212, and the cyan toner developing unit 213 are supported by the YMC developing unit supporting unit 214, and each perform development of the corresponding color. The YMC developing device support section 214 rotates and conveys a developing device for a desired color toner to a position where it can be developed on the photosensitive drum 209. A laser driver (not shown) provided in the scanner unit 216 forms an image on the photosensitive drum 209 while turning on / off the semiconductor laser (not shown) in accordance with the dot data sent from the controller unit 104 in FIG. Then, scanning in the main scanning direction forms a latent image on the main scanning line.

  The intermediate transfer drum 205 rotates at a predetermined speed during printing, and the toner image formed on the photosensitive drum 209 is transferred. The latent image on the photosensitive drum 209 is visualized as a toner image by the black toner developing device 210, the yellow toner developing device 211, the magenta toner developing device 212, and the cyan toner developing device 213 in parallel with the formation, and further rotated in parallel. Is transferred to the intermediate transfer drum 205, and a toner image of one page size is formed on the intermediate transfer drum 205. In the mono-color mode, a one-page toner image (hereinafter referred to as a plane) for one color is formed on the intermediate transfer drum 205. In the full color mode, the intermediate transfer drum 205 is formed by superimposing four planes of a black toner developing unit 210, a yellow toner developing unit 211, a magenta toner developing unit 212, and a cyan toner developing unit 213.

  The secondary transfer roller 231 is charged in a state where the sheet 201 enters between the intermediate transfer drum 205 and the secondary transfer roller 231, and transfers the toner image on the intermediate transfer drum 205 onto the intermediate sheet 201 ( Secondary transfer). The fixing heater 215 and the fixing rollers 232 and 232 ′ heat and fix the toner image on the paper 201. Upon receiving the secondary transfer, the sheet 201 is further conveyed, the toner image is heated and fixed by the fixing rollers 217 and 217 ′, and is discharged onto the sheet discharge tray 220 through the conveyance rollers 218 and 219.

  In the color laser beam printer 102 of this embodiment, the latent image formation and transfer processes are performed in the order of yellow, magenta, cyan, and black. The yellow toner developing unit 211, the magenta toner developing unit 212, the cyan toner developing unit 213, and the black toner developing unit 210 described above are each a cassette type casing, and can be detached from the main body. Therefore, hereinafter, 211 is referred to as a Y cartridge, 212 as an M cartridge, 213 as a C cartridge, and 210 as a K cartridge.

  The engine unit 103 in FIG. 2 can select the paper discharge tray 220 and the reverse refeed unit 234 as the transport destination of the sheet 201 after the fixing. This designation is designated from the controller unit 104 through the serial communication. When the paper 201 enters the reverse refeed unit 234, the paper 201 is once transported in the direction of the transport roller 233. When the sensor (not shown) detects the trailing edge of the sheet, the engine unit 103 reverses the rotation of the conveying roller 233 and conveys the sheet 201 to the conveying rollers 223 and 224. If a double-sided paper refeeding unit is designated as the paper feed port, the paper is re-fed to the transport roller 204 with the paper surface reversed, so that double-sided printing is possible through the above printing process.

  As described above, the engine unit 103 of the color laser beam printer 102 according to the present embodiment realizes full-color printing and mono-color printing by forming a toner image for one page on the intermediate transfer drum 205. Therefore, the outer peripheral length of the intermediate transfer drum 205 is longer than the long side of the maximum printable paper size. For this reason, in order to improve the printing throughput by reducing the sheet conveyance interval, a toner image of two pages is formed on the intermediate transfer drum 205 on a sheet having a sheet length equal to or less than half the maximum sheet length. It has a mode for continuously printing two pages by continuously feeding paper.

  Hereinafter, the above-described continuous printing for two pages is referred to as a two-page forming mode, and normal printing is referred to as a one-page forming mode (or normal printing mode). In the present embodiment, the maximum paper size is, for example, twice or more the A4 size horizontal feed, and continuous printing for the two pages is possible during A4 horizontal feed.

  4 and 5 are diagrams showing a printing protocol between the engine unit 103 and the controller unit 104 of the color laser beam printer 102 according to the first embodiment of the present invention, using a timing chart of interface signals. In the figure, PRNT is a signal that the controller unit 104 requests to start printing, TOP is a timing signal that the engine unit 103 requests image data (video signal) from the controller unit 104, VDO is image data, and a clock signal One page is sent from the controller unit 104 in synchronization with (not shown).

  When the engine unit 103 detects TRUE of the PRNT signal, the engine unit 103 starts a printing operation and sets the TOP signal to TRUE for the controller unit 104 for a predetermined period. When the controller unit 104 detects TRUE of the TOP signal, the controller unit 104 transmits a VDO signal for one page in synchronization therewith. The engine unit 103 forms an image according to the VDO signal.

  FIG. 4 shows a timing chart of the mono color mode. The engine unit 103 issues one TOP signal for the PRNT signal of the controller unit 104 in the one-page formation mode, and two times for the PRNT signal of the controller unit 104 in the two-page formation mode. Issue. The controller unit 104 sets the PRNT signal to TRUE after printing preparation for two pages is completed, and synchronizes the first page image data with the next TOP signal in synchronization with the first TOP signal from the engine unit 103. The image data of the second page is sent out.

  FIG. 5 shows a timing chart of the full color mode. The engine unit 103 issues a TOP signal for four colors of yellow, magenta, cyan, and black to the PRNT signal of the controller unit 104 in the one-page forming mode, and the PRNT signal of the controller unit 104 in the two-page forming mode. In response to this, a total of eight TOP signals of YI (first page of yellow), Y2 (second page of yellow), M1, M2, C1, C2, K1, and K2 are issued.

