JP2018036408A - Image forming apparatus, method, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus, method, and program that can efficiently feed paper without being affected by respective paper feed distances of a plurality of paper feed mechanisms, and maximize printing speed performance of the image forming apparatus.SOLUTION: An image forming apparatus according to the present invention comprises: a plurality of paper feed mechanisms that each feed a medium to a conveyance path; an image forming part that forms an image on the medium fed from any one of the plurality of paper feed mechanisms; and a control part that, when images are continuously formed on media fed from different paper feed mechanisms, feeds back information on the time at which the paper feed mechanism feeding a preceding medium starts paper feeding, and controls paper feed processing on the paper feed mechanism feeding a subsequent medium.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image forming apparatus, method, and program.

  2. Description of the Related Art Conventionally, there is an image forming apparatus that includes a plurality of paper feed mechanisms (hereinafter referred to as paper feed trays) and performs printing on paper fed from different paper feed trays (see Patent Document 1).

JP 2010-247400 A

  However, when continuous printing is performed on paper fed from different paper feed trays, the paper feed distance from the paper feed position to the registration position of each paper feed tray is different. There may be a case where printing is not in time.

  For example, the distance between paper sheets fed from a paper feed tray with a short paper feed distance and paper fed from a paper feed tray with a long paper feed distance may become long. The forming apparatus may not be able to exhibit its original printing speed.

  The present invention has been made in view of such problems, and an object thereof is to provide an image forming apparatus, method, and program capable of maximizing printing speed performance.

  In order to achieve the above object, an image forming apparatus according to a first aspect of the present invention includes: (1) a plurality of sheet feeding mechanisms that feed a medium to a conveyance path; and (2) any of a plurality of sheet feeding mechanisms. An image forming unit that forms an image on a medium fed from the sheet, and (3) a sheet feeding mechanism that feeds a preceding medium when image formation is continuously performed on each medium fed from a different sheet feeding mechanism The image forming apparatus includes a control unit that feeds back the sheet feeding start time information and controls a sheet feeding process of a sheet feeding mechanism that feeds a subsequent medium.

  According to a second aspect of the present invention, there is provided an image forming method of an image forming apparatus including a plurality of paper feeding mechanisms and an image forming unit, wherein the control unit continuously applies to each medium fed from different paper feeding mechanisms. When the image formation is performed, the feed start time information of the paper feed mechanism that feeds the preceding medium is fed back to control the paper feed process of the paper feed mechanism that feeds the subsequent medium. An image forming method.

  An image forming program according to a third aspect of the present invention includes a plurality of sheet feeding mechanisms that feed a medium to a conveyance path, and an image forming unit that forms an image on a medium fed from any of the plurality of sheet feeding mechanisms. In the image forming program of the image forming apparatus, the paper feed start time of the paper feed mechanism that feeds the preceding medium when the computer forms images continuously on the respective media fed from different paper feed mechanisms An image forming program that functions as a control unit that feeds back information and controls a sheet feeding process of a sheet feeding mechanism that feeds a subsequent medium.

  According to the present invention, the feed start time information of the paper feed mechanism that feeds the preceding medium is fed back, and the paper feed process of the paper feed mechanism that feeds the subsequent medium is controlled. Efficient paper feeding is possible without being affected by the paper feeding distance, and the printing speed performance of the image forming apparatus can be fully exhibited.

2 is a block diagram illustrating an internal configuration of a control system of the image forming apparatus according to the embodiment. FIG. 1 is a configuration diagram illustrating a configuration of an image forming apparatus according to an embodiment. It is a block diagram which shows the structure of the ID unit which concerns on embodiment. 6 is a flowchart illustrating an operation of paper feed processing in the image forming apparatus according to the embodiment (part 1). 6 is a flowchart illustrating an operation of paper feed processing in the image forming apparatus according to the embodiment (part 2). 6 is a timing chart illustrating a paper feed start process according to the embodiment. It is a block diagram which shows the structure of the page information which concerns on embodiment. It is a block diagram which shows the structure of the paper feed timing setting information which concerns on embodiment.

(A) Main Embodiments Hereinafter, embodiments of an image forming apparatus, method, and program according to the present invention will be described in detail with reference to the drawings.

(A-1) Configuration of Embodiment FIG. 2 is a configuration diagram illustrating a configuration of an image forming apparatus according to the embodiment.

