Image forming apparatus

Abstract

An image forming apparatus is disclosed. An image forming apparatus includes an image forming portion, a driving portion configured to rotationally drive an image bearing member, a sheet supporting portion configured to support a sheet, a sheet blowing portion configured to perform a blowing operation, a sheet feeding portion configured to perform a feeding operation, and a control portion, and a control section configured to execute a mode in which the blowing operation is executed in a state in which the feeding operation is stopped in a predetermined period after a sheet fed by the sheet feeding section passes through the transfer position and before a subsequent sheet fed by the sheet feeding section passes through the transfer position, the toner image formed by the image forming portion is transferred to the sheet at a transfer position. The control portion is configured to control the driving portion to stop rotation of the image bearing member during the mode.

Description

Technical Field

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

[0002] JP H04-023747 A discloses a sheet feeding device including: a side guide defining the position of one side of a sheet; and a small blower attached to the side guide and blowing air toward the end surface of the sheet. US2023 / 0219776 describes that an air release part performs a blowing operation, and then a sheet feeding part performs a feeding operation in a state where the blowing operation is stopped.

[0003] In the configuration of US 2023 / 0219776, if the rotational drive of the photosensitive drum is continued during a period in which a job of forming images on a plurality of sheets is performed and a feeding operation is stopped to perform a blowing operation, the amount of wear of the photosensitive drum relative to the cumulative number of printed sheets increases. As a result, the number of printable sheets of the photosensitive drum may decrease. That is, in an image forming apparatus that performs an adjustment operation during job execution, it is required to suppress a decrease in the number of printable sheets of the photosensitive member. Summary of the invention

[0004] The present invention provides an image forming apparatus which can suppress a decrease in the number of printable sheets of a photosensitive member when a blowing operation of blowing air toward sheets is performed during job execution and in a state where a feeding operation of feeding sheets is stopped.

[0005] According to one aspect of the present invention, an image forming device configured to form an image on a sheet includes: an image forming portion, the image forming portion including: a rotatable image bearing member; a charging unit, the charging unit configured to charge the image bearing member; an exposure unit, the exposure unit configured to expose the image bearing member charged by the charging unit to form an electrostatic latent image on the image bearing member; and a developing unit, the developing unit configured to develop the electrostatic latent image formed on the image bearing member with a developer; a driving portion, the driving portion configured to rotationally drive the image bearing member; a sheet supporting portion, the sheet supporting portion configured to support the sheet; and a sheet blowing portion, the sheet blowing portion. A sheet feeding portion configured to perform a blowing operation of blowing air toward a sheet supported on the sheet supporting portion; a sheet feeding portion configured to perform a feeding operation of feeding a sheet supported on the sheet supporting portion; and a control portion configured to execute the following mode: in a predetermined period of time after a sheet fed by the sheet feeding portion passes through a transfer position and before a subsequent sheet fed by the sheet feeding portion passes through the transfer position, the blowing operation is performed in a state where the feeding operation is stopped, and a colorant image formed by the image forming portion is transferred to the sheet at the transfer position, wherein the control portion is configured to control the driving portion to stop the rotation of the image bearing member during the mode.

[0006] According to another aspect of the present invention, an image forming device configured to form an image on a sheet includes: an image forming part, the image forming part including: a rotatable image bearing member; a charging unit, the charging unit configured to charge the image bearing member; an exposure unit, the exposure unit configured to expose the image bearing member charged by the charging unit to form an electrostatic latent image on the image bearing member; and a developing unit, the developing unit configured to develop the electrostatic latent image formed on the image bearing member with a developer; a driving part, the driving part configured to rotationally drive the image bearing member; a sheet supporting part, the sheet supporting part configured to support the sheet; and a sheet blowing part, the sheet blowing part configured to perform a blow to the sheet supported on the sheet supporting part. a sheet feeding portion, the sheet feeding portion being configured to perform a feeding operation of feeding the sheet supported on the sheet supporting portion; and a control portion, the control portion being configured to execute the following mode: in a predetermined period of time after a sheet fed by the sheet feeding portion passes through a transfer position and before a subsequent sheet fed by the sheet feeding portion passes through the transfer position, the blowing operation is performed in a state where the feeding operation is stopped, and a toner image formed by the image forming portion is transferred to the sheet at the transfer position, wherein the control portion is configured to control the driving portion during the mode so that a rotation speed of the image bearing member during the mode is slower than a rotation speed of the image bearing member during formation of an image on the sheet.