  The controller unit 104 sets the PRNT signal to TRUE after two pages are ready for printing, and synchronizes the yellow image data of the first page with the next TOP signal in synchronization with the first TOP signal from the engine unit 103. The second page of yellow image data is sent out, and similarly, the first page magenta, the second page magenta, the first page cyan, the second page cyan, the first page black, and the second page black. Each image data is sent out.

  Note that the change of the one-page formation mode and the two-page formation mode in the color laser beam printer 102 described above is performed by sending the serial communication instruction from the controller unit 104 to the engine unit 103.

  FIG. 6 is a diagram showing that the two-page forming mode is effective for throughput in the color laser beam printer 102 according to the first embodiment of the present invention. In the figure, the same name has already been explained in FIGS. T1 is an image formation interval in the 2-page formation mode, and T2 is an image formation interval in the 1-page formation mode. In the one-page forming mode, the TOP signal issuance timing is the same T2 for both A4 landscape feed and maximum sheet size. Therefore, when the maximum throughput is expressed by the number of printed sheets per minute, the maximum size and the minimum size are the same. On the other hand, when the 2-page formation mode is used, the TOP issuance timing becomes T1 as shown in the figure, and the number of printed sheets per minute is doubled.

  Like the known engine, the engine unit 103 according to the present embodiment lowers the temperature rise voltage of the laser scanning and fixing unit and shifts to an idling state unless the TRUE of the PRNT signal is detected within a predetermined time from the TOP signal of the previous page. To do. Since the start of printing of the first page from the idling state cannot be started until the rotation of the scanner motor (not shown) for laser scanning is stabilized and the temperature of the fixing unit is completed, the controller unit 104 can transmit the PRNT signal as much as possible. Is set to TRUE within a predetermined time to control the throughput.

FIG. 7 is a timing chart for continuous printing in the two-page forming mode and the one-page forming mode in the color laser beam printer 102 according to the first embodiment of the present invention. In the figure, the same name has already been explained in FIGS. T3 represents the time from the TOP signal TRUE of the previous page to the detection of the PRNT signal TRUE capable of maintaining the throughput in the 1-page formation mode. T4 represents the time from the TOP signal TRUE of the previous page in the 2-page formation mode to the detection of the PRNT signal TRUE capable of maintaining the throughput. As shown in the figure, in the 2-page formation mode, the timing for issuing the TOP signal is shorter than that in the 1-page formation mode, and therefore the time T4 is shorter than that in T3.
T3> T4
In the present embodiment, the controller unit 104 dynamically monitors the number of pages that can start printing inside, and shifts the engine unit 103 to the two-page formation mode when two pages are ready. Also, when only one page is accumulated, the throughput maintenance time is managed according to whether the previous page is in the 1-page formation mode or the 2-page formation mode, and the wait time until 2 pages are accumulated. Or whether to start printing in the one-page forming mode.

  FIG. 1 is a block diagram showing an electrical configuration of the controller unit 104 of the color laser beam printer 102 according to the first embodiment of the present invention. The controller unit 103 of the color laser beam printer 102 according to the first embodiment of the present invention includes a panel interface unit 301, a host interface unit 302, an image data generation unit 303, a ROM 304, an image memory 305, an engine interface unit 306, and a RAM 307. , A DMA (Direct Memory Access) control unit 308, a CPU 309, an EEPROM (Electrically Erasable Programmable ROM) 310, and a system bus 311.

  The function of each unit will be described in detail. The panel interface unit 301 receives various settings and instructions from the operator from the panel unit 105 through data communication with the panel unit 105 in FIG. The host interface unit 302 is a signal input / output unit with the external device 101 such as the host computer of FIG. The engine interface unit 306 is a signal input / output unit with the engine unit 103 in FIG. 2, and transmits a data signal from an output buffer register (not shown) and controls communication with the engine unit 103.

  The image data generator 303 generates bitmap data for actual printing based on the control code data sent from the external device 101. The image memory 305 stores image data. The CPU 309 is responsible for overall control of the controller unit 104, and will be described later with reference to flowcharts of FIGS. 10, 11, and 12 (first embodiment), and FIGS. 13 and 14 (second embodiment). ), And the process shown in the flowcharts of FIGS. 18 to 21 (third embodiment). The ROM 304 stores a control code for the CPU 309. A RAM 307 is a temporary storage memory used by the CPU 309. The DMA control unit 308 transfers the bitmap data in the image memory 305 to the engine interface unit 306 according to an instruction from the CPU 309. The EEPROM 310 is an electrically erasable memory, and stores predetermined data.

  The system bus 311 has an address bus and a data bus. The panel interface unit 301, the host interface unit 302, the image data generation unit 303, the ROM 304, the image memory 305, the engine interface unit 306, the RAM 307, the DMA control unit 308, the CPU 309, and the EEPROM 310 are each connected to the system bus 311 and connected to the system. All functional units on the bus 311 can be accessed. The control code for controlling the CPU 309 is determined by an OS (operating system) that performs time-sharing 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. Shall be composed.