  2, an image forming apparatus 1 according to the embodiment includes image drum units (ID units) 2-1 to 2-4 as image forming units, a transfer belt 3, and LED heads 4-1 to 4-4 as exposure apparatuses. , Transfer rollers 5-1 to 5-4 as transfer members, paper feed roller 6-1, transport roller 7-1, paper feed tray 8-1, paper feed sensor 9, registration roller 10, write sensor 11, fixing device 12, a discharge sensor 13, and an operation display unit 14.

  In addition, the image forming apparatus 1 has three optional paper feeding devices 15-1 to 15-3 attached to the lower side of the main body, and each of the optional paper feeding devices 15-1 to 15-3 is fed. It has rollers 6-2 to 6-4, transport rollers 7-2 to 7-4, and paper feed trays 8-2 to 8-4.

  In this embodiment, three optional sheet feeding devices 15-1 to 15-3 are attached to the image forming apparatus 1, and the image forming apparatus 1 feeds from four sheet feeding trays 8-1 to 8-4. Can be printed on paper to be printed. The image forming apparatus 1 can be widely applied as long as it includes a plurality of paper feed trays, and the number of the optional paper feed devices 15-1 to 15-3 is not particularly limited.

  The paper feed trays 8-1 to 8-4 store paper as a medium, and are paper feed mechanisms that feed the stored paper one by one to the transport path.

  Each of the paper feed rollers 6-1 to 6-4 takes out one sheet of paper stored in each of the paper feed trays 8-1 to 8-4, and each of the transport rollers 7-1 to 7-4 The paper taken out by the paper rollers 6-1 to 6-4 is conveyed to the conveyance path.

  Hereinafter, for convenience of explanation, the paper feed tray 8-1 is “tray 1”, the paper feed tray 8-2 is “tray 2”, the paper feed tray 8-3 is “tray 3”, and the paper feed tray 8-4 is “tray”. Also called “4”.

  The operation display unit 14 is an operation panel that receives an operation by a user, and receives input information or displays an apparatus state or the like. The operation display unit 14 includes, for example, a touch panel display, operation keys, and the like.

  Each of the ID units 2-1 to 2-4 uses a developer (toner) of black (K), yellow (Y), magenta (M), and cyan (C) on the sheet conveyed by the transfer belt 3. On the other hand, the toner image is transferred and the image is recorded on the paper. Each ID unit 2-1 to 2-4 uses an ID unit 2-1 using a black (K) developer and a black (Y) developer along the sheet conveyance direction by the transfer belt 3. The ID unit 2-2, the ID unit 2-3 using a magenta (M) developer, and the ID unit 2-4 using a cyan (C) developer are arranged in this order. The arrangement order of the ID units 2-1 to 2-4 is not particularly limited.

  FIG. 3 is a configuration diagram illustrating a configuration of the ID units 2-1 to 2-4 according to the embodiment. Since the configurations of the ID units 2-1 to 2-4 are the same, FIG. 3 shows the configuration of the ID unit 2-1 on behalf of the ID units 2-1 to 2-4.

  In FIG. 3, the ID unit 2-1 includes an image drum 22 as a photoconductor, a developer container 24 that stores toner as a developer, a charging roller 21 that uniformly charges the surface of the image drum 22, and an image drum 22. A developing roller 23 or the like is provided as a developing unit that transfers toner to the electrostatic latent image formed on the surface.

  Each LED head 4-1 to 4-4 irradiates the surface of the image drum 22 with light based on print data in order to form an electrostatic latent image on the surface of the image drum 22.

  The transfer belt 3 conveys each sheet in order to transfer the toner image formed on the surface of the image drum 22 of each ID unit 2-1 to 2-4 to each sheet. The transfer belt 3 is formed in a seamless endless shape by, for example, a high-resistance semiconductive plastic film. The upper surface portion of the transfer belt 3 stretched by the conveying roller is disposed between the image drum 22 of each ID unit 2-1 to 2-4 and each transfer roller 5-1 to 5-4.

  The paper feed sensor 9 detects the paper transported on the transport path.

  As shown in FIG. 2, the registration roller 10 is disposed between the paper feed sensor 9 and the writing sensor 11, and transports the paper transported from each of the paper feed trays 8-1 to 8-4.

