Image forming apparatus

Abstract

To prevent a decrease in productivity of an image forming apparatus.SOLUTION: An image forming apparatus includes: an image forming unit, a first sheet supporting unit, a first sheet feeding unit, a second sheet supporting unit rotatably provided on a side surface of an apparatus main body, and an air blowing unit that blows air, in which when an image is formed on a sheet fed from the first sheet supporting unit and then an image is formed on a sheet fed from the second sheet supporting unit, and air is blown onto the sheet supported by the second sheet supporting unit by the air blowing unit before a printing operation on the sheet fed from the first sheet feeding unit is completed.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus for forming an image on a sheet. [Background technology]

[0002] For example, image forming apparatuses such as copiers, facsimiles, and printers are equipped with a sheet feeding device for setting a stack of sheets to be supplied to an image forming section where an image is formed. The sheet feeding device has a feeding cassette section provided at the bottom of the image forming apparatus main body, a manual feeding section provided on the side of the image forming apparatus, and the like.

[0003] Patent Document 1 discloses a sheet feeding device that blows air onto sheets set in the device to separate them. The device disclosed in Patent Document 1 blows air for a predetermined period of time, then stops blowing air and feeds the sheets. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2023-102814 Summary of the Invention [Problem to be solved by the invention]

[0005] In the device of Patent Document 1, while the sheets are being sorted, the sheet feeding section cannot feed the sheets, and the sheet feeding from the feeding section must wait until the air blowing is completed, which may result in a decrease in productivity.

[0006] SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus capable of preventing a decrease in productivity. [Means for solving the problem]

[0007] The image forming apparatus of the present invention comprises an image forming unit that forms an image on a sheet, a first sheet support unit that supports a sheet, a first sheet feeding unit that feeds the sheet supported by the first sheet supporting unit, a second sheet supporting unit that is rotatably provided on the side of the device main body including the image forming unit and supports the sheet, an air blowing unit that blows air onto the sheet supported by the second sheet supporting unit, a second sheet feeding unit that feeds the sheet supported by the second sheet supporting unit that has been blown with air by the air blowing unit, and a control unit that, when an image is formed on a sheet fed from the second sheet supporting unit after an image is formed on a sheet fed from the first sheet supporting unit, controls the air blowing unit to blow air onto the sheet supported by the second sheet supporting unit before the printing operation on the sheet fed from the first sheet feeding unit is completed. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide an image forming apparatus that can prevent a decrease in productivity. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view of an image forming apparatus according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a control block diagram of the sheet feeding device according to the first embodiment of the present invention. [Figure 3] FIG. 2 is a schematic diagram showing the configuration of a manual feeding section according to the first embodiment of the present invention. [Figure 4] FIG. 4 is a schematic view showing a state in which an air blowing operation is performed in the manual feeding section according to the first embodiment of the present invention. [Figure 5] FIG. 3 is an explanatory diagram illustrating setting of sheet information according to the first embodiment of the present invention. [Figure 6] 5 is a flowchart showing a procedure for setting sheet information according to the first embodiment of the present invention. [Figure 7] FIG. 2 is a diagram showing print job scheduling according to the first embodiment of the present invention. [Figure 8]5 is a flowchart showing an air blowing process determination according to the first embodiment of the present invention. [Figure 9] 5 is a flowchart of sheet feeding control according to the first embodiment of the present invention. [Figure 10] FIG. 1 is a diagram showing the effect of productivity achieved by implementing the first embodiment of the present invention. [Figure 11] 10 is a flowchart of air blowing control according to a second embodiment of the present invention. [Figure 12] FIG. 10 is a diagram showing the effect of productivity achieved by implementing the second embodiment of the present invention. [Figure 13] 10 is a timing chart of air blowing control according to a second embodiment of the present invention. [Figure 14] 10 is a flowchart of sheet feeding control according to the third embodiment of the present invention. [Figure 15] FIG. 10 is a timing chart of air blowing control according to a third embodiment of the present invention. [Figure 16] 1 is a cross-sectional view of an image forming apparatus according to a first embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] <Embodiment 1> Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Fig. 1 is a cross-sectional view of an image forming system according to this embodiment. As shown in Fig. 1, an image forming system 600 includes an image forming apparatus 201 and a feeding deck 500 connected to the image forming apparatus 201. The feeding deck 500 is connected to the right side of the image forming apparatus 201 in Fig. 1, and is configured to be able to feed a sheet S to the image forming apparatus.

[0011] <Image forming device> In Fig. 1, 201 is an image forming apparatus, 201A is an image forming apparatus main body, and 201B is an image forming unit that forms an image on a sheet. 202 is an image reading device installed horizontally above the image forming apparatus main body 201A, and the image forming apparatus main body 201A is equipped with the image forming unit 201B. In addition, an ejection space V for ejecting sheets is formed between the image reading device 202 and the image forming apparatus main body 201A. Note that an operation unit 730 composed of a touch panel or the like that can display a screen is disposed above the image forming apparatus main body 201A.

[0012] Image forming unit 201B, which is an image forming means, is provided in the center in the vertical direction of image forming apparatus main body 201A, and mainly includes a laser scanner 210, a process cartridge 211, and a toner cartridge 215. Furthermore, process cartridge 211 is a four-drum full-color type, and includes four color process cartridges (211Y, 211M, 211C, and 211K) of yellow (Y), magenta (M), cyan (C), and black (K). Each process cartridge 211 includes a photosensitive drum 212, a charger 213, which is a charging means, and a developer 214, which is a developing means.