  The components of the color laser beam printer 102 according to the first embodiment of the present invention, the second embodiment to be described later, and the third embodiment to be described later, and the constituent elements in the claims. The correspondence is as follows. The color laser beam printer 102 corresponds to the printing apparatus in the claims, the external device 101 corresponds to the external apparatus in the claims, and the CPU 309 of the controller unit 104 corresponds to the control means and the conversion means in the claims. The host interface unit 302 of the controller unit 104 corresponds to the receiving unit in the claims, the image memory 305 of the controller unit 104 corresponds to the storage unit in the claims, and the engine unit 103 is in the claims. Corresponding to the image forming means, the intermediate transfer drum 205 corresponds to the charging medium in the claims, and the cassette paper feeding clutch 203 and the paper feeding roller 204 correspond to the conveying means in the claims.

  FIG. 8 is a diagram showing a data flow in the color laser beam printer 102 according to the first embodiment of the present invention. The analysis development task, page operation task, and engine monitoring task in the figure are tasks having the CPU 309 of the controller unit 104 as an entity as described above, and can be logically operated in parallel.

  FIG. 9 is a diagram showing the structure of the page table PT in FIG. 8 according to the first embodiment of the present invention.

  In the figure, the page table PT is a table for logically recognizing each page by the CPU 309 of the controller unit 104, and the entity exists as a continuous area in the control information storage area (not shown) of the RAM 307, and the page management Acquisition and release are managed by a functional unit (not shown). The “raster pointer” in the figure is the head pointer of an area for one page in the image memory 305, and the CPU 309 selects the corresponding area (not shown) in the image memory 305 for each page at the time of power-on initialization. And link here.

PT3 is a “status flag” and is an area for storing a flag indicating the status of the page.
"Release flag"
"Deployment end flag"
"Print start flag"
"Paper end flag"
There is. The page formation mode is
"One page formation mode"
“First page in 2-page formation mode”
“Second page in 2-page formation mode”
There is.

  Below, the data flow of FIG. 8 is demonstrated. Print data (control code, PDL (Page Description Language), etc.) input from the external device 101 to the color laser beam printer 102 is stored in a predetermined block unit in the host interface unit 302. When the analysis expansion task detects data in the host interface unit 302, it acquires a page table. Then, the data is analyzed in units of one block, and the image formation information (PDL graphic drawing command, character code, etc.) is used using the image data generation unit 303 (not shown in FIG. 8) or by the CPU 309 itself. Intermediate data is created and stored as intermediate data in an area indicated by “raster pointer PT2” of the page table PT.

  This intermediate data is compressed data in units of image objects, and has a known data structure that can generate raster data by expanding an image of one page for each predetermined band.

  In addition, the analysis task accumulates the predicted time information required to generate raster data from the intermediate data included in each band at the time of generating intermediate data, and derives predicted time information for each band. Is stored in the band information area in the header area of the intermediate data, and it is determined whether or not the predicted time information is in time for the transfer rate of the VDO signal, and the result is stored.

  Further, control information for the printer (number of copies, paper feed selection, etc.) is stored in a page table. After the analysis and expansion of the data for one page is completed, “decompression end” is set to TRUE and the data is enqueued in a page queue having a FIFO (First In First Out) structure.

  The page operation task simultaneously monitors the “status flag” of all pages in the page queue and changes the transport procedure according to the status to realize printing.

  As will be described in detail in the third embodiment, specifically, in the case of the 1-page formation mode, for the first two bands before printing and the band whose prediction time determination result is “NG” Allocate a memory area for raster development. Then, after the expansion (rasterization processing) of all assigned bands is completed (the allocation and the band expansion are collectively referred to as pre-development (pre-rendering)), the PRNT signal is set to “TRUE” and the transfer task (not shown) is performed thereafter. The band expansion and the VDO transfer are operated in parallel.

  On the other hand, in the 2-page formation mode, a task expansion memory area is allocated to the first two bands of the first page and the band whose prediction time determination result is “NG” before printing. After the expansion of all assigned bands is completed, the PRNT signal is set to “TRUE”, and thereafter the band expansion and the VDO transfer are operated in parallel by a transfer task (not shown).

  Then, the page table PT whose discharge end flag is “TRUE” is dequeued from the page queue and returned to the page management function unit. The engine monitoring task communicates with the engine unit 103 at a predetermined cycle via the engine interface unit 306, and updates the “status flag” when a factor that changes the state of the page occurs.

  FIGS. 10 and 11 are flowcharts showing an example of a first data processing procedure in the color laser beam printer 102 according to the first embodiment of the present invention configured as described above. This corresponds to the detailed procedure of the page operation task shown in.

  When the page operation task is woken up when the power is turned on (step S1), the page queue is monitored at a predetermined cycle. When the page operation task detects the presence of page N in the page queue in the state of “deployment end flag = ON” and “printing start flag = OFF” (step S2), the presence of page N + 1 as the next page and the development end flag are determined. (Step S3). If page N + 1 exists (Yes in step S3), the page operation task executes a print routine in a two-page formation mode of N and N + 1 (step S4).

  On the other hand, if the page N + 1 has not finished being developed (No in step S3), if the engine unit 103 is currently executing printing, the print mode of that page, that is, the previous page (N-1) is determined ( Step S5) In the 1-page formation mode, the page operation task is set to T3 in FIG. 7 at the final print start time (TOP signal issue time) assigned to a predetermined address in the temporary storage RAM 307 of the controller unit 104. Is added (step S6), and if it is the two-page formation mode, the page operation task calculates time T5 with addition of T4 in FIG. 7 (step S7). When the page operation task compares the current time with T5 and determines that there is no margin in the print start instruction (No in step S8), the page N is printed in the one-page formation mode. If there is still a margin in the print start instruction (Yes in step S8), the process returns to step S2.

