JP2005331968A - Image forming apparatus and control method for the image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the throughput in a printing process to paper which is smaller than the maximum paper size, in a printing system by an electrophotographic process. <P>SOLUTION: When data for one block is received via a host I/F, a page data is expanded and inputted to page queue. When expansion of continuing pages N and M are finished (S2, S3), image-forming conditions for them are compared with each other, to determine which of a one page forming mode for forming only one page on an intermediate transfer drum, or a two pages forming mode for forming more than one page is to be used. Comparison of the image-forming conditions is carried out for conditions, such as a paper supply opening (S4), color mode (S5), transport mode (S6), a paper-ejecting mode (S7), paper size (S8), printing mode (S9), toner concentration (S10) and resolution (S11); and when these agree, printing is carried out using the two-page formation mode. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

    The present invention relates to an image forming apparatus that forms an image based on image data and a control method thereof.

  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 color toners by a known electrophotographic process, and various types of processes have been proposed.

  For example, 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, and then a toner image for four colors is formed on a sheet. An intermediate transfer method is known in which image formation is performed by transferring and fixing at a time.

  In this intermediate transfer system, as shown in FIG. 11, four color toner images 1001 to 1004 of C (cyan), M (magenta), Y (yellow), and K (black: hereinafter also referred to as Bk) are transferred onto a photosensitive drum. Then, this is transferred to the intermediate transfer body 1100 and superimposed, and then transferred from the intermediate transfer body 1100 to the paper 1200. Normally, cylindrical drums are used for the photosensitive drum and the intermediate transfer member, but these image forming surfaces are shown in a developed state in FIG. 11 and FIG.

In such an intermediate transfer method, since the positional relationship between the photosensitive drum and the intermediate transfer member is physically fixed, four color misregistrations are produced as compared with a method in which one color is transferred to a sheet without using the intermediate transfer member. It has the advantage of being easy to prevent.
Japanese Patent Laid-Open No. 10-243133

  However, the intermediate transfer type image forming method requires an intermediate transfer body having a corresponding maximum paper size, and there is a problem that the printing throughput is reduced with a paper smaller than that.

  That is, as shown in FIG. 12, if the maximum paper size supported by the printer is x × y, the size of the intermediate transfer member must also have the size of x × y. The left side of FIG. 12 shows a state when an image is transferred from the intermediate transfer body 1100 to the paper 1200 having the maximum paper size. As shown on the right side of FIG. 12, the paper 1200 is half of x × y / 2. If the size is one page, printing of one page is performed using half of the intermediate transfer member 1100.

  Therefore, when forming an image in units of one page with a paper smaller than the maximum paper size, there is a problem that the maximum number of prints per minute cannot be made larger than the maximum paper size for any size printing. was there.

  An object of the present invention is to solve the above-described problems and to improve the throughput of printing processing on paper smaller than the maximum paper size in image formation by an electrophotographic process.

In order to solve the above problems, in the present invention, in an image forming apparatus that forms an image based on image data and a control method thereof,
Received reception data including image data in page units for image formation by the image forming apparatus from an external device,
Based on the received data received, data relating to image forming conditions for forming the image data is generated,
Based on the page unit image data included in the received data received, on the transfer body holding the developer image, the developer image is formed in page units with a predetermined image formation interval;
When transferring the developer image formed on the transfer body from the transfer body to the paper in page units,
The predetermined image formation when the first image forming condition relating to the image data of the first page matches the second image forming condition relating to the image data of the second page to be formed subsequently to the first page. A configuration is adopted in which the interval (T1) is controlled to be shorter than the predetermined image formation interval (T2) when the first image forming condition and the second image forming condition do not match.

  According to the present invention, the first image forming condition relating to the image data of the first page and the second image forming condition relating to the image data of the second page to be subsequently formed on the first page coincide with each other. Since the image forming interval is shorter than the predetermined image forming interval when the first image forming condition and the second image forming condition do not match, the throughput when the image forming conditions of a plurality of continuous pages match is maximized. Thus, it is possible to provide an image forming apparatus that does not cause unnecessary errors when the image forming conditions of a plurality of continuous pages do not match, and a control method therefor.