[0013] An intermediate transfer unit 201C is disposed above the process cartridge 211. The intermediate transfer unit 201C includes an intermediate transfer belt 216 wound around a drive roller 216a and a tension roller 216b. A primary transfer roller 219 is disposed inside the intermediate transfer belt 216 and abuts against the intermediate transfer belt 216 at a position facing the photosensitive drum 212. The intermediate transfer belt 216 is rotated in the direction indicated by the arrow by the drive roller 216a, which is driven by a drive unit (not shown). The negative color toner images on the photosensitive drums are superimposed and transferred to the intermediate transfer belt 216 in the order of YMCK by the primary transfer roller 219. A secondary transfer roller 217 is disposed opposite the drive roller 216a of the intermediate transfer unit 201C and transfers the color image formed on the intermediate transfer belt to the sheet S. The intermediate transfer belt 216 and the secondary transfer roller 217 constitute a secondary transfer section 201D. The toner cartridge 215 is disposed above the intermediate transfer unit 201C.

[0014] Furthermore, above the secondary transfer roller 217, a fixing unit 201E having a pressure roller 220a and a heating roller 220b is disposed.

[0015] In addition, a first discharge roller pair 225a, a second discharge roller pair 225b, and a double-sided reversing unit 201F are arranged in the upper left of the fixing unit 201E. The double-sided reversing unit 201F is provided with a reversing roller pair 222 that can rotate forward and backward, and a re-conveying path R that conveys the sheet with an image formed on one side to the image forming unit 201B again.

[0016] A sheet feeding unit 230 is provided at the bottom of the image forming apparatus main body 201A, which feeds set sheets S to the image forming section 201B. The sheet feeding unit 230 includes a feeding cassette 1 that stores sheets, and a sheet feeding section that feeds the sheets S stored in the feeding cassette 1. The sheet feeding section includes a pickup roller 2, and a feed roller 3 and a retard roller 4 that serve as separation means for separating sheets S that have been fed from the pickup roller 2 and have been fed in multiple positions. The feeding cassette 1, which serves as a first sheet support section, is supported by the image forming apparatus main body 201A so that it can be pulled out from the image forming apparatus main body 201A when the user wants to replenish sheets.

[0017] Also, a manual feed unit 235 that sends set sheets S to the image forming unit 201B is provided on the right side surface of the image forming apparatus main body 201A in FIG. 1. The manual feed unit 235 includes a manual feed tray unit 6 that supports the sheets S, and, like the sheet feed unit 230, includes a sheet feeding means and a separation means. The manual feed tray unit 6 is rotatable relative to the image forming apparatus main body 201A and can be moved between a storage position where it is stored in the image forming apparatus main body and a feed position where it is opened from the image forming apparatus main body. FIG. 1 shows the manual feed tray unit 6 in the feed position. The user sets a stack of sheets on the manual feed tray unit 6 in the feed position. FIG. 15 shows the manual feed tray unit 6 in the storage position. When it is in the storage position, the user cannot set a stack of sheets on the manual feed tray unit 6. 1 of the image forming apparatus main body 201A, below the manual feed unit 235, there is provided a feed deck 500 that feeds the set sheets S to the image forming unit 201B. The manual feed unit 235 will be described in detail later.

[0018] Next, the image forming operation of the image forming apparatus 201 will be described. First, image information of an original is read by the image reading device 202. After image processing, this image information is converted into an electrical signal and transmitted to the laser scanner 210 of the image forming unit 201B. In the image forming unit 201B, the surface of the photosensitive drum 212, the surface of which has been uniformly charged to a predetermined polarity and potential by the charger 213, is sequentially exposed to laser light. As a result, electrostatic latent images of yellow, magenta, cyan, and black are sequentially formed on the photosensitive drum of each process cartridge 211, respectively.

[0019] Thereafter, this electrostatic latent image is developed and visualized with toner of each color, and the toner images of each color on each photosensitive drum are transferred in order onto the intermediate transfer belt 216 in a superimposed manner by a primary transfer bias applied to the primary transfer roller 219. As a result, a toner image is formed on the intermediate transfer belt 216.

[0020] Meanwhile, the sheet S fed by the feed rollers 3 of the sheet feeding unit 230 is conveyed to a pair of registration rollers (hereinafter referred to as the registration roller pair) 240, which consists of a drive roller and a driven roller. At this time, the driving of the registration roller pair 240 is stopped, and the leading edge of the sheet S abuts against the nip portion of the registration roller pair 240. As a result, the leading edge of the sheet S is forced to follow the nip portion of the registration roller pair 240. Thereafter, as the feed rollers 3 continue to convey the sheet S, a flexure (loop) is formed in the sheet S, and when a predetermined loop amount is reached, the registration roller pair 240 is driven. As a result, the registration roller pair 240 corrects the skew of the leading edge of the sheet S, and the sheet S with the skew corrected is conveyed to the secondary transfer portion 201D by the registration roller pair 240. Subsequently, in the secondary transfer portion 201D, the toner images are transferred collectively onto the sheet S by a secondary transfer bias applied to the secondary transfer roller 217. The sheet S onto which the toner image has been transferred is then conveyed to the fixing section 201E, where the toner of each color is melted and mixed under heat and pressure, and fixed onto the sheet S as a color image.