  The writing sensor 11 detects the leading edge of the paper conveyed by the registration roller 10 in order to adjust the position and timing of recording the toner image on the conveyed paper. The paper that has passed through the writing sensor 11 is guided between the transfer belt 3 and each image drum 22, and the toner image on the surface of each image drum 22 is transferred onto the paper.

  The fixing device 12 fixes the toner image transferred onto the paper on the paper. The sheet on which the image is fixed is conveyed by a discharge roller and discharged.

  A discharge sensor 13 is provided further downstream of the fixing device 12, and the discharge sensor 13 monitors jamming of the fixing device 12 and winding of paper.

  FIG. 1 is a block diagram illustrating an internal configuration of a control system of the image forming apparatus 1 according to the embodiment.

  In FIG. 1, the image forming apparatus 1 includes a controller unit (hereinafter referred to as “CU”) 30 and a print engine unit (hereinafter referred to as “PU”) 40.

  The CU 30 and the PU 40 are connected by a video interface (video I / F) 57 and a communication interface (communication I / F) 58.

  The CU 30 converts the print data acquired from the host computer 60 as the host device to the image data via the video I / F 57 and transfers the converted image data (for example, DMA (Direct Memory Access) transfer or the like). . In addition, the CU 30 and the PU 40 transmit and receive commands and various information via the communication I / F 58.

  In FIG. 1, a CU 30 includes a CPU 31 as an arithmetic processing unit, a ROM 32, a RAM 33 as a work area, an EEPROM 34 as a nonvolatile memory, and a host interface (host I / F) 35.

  The CPU 31 reads the processing program stored in the ROM 32, uses the RAM 33 as a work area, and executes the processing program using necessary information.

  The CPU 31 converts the print data acquired from the host computer 60 via the host I / F 35 into image data expanded into a bitmap, transfers the image data to the PU 40, and issues a print command to the PU 41. The EEPROM 34 stores adjustment values and the like necessary for processing various functions.

  The PU 40 is responsible for the image forming processing operation of the image forming apparatus 1. In FIG. 1, the PU 40 includes a CPU 41 as an arithmetic processing unit, a ROM 42, a RAM 43 as a work area, an EEPROM 44 as a nonvolatile memory, an image processing unit 45, and a UART (Universal Asynchronous Receiver Transmitter) 46.

  The CPU 41 reads the processing program stored in the ROM 42, uses the RAM 43 as a work area, executes the processing program using necessary information, and performs image forming processing. Further, the CPU 41 may perform paper feed start processing for a plurality of pages simultaneously in parallel by, for example, multitasking. Further, as will be described in detail in the operation section, the CPU 41 feeds the preceding medium when the image is continuously formed on each sheet fed from different sheet feeding trays 8-1 to 8-4. The paper feed start time information of the paper tray 8 is fed back to control the paper feed processing of the paper feed tray 8 that feeds subsequent media.

  The EEPROM 44 stores various adjustment values for executing the image forming process. Particularly in this embodiment, the EEPROM 44 stores paper feed timing setting information. A detailed description of the paper feed timing setting information will be described in detail in the operation section.

  The CPU 41 monitors sensor information from various sensors (for example, the writing sensor 11, the paper feed sensor 9, the paper travel sensor 55, the temperature / humidity sensor 56, etc.) in accordance with commands from the CU 30, and various motors (for example, the main motor 51). Etc.) is controlled. Further, the CPU 41 controls the energization of the paper feed roller clutch 52, the registration roller clutch 53, the fixing heater 54, etc., and performs the operation control and high voltage control of the printing system mechanism.

  The image processing unit 45 processes the image data acquired from the CU 30 according to the interface of the LED head 4, and transfers the processed image data to the LED head 4.

  Under the control of the CPU 41, the UART 46 transmits a command to each option sheet feeding device 15-1 to 15-3 by asynchronous serial communication, or status information from each option sheet feeding device 15-1 to 15-3. Or get.

(A-2) Operation According to Embodiment FIGS. 4 and 5 are flowcharts showing the operation of paper feed processing in the image forming apparatus 1 according to the embodiment.

  FIG. 6 is a timing chart illustrating a paper feed start process according to the embodiment.