[0007] Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 is a schematic diagram of an image forming apparatus according to an embodiment.

[0009] Figure 2 is a block diagram illustrating a control system of the image forming apparatus according to the embodiment.

[0010] Figure 3 is a schematic diagram illustrating an extension feeder according to an embodiment.

[0011] Figure 4 is a schematic diagram illustrating an extension feeder according to an embodiment.

[0012] Figure 5 is a flowchart illustrating a print job control method according to an embodiment.

[0013] Figure 6 is a graph showing the relationship between environmental conditions and air blowing time in Example 1.

[0014] Figure 7 is a flowchart illustrating a print job control method according to Example 1.

[0015] Figure 8 is a sequence diagram illustrating an operation state of the image forming apparatus according to Example 1.

[0016] Fig. 9 is a flowchart illustrating a print job control method according to Example 1.

[0017] Fig.10 is a sequence diagram showing an operation state of the image forming apparatus in Example 1.

[0018] Fig.11A is a graph illustrating the relationship between the length of the air blowing time and the rate of decrease in the number of printable sheets of the photosensitive drum.

[0019] Fig. 11B is a graph illustrating the relationship between the length of the air blowing time and the rate of decrease in productivity of the image forming apparatus.

[0020] Fig.12 is a flowchart illustrating a print job control method of Example 2.

[0021] Fig.13 is a sequence diagram showing an operation state of the image forming apparatus in Example 2.

[0022] Fig.14 is a flowchart illustrating a print job control method in Example 3.

[0023] Fig.15 is a sequence diagram showing an operation state of the image forming apparatus in Example 3. DETAILED DESCRIPTION

[0024] Hereinafter, embodiments according to the present disclosure will be described with reference to the accompanying drawings.

[0025] Figure 1 1 is a diagram illustrating a schematic configuration of an image forming apparatus 200 according to an embodiment. The image forming apparatus 200 includes a printer 201 as an image forming apparatus main body and an extension feeder 500 connected to the printer 201. The extension feeder 500 is connected to Figure 1 , and is configured to feed the sheet S to the printer 201 .

[0026] The image forming apparatus 200 is a system (image forming system) including a printer 201 that can be used alone as an image forming apparatus and an extension feeder 500 as an optional device connected to the printer 201. The image forming apparatus 200 may include optional devices in addition to the extension feeder 500. Examples of such optional devices include a sheet processing device (finisher) that performs processing such as stapling processing on sheets on which images have been formed by the printer 201, and a large-capacity stacker configured to load a large amount of printed products.

[0027] Image forming device like Figure 1 As shown in , the printer 201 includes a printer body 201A, an image reading device 202, and an operation unit 730. The printer body 201A includes an image forming portion 201B as a component or an image forming unit for forming an image. The image reading device 202 is installed above the printer body 201A in a substantially horizontal posture. A sheet discharge space V is formed between the image reading device 202 and the printer body 201A. The operation unit 730 is disposed above the printer body 201A and on the front side of the image reading device 202. The operation unit 730 is a user interface of the image forming device 200, and includes a display unit (such as a touch panel) configured to display a screen and an input unit (such as a numeric keypad and a print execution button).