[0021] Thereafter, the sheet S on which the image has been fixed is discharged into the discharge space V by a first discharge roller pair 225a and a second discharge roller pair 225b provided downstream of the fixing unit 201E, and is stacked on a stacking unit 223 formed on the bottom surface of the discharge space V. When images are formed on both sides of the sheet S, after the images are fixed, the sheet S is transported to a re-conveyance path R by a reversing roller pair 222, and is transported again to the image forming unit 201B.

[0022] As described above, the image forming process for forming an image and the sheet transport process for transporting a sheet to form an image on it are linked together to form an image on the sheet.

[0023] <Manual feed section> Next, the manual feed unit 235 as a sheet feeding device will be described in detail with reference to FIGS.

[0024] First, the control configuration for sheet feeding in the manual feed unit will be described with reference to the control block diagram in FIG. 2. The control unit 100 according to this embodiment is provided in, for example, the image forming apparatus 201, and includes a CPU 101, a ROM 102, and a RAM 103. The control unit 100 is a control means that controls the image forming apparatus 201, the feed deck 500, and the manual feed unit 235 in an integrated manner. The control unit 100 is connected to a host device 900 and an operation unit 730, and performs signal processing and sequence control for various process devices while exchanging information with them. The host device 900 is an external device such as a personal computer, image scanner, or facsimile machine.

[0025] Furthermore, control unit 100 is connected to fan control unit 402, feed motor 520 as a motor that drives pickup roller 501, feed sensor 505, manual feed tray paper presence / absence sensor 401, etc. Fan control unit 402 also controls the rotation of fan motors 511b and 512b (described later) while simultaneously detecting malfunctions. Whether or not a malfunction has occurred can be determined by counting the number of fan rotations and determining whether or not the intended number of rotations has been reached.

[0026] 3 is a schematic diagram showing the configuration of the manual feed unit 235 according to this embodiment. The manual feed unit 235 includes a manual tray unit 6 and a sheet feed unit 506 that feeds a sheet and separates the sheet stack. The sheet feed unit 506 includes a pickup roller 501 as a feed roller that contacts the top sheet of the sheet stack and feeds the top sheet. The sheet feed unit 506 also includes a feed roller 502 and a retard roller 503 as a separation unit that separates the sheet S fed from the pickup roller 501. In the manual feed unit 235, a pull-out roller 504 is disposed downstream of the feed roller 502 in the sheet feeding direction to pull out the sheet S from the feed roller 502 and feed it toward the registration roller pair 240. Furthermore, in the sheet feeding direction, a feeding sensor 505 serving as a sheet detection means is disposed between the feed roller 502 and the pull-out roller 504, that is, downstream in the feeding direction of the sheet feeding unit 506. This feeding sensor 505 detects the passage of the sheet S by outputting a signal depending on the presence or absence of the sheet S.

[0027] 3, the manual feed tray unit 6 serving as the second sheet support unit is provided with a manual feed tray base 515 and a lifter plate 514 that supports a stack of sheets S. The lifter plate 514 is also provided with a sheet presence / absence detection sensor 401, allowing the control unit to determine whether a sheet stack has been placed on the lifter plate 514. The height position of the lifter plate 514 is controlled by a lifting mechanism (not shown) in accordance with the amount of sheets S stacked. The manual feed tray unit 6 is also provided with side edge restriction plates 511 and 512, which restrict the positions of the widthwise ends (side edges of the sheets) of the sheets S set on the lifter plate 514.

[0028] In addition, side edge restricting plates 511 and 512 are provided with air blowing sections 511A and 512A, respectively, as air blowing sections. Air blowing section 511A of side edge restricting plate 511 has fan 511b driven by fan motor 511M (see FIG. 2) and blowing nozzle 511a that guides the air blown from fan 511b and blows it from the side of the sheet stack. Similarly, air blowing section 512A of side edge restricting plate 512 has fan 512b driven by fan motor 512M (see FIG. 2) and blowing nozzle 512a that guides the air blown from fan 512b and blows it from the side of the sheet stack. In addition, the side end regulating plates 511, 512 are provided with floating suppression plates 511c, 512c near the blowing nozzles 511a, 512a to prevent the sheet S, to which air is blown, from floating up and climbing over the side end regulating plates 511, 512.

[0029] Next, the state of the sheets S when air is blown from the side edges of the sheet stack by the air blowing units 511A and 512A will be described with reference to Fig. 4. Fig. 4 is a schematic diagram showing a state in which an air blowing operation by a fan (hereinafter referred to as "air blowing operation") is performed in the manual feed unit 235 according to this embodiment.

[0030] As shown in FIG. 4, air is blown toward the sides of the sheet stack from fans 511b and 512b of air blowing units 511A and 512A as indicated by arrows A1 and A2. As a result, several to several tens of sheets S at the top of the stack of sheets are raised. The uppermost raised sheet contacts lift-up suppression plates 511c and 512c, thereby restricting the lift-up of sheets S. This air-blowing action reduces the adhesion between sheets. Even sheets S with smooth surfaces, such as coated paper, can be separated and fed one by one by feed roller 502 and retard roller 503.