  Here, when the image forming apparatus 1 performs continuous printing of four pages, the paper feed tray 8-1 (tray 1) and the paper feed tray 8- The operation in the case of printing on each sheet fed alternately with 4 (tray 4) is illustrated. In other words, an operation in the case where the image forming apparatus 1 performs printing on sheets fed in the order of “tray 1”, “tray 4”, “tray 1”, and “tray 4” will be exemplified with reference to the drawings.

  First, in the image forming apparatus 1, the CU 30 acquires print data from the host computer 60 and creates a print command. The CU 30 transfers the image data obtained by expanding the print data from the host computer 60 into a bitmap to the PU 40 via the video I / F 57.

  In the PU 40, the CPU 41 creates page information related to the start of printing for each page based on the print command from the CU 30.

  FIG. 7 is a configuration diagram illustrating a configuration of page information according to the embodiment.

  In FIG. 7, the page information according to the embodiment roughly includes “page ID”, “parameter”, and “control information”.

  “Page ID” is information for identifying the number of pages related to printing. For example, the first page, the second page, and the like are identification information.

  “Parameter” is information indicating adjustment values relating to various types of print setting information. For example, the “parameter” includes “paper size”, “paper tray”, “print DPI”, “media type”, “color / monochrome”, “double-sided / single-sided”, “paper size check”, “darkness”. , “Paper length”, “paper width”, “paper thickness”, “stacker”, “soft 4 gradation”, “left margin length”, “right margin length”, “top margin length”, “bottom margin length” There is an adjustment value of the print setting information. Information belonging to “parameters” includes information corresponding to various print setting information, and is not limited to that illustrated in FIG.

  “Control information” is information indicating adjustment values relating to print control. For example, the “control information” includes adjustment values related to printing control such as “printing speed”, “heater temperature”, “writing sensor ON time”, and “paper feed start time”.

  Here, the “control information” according to this embodiment has “paper feed start time” as a new item in addition to the conventional control information.

  “Paper feed start time” is paper feed start time information indicating a time (timing time) for feeding paper from a corresponding paper feed tray in order to print each page. As will be described later, the CPU 41 of the PU 40 determines the feed start time of the subsequent page for each page in consideration of the “ON time” of the writing sensor 11, the feed start time of the preceding page, and the like. The paper feed start time thus set is set (recorded) in “paper feed start time” of “control information”.

(Feeding start processing for the first page)
The paper feed start process for the first page will be described with reference to the flowcharts of FIGS.

  When the CPU 41 acquires page information in step S101, the process proceeds to step S102.

  In step S <b> 102, the CPU 41 determines whether there is preceding printing based on the “page ID” of the page information. In this case, “page ID: 01” indicating that the first page is printed and there is no preceding page (preceding medium), the process proceeds to step S116 (S102: False).

  In step S116, the CPU 41 sets the current time as the “paper feed start time” in the control information of FIG. 7 with the current time as the paper feed start time.

  In step S117, the CPU 41 refers to the page information shown in FIG. 7 and instructs the sheet feed tray set as “sheet feed tray” to start feeding at a time based on the set value of “sheet feed start time”. To do. As a result, the paper feed trays 8-1 to 8-4 that have received the paper feed start command start feeding paper to the conveyance path.

  Here, “tray 1” is set in the “paper feed tray” of the page information of the first page, and “current time” is set in the “paper feed start time” of the page information. The first to first page sheets are sent to the conveyance path.

  Referring to the timing chart of FIG. 6, after the main motor 51 starts driving, the paper feed roller 6-1 of the tray 1 starts feeding the first page at the timing shown in FIG.

(Feeding start processing for the second page)
Next, the paper feed start process for the second page will be described with reference to FIGS.

  In step S101, the CPU 41 obtains page information, and in the next step S102, the CPU 41 makes a determination based on “page ID indicating printing of the second page. Here, there is a preceding page. The process proceeds to S103 (S102: True).

  In step S <b> 103, the CPU 41 calculates the paper feeding timing of the second page fed from the tray 4 based on the “write sensor ON time” of the page information of the first page.

  Here, a method for calculating the feeding timing of the succeeding page (following medium) will be described with reference to the writing sensor ON time of the preceding page.

  FIG. 8 is a configuration diagram illustrating a configuration of sheet feed timing setting information according to the embodiment.