  The best mode for carrying out the invention will be described below based on the embodiments shown in the drawings.

  Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

  FIG. 1 shows the configuration of a system including the color laser printer of this embodiment. In FIG. 1, 101 is an external device such as a host computer, and 102 is a color laser beam printer to which this embodiment is applied.

  The color laser beam printer 102 overlays the four colors Y, M, C, and Bk on the paper by actually forming a latent image on the photosensitive drum for each dot data of the four colors Y, M, C, and Bk. And an engine unit 103 that performs printing by heat fixing. The hardware structure of the engine unit 103 will be described later.

  The printing operation of the engine unit 103 receives code data and image data (RGB, YMCK) sent from the external device 101, and generates page information including dot data of Y, M, C, and Bk colors based on this data. The controller unit 104 sequentially transmits dot data to the engine unit 103.

  Further, the color laser beam printer 102 of FIG. 1 has a panel unit 105a composed of a display unit, operation keys, and the like, and an operator (user) operates the panel unit 105a, thereby allowing the color laser beam printer 102 to operate. The operation can be specified.

  The controller unit 104 and the engine unit 103 are connected by a predetermined video interface, and information exchange is performed by serial communication of commands / status in units of 8 bits. Communication between the external device 101 and the color laser beam printer 102 is performed via a bidirectional parallel port, a serial port, or a network interface such as Ethernet (registered trademark).

  FIG. 2 shows the configuration of the engine unit 103 of the color laser beam printer of this embodiment.

  In FIG. 2, reference numeral 201 denotes a paper that is a recording medium, and 202 denotes a paper cassette that holds the paper 201. A cassette feeding clutch 203 separates only the uppermost sheet 201 of the sheet 201 placed on the sheet cassette 202, and the leading edge of the sheet separated by a driving unit (not shown) is fed to the sheet feeding roller 204. The cam that is transported to a position rotates intermittently each time paper is fed, and feeds one sheet corresponding to one rotation.

  When the sheet is conveyed by the sheet feeding clutch 203, the sheet feeding roller 204 rotates while lightly inserting the sheet 201 and conveys the sheet 201. Reference numeral 222a is a paper tray, and 221a is a manual paper feed clutch, which can feed not only paper from the paper cassette 202 but also manually feed paper one by one from the paper tray 222a.

  Reference numeral 209 denotes a photosensitive drum, and 208 denotes a drum cartridge including the photosensitive drum. Reference numeral 210 denotes a Bk: black toner developer; 211, a Y: yellow toner developer; 212, an M: magenta toner developer; 213, a C: cyan toner developer; 214, a YMC developer support unit; The developing device support portion 214 is disposed in contact with the photosensitive drum 209 and is rotated by a driving unit (not shown) so that the developing device for the toner of any of the above colors can be moved to the developing position facing the photosensitive drum 209. ing.

  Reference numeral 216 denotes a scanner unit including a laser driver. The laser driver 215 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. Scanning in the scanning direction forms a latent image on the main scanning line.

  Reference numeral 205 denotes an intermediate transfer drum. The intermediate transfer drum 205 rotates at a predetermined speed during printing. The toner image is composed of a charged body similar to the intermediate transfer drum 205 and is formed on the photosensitive drum 208 by a transfer charger (not shown). In the case of color printing, the toner image of each color on the intermediate transfer drum 205 is transferred. Is synthesized.

  That is, in parallel with the latent image formation performed by exposing the photosensitive drum 209 with a laser, each toner image is visualized as a toner image of each color by a developing device of a predetermined color toner among the developing devices 210, 211, 212, and 213. Further, the toner image is transferred to an intermediate transfer drum that rotates in parallel, and a toner image of one page size is formed on the intermediate transfer drum. In the mono-color mode, a one-page toner image for one color (hereinafter, this one-page toner image is also referred to as a plane) is formed on the intermediate transfer drum. In the full color mode, four planes of developing devices 210, 211, 212, and 213 are superimposed on the intermediate transfer drum.