[0028] The image forming portion 201B of the present embodiment is an intermediate transfer tandem type electronic photographic mechanism. In other words, the image forming portion 201B is a 4-drum full-color system. The image forming portion 201B includes an exposure unit 210 and four process cartridges 211Y, 211M, 211C, and 211K that form toner images of four colors, namely yellow (Y), magenta (M), cyan (C), and black (K). The image forming portion 201B includes an intermediate transfer unit 201C, a secondary transfer roller 217, and a fixing portion 201E. In addition, the image forming portion 201B includes various motors (a drum drive motor 610, a belt drive motor 611, a developer drive motor 612, etc.) and various high voltage power supplies (a charging power supply 600, a developer power supply 601, a primary transfer power supply 602, etc.) ( Figure 2 ).

[0029] Each of the process cartridges 211Y, 211M, 211C, and 211K has a photosensitive drum 212 as a photosensitive member (image bearing member), and is a process unit for forming a toner image by an electrophotographic process on the surface of the photosensitive drum 212. Each of the process cartridges 211Y, 211M, 211C, and 211K is detachable from a cartridge mounting unit provided in the printer body 201A.

[0030] Each of the process cartridges 211Y, 211M, 211C, and 211K includes a photosensitive drum 212, a charger 213 as a charging unit or charging member, a developing unit 214 as a developing unit or developing member, and a cleaning blade 231 as a cleaning unit or cleaning member. The photosensitive drum 212 is a photosensitive member molded into a drum shape (cylindrical shape), and includes a photosensitive layer made of a photosensitive material such as an organic photosensitive material. The charger 213 is, for example, a charging roller disposed to contact or approach the surface (peripheral surface) of the photosensitive drum 212 and to charge the surface of the photosensitive drum 212 by proximity discharge. The charger 213 is not limited to a charging roller, and may be, for example, a corona charger that charges the surface of the photosensitive drum 212 by corona discharge from a wire. The developing unit 214 includes a housing portion (developing container) that accommodates a developer containing a toner, and a developing roller 214a (developer carrying member) that carries the developer and supplies the developer to the photosensitive drum 212.

[0031] The cleaning blade 231 is a plate-like member having appropriate elasticity and extending in the direction of the rotation axis of the photosensitive drum 212. In the cleaning blade 231, the blade tip contacts the surface of the photosensitive drum 212 with a predetermined contact pressure. In the present embodiment, the cleaning blade 231 is disposed so that the direction toward the tip of the cleaning blade 231 is opposite to the rotation direction of the photosensitive drum 212 (reverse direction). Note that the cleaning blade 231 may be disposed so that the direction toward the tip of the cleaning blade 231 is the direction along the rotation direction of the photosensitive drum 212 (width direction).

[0032] The printer body 201A also includes a toner cartridge 215 for supplying toner to the developing units 214 of the process cartridges 211Y, 211M, 211C, and 211K.

[0033] The intermediate transfer unit 201C is disposed above the four process boxes 211Y to 211K. The intermediate transfer unit 201C includes an intermediate transfer belt 216 as an intermediate transfer member, a drive roller 216a, a tension roller 216b, and four primary transfer rollers 219. The intermediate transfer belt 216 is an endless belt wound around the drive roller 216a and the tension roller 216b. Each primary transfer roller 219 is disposed inside the intermediate transfer belt 216 to abut against the intermediate transfer belt 216 at a position facing a corresponding one of the photosensitive drums 212. If the drive roller 216a is driven by a driving portion (not shown), the intermediate transfer belt 216 rotates in the arrow direction in the figure.

[0034] The secondary transfer roller 217 is disposed so as to contact the outer surface of the intermediate transfer belt 216 at a position facing the driving roller 216 a. The secondary transfer roller 217 is an example of a transfer unit or a transfer member (secondary transfer unit / member) that transfers the image formed on the intermediate transfer belt 216 to the sheet S. The secondary transfer portion 201D is formed as a nip portion between the intermediate transfer belt 216 and the secondary transfer roller 217.