  The paper feed timing setting information is setting information necessary for deriving the paper feed start times of the plurality of paper feed trays 8-1 to 8-4. That is, the paper feed timing setting information includes the printing speed of the image forming apparatus 1, the distance that the paper is transported from each of the paper feed trays 8-1 to 8-4 to the registration roller 10, and the inter-paper distance during continuous printing. It is information about etc.

  The paper feed timing setting information includes the apparatus design information shown in FIG. 8A and the paper feed tray design information shown in FIG.

  As illustrated in FIG. 8A, the apparatus design information includes “printing speed (V)”, “distance from paper leading edge to paper feeding roller (L1) when setting paper”, “registration roller writing sensor This includes the distance to the ON position (L7on), “resist bump equivalent (δ1)”, and “inter-paper distance (δ2)”.

  Further, as illustrated in FIG. 8B, the paper feed tray design information includes the distance from the paper feed rollers 6-1 to 6-4 to the registration rollers 10 of the paper feed trays 8-1 to 8-4. Is included. Here, the distance of the tray 1 (from the paper feeding roller 6-1 to the registration roller 10) is L3a, the distance of the tray 2 (from the paper feeding roller 6-2 to the registration roller 10) is L3b, and the tray 1 (the paper feeding roller 6). -3 to the registration roller 10) is L3c, and the distance from the tray 1 (from the paper feed roller 6-4 to the registration roller 10) is L3d.

  The CPU 41 refers to the paper feed timing setting information (FIGS. 8A and 8B), and determines the paper feed timing of the succeeding page based on the write sensor ON time of the preceding page according to the equation (1). calculate. That is, the CPU 41 calculates a time t5b from the tray 4 to feeding the second page of paper based on the ON time of the first page writing sensor 11 which is the preceding page, according to the equation (1).

  If the set values in FIGS. 8A and 8B are substituted into equation (1), equation (2) is obtained.

  In step S <b> 104, the CPU 41 determines whether or not the feeding of the second page of the tray 4 is in time for printing performed at the printing speed set in the image forming apparatus 1 based on the calculation result of the expression (2). Judging.

  In this case, as shown in Expression (2), the sheet feed start time t5b (= −920 mm) for the second page from the tray 4 is a negative value. This means that the second page of paper should be fed from the tray 4 before the ON time of the first page writing sensor 11. Therefore, the CPU 41 determines that the paper feeding from the tray 4 is not in time for printing performed at the printing speed set in the image forming apparatus 1, and proceeds to step S105 (step S104: False).

  In step S <b> 105, the CPU 41 calculates the paper feed timing of the second page fed from the tray 4 based on the “paper feed start time” of the page information of the first page.

  Here, a method for calculating the feeding timing of the succeeding page will be described with reference to the feeding start time of the preceding page.

  The CPU 41 refers to the paper feed timing setting information (FIGS. 8A and 8B), and determines the paper feed timing of the subsequent page based on the paper feed start time of the previous page according to Equation (3). calculate. That is, the CPU 41 calculates the time t5d until the second sheet is fed from the tray 4 with reference to the feeding start time from the tray 1 of the first page, which is the preceding page, according to the equation (3). .

  If the set values in FIGS. 8A and 8B are substituted into equation (3), equation (4) is obtained.

  In step S <b> 106, the CPU 41 feeds the second page, which is the subsequent page, before feeding the tray 1 that feeds the first page, which is the preceding page, based on the calculation result of Expression (4). It is determined whether or not paper should be fed from the tray 4.

  In this case, as shown in Expression (4), the sheet feed start time t5d (= −276 mm) for the second page from the tray 4 is a negative value. This means that the feeding of the second page of paper from the tray 4 should be started before the feeding start time of the first page. In other words, the CPU 41 determines that the second page, which is the subsequent page, does not meet the image formation timing if the paper feeding is started after the feeding timing of the first page, which is the preceding page. It is determined that the second page from the tray 4 is fed before the paper feed start time of step S107, and the process proceeds to step S107 (step S106: True).

  In step S <b> 107, the CPU 41 refers to the page information of the first page that is the preceding page, and determines whether the “paper feed start time” of the first page has been determined. In this case, since the “sheet feeding start time” for the first page has been determined, the process proceeds to step S108 (step S107: True). If the “paper feed start time” of the preceding page is not determined, the process returns to step S107, and the CPU 41 waits until the “paper feed start time” of the preceding page is determined.