  Reference numeral 214 denotes a secondary transfer roller. The sheet 201 is charged while the sheet 201 is interposed between the intermediate transfer drum 205 and the secondary transfer roller 214, and the toner image on the intermediate transfer drum 205 is interposed between the sheet 201 and the sheet 201. (Secondary transfer).

  Reference numeral 215a is a fixing heater for heating and fixing the toner image on the paper 201, and 216a and 216b are fixing rollers. Upon receiving the secondary transfer, the sheet 201 is further conveyed, the toner image is heated and fixed by the fixing rollers 216a and 216b, and is discharged onto the sheet discharge tray 220 through the conveyance rollers 217, 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. Each of the yellow toner developing device 211, the magenta toner developing device 212, the cyan toner developing device 213, and the black toner developing device 210 is a cassette type casing, and can be detached from the main body. Therefore, in these developer units, 211 is also referred to as a Y cartridge, 212 as an M cartridge, 213 as a C cartridge, and 210 as a K cartridge.

  Reference numeral 221 denotes a reverse refeed unit, which includes transport rollers 222, 223, and 224. The reversal refeed unit 221 is mainly for reversing paper that has been printed on one side in double-sided printing or the like and supplying it again to the print engine. The engine unit 103 can select the paper discharge tray 220 and the reverse refeed unit 221 as the transport destination of the paper 201 after the fixing, and this designation is performed from the controller unit 104 through the serial communication. When paper feeding to the reverse refeed unit 221 is designated, the paper 201 enters the reverse refeed unit 221 and is once transported in the direction of the transport roller 222. When the engine unit 103 detects the trailing edge of the sheet with a sensor (not shown), the rotation of the conveying roller 222 is reversed and the sheet 201 is conveyed to the conveying rollers 223 and 224. When the reverse refeed unit 221 is designated as the paper feed port in this way, the paper is re-fed to the transport roller 204 with the paper surface reversed, so that duplex printing can be performed through the above printing process. .

  As described above, the engine unit 103 of this embodiment can perform full-color printing and mono-color printing by forming a toner image for one page on the intermediate transfer drum 205.

  As described in the section of the conventional example, also in this embodiment, the outer peripheral length of the intermediate transfer drum 205 is ensured to be longer than the long side of the maximum printable paper size.

  In this embodiment, in order to improve the throughput of the printing process by reducing the sheet conveyance interval, two pages of toner images are formed on the intermediate transfer drum 205 on a sheet having a sheet length equal to or less than half the maximum sheet length. A mode is provided in which two pages are continuously printed by continuously feeding two sheets. In the following, continuous printing for the 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). The paper size supported by the print engine is arbitrary, but in this embodiment, the maximum paper size is set to a size that is at least twice the A4 size lateral feed (size equivalent to A3), and the intermediate transfer drum 205 has a size corresponding to this. Shall have. It is assumed that continuous printing is possible on two pages of A4 paper during A4 landscape feed.

  3 and 4 show a printing protocol between the printer engine unit 103 and the controller unit 104 of the color laser beam printer according to the present embodiment by a timing chart of interface signals.

  3 and 4, PRNT is a signal for the controller unit 104 to request printing, TOP is a timing signal for the engine unit 103 to request image data (video signal) from the controller unit 104, and VDO is image data. The controller unit 104 sends out one page in synchronization with a clock signal (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 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.

  3 shows a timing chart in the mono color mode, and FIG. 4 shows a timing chart in the full color mode.