[0031] It is also possible to prevent coated paper from being fed from the feed cassette 1 by not providing a fan for blowing air onto the side of the sheet stack. Here, the fact that coated paper cannot be fed means that coated paper is outside the specifications of the image forming apparatus.

[0032] <Sheet type settings> Setting of sheet information such as the size and type of the sheet set in the manual feed tray 6 will be described with reference to FIGS.

[0033] Various settings for the sheet are set using an operation unit 730. Fig. 5(a) is a diagram showing the operation unit 730 in the image forming apparatus of Fig. 1. The operation unit 730 is provided with a start key 702 for starting the image forming operation, a stop key 703 for interrupting the image forming operation, numeric keys 704 to 712 and 714 for setting numbers etc., an ID key 713, a clear key 715, a reset key 716, etc. Also provided is a display unit 720 with a touch panel formed on the top, and soft keys can be created on the screen.

[0034] When the user presses the "Paper Selection" button on the display unit 720 shown in FIG. 5(a), the control unit 100 transitions to a paper feed stage selection screen shown in FIG. 5(b) (S201). Then, the user selects which paper feed stage to feed sheets from (S202). That is, in S202, the user selects which of the four paper feed cassettes 1, the manual feed tray unit 6, or the feed deck 500 to feed sheets from, which are provided in the image forming apparatus main body 201A. Here, the user selects the manual feed tray and presses the "Next" button (S203). When the button is pressed, the control unit 100 transitions to a paper size setting screen shown in FIG. 5(c). Here, the user selects A3, which is set in the manual feed tray unit (S204), and presses the "Next" button (S205). The control unit 100 transitions to a sheet type setting screen shown in FIG. 5(d). Here, the user selects the type of sheet set in the sheet storage unit (S206) and presses the "OK" button (S207). When the button is pressed, the set sheet information is saved in RAM 103 (S208). The screen transitions to the initial screen in Figure 5(a), and the sheet registration process is completed (S209).

[0035] After setting the sheet information, pressing the start key 702 on the operation display device 700 causes the control unit 100 to start the job. The control unit 100 then feeds a sheet from the selected sheet storage unit. Note that it is not necessary to set the sheet information every time before starting a job. For example, if you load plain A3 paper into the manual feed tray and then execute a job, and then want to execute a job to feed plain A3 paper from the manual feed tray again, you can simply press the start key 702. By setting sheet information corresponding to each paper feed tray in this way, the image forming apparatus executes various sheet transport controls and image formation controls based on the sheet information. Note that in this embodiment, the sheet information for which air blowing control is executed is the case where the manual feed tray is selected and coated paper 1, coated paper 2, or coated paper 3 is selected as the paper type.

[0036] <Print job scheduling> Next, a description will be given of print job scheduling according to this embodiment. CPU 101 receives print data from host device 900 or operation unit 730, and stores print job content data (hereinafter referred to as "job content") in RAM (103).

[0037] FIG. 7 is a diagram illustrating job scheduling according to this embodiment. Here, the job contents show data for four pages (630a, 630b, 631a, and 631b). The data is the print data content for each page (hereinafter referred to as "page data") and includes information such as sheet size, image, paper feed unit (paper feed tray), and sheet type. For example, the first page data (hereinafter, page data may be simply referred to as "page") 630a and the second page 630b have an A4 sheet size, a color image, and a paper feed tray (feed source) set to the cassette feed unit. The sheet type for the first page data is set to plain paper. Similarly, the third page 631a and the fourth page 631b have an A3 sheet size, a color image, a paper feed tray set to the manual feed unit, and a sheet type set to coated paper. The means of storing page data in advance, as in this embodiment, is defined as "job scheduling." In this embodiment, a printing mode in which sheets are fed from a plurality of feeding sources in order to form images successively on different types of sheets is defined as a mixed sheet printing job.

[0038] CPU 101 can receive the above page data for multiple pages in advance from host device 900 or operation unit 730. In FIG. 7, CPU 101 receives the page data in the order of printing, namely, first page 630a, second page 630b, third page 631a, and fourth page 631b, and stores the received data in RAM 103. When CPU 101 receives new data, it sequentially adds the new data to the end of the data, next to fourth page 631b. CPU 101 also erases one page at a time each time printing of page data is completed. For example, in FIG. 7, each time printing of the page data is completed, page 630a, second page 630b, third page 631a, and fourth page 631b are erased in this order.

[0039] 7 shows an example of four pages (four pages for single-sided printing only), but the CPU 101 can perform job scheduling on the RAM (103) for page data for several to several tens of pages, and is not limited to four pages. The CPU 101 can grasp the contents of the job scheduling each time new page data is input, and can determine in advance from which paper feed tray the page will be fed.

[0040] <Air spray judgment processing> Next, the air blowing determination process will be described with reference to Fig. 8. Fig. 8 is a flowchart showing the air blowing process determination process.

[0041] As described above, when the air blowing operation is performed, the top few to several tens of sheets of the sheet stack are separated and floated, as shown in Figure 4, and the adhesion between those sheets is reduced. As a result, it becomes possible to continuously feed sheets with a high sheet adhesion force, such as coated paper. However, since the number of sheets that can be floated by one air blowing operation is limited, it is necessary to perform the air blowing operation again after a predetermined number of sheets have been fed.