  Next, a print execution routine in the color laser beam printer 102 according to the first embodiment of the present invention will be described based on the flowchart of FIG. FIG. 12 is a control flowchart of the print execution routine.

  The print execution routine notifies the page formation mode determined by the page operation task to the engine unit 103 (step S12) when the print execution is started (step S12), sets the PRTN signal to TRUE (step S13), and the TOP signal is Wait until TRUE (step S14). When the print execution routine detects the TOP signal TRUE, the DMA control unit 308 and the engine interface unit 306 of the controller unit 104 are activated to start image transfer (step S15). Further, the time at that time is stored as the final print start time (step S16), and the process is terminated.

  Through the configuration and control of the color laser beam printer 102 as described above, the throughput of the electrophotographic color laser beam printer 102 (printing apparatus) that forms a toner image of a plurality of pages before transferring the toner image onto a sheet. Can be maximized.

  As described above, according to the color laser beam printer according to the first embodiment of the present invention, the host interface unit 302 of the controller unit 104 that receives print data from the external device 101 and the image data for a plurality of pages. The image memory 305 of the controller unit 104 that can be stored and the toner image formed for each color are superposed and held on the intermediate transfer member 205, and transferred to a sheet of paper to form a full-color image and a mono-color image can also be formed The engine unit 103 analyzes the print data and converts it into image data for each page, converts the image data into data for each of a plurality of color components, and the number of pages of the image data, and the formation mode at the switching timing is 1 page. Whether the printing mode or the two-page printing mode, the time condition until the start of printing and the image data Depending on the product state, and a CPU309 of the controller 104 to execute the image forming engine 103 switch on one page forming mode or two-page forming mode, performing an operation and effects as described below.

  In the above configuration, the CPU 309 of the controller unit 104 dynamically monitors the number of pages where printing can be started, and shifts the engine unit 103 to the two-page forming mode when two pages are ready. Also, when only one page is accumulated, the throughput maintenance time is managed depending on whether the previous page is in the 1-page formation mode or the 2-page formation mode, and waits until 2 pages are accumulated. Or whether to start printing in the one-page forming mode.

  That is, when the sheet length is ½ or less of the maximum sheet size, the maximum number of printed sheets per minute is improved by providing a two-page forming mode for forming a toner image for a plurality of pages on the intermediate transfer member. . Further, whether the two-page forming mode for forming the toner images for the plurality of pages or the one-page forming mode for forming the toner image for one page is determined. Is determined according to which mode. Furthermore, the determination as to whether or not the two-page formation mode is possible is performed for pages with consecutive page numbers.

  Therefore, according to the first embodiment of the present invention, it is possible to maximize the printing throughput of the intermediate transfer method, and to provide a color laser beam printer that achieves both printing quality and speed as well as an effect of preventing color misregistration. There is an effect that can be.

[2] Second Embodiment A system including a color laser beam printer according to a second embodiment of the present invention is similar to that of the first embodiment described above, from the external device 101 and the color laser beam printer 102. It is roughly structured. Furthermore, the color laser beam printer 102 includes an engine unit 103, a controller unit 104, and a panel unit 105 (see FIG. 2 above).

  Similarly to the first embodiment, the engine unit 103 of the color laser beam printer 102 according to the second embodiment of the present invention includes a paper cassette 202, a cassette paper feed clutch 203, a paper feed roller 204, Intermediate transfer drum 205, drum cartridge 208, photosensitive drum 209, black toner developer 210, yellow toner developer 211, magenta toner developer 212, cyan toner developer 213, YMC developer support 214, fixing heater 215, scanner unit 216, a reversal refeed unit having a secondary transfer roller 231, a fixing roller 217, 232, a transport roller 218, 219, a paper discharge tray 220, a manual paper feed clutch 221, a paper feed table 222, and a transport roller 223, 224, 233 234 (see FIG. 3 above)

  In addition, the controller unit 103 of the color laser beam printer 102 according to the second embodiment of the present invention has a panel interface unit 301, a host interface unit 302, and an image data generation unit 303, as in the first embodiment. ROM 304, image memory 305, engine interface unit 306, RAM 307, DMA control unit 308, CPU 309, EEPROM 310, and system bus 311 (see FIG. 1 above). The configuration of each part of FIG. 2, FIG. 3, and FIG. 1 has been described in detail in the first embodiment, so that the description thereof is omitted.

  Since the first embodiment uses single-sided printing as an example, the two-page formation mode is determined for continuous pages (N and N + 1), but both sides are printed using the reverse refeed unit 234 shown in FIG. Whether or not printing is performed, whether or not the two-page forming mode is possible is not limited to continuous pages.

  FIGS. 13 and 14 are flowcharts showing an example of a second data processing procedure in the color laser beam printer 102 according to the second embodiment of the present invention configured as described above. This corresponds to the detailed procedure of the page operation task shown in.

  First, regardless of the page formation mode, when printing in the order of page Q, page N, and page M, when the page operation task is awakened when the power is turned on (step S21), the page queue is monitored at a predetermined interval. When the page operation task detects the presence of the page N in the state of “development end flag = ON” and “printing start flag = OFF” in the page queue (step S22), it determines the presence of page M and the expansion end flag (step S23). ). If page M exists (Yes in step S23), the printing routine is executed in the two-page formation mode of N and M (step S24).