  In FIG. 3, the engine unit 103 issues a single TOP signal to the PRNT signal of the controller unit 104 in the one-page formation mode. In the 2-page formation mode, the TOP signal is issued twice for the PRNT signal of the controller unit 104. After the preparation for printing for two pages is completed, the controller unit 104 sets the PRNT signal to TRUE, and synchronizes the image data of the first page with the next TOP signal in synchronization with the first TOP signal from the engine unit 103. Then, the image data of the second page is transmitted.

  In FIG. 4, 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 formation mode. In the two-page formation mode, a total of eight times of Y1 (first page of yellow), Y2 (second page of yellow), M1, M2, C1, C2, K1, and K2 with respect to the PRNT signal of the controller unit 104. Issue a TOP signal. After the preparation for printing for two pages is completed, the controller unit 104 sets the PRNT signal to TRUE, and in synchronization with the first TOP signal from the engine unit 103, converts the yellow image data of the first page to the next TOP signal. Synchronously with the yellow image data for the second page, 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. Send it out.

  An instruction to change between the 1-page formation mode and the 2-page formation mode is sent from the controller unit 104 to the engine unit 103 via serial communication.

  FIG. 5 shows the throughput improvement effect of the two-page formation mode of this embodiment. In FIG. 5, TOP is the top signal described in FIGS. In FIG. 5, the left side shows the 2-page forming mode, the center and the right side show the 1-page forming mode, and the right side particularly shows the state when the paper of the maximum paper size is conveyed. Reference numeral T1 indicates an image forming interval in the 2-page forming mode (left side in FIG. 5), and T2 indicates an image forming interval in the 1-page mode (center and right side in FIG. 5).

  As shown in the figure, in the one-page formation mode, the TOP signal issuance timing is the same T2 in both A4 landscape feed and the 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. This is the problem shown in the section of the conventional example.

  On the other hand, when the two-page formation mode of the present embodiment is used, the TOP signal issuance interval is T1, which is half of T2, as shown in the left side of FIG.

  As described above, the two-page forming mode is extremely effective for improving the throughput in the printing process using the intermediate transfer drum 205. However, for example, serial communication between two pages is performed in order to form an image in the continuous printing process. It is extremely difficult to reflect the designation from the controller unit 104 in printing. In addition, when such settings extend to printing process parameters, it becomes more difficult due to process, mechanical structure, and time constraints. For example, in the two-page forming mode, when the image forming conditions of two pages to be formed are completely different, it is very difficult to reflect this on each of the two pages.

  Therefore, in the present embodiment, even when the print size is a size that allows the two-page forming mode, the two-page forming mode is not suitable when the two-page forming mode is not suitable due to different image forming conditions for two consecutive pages. The controller unit 104 performs control not to execute.

  FIG. 6 shows a block diagram of the controller unit 103 of the present embodiment.

  In FIG. 6, reference numeral 301 denotes a panel interface unit that receives various settings and instructions from the operator by data communication with the panel unit 105a, and 302 denotes input / output of signals to / from an external device 101 such as a host computer. It is a host interface part which is a part. As described above, the host interface unit 302 includes a network interface such as a bidirectional parallel port, a serial port, or Ethernet (registered trademark).

  Reference numeral 306 denotes an engine interface unit that is an input / output unit for signals to and from the printer engine unit 105. The engine interface unit transmits a data signal from an output buffer register (not shown) and controls communication with the printer engine 105.

  Reference numeral 303 is an image data generation unit that generates bitmap data for actual printing based on control code data sent from the external device 101, 305 is an image memory for storing image data, and 309 is a printer. A CPU 304 that controls the entire controller unit 103 is a ROM that stores a control code of the CPU 309, and a temporary storage RAM 307 is used by the CPU. Reference numeral 310 denotes an EEPROM which is a nonvolatile memory means. A DMA control unit 308 transfers bitmap data in the image memory to the engine interface unit 306 in accordance with an instruction from the CPU 309.

  Reference numeral 311 denotes a system bus having 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. All the functional units above can be accessed.

  The control code for controlling the CPU 309 is composed of an OS that performs time-sharing control in units of load modules called tasks and the like, and a plurality of load modules (tasks) that operate in units of functions by a system clock (not shown). To do.