[0042] To achieve this operation, the control unit 100 stores in ROM (102) the number of sheets at which air should be blown at intervals. Here, let's assume that this number is 10 sheets. Also, in RAM (103) there is a sheet counter that counts the number of sheets fed from the manual paper feeder.

[0043] On the other hand, even if the sheet counter has not reached the predetermined number of sheets, if a predetermined time has passed since the previous air blowing, the effectiveness of the air blowing will decrease and the sheets will again adhere to each other. Therefore, the air blowing operation will be performed when a predetermined time has passed since the previous air blowing. To achieve this operation, the control unit 100 stores in the ROM (102) a predetermined time interval (e.g., 3 hours) for when air blowing should be performed.

[0044] First, CPU 101 compares the number of sheets counter with a predetermined number of sheets, which is 10 (S771). If the number of sheets counter is equal to or greater than the predetermined number (10), CPU 101 controls fan motors 511b and 512b so that air blowing is performed (S773). Next, CPU 101 clears the number of sheets counter to zero (S774), and starts and ends timer A (S775) and timer B (S777) (S776). Timer A (S775) is used to determine the time elapsed since the previous air blowing (S772). Timer B (S777) is used to determine the completion of air blowing (S806 in FIG. 9, described below) after this flow ends.

[0045] On the other hand, if the sheet number counter is less than the predetermined number (10 sheets), CPU 101 determines the time elapsed since the previous air blowing time (S772). If the predetermined time (e.g., 3 hours) has elapsed, CPU 101 controls fan motors 511b and 512b to perform the air blowing process (S773). If the predetermined time has not elapsed, CPU 101 ends the process (S776).

[0046] Furthermore, this process may end even if the air blowing process in this flowchart has not been completed (S776). This is because there is no need to wait for the completion of the air blowing process until the manual feed unit starts feeding the sheet. Waiting for the process to complete is performed when manual paper feeding is performed (S806 in FIG. 9, which will be described later). Note that the CPU 101 sets the counter to a value greater than 10 (e.g., 255) when the power is turned on, thereby ensuring that the initial air blowing process is performed for jobs after the power is turned on.

[0047] <Sheet feeding control> Next, sheet feeding control according to the first embodiment will be described with reference to Fig. 9. Fig. 9 is a flowchart showing sheet feeding control according to the first embodiment.

[0048] After the image forming apparatus is powered on (S800), CPU 101 waits for a job to be input from host device 900 or operation unit 730 (S801). When CPU 101 receives a job, it starts a preparation operation for printing (hereinafter referred to as "pre-rotation") (S802). Pre-rotation refers to initialization processing for image formation, such as waiting for laser scanner 210 of image forming unit 201 to reach a predetermined speed, waiting for photosensitive drum 212 to be charged by charger 213, and waiting for fixing unit 201E to reach a predetermined temperature.

[0049] Next, in parallel with the pre-rotation operation, CPU 101 determines, based on the scheduling details as described above with reference to FIG. 7, whether there is a manual paper feed job requiring air blowing control for a stack of coated paper (S803). For example, in FIG. 7, pre-rotation begins with page data for only the first page 630a at the start of pre-rotation. In parallel with the start of pre-rotation, CPU 101 sequentially receives the second page 630b, the second page 631a, and the third page 631b. The number of pages that can be received depends on the size of the print data, the state of communication traffic with the host device 900, and the time of pre-rotation. If CPU 101 receives 631a before the end of pre-rotation (S804), it determines that there is a manual paper feed requiring air blowing control, and performs the air blowing determination process (S770) described above.

[0050] In determining the contents of the job scheduling (S803), if no page data for manual paper feed requiring air blowing control is received (for example, paper feed unit: manual paper feed unit, type: plain paper), the following occurs: That is, the CPU 101 waits for the completion of the pre-rotation (S804) without executing the air blowing determination process (S770).

[0051] The air blowing determination process (S770) is performed in parallel with the "pre-rotation" operation. However, the pre-rotation completion determination (S804) determines whether the sheet is being charged and the fixing temperature is being reached, and does not wait for the completion of the air blowing process (S773 in FIG. 8). After the pre-rotation is completed (S804), a determination is made for each page as to whether it is being manually fed (S805).

[0052] If the paper is not being fed from a manual feed, the CPU 101 feeds paper from the corresponding other paper feed tray (another paper feed source) (S811). If the paper is being fed from a manual feed, the CPU 101 performs air blowing determination processing (S770). However, if the air blowing determination processing (S770) is the determination processing for the first sheet after the previous rotation and air blowing has already been performed in the previous rotation, air blowing is not performed because the sheet number counter is zero and no time has passed. Also, if the air blowing determination processing (S770) is performed during job execution and the sheet number counter value is 10 or more, the CPU 101 controls the fan motors 511b and 512b to perform air blowing.