  In step S <b> 108, the CPU 41 calculates the paper feed start time of the subsequent page with reference to the “paper feed start time” of the page information of the preceding page.

  In this case, the CPU 41 adds the paper feed start time t5d calculated by the formula (4) to the “paper feed start time” of the page information of the first page according to the formula (5), and the second page. An eye feed start time T5 is calculated.

T5 = leading page feed start time + t5d (5)
In step S113, the CPU 41 determines whether or not the current time has passed the paper feed start time T5 calculated by equation (5). In this case, since the current time has passed the paper feed start time for the second page, the process proceeds to step S116 (step S113: True).

  In step S116, the CPU 41 sets (records) the current time in the “paper feed start time” of the page information of the second page.

  In step S117, the CPU 41 refers to the page information of the second page and issues a paper feed start command to the tray 4 set to “paper feed tray”. As a result, the tray 4 that has received the paper feed start command starts paper feed to the transport path.

  Explaining with reference to the time chart of FIG. 6, at the timing of FIG. 6B, the paper feed roller 6-4 of the tray 4 starts feeding the second page. That is, as shown in FIG. 6, the feeding of the second page from the tray 4 is performed at the same timing as the feeding of the first page from the tray 1.

(Feeding start processing for the third page)
Next, the paper feed start process for the third page will be described. In step S101, the CPU 41 acquires page information. In step S102, the CPU 41 determines that there is preceding printing based on the “page ID” of the page information of the third page, and proceeds to step S103 (step S102: True).

  In step S <b> 103, the CPU 41 calculates the feeding timing of the third page based on the “write sensor ON time” of the page information of the second page that is the preceding page.

  Here, the calculation formula for feeding paper from the tray 1 is as follows.

  If the set values in FIGS. 8A and 8B are substituted into equation (6), equation (7) is obtained.

  In step S104, the CPU 41 determines whether the third page of the tray 1 is in time for feeding based on the calculation result of the equation (7). In this case, the feeding start time t5a for the third page from the tray 1 is a positive value as shown in Expression (7). That is, the CPU 41 determines that the paper feed from the tray 1 is in time, and proceeds to step S109 (step S104: True).

  In step S <b> 109, the CPU 41 refers to the “writing sensor ON time” of the page information of the preceding page, and determines whether the preceding page has passed the position of the writing sensor 11. If the preceding page has not passed the position of the writing sensor 11, the process returns to step S109 and waits until the preceding page passes the position of the writing sensor 11.

  Referring to the timing chart of FIG. 6, as shown in FIGS. 6C and 6D, when the writing sensor 11 detects the second page, which is the preceding page, the process proceeds from step S109 to the next step. Proceed to S110.

  In step S <b> 110, the CPU 41 calculates the paper feed start time for the subsequent page on the basis of the write sensor arrival time for the previous page.

  In this case, the CPU 41 adds the feeding start time t5a of the second page calculated by the equation (7) to the writing sensor arrival time of the second page according to the equation (8), and starts the feeding of the third page. Time T5 is calculated.

T5 = leading page writing sensor arrival time + t5d (8)
In step S113, the CPU 41 determines whether or not the current time has passed the paper feed start time T5 calculated by equation (8). In this case, since the current time has not passed the paper feed start time T5 of the third page, the process proceeds to step S114 (step S113: False).

  In step S114, the CPU 41 records the paper feed start time T5 calculated in S110 in the “paper feed start time” of the page information of the third page.

  In step S115, the process waits until the current time passes the paper feed start time T5 for the third page.

  Here, as shown in FIG. 6C, the OFF period of the writing sensor 11 may be longer than the time corresponding to the specified inter-paper distance during continuous printing. That is, even if the second page of paper is started to be fed from the tray 4 immediately after the first page of paper is fed from the tray 1, the distance between the first page and the second page is defined. It will be longer than the distance between papers.

(Fourth page feed start processing)
Next, the paper supply start process for the fourth page will be described. The paper feed start process for the fourth page starts while the paper feed start process for the third page is waiting in step S115.

  In step S101, the CPU 41 acquires page information. In step S102, since there is preceding printing, the process proceeds to step S103 (step S102: True).