  FIG. 7 is a diagram illustrating a data flow according to the present embodiment. The analysis development task 701, page operation task 702, and engine monitoring task 703 in the figure are tasks whose execution subject is the CPU 309 as described above, and are logically operated in parallel.

  In FIG. 7, upon receiving one block of data via the host interface 302, the analysis and expansion task 701 performs font expansion and generates page data (n, n + 1...) That is image data in units of pages. The page data (n, n + 1...) Is input to the page queue 704. The page queue 704 is implemented as a circular buffer using the control data areas of the image memory 305 and the RAM 307, is managed by the page operation task 702, and corresponds to the 1-page formation mode or the 2-page formation mode. The bit data portion is transferred to the engine interface 306 through the control of the engine monitoring task 703 and printed by the printer engine unit 105. The processing of each task in FIG. 7 will be described in detail later.

  More specifically, the page data is managed by a data structure as shown below.

  FIG. 8 shows the structure of the page table 802 for managing the page data in FIG. The page table 802 is a table for logically recognizing each page in the CPU 309. The entity is allocated as a continuous area to a control information storage area (not shown) in the RAM 307 and is executed by a page management function unit (not shown). Acquisition and release are managed.

  The page table 802 is identified by the page number 803 that is the top field. This page number 803 may be independent of the page number in the job, and is used internally as a number that can uniquely identify each page table.

  A raster pointer 804 in the page table 802 is a head pointer of a raster area 820 for one page in the image memory 305, and the CPU 309 selects a corresponding area (not shown) in the image memory 305 at the time of power-on initialization. Divide by page and link here.

  The status flag 805 is an area for storing a flag indicating the print processing status of the page, and includes a release flag 805a, a discharge end flag 805b, a print start flag 805c, and a development end flag 805d as shown in the lower part of FIG.

  The page formation mode 806 in the page table 802 is a flag indicating the image formation mode of the page, and the possible values are “1 page formation mode”, “first page of 2 page formation mode”, “2”. There are three states, “second page in page formation mode”.

  Further, the page table 802 has fields (807 to) for storing various control parameters (flags) as shown below.

  The value of the transport mode 807 includes “double-sided printing mode” (using the refeed unit 221) / “single-sided printing mode”.

  The value of the color mode 808 includes “mono color mode” / “full color mode”.

  As the value of the paper discharge mode 809, there are “paper discharge to the paper discharge tray 220” / “paper discharge tray not shown”.

  The value of the paper feed mode 810 includes “paper feed from the paper cassette 202” / “paper feed from the paper feed tray 222” / “select a paper feed port that matches the paper size”.

  As the value of the paper size 811, the size of the formed image is stored. Includes standard sizes (A3, B4, etc.) and non-standard sizes.

  The value of the printing mode 812 is a mode in which the engine unit 103 performs printing by optimizing the control parameters such as the transfer voltage and the conveyance speed in the fixing process corresponding to the media type, and includes “thick paper mode” and “OHP mode”. and so on.

  The value of the toner density 813 is a value that affects the density of the toner image in the engine unit 103. When the value is low, there is a toner saving effect.

  The resolution 814 indicates the resolution of the image, and the numerical values recognized by both the engine unit 103 and the controller unit 104 need to be the same.

  The engine unit 103 according to the present embodiment has at least the conveyance mode (at least the conveyance mode) among the image formation conditions determined by the flag (control parameter) illustrated in FIG. 8 between the first page and the second page in the two-page formation mode. Whether or not reverse re-feeding is performed) 807, paper feed mode (feed port selection) 810, color mode 808, paper discharge mode 809, paper size 811, print mode 812, toner density 813, resolution 814 Cannot be specified (changed).