[0035] The fixing portion 201E is disposed above the secondary transfer portion 201D. The fixing portion 201E includes a heating roller 220b as a heating member (fixing member), a pressure roller 220a as a pressure member, and a heating unit or a heating member for heating the heating roller 220b. A fixing nip portion is formed between the heating roller 220b and the pressure roller 220a. The heating unit is, for example, a halogen lamp or a coil unit for induction heating.

[0036] The printer body 201A further includes a cassette feeding portion 230, a manual feeding portion 235, and a registration roller pair (hereinafter, referred to as a registration roller pair 240). The printer body 201A includes a first sheet discharge roller pair 225a, a second sheet discharge roller pair 225b, a double-sided reversing portion 201F, and a stacking portion 223 (sheet discharge tray).

[0037] The cassette feeding portion 230 is provided at the lower portion of the printer body 201A. In the present embodiment, the printer body 201A includes four stages of cassette feeding portions 230 arranged vertically. The cassette feeding portion 230 feeds the sheets S stacked in the cassette 1 one by one toward the image forming portion 201B through the feeding unit 5.

[0038] Each box feeding portion 230 includes a box 1 (storage unit, storage device and feeding tray) storing sheets S and a feeding unit 5 as a sheet feeding portion or sheet feeding member feeding sheets S. In the box 1, a support plate (middle plate) as a sheet supporting portion supporting a sheet bundle is provided. The feeding unit 5 includes a pickup roller 2 feeding sheets S from the box 1, and a separation roller pair as a separation unit or separation member separating sheets S in the case where the pickup roller 2 feeds a plurality of sheets S. The pair of separation rollers includes a feeding roller 3 rotating along the sheet feeding direction, and a retard roller to which a driving force in a direction opposite to the sheet feeding direction is input via a torque limiter. The roller pair including the retard roller is an example of a separation unit / member, and the sheets S can be separated by, for example, a pad-shaped elastic member (friction pad) adjacent to the feeding roller 3. In addition, the feeding unit 5 including three rollers is an example of a feeding unit / member, and, for example, a separation member such as a friction pad can be in contact with a roller member feeding sheets S from the box 1.

[0039] A manual feeding portion 235 (multi-purpose feeding unit) is provided on the right side portion (side surface) of the printer body 201A. The manual feeding portion 235 includes a manual feeding tray 6 as a sheet supporting portion (sheet supporting unit) that supports the sheet S and a feeding unit 5 as a sheet feeding portion that feeds the sheet S. The configuration of the feeding unit may be the same as that of the feeding unit 5 of the cassette feeding portion 230. The manual feeding portion 235 feeds the sheets S placed on the manual feeding tray 6 protruding to the right side of the printer body 201A by the user one by one toward the image forming portion 201B through the feeding unit 5.

[0040] Note that the cassette feeding portion 230, the manual feeding portion 235, and the extension feeder 500 are all examples of a sheet feeding module that feeds the sheet S in the image forming apparatus 200. The details of the extension feeder 500 will be described later.

[0041] A first sheet discharge roller pair 225a, a second sheet discharge roller pair 225b, and a part of the double-sided reversing section 201F are disposed above the fixing section 201E. The first sheet discharge roller pair 225a and the second sheet discharge roller pair 225b are dischargers that discharge the sheet S on which an image is formed. The double-sided reversing section 201F includes a reversing conveying roller pair 222 configured to rotate in a forward direction and a reversing direction, and a re-conveying path R. In the case of an image forming operation (double-sided printing) in which images are formed on both sides of the sheet S, the double-sided reversing section 201F is configured to reverse the sheet S on which an image is formed on the first surface by the reversing conveying roller pair 222, and to convey the sheet S toward the image forming section 201B again via the re-conveying path R.

[0042] Image forming operation Next, description will be given of an image forming operation of the printer 201. Here, a case where an image is formed on a sheet S based on image information read from a document by the image reading device 202 will be described.