[0053] Next, CPU 101 waits until the air blowing process is completed (S806). This wait for completion also includes waiting for the completion of processes if air blowing was previously performed on the pre-rotation (S802) or the previous page. Therefore, if the air blowing process performed in parallel with the pre-rotation (S802) described above has not yet completed, CPU 101 waits for its completion in judgment S806. The wait for completion of air blowing (S806) is realized by waiting for timer B (S777 in FIG. 8) set in FIG. 9 to reach a predetermined value (10 seconds). When the predetermined time has elapsed on the timer, CPU 101 stops air blowing (S807). Timer B is also reset here (S808). When CPU 101 performs manual sheet feeding (S809), it increments a counter used in the air blowing determination process (S770) (S810). When paper feeding is complete, CPU 101 deletes the page from the job scheduling information in FIG. 7 (S812). Data deletion may be performed immediately after paper feeding if it is limited to the paper feeding process use of this embodiment. Data deletion may also be performed when paper ejection is complete if it is also used for other control purposes, and is not limited to the timing shown in this flow chart. Next, CPU 101 determines whether or not there is a next page (S813), and if there is, determines again whether the page was fed by manual paper feed (S805) and continues printing. On the other hand, if there is no next page, CPU 101 ends the job (S814).

[0054] Figures 10(a) and 10(b) are diagrams showing the effects of the sheet feeding control of Figure 9. Figure 10(a) shows the effect when the sheet feeding control of Figure 9 is implemented, and Figure 10(b) shows the effect when the sheet feeding control of Figure 9 is not implemented.

[0055] In FIG. 10(a), air blowing is performed sufficiently before the sheet on which the image of page 3 (631a) is printed is fed from the manual feed unit 235, i.e., before the printing operation of page 2 (630b) is completed for the sheet from paper feed cassette 1. For example, assume that the pre-rotation after receiving a print job takes 6 seconds and the air blowing takes 10 seconds. Under these conditions, once the pre-rotation is completed, the paper (630a, 630b) from paper feed cassette 1, which does not require air blowing, can begin. In this embodiment, the printing operation here refers to the transfer operation of transferring a toner image to the sheet. Furthermore, for the sheet feeding (631a, 631b) from the manual feed unit that requires air blowing, printing can be continued after the air blowing has finished, without waiting for the time required for air blowing.

[0056] On the other hand, Figure 10(b) shows a case where air blowing is not performed until immediately before the sheet is fed by the manual feed unit. Once the pre-rotation is complete, air blowing is started on the sheets (630a, 630b) from the paper feed trays that do not require air blowing. Next, air blowing is performed just before the manual feed (631a, 631b), which requires air blowing, and once air blowing is complete, the manual feed (631a, 631b) is fed. In other words, in Figure 10(b), after the printing operation for the second page 630b on the sheet whose feed source is paper feed cassette 1 is completed, air blowing is performed to feed the sheet on which the image for the third page 631a will be formed.

[0057] As shown in FIG. 10A, when the control unit determines the content of the print job during pre-rotation before printing begins and determines that manual paper feed will be used (S803), air blowing is performed in parallel with the pre-rotation. This can be said to shorten the total time required to complete the print job compared to the operation shown in FIG. 10B. In this embodiment, it can be said that the time required for air blowing (approximately 10 seconds) is shortened. In other words, the control unit 100 determines the content of the mixed-size print job in advance and determines in advance whether paper will be fed from the manual feed tray that requires air blowing. By knowing the content of the print job in advance, air blowing can be performed even earlier than just before paper feed from a paper feed tray that requires air blowing. By performing air blowing earlier, it is possible to reduce the waiting time for air handling to be completed just before paper feed from a paper feed tray that requires air blowing.

[0058] <Embodiment 2> Next, a second embodiment will be described. In the second embodiment, the sheet feeding control described in the first embodiment, in which the control unit grasps the contents of the print job and, if the sheet requires air blowing control and is being manually fed, performs air blowing in advance, is partially modified. Specifically, the air blowing operation is not only performed from the pre-rotation operation, but also starts after the pre-rotation is completed while the print job for the preceding sheet is being executed (S901 in FIG. 11).

[0059] The difference between FIG. 9 showing the first embodiment and FIG. 11 showing the second embodiment is in the determination of whether manual paper feed requires air blowing control (S805 in FIG. 11). During a print job in which the device has already printed a large number of preceding sheets from a feed unit other than the manual paper feed unit, the following is executed: A determination is made (S901 in FIG. 11) of whether there will be future sheets fed by manual paper feed that will require air blowing control, and an air blowing determination process is executed (S770 in FIG. 11).

[0060] The flow diagram of the second embodiment will be described in order using FIG. 11. The flow is the same as that of the first embodiment except for the flow proceeding from No at S805 to S901, S770, and S811 in the figure, and therefore description thereof will be omitted. In determining whether the manual feed unit is used (S805), if the sheet feed tray from which paper is to be fed is not feeding from the manual feed unit, CPU 101 determines the content of the subsequent job (S901). Here, assuming that 630a, for which job scheduling is performed in FIG. 7, is the sheet to be printed, CPU 101 determines the subsequent page data information. If CPU 101 determines that there is manual paper feed (631a, 631b), CPU 101 performs air blowing determination processing (S770).

[0061] While performing the air blowing determination process (S770), CPU 101 continues feeding from the tray that does not require air blowing (S811). Here, it is assumed that air blowing for a predetermined period of time will be completed before manual feeding. For this reason, CPU 101 determines whether air blowing is being performed even during other tray feeding (S811) that does not require air blowing (S815). CPU 101 determines whether air blowing for a predetermined period of time has been completed (S816). If air blowing has been completed, CPU 101 ends air blowing (S817). Note that if the time has not elapsed, the process proceeds to S813, and CPU 101 determines YES in S813. Then, if manual feeding is not being performed in S805, CPU 101 makes the determination again in S816.