  Hereinafter, the data flow of FIG. 7 will be described. Print data (control code, PDL, etc.) input from the external device 101 is stored in a predetermined block unit in the host interface unit 302. When the analysis expansion task 701 detects data in the host I / F unit 302, it acquires a page table. The data is analyzed in units of one block, and image formation information (PDL graphic drawing command, character code, etc.) is developed using the image data generation unit 303 (not shown in FIG. 4) or by the CPU 309 itself. Are stored in the area indicated by the “raster pointer” of the page table. Also, 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, “end of expansion” is set to TRUE, and the data is enqueued (stored in the queue) in the page queue having the FIFO structure.

  The page operation task 702 simultaneously monitors “status flags” of all pages in the page queue, and performs printing by changing the transport procedure according to the status. The page table whose “discharge end flag” is TRUE is dequeued (removed) from the page queue and returned to the page management function unit.

  The engine monitoring task 703 communicates with the printer engine unit 105 via the engine I / F unit 306 in a predetermined cycle, and updates the “status flag” when a factor that changes the page status occurs.

  FIG. 9 is a flowchart showing the flow of the page operation task 702 of this embodiment. The illustrated procedure is executed by the CPU 309.

  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 presence of the page N in the state of “development end flag = ON” and “print start flag = OFF” is detected in the page queue (step S2), the presence of the next page, page M, and the development end flag are determined (step S2). S3). When the page M exists and the possibility of the two-page forming mode of the page N and the page M is recognized, the setting states (image forming conditions) of various control information of the page N and the page M are compared. That is, it is checked whether the setting states of the various control information on page N and page M that can start printing are the same. Specifically, this is done by comparing the states of the flags shown in FIG. 8 as follows.

  First, is the paper feed port 810 the same (step S4), then the color mode 808 is the same (step S5), the transport mode 807 is the same (step S6), and then It is checked whether the paper discharge mode 809 is the same (step S7).

  Next, it is checked whether or not the paper sizes 811 are the same (step S8). In this step S8, it is confirmed whether the size of the page N and the page M is equal to or less than ½ of the maximum sheet size (however, this may be confirmed by providing another step immediately after step S3 or the like). Good).

  Further, whether the printing mode 812 such as “thick paper mode” or “OHP mode” is the same (step S9), the toner density 813 is the same (step S10), and the resolution 814 is the same (step S10). Step S11) is compared, and if all are the same, a printing routine for printing page N and page M in the two-page formation mode is executed (step S13).

  If it is determined as a result of the comparison in steps S4, S5, S6, S7, S8, S9, S10, and S11 that the various control information setting states of page N and page M are different, page N is formed as one page. A printing routine for printing in the mode is executed (step S12).

  FIG. 10 is a control flowchart of the print execution routine. When the print execution routine is activated (step S11), it notifies the page forming mode to the engine unit 103 (step S12), sets the PRNT signal to TRUE (step S13), and waits until the TOP signal becomes TRUE (step S14). . When TRUE of the TOP signal is detected, the DMA control unit 308 and the engine interface unit 306 are activated to start image transfer (step S15) and end (step S16). In this manner, printing is performed in the one-page forming mode or the two-page forming mode according to the signal sequences shown in FIG. 3 (monochromatic printing) and FIG. 4 (color printing).

  As described above, when the image size of two consecutive pages is ½ (less than) the maximum paper size, the control for forming a plurality of pages of toner images on the intermediate transfer drum 205 before transferring the toner image to the paper. Although an example is shown, the number of pages formed on the intermediate transfer drum 205 is not limited to two, and a larger number of pages can be formed on the intermediate transfer drum 205 if the page size is smaller.

  As described above, according to the present embodiment, when the image size of a plurality of continuous pages is ½ or less of the maximum paper size, a plurality of toner images are transferred onto the intermediate transfer drum 205 before transferring the toner image onto the paper. By forming the toner image of the page, the throughput of the printing process can be maximized, and by performing the intermediate transfer, a high-quality print output without color misregistration can be obtained.