  On the other hand, if the page M has not been expanded (No in step S23), and if the engine unit 103 is currently executing printing, depending on the printing mode of the page Q (step S25), it may be in the 1-page formation mode. For example, the time T5 is calculated by adding T3 in FIG. 7 to the final printing start time (TOP signal issuance time) assigned to a predetermined address in the temporary storage RAM 307 of the controller unit 104 (step S26), page 2 If it is the formation mode, time T5 is calculated by adding T4 in FIG. 7 (step S27). When the current time is compared with T5 and it is determined that there is no margin in the print start instruction (No in step S28), page N is printed in the one-page formation mode. If there is still a margin in the print start instruction (Yes in step S28), the process returns to step S22.

  As described above, according to the color laser beam printer according to the second embodiment of the present invention, the host interface unit 302 of the controller unit 104 that receives print data from the external device 101 and the image data for a plurality of pages. The image memory 305 of the controller unit 104 that can be stored and the toner image formed for each color are superposed and held on the intermediate transfer member 205, and transferred to a sheet of paper to form a full-color image and a mono-color image can also be formed The engine unit 103 analyzes the print data and converts it into image data for each page, converts the image data into data for each of a plurality of color components, and the number of pages of the image data, and the formation mode at the switching timing is 1 page. Whether the printing mode or the two-page printing mode, the time condition until the start of printing and the image data Depending on the product state, and a CPU309 of the controller 104 to execute the image forming engine 103 switch on one page forming mode or two-page forming mode, performing an operation and effects as described below.

  In the above configuration, the CPU 309 of the controller unit 104 dynamically monitors the number of pages where printing can be started, and shifts the engine unit 103 to the two-page forming mode when two pages are ready. Also, when only one page is accumulated, the throughput maintenance time is managed depending on whether the previous page is in the 1-page formation mode or the 2-page formation mode, and waits until 2 pages are accumulated. Or whether to start printing in the one-page forming mode.

  That is, when the sheet length is ½ or less of the maximum sheet size, the maximum number of printed sheets per minute is improved by providing a two-page forming mode for forming a toner image for a plurality of pages on the intermediate transfer member. . Further, whether the two-page forming mode for forming the toner images for the plurality of pages or the one-page forming mode for forming the toner image for one page is determined. Is determined according to which mode. Furthermore, the determination of whether or not the two-page formation mode is possible is also performed for pages with discontinuous page numbers.

  Accordingly, in the second embodiment of the present invention, as in the first embodiment, it is possible to maximize the printing throughput of the intermediate transfer method, and the print quality and speed as well as the effect of preventing color misregistration. There is an effect that it is possible to provide a color laser beam printer compatible with the above.

[3] Third Embodiment A system including a color laser beam printer according to a third embodiment of the present invention is similar to the first and second embodiments described above in that an external device 101 and a color laser beam are used. The printer 102 is generally configured. Furthermore, the color laser beam printer 102 includes an engine unit 103, a controller unit 104, and a panel unit 105 (see FIG. 2 above).

  The third embodiment corresponds to the processing after the two-page formation mode is determined in the above-described embodiment. In this embodiment, the controller unit 104 further switches the timing for setting the PRNT signal to “TRUE” before and after the preceding development during continuous printing, and according to the total time required for the preceding development, the page formation mode Is dynamically switched to maximize the print throughput performance of the engine unit 103.

  FIG. 15 is a diagram for explaining the raster data generation processing operation in the two-page formation mode by the controller unit 104 shown in FIG. Note that the arrow indicates the sheet conveyance direction.

  In the figure, page N and page M are A4 size laterally fed pages. The band information area BI is shown as an example when the page N and the page M are formed in the two-page formation mode.

  BI-1 is a band ID, A1 to A6 correspond to the band ID of the first page, and B1 to B6 correspond to the band ID of the second page. BI-2 indicates a development time, BI-3 indicates memory allocation, and logically indicates the contents of the band information area BI.

  Note that “OK” shown in the area of the development time BI-2 is a case where the development time is in time for the VDO transfer rate, and “NG” is a case where the time is not in time. “M1”, “M2”, “M3”, “M4”, and “M5” shown in the area of the memory allocation BI-3 are the start addresses of the memory areas for storing raster data. Bands to which the same memory is allocated are reused after VDO transfer.

  FIGS. 16 and 17 are timing charts for explaining the page development processing operation in the print control apparatus according to the present embodiment. The timing at which the controller unit 104 generates VDO data and the PRNT signal are set to “TRUE” in continuous printing. Corresponds to the relationship.

  In the figure, PRNT, TOP, and VDO are the same as those described in FIG.

  In the figure, “Previous TOP” represents the timing of “TRUE” of the TOP signal of the previous page, and “Decision Timing” is the timing at which the controller unit 104 determines the control method.

  T6 is the time from TRUE of the TOP signal of the previous page to “determination timing”. T5 is the TOP interval when the process speed of the engine unit 103 is maximum in the 2-page formation mode.

  T7 and T8 are the total time required for preceding development of page N and page M in the two-page formation mode. T9 is the time from when the engine unit 103 receives “TRUE” of the PRNT signal from a predetermined idling state until the TOP signal is set to “TRUE” again in the 2-page formation mode.

  Here, pattern 1 is a case where the two-page formation mode is processed with the highest throughput. Since the determination timing and the preceding development are completed during T5, the printing process is performed without waste.

  Pattern 2 is a case where the two-page formation mode is performed, but the idling state is temporarily entered, so that the throughput is somewhat lowered.

  T10 and T12 are total times required for preceding development of page N in the one-page formation mode. T11 is the TOP interval when the process speed of the engine unit 103 is maximum in the one-page formation mode. T13 is the time from when the engine unit 103 receives “TRUE” of the PRNT signal to the “TRUE” of the TOP signal again from the predetermined idling state in the one-page formation mode.