[0062] CPU 101 determines whether or not there is a next page (S813). If CPU 101 determines that there is a next page, that is, a third page 631a or a fourth page 631b, it again determines whether or not the page is manually fed (S805) and continues printing. After printing of first page 630a and second page 630b is complete, CPU 101 then feeds sheets for printing on third page 631a and fourth page 631b, which require air blowing via manual paper feed. That is, CPU 101 follows the flow of the air blowing determination process (S770, S806, S807, S808, S809, S810) described above. If it determines (S813) that there is no next page, CPU 101 ends the job (S814).

[0063] In this embodiment, the air blowing process is carried out in parallel with the image forming process shown in FIG.

[0064] As described above, the laser scanner 210 sequentially performs laser light scanning 851 for image formation on the preceding sheets (630a, 630b) from the paper feed tray, which does not require air blowing in the image formation process. Then, transfer (852) is performed onto the paper by the secondary transfer roller 217. In other words, the rotation of the fan, which is the air blowing process for feeding the sheets (631a, 631b) from the manual paper feed, is performed during the image formation process for the preceding sheets (630a, 630b). Note that the image formation process here refers to the process from laser light scanning by the laser scanner 201 to transferring the image onto the paper.

[0065] In this embodiment, as shown in Fig. 13, when the timing for determining whether manual paper feed is performed (S805) is synchronized with the timing for emitting laser light for the preceding paper, the start of air blowing is synchronized (853) with the start of laser light scanning 851. However, the start of fan rotation (853) shown in Fig. 13 is just one example, and the start of air blowing may be synchronized with the start of transfer of a toner image to the preceding paper (630a) (852). The start of air blowing may also be synchronized with the start of feeding of the preceding paper 630a.

[0066] In addition to the results obtained in the pre-rotation of Fig. 10(a), the flow diagram of Fig. 11 also provides the same effect during the job as shown in Fig. 12. Fig. 12(a) shows the case where the flow diagram of Fig. 11 is implemented in accordance with the second embodiment, and Fig. 12(b) shows the case where the flow diagram of Fig. 11 is not implemented in accordance with the second embodiment.

[0067] In Figure 12(a), while paper (630a, 630b) is being transported from a paper feed tray that does not require air blowing, the presence or absence of subsequent paper (631a, 631b) from the manual feed unit that requires air blowing is determined. Because air blowing begins before the paper (631a, 631b) is fed from the manual feed unit, the wait time until air blowing ends can be reduced. On the other hand, in Figure 12(b), air blowing is not performed until immediately before the paper (631a, 631b) from the manual feed that requires air blowing is fed. In this case, printing must wait from the start of air blowing until air blowing ends, so Figure 12(a) is more effective in reducing productivity.

[0068] The above reduction effect depends on the number of pages in the page information for job scheduling, and the more pages that can be determined in advance, the easier it is to secure the time from the start to the end of air blowing in advance for paper feeding, maximizing the effect.If job scheduling can be determined further in advance than the point at which air blowing starts in Figure 12(a), the time required for air blowing (10 seconds) can be reduced.

[0069] Also, in Figure 12, if the printing order of the paper (631a, 631b) from the manual feed unit is positioned before the paper transport (630a, 630b) from the paper feed stage that does not require air blowing, the result will be the same as Figures 9 and 10 described above.

[0070] <Embodiment 3> In the first embodiment (FIG. 9) and the second embodiment (FIG. 11), air blowing is performed while the sheet feeding from the manual feed is stopped, and a predetermined number of sheets are fed with the air blowing stopped. In the third embodiment (FIG. 14), an embodiment in which air blowing continues while sheets are being fed from the manual feed will be described.

[0071] The basic flow from S800 to S804 in FIG. 14 is the same as that in FIG. 11 of the second embodiment, and therefore description thereof will be omitted. After the pre-rotation ends (S804), CPU 101 determines whether paper is being fed from a manual paper feed (S805). If it is manual paper feed, CPU 101 determines whether air is being blown (S819). If air is not being blown, CPU 101 controls fan motors 511b and 512b to blow air (S770). Next, CPU 101 waits for a predetermined time for blowing (S806) and then executes paper feeding from the manual feed (S809). If it is determined in determination S819 that air blowing is already being executed, CPU 101 continues paper feeding (S809).

[0072] Next, CPU 101 deletes the information indicating that paper has been fed from the job scheduling information of Fig. 7 for that page (S812). CPU 101 determines whether there is a request for the next paper (S813). If the next paper is also manually fed (S805), CPU 101 executes the flow of S819 to S809 described above.

[0073] Furthermore, if the aforementioned judgment (S805) determines that the sheet is not being fed manually, CPU 101 judges whether there will be any sheets to be fed manually in the future (S901) by judging the job scheduling contents of FIG. 7.