  In addition, according to the present embodiment, only when the image size of a plurality of continuous pages is ½ or less of the maximum paper size and the image forming conditions of those pages are the same, the plurality of pages are intermediately transferred. Since it is determined whether or not the two-page forming mode is formed depending on whether or not the image forming conditions are the same, the engine unit 103 determines whether or not to perform the two-page forming mode. The apparatus and control software can be configured easily and inexpensively, and accurate image formation can be performed under the image forming conditions specified by the external device 101 such as a host computer.

  In particular, in the above-described embodiment, the transport mode (whether reverse refeeding is performed) 807, the paper feed mode (selection of paper feed port) 810, the color mode 808, the paper discharge mode 809, the paper size 811, the print mode 812, Whether or not to form a plurality of pages on the intermediate transfer drum 205 on condition that the image forming conditions indicated by the parameter designation (change) of the toner density 813 and the resolution 814 match each other in a plurality of continuous pages. Therefore, the two-page forming mode can be used only when the above-described image forming conditions match. For example, when these conditions are different in consecutive pages, one page is used. Since the formation mode is used, it is specified from the external device 101 such as the host computer without causing an unnecessary error. Can be reproduced accurately Rino image forming conditions, it is possible to perform image formation of high quality.

  The present invention is effective in an electrophotographic printing apparatus that forms a toner image of a plurality of pages before transferring a toner image onto a sheet. In a monocolor laser beam printer, an intermediate transfer member is used. Any image forming apparatus can be implemented without being limited to the image forming method.

  The control procedure of the present invention can be stored in a computer-readable storage medium as a program for a control device (such as a CPU) of the printing device and supplied to the printing device.

  The present invention can be applied as various image forming apparatuses that form images based on image data and control methods thereof.

1 is a block diagram showing a configuration of an entire system including a laser beam printer adopting the present invention. It is explanatory drawing which shows the structure of the printer engine of the laser beam printer which employ | adopted this invention. It is explanatory drawing which showed the signal interface in the monochromatic printing of the printer engine and controller of a laser beam printer which employ | adopted this invention. It is explanatory drawing which showed the signal interface in the color printing of the printer engine and controller of a laser beam printer which employ | adopted this invention. It is explanatory drawing which showed the effect of the laser beam printer which employ | adopted this invention. It is the block diagram which showed the structure of the control circuit of the controller of the laser beam printer which employ | adopted this invention. It is explanatory drawing which showed the data flow in the laser beam printer which employ | adopted this invention. It is explanatory drawing which showed the data structure for managing the page data in the laser beam printer which employ | adopted this invention. It is the flowchart figure which showed the flow of the printing control procedure in the laser beam printer which employ | adopted this invention. It is the flowchart figure which showed the flow of the printing control procedure in the laser beam printer which employ | adopted this invention. It is explanatory drawing which showed the outline of the printing system using an intermediate transfer body. It is explanatory drawing which showed the problem of the printing system using an intermediate transfer body.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 External apparatus 103 Engine part 104 Controller part 105a Panel part 201 Paper 202 Paper cassette 204 Paper feed roller 205 Intermediate transfer drum 209 Photosensitive drum 210 Black toner developing device 214 Developing device support part 216a, 216b Fixing roller 221 Reverse refeeding unit 306 Engine interface 701 Analysis development task 702 Page operation task 703 Engine monitoring task 704 Page queue 802 Page table 803 Page number 804 Raster pointer 805a Release flag 805b Discharge end flag 805c Print start flag 805d Expansion end flag

Claims (9)