  Here, pattern 3 is a case where the printing process is performed without waste because the determination timing and the preceding development are completed during T5 in the one-page formation mode.

  Pattern 4 is a case where, in the one-page formation mode, the determination timing and the preceding development are not completed during T5, so that the engine is temporarily in an idling state and throughput is reduced.

  A1 to A6 on the CPU 309 line indicate development of each band of page N, and B1 to B6 indicate development of each band of page M. A1 to A6 on the VDO line indicate raster transfer of page N, and B1 to B6 indicate raster transfer of each band of page M.

  Further, although not shown, a time T14 for defining the PRNT signal as “TRUE” is defined so that the TOP signal of the previous page maintains the continuous printing state from “TRUE”. That is, if the previous page is the 1-page formation mode, it is T3 (see FIG. 7), and if the previous page is the 2-page formation mode, it is T4 (see FIG. 7).

  18 to 20 are flowcharts showing an example of a third data processing procedure in the print control apparatus according to the present embodiment, and correspond to the detailed procedure of the page operation task shown in FIG. S1801 to S1835 indicate each step.

  When the above-described page operation task is activated when the power is turned on, the page queue is monitored in a predetermined synchronization. In step S1801, when the page operation task detects the presence of the page N in the “development end flag = ON” and “print start flag = OFF” state in the page queue, the page operation task displays the presence of the next page, page M, and the expansion end flag. If it is determined (S1802) and it is determined that the page M does not exist, the time TSUMl required for the preceding development of the page N is accumulated (S1803). Next, the page operation task determines whether or not T6 + TSUM1 <T5 when the engine unit 103 is performing continuous printing (S1804). If it is determined that T6 + TSUM1> T5, the one page formation mode is set to the engine unit. 103 is instructed (S1808), and the preceding band is developed (S1809). After the development, the PRNT signal is set to “TRUE” (S1810).

  In this case, as shown in FIG. 17, the time required for the preceding expansion is “T12 = TSUM1”, and T13 is the time from the time when the PRNT signal becomes “TRUE” until the TOP signal is “TRUE”. This is the case of “pattern 4”.

  On the other hand, if it is determined in step (S1804) that the page operation task is T6 + TSUM1 <T5, the 1-page formation mode is instructed to the engine unit 103 (S1805), and the PRNT signal is set to “TRUE” (S1806). The preceding band is developed (S1807).

  In this case, as shown in FIG. 17, the time required for the prior development is “T10 = TSUM1”, and T11 is the time from the time when the PRNT signal becomes “TRUE” until the TOP signal is “TRUE”. This is a case of “Pattern 3” (TOP interval in the 1-page mode).

  On the other hand, if it is determined in step (S1802) that the page M exists, the flow shifts to the flow shown in FIG. 19 in order to shift to the 2-page formation mode as described in the first embodiment. Then, the page operation task accumulates the time TSUM1 required for the preceding expansion of the page N (S1815) and the time TSUM2 required for the preceding expansion of the page M (S1816).

  Next, the page operation task determines whether or not T6 + (TSUM1 + TSUM2) <T5 is satisfied (S1817). If it is determined that T6 + (TSUM1 + TSUM2) <T5 is satisfied, the 2-page formation mode is set in the engine unit 103. After instructing (S1818) and setting the PRNT signal to “TRUE” (S1819), the preceding band is developed (S1820).

  In this case, as shown in FIG. 16, the PRNT signal is set to “TRUE” to instruct the engine unit 103 to continue continuous printing, and “pattern 1” can start printing in the shortest time T5.

  On the other hand, if it is determined in step (S1817) that T6 + (TSUM1 + TSUM2)> T5, the page operation task determines whether T6 + (TSUM1 + TSUM2) <T14 is satisfied (S1821), and T6 + (TSUM1 + TSUM2). If it is determined that <T14 is established, the 2-page formation mode is instructed to the engine unit 103 (S1822), the preceding band is developed (S1823), and the PRNT signal is set to "TRUE" after the development (S1824).

  Thus, as shown in pattern 2 in FIG. 16, if the previous page is in the 1-page formation mode, the definitions of time T3 and time T4 are as described above. Therefore, the TOP signal in this case is compared with time T5. Although it may be slow, since it does not shift to idling, a significant decrease in throughput can be prevented.

  On the other hand, if T6 + (TSUM1 + TSUM2)> T5 in step (S1817) and T6 + (TSUM1 + TSUM2)> T14 in step (S1821), it is determined that the two-page formation mode is impossible, and one page In order to shift to the formation mode, the flow moves to the flow shown in FIG. Then, the page operation task determines whether or not T6 + TSUM1 <T5 is satisfied (S1825). If it is determined that T6 + TSUM1 <T5 is satisfied, the page operation task is instructed to the engine unit 103 (S1826), and the PRNT signal is set to “ "TRUE" (S1827), the preceding band is developed (S1828), and the process returns to step (S1811). This corresponds to the pattern 3 shown in FIG.

  On the other hand, if it is determined in step (S1825) that T6 + TSUM1> T5, the page operation task determines whether T6 + TSUM1 <T14 is satisfied (S1829), and if it is determined that T6 + TSUM1 <T14 is satisfied. Instructs the engine unit 103 about the 1-page formation mode (S1830), expands the preceding band (S1831), sets the PRNT signal to “TRUE” after the expansion (S1832), and returns to step (S1811). This corresponds to the pattern 4 shown in FIG.