  In step S <b> 103, the CPU 41 calculates the feeding timing of the fourth page based on the “write sensor ON time” of the page information of the third page, which is the preceding page.

  In this case, the paper feed timing calculation result for the fourth page is the same as the paper feed timing calculation result for the second page as shown in Equation (9).

t5b≈−0.920 = −920 ms (9)
In step S104, the CPU 41 has a negative value for the paper feed start time t5b (= −920 mm) for the second page from the tray 4 according to equation (9). Therefore, the CPU 41 determines that the sheet feeding from the tray 4 is not in time, and proceeds to step S105 (step S104: False).

  In step S <b> 105, the CPU 41 calculates the paper feed timing based on the “paper feed start time” of the page information of the third page of the preceding page.

  Again, the paper feed timing calculation result for the fourth page is the same as the paper feed timing calculation result for the second page as shown in equation (10).

t5d≈−0.276 = −276 ms (10)
In step S <b> 106, the CPU 41 determines whether or not the paper for the fourth page of the tray 4 can be fed in time based on the calculation result of the equation (10).

  In this case, the CPU 41 determines that the fourth page from the tray 4 is fed before the feeding start time of the third page, and proceeds to step S107 (step S106: True).

  Note that here, the case where the fourth page is fed earlier than the third page is illustrated, but if it is determined that this is not the case, the process proceeds to step S111. In step S111, the CPU 41 determines whether or not the preceding page has started feeding, calculates the feeding start time of the succeeding page based on the feeding timing of the preceding page, and proceeds to step S113.

  In step S107, the CPU 41 refers to the page information of the third page, which is the preceding page, and determines whether or not the “sheet feeding start time” for the third page has been determined. In this case, since the “sheet feeding start time” for the third page has been determined, the process proceeds to step S108 (step S107: True).

  In step S108, the CPU 41 adds the feed start time t5d of the fourth page to the “feed start time” of the page information of the third page according to the equation (5), and the feed start time of the fourth page. T5 is calculated.

  In step S113, the CPU 41 determines whether or not the current time has passed the paper feed start time T5 for the fourth page. In this case, since the current time has not passed the paper feed start time of the fourth page, the process proceeds to step S114 (step S114: False).

  In step S114, the CPU 41 records the paper feed start time T5 of the fourth page in the “paper feed start time” of the page information of the fourth page.

  In step S115, the process waits until the current time passes the paper feed start time T5 for the third page.

  Here, the description will be made with reference to the timing chart of FIG. 6. Feeding of the fourth page from the tray 4 is started at the timing of FIG.

  Then, after feeding of the fourth page from the tray 4 is started, feeding of the third page from the tray 1 is started at the timing of FIG.

  Thereby, as shown in (g) of the time chart of FIG. 6, it is possible to maintain the specified inter-paper distance and to maximize the printing speed performance.

(A-3) Effect of Embodiment As described above, before starting the paper feeding from the paper feeding tray, first, the paper feeding start time is determined. The paper feed start time for subsequent printing is determined based on the paper feed start time.

  In the case of continuous printing between trays with significantly different feed distances, feeding of subsequent printing can be started before starting of feeding of preceding printing. Accordingly, it is possible to provide an image forming apparatus that conveys a sheet without reducing the sheet conveyance speed by maintaining the sheet interval with the subsequent sheet and continuing the conveyance.

(B) Other Embodiments Although various modified embodiments have been mentioned in the above-described embodiments, the present invention can also be applied to the following modified embodiments.

  (B-1) In the above-described embodiment, the electrophotographic printer is exemplified as the image forming apparatus. However, the present invention can also be applied to a copier, a facsimile, or a multifunction machine having the functions of the printer. is there.

  (B-2) In the above-described embodiment, the LED head has been described as means for writing a latent image on the image drum. However, the present invention is not limited to this, and for example, a latent image is formed on the surface of the image drum by a laser head. The method of writing may be used.

  (B-3) Further, in the above-described embodiment, the image forming apparatus including the four-stage sheet feeding tray is illustrated, but the image forming apparatus may include five or more sheet feeding trays. Furthermore, a front feeder, a multi-purpose tray, a large capacity tray, or the like may be combined with this.