[0043] First, if the image information of the document is read by the image reading device 202, the image information is subjected to image processing and then transmitted to the exposure unit 210 of the image forming part 201B as a video signal. In the image forming part 201B, the photosensitive drum 212 is rotationally driven in advance at a predetermined peripheral speed in each of the process boxes 211Y to 211K. The charger 213 charges the surface of the corresponding photosensitive drum 212 uniformly to a predetermined polarity and potential by being applied with a charging bias (charging voltage). The exposure unit 210 irradiates each photosensitive drum 212 with light based on the video signal to expose the photosensitive drum 212. As a result, electrostatic latent images corresponding to the monochrome images of yellow, magenta, cyan and black are formed on each photosensitive drum 212. The developing unit 214 supplies a developer containing a toner to the corresponding photosensitive drum 212, and develops the electrostatic latent image into a monochrome toner image. Specifically, if a developing bias (developing voltage) is applied to the developing roller 214a, the toner is transferred from the developing roller 214a to the photosensitive drum 212 by the potential difference between the surface of the photosensitive drum 212 and the developing roller 214a. As a result, the toner adheres according to the potential distribution on the surface of the photosensitive drum 212, and the electrostatic latent image is visualized as a toner image.

[0044] Thereafter, if a transfer bias (primary transfer voltage) is applied to each primary transfer roller 219, a single-color toner image is primarily transferred from each photosensitive drum 212 to the intermediate transfer belt 216. During the primary transfer, multiple transfers are performed so that the single-color toner images of four colors overlap each other, thereby forming a full-color toner image on the intermediate transfer belt 216. Foreign matter (such as transfer residual toner) remaining on the photosensitive drum 212 without being transferred to the intermediate transfer belt 216 is scraped off by the cleaning blade 231 and removed from the surface of the photosensitive drum 212.

[0045] In parallel with the image forming portion 201B creating a toner image, sheets S are fed one by one toward the image forming portion 201B from any one of the cassette feeding portion 230, the manual feeding portion 235, and the extension feeder 500. For example, if the sheet S is fed from the cassette feeding portion 230, the sheet S is fed from the cassette 1 by the pickup roller 2, and the sheet S is conveyed toward the registration roller pair 240 by the feed roller 3.

[0046] The leading end of the sheet S abuts against the nip portion of the registration roller pair 240 in the stopped state, and forms a deflection (loop) of the sheet S. Therefore, the leading end of the sheet S turns to follow the nip portion of the registration roller pair 240, and the relatively slight skew of the sheet S is corrected. Thereafter, the driving of the registration roller pair 240 is started, and the sheet S is conveyed to the secondary transfer portion 201D.

[0047] In the secondary transfer section 201D, if a transfer bias (secondary transfer voltage) is applied to the secondary transfer roller 217, the image (full-color toner image) is secondarily transferred from the intermediate transfer belt 216 to the sheet S. The sheet S having passed the secondary transfer section 201D is conveyed to the fixing section 201E and subjected to image fixing processing. The fixing section 201E heats and presses the toner on the sheet S while gripping and conveying the sheet S at the fixing nip section, thereby fixing the image on the sheet S.

[0048] In the case of single-sided printing in which an image is formed only on the first surface of the sheet S, the sheet S having passed through the fixing portion 201E is discharged to the sheet discharge space V by the first sheet discharge roller pair 225a or the second sheet discharge roller pair 225b, and is stacked on the stacking portion 223 provided at the bottom of the sheet discharge space V. In the case of double-sided printing in which an image is formed on the first surface and the second surface of the sheet S, the sheet S having the image transferred on the first surface and having passed through the fixing portion 201E is sent out to the reverse conveying roller pair 222. The sheet S is reversely conveyed by the reverse conveying roller pair 222, conveyed again to the registration roller pair 240 via the re-conveying path R, and subjected to skew feed correction. Then, an image is formed on the second surface of the sheet S while the sheet S passes through the secondary transfer portion 201D and the fixing portion 201E again. The sheet S on which images are formed on the first and second surfaces is discharged to the sheet discharge space V by the first sheet discharge roller pair 225 a or the second sheet discharge roller pair 225 b , and is stacked on the stacking portion 223 .