  On the other hand, if it is determined in step (S1829) that T6 + TSUM1> T14, since a significant decrease in throughput cannot be prevented even in the formation of one page, the two-page formation mode is instructed to the engine unit 103 (S1833). (S1834), after the expansion, the PRNT signal is set to "TRUE" (S1835), and the process returns to step (S1811). This corresponds to the pattern 2 shown in FIG.

  Next, it waits until the TOP signal becomes “TRUE” (S1811). When the TOP signal becomes “TRUE”, the DMA control unit 308 and the engine interface unit 306 are activated (S1812) to start image transfer. . Further, the time at that time is stored as the final printing start time (S1813). Further, the transfer task is activated (S1814), the process returns to step (S1801), and the next page is processed.

  FIG. 21 is a flowchart showing an example of a print execution processing procedure in the print control apparatus according to the present embodiment, and corresponds to the detailed procedure of the print execution routine. Note that S2101 to S2105 indicate each step.

  The print execution routine notifies the page forming mode to the engine unit 103 (S2101), sets the PRNT signal to “TRUE” (S2102), and waits until the TOP signal becomes “TRUE” (S2103). When it is detected that the TOP signal becomes “TRUE”, the DMA control unit 308 and the engine interface unit 306 are activated to start image transfer (S2104). Further, the time at that time is stored as a final print start time in a predetermined area of the RAM 307 (S2105), and the process is terminated. This final printing start time is the calculation reference for T6 and T5 on the next page.

  In this way, in the two-page forming mode, by determining by combining the band processing for the two pages, it is possible to maximize the printing throughput by banding.

  Note that the print control apparatus according to the present embodiment is effective in an electrophotographic printing apparatus that forms a plurality of pages of toner images before transferring the toner images to a sheet.

  Therefore, the monochromatic laser beam printer is effective as long as it is an image forming apparatus of the above method.

  In addition, the printing control apparatus according to the present embodiment is not limited to an intermediate transfer type printing apparatus, but is also effective in a system in which a printing paper (recording medium) is pasted on a conventional transfer drum and a toner image is formed on the printing paper. is there. In this case, if the structure is such that the paper is fed in advance, the printing paper is stopped at a predetermined position, and the paper is fed from the predetermined position to the transfer drum by a paper feed signal, the same as the intermediate transfer system. This is effective because it is possible to form an image that matches the timing.

  According to the above embodiment, when the paper length is ½ or less of the maximum paper size, a mode for forming a toner image for a plurality of pages on the intermediate transfer member is provided, and the maximum number of images formed per minute is set. When improving, predict the development processing time of each band in the banding mode, determine the formation mode according to the prediction time and the conditions of maintaining the throughput of the printer engine, and maintain the continuous image formation of the engine Accordingly, the image formation is performed by switching the order of band development and printing start, so that it is possible to maximize the image formation throughput of the intermediate transfer method, and color images that are compatible with printing quality and speed with the effect of preventing color misregistration. Can be formed.

  In addition, it is possible to increase the image forming throughput of the intermediate transfer method by banding image formation.

  The configuration of a data processing program that can be read out by a printing system to which the printing control apparatus according to the present invention can be applied will be described below with reference to the memory map shown in FIG.

  FIG. 22 is a diagram illustrating a memory map of a storage medium that stores various data processing programs that can be read by a printing system to which the printing control apparatus according to the present invention can be applied.

  Although not particularly illustrated, information for managing a program group stored in the storage medium, for example, version information, creator, etc. is also stored, and information depending on the OS on the program reading side, for example, a program is identified and displayed. Icons may also be stored.

  Further, data depending on various programs is also managed in the directory. In addition, a program for installing various programs in the computer, and a program for decompressing when the program to be installed is compressed may be stored.

  The functions shown in FIGS. 10 to 12, 13 to 14, 18 to 20, and 21 in the present embodiment may be performed by a host computer by a program installed from the outside. In this case, the present invention is applied even when an information group including a program is supplied to the output device from a storage medium such as a CD-ROM, a flash memory, or an FD, or from an external storage medium via a network. Is.

  As described above, a storage medium storing software program codes for realizing the functions of the above-described embodiments is supplied to the system or apparatus, and the computer (or CPU or MPU) of the system or apparatus stores the storage medium in the storage medium. It goes without saying that the object of the present invention can also be achieved by reading and executing the programmed program code.

  In this case, the program code itself read from the storage medium realizes the novel function of the present invention, and the storage medium storing the program code constitutes the present invention.

  As a storage medium for supplying the program code, for example, floppy (registered trademark) disk, hard disk, optical disk, magneto-optical disk, CD-ROM, CD-R, magnetic tape, nonvolatile memory card, ROM, EEPROM, etc. Can be used.

  Further, by executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but also an OS (operating system) or the like running on the computer based on the instruction of the program code. It goes without saying that a case where the function of the above-described embodiment is realized by performing part or all of the actual processing and the processing is included.

  Further, after the program code read from the storage medium is written to a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, the function expansion is performed based on the instruction of the program code. It goes without saying that the case where the CPU or the like provided in the board or the function expansion unit performs part or all of the actual processing and the functions of the above-described embodiments are realized by the processing.