  (B-4) In the above-described embodiment, when continuous printing is performed from different paper feeding trays among the plurality of paper feeding trays, each time a continuous printing command is input, The case of adjusting the paper feed timing is illustrated. However, when paper is fed from different paper feed trays, the paper size stored in each paper feed tray may be determined in advance, so when different sizes of paper are fed from each paper feed tray The job of the two sheets fed in succession (that is, the preceding fed sheet and the succeeding sheet) is stored as a set of job results, and then the same two sheets When a command for continuous printing of paper is generated, paper may be fed from each paper feed tray with reference to a past set of stored job results.

DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus, 2 ... Image drum unit, 3 ... Transfer belt, 4 ... LED head, 5 ... Transfer roller, 6-1 to 6-4 ... Feed roller, 7-1 to 7-4 ... Conveyance roller, 8 -1 to 8-4: sheet feeding tray, 9: sheet feeding sensor, 10: registration roller 10: writing sensor, 12: fixing device, 13: discharge sensor, 14: operation display unit, 15-1 to 15-3 ... Optional paper feeder,
30 ... CU, 31 ... CPU, 32 ... ROM, 33 ... RAM, 34 ... EEPROM, 35 ... Host interface (host I / F),
40 ... PU, 41 ... CPU, 42 ... ROM, 43 ... RAM, 44 ... EEPROM, 45 ... image processing unit, 49 ... UART.

Claims (9)

A plurality of paper feed mechanisms for feeding media to the transport path;
An image forming unit that forms an image on a medium fed from any of the plurality of paper feed mechanisms;
When image formation is continuously performed on each medium fed from different paper feeding mechanisms, paper feeding start time information of a paper feeding mechanism that feeds the preceding medium is fed back, and paper feeding that feeds the subsequent medium is performed. An image forming apparatus comprising: a control unit that controls sheet feeding processing of the mechanism. The control unit is
Deriving the sheet feeding timing of the subsequent sheet feeding mechanism for feeding the subsequent medium based on the sheet feeding timing of the preceding sheet feeding mechanism for feeding the preceding medium,
If the succeeding medium does not meet the image forming timing if the sheet feeding is started after the feeding timing of the preceding medium, feeding from the succeeding sheet feeding mechanism is started before the preceding sheet feeding mechanism. The image forming apparatus according to claim 1.   The image according to claim 2, wherein the control unit determines a sheet feeding timing of the subsequent sheet feeding mechanism based on a sheet feeding timing of the preceding sheet feeding mechanism that has not started sheet feeding. Forming equipment. The control unit is
Deriving the sheet feeding timing of the subsequent sheet feeding mechanism for feeding the subsequent medium based on the sheet feeding timing of the preceding sheet feeding mechanism for feeding the preceding medium,
2. The image forming apparatus according to claim 1, wherein when the succeeding medium is in time for image formation, feeding from the succeeding sheet feeding mechanism is started after feeding of the preceding sheet feeding mechanism is started.   The image forming apparatus according to claim 4, wherein the control unit determines a sheet feeding timing of the subsequent sheet feeding mechanism based on a sheet feeding timing of the preceding sheet feeding mechanism that has started feeding. .   The control unit obtains the sheet feeding timing of each sheet feeding mechanism based on at least a preset image forming speed, a distance from the position of each sheet feeding mechanism to the registration position, and a distance between the media. The image forming apparatus according to claim 1, wherein:   The image forming apparatus according to claim 1, wherein the control unit executes paper feeding processes of the plurality of paper feeding mechanisms in parallel. In an image forming method of an image forming apparatus including a plurality of paper feeding mechanisms and an image forming unit,
The control unit
When image formation is continuously performed on each medium fed from different paper feeding mechanisms, paper feeding start time information of a paper feeding mechanism that feeds the preceding medium is fed back, and paper feeding that feeds the subsequent medium is performed. An image forming method characterized by controlling paper feed processing of a mechanism. A plurality of paper feed mechanisms for feeding media to the transport path;
In an image forming program of an image forming apparatus comprising: an image forming unit that forms an image on a medium fed from any of the plurality of paper feed mechanisms;
Computer
When image formation is continuously performed on each medium fed from different paper feeding mechanisms, paper feeding start time information of a paper feeding mechanism that feeds the preceding medium is fed back, and paper feeding that feeds the subsequent medium is performed. An image forming program that functions as a control unit that controls sheet feeding processing of a mechanism.

Images