An image forming apparatus that forms an image based on image data,
Receiving means for receiving, from an external device, received data including image data in units of pages for forming an image in the image forming apparatus;
Generating means for generating data relating to image forming conditions for forming the image data based on the received data received by the receiving means;
Based on the page unit image data included in the received data received by the receiving unit, the developer image is formed in page units with a predetermined image formation interval on a transfer body holding the developer image. Image forming means,
Transfer means for transferring the developer image formed on the transfer body by the image forming means from the transfer body to a sheet in page units;
The predetermined image formation when the first image forming condition relating to the image data of the first page matches the second image forming condition relating to the image data of the second page to be formed subsequently to the first page. An image having control means for controlling the image forming means to make the interval shorter than the predetermined image forming interval when the first image forming condition and the second image forming condition do not coincide with each other. Forming equipment. The transfer body rotates in a predetermined rotation direction,
When the first image forming condition and the second image forming condition coincide with each other, the control unit is configured to transfer the first developer image related to the image data of the first page after the transfer is started. The predetermined image forming interval is controlled so that the transfer of the second developer image related to the image data of the second page is started before the first rotation of the image, and the first image forming condition and the second image forming condition are controlled. If the image forming conditions do not match, the predetermined image formation is performed so that the transfer of the second developer image is started after at least one rotation of the transfer body after the transfer of the first developer image is started. The image forming apparatus according to claim 1, wherein the interval is controlled. The received data includes data relating to the image forming conditions,
The image forming apparatus according to claim 1, wherein the generation unit generates data related to the image forming condition by analyzing the received data.   In the case where the first image forming condition relating to the image data of the first page and the second image forming condition relating to the image data of the second page to be subsequently formed on the first page coincide with each other. The predetermined image forming interval when the size of the first page and the second page is equal to or smaller than a predetermined size is the case where the first image forming condition and the second image forming condition do not match. 4. The image forming apparatus according to claim 1, wherein the first page and the second page are shorter than the predetermined image forming interval when the sizes of the first page and the second page are equal to or smaller than a predetermined size. 5. .   The image forming apparatus according to claim 4, wherein the predetermined size is half of a maximum size that the image forming unit can form on the transfer body. The image forming means may be a full color mode for forming a color developer image by sequentially superimposing developer images for a plurality of colors on the transfer body, or a monocolor for forming only a developer image of a specific color among the plurality of colors. Forming the developer image in any of the color modes,
The control means sets the predetermined image forming interval when the first image forming condition related to the color mode and the second image forming condition match, the first image forming condition related to the color mode, and the 6. The image forming apparatus according to claim 1, wherein the image forming unit is controlled so as to be shorter than the predetermined image forming interval when the second image forming conditions do not match. A paper feeding means for feeding the paper on which the developer image is to be transferred by the transfer means by designating one of a plurality of paper feeding paths;
The control means sets the predetermined image forming interval when the first image forming condition regarding the paper feed path and the second image forming condition coincide with each other as the first image forming condition regarding the paper feed path. 6. The image forming apparatus according to claim 1, wherein the image forming unit is controlled so as to be shorter than the predetermined image forming interval when the second image forming condition and the second image forming condition do not match. A plurality of discharge means for discharging the paper having the developer image transferred thereon by the transfer means;
The control unit determines the predetermined image formation interval when the first image forming condition for the discharging unit and the second image forming condition match, and the first image forming condition for the discharging unit and the first image forming condition. 6. The image forming apparatus according to claim 1, wherein the image forming unit is controlled so as to be shorter than the predetermined image forming interval when the second image forming conditions do not match. A control method for an image forming apparatus for forming an image based on image data,
A reception step of receiving, from an external device, reception data including image data in units of pages for forming an image in the image forming apparatus;
A generating step for generating data relating to an image forming condition for forming the image data based on the received data received in the receiving step;
Based on the page-unit image data included in the reception data received in the reception step, the developer image is transferred in page units with a predetermined image formation interval on a transfer body holding the developer image. An image forming step to be formed;
A transfer step of transferring the developer image formed on the transfer body in the image forming step from the transfer body to a sheet in page units,
In the image forming step, when the first image forming condition relating to the image data of the first page matches the second image forming condition relating to the image data of the second page to be subsequently formed on the first page. Forming the developer image such that the predetermined image forming interval is shorter than the predetermined image forming interval when the first image forming condition and the second image forming condition do not coincide with each other. Control method for image forming apparatus.

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