It is a block diagram which shows the electric constitution of the controller part of the color laser beam printer which concerns on the 1st and 2nd embodiment of this invention. 1 is a block diagram showing an overall configuration of a system including a color laser beam printer according to first and second embodiments of the present invention. It is a block diagram which shows the structure of the engine part of the color laser beam printer which concerns on the 1st and 2nd embodiment of this invention. It is explanatory drawing of the interface of the engine part and controller part of the color laser beam printer which concerns on the 1st and 2nd embodiment of this invention. It is explanatory drawing of the interface of the engine part and controller part of the color laser beam printer which concerns on the 1st and 2nd embodiment of this invention. It is explanatory drawing of the printing mode of the engine part of the color laser beam printer which concerns on the 1st and 2nd embodiment of this invention. It is explanatory drawing of the interface of the engine part and controller part of the color laser beam printer which concerns on the 1st and 2nd embodiment of this invention. It is explanatory drawing of the data flow which concerns on the 1st Embodiment of this invention, and a control flow. It is explanatory drawing which shows the logical map structure of the non-volatile memory which concerns on the 1st and 2nd embodiment of this invention. It is a flowchart which shows operation | movement of CPU of the controller part of the color laser beam printer which concerns on the 1st Embodiment of this invention. It is a flowchart which shows operation | movement of CPU of the controller part of the color laser beam printer which concerns on the 1st Embodiment of this invention. It is a flowchart which shows operation | movement of CPU of the controller part of the color laser beam printer which concerns on the 1st Embodiment of this invention. It is a flowchart which shows operation | movement of CPU of the controller part of the color laser beam printer which concerns on the 2nd Embodiment of this invention. It is a flowchart which shows operation | movement of CPU of the controller part of the color laser beam printer which concerns on the 2nd Embodiment of this invention. FIG. 6 is a diagram for explaining raster data generation processing operation in a two-page formation mode by a controller unit shown in FIG. 2. 6 is a timing chart for explaining a page expansion processing operation in the print control apparatus according to the embodiment. 6 is a timing chart for explaining a page expansion processing operation in the print control apparatus according to the embodiment. 10 is a flowchart illustrating an example of a third data processing procedure in the print control apparatus according to the present embodiment. 10 is a flowchart illustrating an example of a third data processing procedure in the print control apparatus according to the present embodiment. 10 is a flowchart illustrating an example of a third data processing procedure in the print control apparatus according to the present embodiment. 10 is a flowchart illustrating an example of a fourth data processing procedure in the print control apparatus according to the present embodiment. It is a figure explaining the memory map of the storage medium which stores the various data processing program which can be read with the printing system which can apply the printing control apparatus which concerns on this invention. It is explanatory drawing of the intermediate transfer system which concerns on a prior art example. It is explanatory drawing for demonstrating the subject of the intermediate transfer system concerning a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 External apparatus 102 Color laser beam printer 103 Engine part 104 Controller part 203 Cassette feed clutch 204 Paper feed roller 205 Intermediate transfer drum 302 Host interface part 305 Image memory 309 CPU

Claims (5)

Image forming means capable of forming an image of a plurality of pages based on print data received from an external device in an image forming area;
Prediction means for calculating prediction information for predicting a development processing time for developing from the intermediate data based on the print data into a bitmap image, in units of pages;
Based on the prediction information calculated by the prediction means, the first formation for outputting a signal requesting image formation after the development of the band whose band development processing time is not in time for the image forming process speed in the image forming means is completed. The image forming is performed by switching between the mode and the second forming mode in which, after outputting a signal requesting image formation, the band development processing time starts the development of the band that does not meet the image forming process speed in the image forming means. An image forming apparatus comprising: a control unit configured to perform the control. A determination unit that determines whether or not the expansion processing time of each band of each page predicted by the prediction unit exceeds a continuous image formation interval of a plurality of pages;
When the determination unit determines that the development processing time exceeds the continuous image formation interval of a plurality of pages, the control unit causes the first formation mode to perform image formation, and the determination unit 2. The image according to claim 1, wherein when it is determined that the expansion processing time does not exceed a continuous image formation interval of a plurality of pages, the control unit causes image formation in the second formation mode. Forming equipment. An image forming process capable of forming an image of a plurality of pages based on print data received from an external device in an image forming area;
A prediction step of calculating, for each page, prediction information for predicting the expansion processing time for expanding the intermediate data based on the print data into a bitmap image;
Based on the prediction information calculated in the prediction step, the first formation that outputs a signal requesting image formation after the development of the band whose band development processing time is not in time for the image forming process speed in the image forming step is completed. The image forming is performed by switching between the mode and the second forming mode in which the band development processing time is not in time for the image forming process speed in the image forming process after outputting the signal requesting the image forming. An image forming method comprising: a control step to perform. A determination step of determining whether or not the expansion processing time of each band of each page predicted by the prediction step exceeds a continuous image formation interval of a plurality of pages;
When it is determined by the determination step that the development processing time exceeds a continuous image formation interval of a plurality of pages, the control step causes image formation in the first formation mode. 4. The image according to claim 3, wherein when it is determined that the development processing time does not exceed a continuous image formation interval of a plurality of pages, the control step causes image formation to be performed in the second formation mode. 5. Forming method. An image forming process capable of forming an image of a plurality of pages based on print data received from an external device in an image forming area;
A prediction step of calculating, for each page, prediction information for predicting the expansion processing time for expanding the intermediate data based on the print data into a bitmap image;
Based on the prediction information calculated in the prediction step, the first formation that outputs a signal requesting image formation after the development of the band whose band development processing time is not in time for the image forming process speed in the image forming step is completed. The image forming is performed by switching between the mode and the second forming mode in which the band development processing time is not in time for the image forming process speed in the image forming process after outputting the signal requesting the image forming. A storage medium storing a computer-readable program for causing a computer to execute a control process to be performed.

Images