[0074] If there is a sheet to be manually fed, CPU 101 controls fan motors 511b and 512b to perform air blowing in advance (S770). Furthermore, if the aforementioned determination (S901) indicates that there will be no future manual sheet feeds requiring air blowing, CPU 101 stops air blowing (S807) and performs sheet feed (S811). It is possible that air blowing will be completed for a predetermined period of time before the manual sheet feed. While air blowing is in progress, adjustments such as waiting for the fixing temperature of fixing unit 201E may be made, resulting in a delay before the manual sheet feed. To prevent excessive air blowing, during the other-stage sheet feed (S811), CPU 101 determines whether the manual sheet feed will be continued as is or whether an adjustment operation will be made and the manual sheet feed will be delayed for a predetermined period of time (S820). If the manual sheet feed will be delayed, air blowing is terminated (S817).

[0075] In the aforementioned determination (S901), it is also possible to provide a delay in stopping the air blowing (S807). This is to prevent a decrease in productivity caused by a predetermined wait time (S806) between the resumption of air blowing (S770) and the feeding of sheets (S809) if manually fed paper occurs after the fan rotation has stopped. As a countermeasure, for example, a counter for the number of sheets until the fan rotation stops during the other tray paper feeding (S811) can be provided, for example, for one to three sheets, and the execution of stopping the air blowing (S807) can be delayed until the set number of sheets is reached.

[0076] FIG. 15 illustrates the ON / OFF of fan motors 511b and 512b. If it is determined in step S901 of FIG. 14 that there will be a sheet fed by manual paper feed in the future that requires air blowing control, CPU 101 turns on (drives) fan motors 511b and 512b (951 of FIG. 15) to rotate the fans. This causes air blowing to be performed prior to feeding of the sheet from the manual paper feed unit. Note that FIG. 15 illustrates an example in which the timing (951) for turning on fan motors 511b and 512b is the same as the feeding timing of the preceding sheet. However, as shown in FIG. 13, the timing for turning on fan motors 511b and 512b may also be the timing (851 of FIG. 13) of laser light for forming an image on the preceding sheet, for example. Next, air blowing continues while transporting the paper (631a, 631b) that requires air blowing from the manual feed section, and when the sheet feeding from the manual feed section is completed, the fan motors 511b, 512b are turned off (stopped) (952 in Figure 15).

[0077] Also, as with the above-mentioned determination S820, adjustments may be made while air is being blown, such as waiting for the fixing unit 201E to reach the fixing temperature. Even in this case, the fan may continue to rotate. The fan may also be stopped for "noise reduction" or other reasons. Restarting after stopping follows the flow shown in FIG. 14, omitting the start (S800) of the fan, pre-rotation (S802), and end of pre-rotation (S804).

[0078] As described above, even in the embodiment in which air blowing continues during manual paper feeding, the same reduction effect as in FIG. 11 can be obtained.

[0079] In all of the above-described embodiments, the image forming unit (printing unit) is an electrophotographic type, but the image forming apparatus may also be equipped with an inkjet type image forming unit. [Explanation of symbols]

[0080] 100 control section 103 RAM (setting means) 1 Feeding cassette (first sheet support portion) 4 Sheet feeding section (first sheet feeding section) 201B Image forming section 506 Sheet feeding unit (second sheet feeding unit) 511A, 512A Air blowing section 511b,512b Fan 6 Manual feed tray section (second sheet support section) S seat

Claims

1. an image forming unit that forms an image on a sheet; a first seat support portion that supports the seat; a first sheet feeding section that feeds the sheet supported by the first sheet supporting section; a second sheet support section rotatably provided on a side surface of the apparatus body including the image forming section and configured to support a sheet; an air blowing unit that blows air onto the sheet supported by the second sheet supporting unit; a second sheet feeding unit configured to feed the sheet supported by the second sheet supporting unit onto which air has been blown by the air blowing unit; a control unit that controls the air blowing unit to blow air onto the sheet supported by the second sheet supporting unit before a printing operation on the sheet fed from the first sheet feeding unit is completed when an image is formed on the sheet fed from the first sheet supporting unit and then an image is formed on the sheet fed from the second sheet supporting unit; An image forming apparatus comprising:

2. A setting unit for setting a print job is provided, the control means controls the air blowing unit to blow air onto the sheet supported by the second sheet support unit while a printing operation is being performed on the sheet fed by the first sheet feeding unit based on the information of the print job set by the setting means.

2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

3. a counting unit that counts the number of sheets fed from the second sheet feeding unit, the control unit executes an operation of blowing air onto the sheets supported by the second sheet support unit when the number of fed sheets counted by the counting unit is smaller than a predetermined number.

2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

4. the second sheet feeding unit feeds the sheet supported by the second sheet supporting unit when the air blowing unit is not performing the air blowing operation; 2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

5. the second sheet feeding unit feeds the sheet supported by the second sheet supporting unit in a state in which air is blown from the air blowing unit onto the sheet supported by the second sheet supporting unit; 2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

6. a setting unit for setting a mixed sheet printing job that executes a first printing job in which a sheet is fed from the first sheet supporting unit and an image is formed, followed by a second printing job in which a sheet is fed from the second sheet supporting unit and an image is formed, the control means controls the air blowing unit to blow air onto the sheet on the second sheet supporting unit before the sheet is fed from the first sheet feeding unit and the first print job is completed.

2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

7. the first sheet support section is provided at a lower portion of an apparatus main body including the image forming section; 2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

Images