[0049] Extension Feeder Next, we will refer to Figure 1 , Figure 3 and Figure 4 The details of the extension feeder 500 are described. Figure 3 is a schematic diagram illustrating the configuration of the extension feeder 500 according to the present embodiment. Figure 4 : is a schematic diagram illustrating a cross section of the extension feeder 500 according to the present embodiment cut in the sheet width direction.

[0050] The extension feeder 500 is a large-capacity sheet feeding device configured to accommodate and continuously feed more sheets S than the cassette feeding portion 230 in the printer 201. Figure 1 As shown in , the extension feeder 500 includes a storage device 510 (storage shelf) as a sheet storage device, a feeding unit 506 as a feeding portion that feeds sheets, a pulling roller pair 504 , and a feeding sensor 505 .

[0051] The feeding unit 506 includes a pickup roller 501 that feeds a sheet S from a storage device 510, and a separation roller pair as a separation unit or separation member that separates the sheets S in a case where the pickup roller 501 feeds a plurality of sheets S. The pair of separation rollers includes a feed roller 502 that rotates in a sheet feeding direction, and a retard roller 503 to which a driving force in a direction opposite to the sheet feeding direction is input via a torque limiter.

[0052] The traction roller pair 504 is disposed on the downstream side of the feed roller pair 502 in the feeding direction. The traction roller pair 504 pulls the sheet S from the separation roller pair and conveys the sheet S toward the printer 201. The feeding sensor 505 detects the sheet S at a detection position between the feed roller 502 and the traction roller pair 504 in the sheet feeding direction. The feeding sensor 505 outputs a detection signal corresponding to the presence or absence of the sheet S at the detection position. The control portion of the extension feeder 500 or the printer 201 can detect the passage of the sheet S based on the detection signal of the feeding sensor 505 and monitor the feeding operation.

[0053] like Figure 3 As shown in FIG. 5 , the storage device 510 includes a lifting plate 514 , side end restriction plates 511 and 512 , a rear edge restriction plate 513 , and air blowing portions 511A and 512A.

[0054] The lifting plate 514 is a sheet supporting portion (stacking portion) on which a plurality of sheets S (sheet bundle) are stacked and supports the stacked sheet bundle. The lifting plate 514 can be raised and lowered relative to the housing of the storage device 510 by a lifting mechanism (hanging wire and wire winding mechanism) (not shown). The position of the lifting plate 514 is controlled according to the stacking amount of the sheet bundle so that, for example, the uppermost sheet S has a height fed by the feeding unit 506.

[0055] The side end restriction plates 511 and 512 restrict the positions of the ends of the sheets S stacked on the lifting plate 514 (side ends of the sheets S) in the sheet width direction orthogonal to the sheet feeding direction. The trailing edge restriction plate 513 restricts the position of the upstream end of the sheet S (the trailing edge of the sheet) in the sheet feeding direction.

[0056] The air blowing portions 511A and 512A are mechanisms (sheet blowing portions) configured to loosen the sheets S by blowing air toward the end faces of the sheet bundle loaded on the lifting plate 514. The "loosening" of the sheets S means that the adhesion between the overlapping sheets is weakened, so that the sheets S are easily separated when fed by the feeding unit 506 (double feeding is less likely to occur).

[0057] like Figure 3 and Figure 4 As shown in FIG. 1 , air blowing portions 511A and 512A of the present embodiment are incorporated in the side end restricting plates 511 and 512 , respectively.

[0058] The air blowing portion 511A includes a fan 511b and a blowing nozzle 511a. The fan 511b is a unit in which a rotary blade that generates an air flow and a motor that rotates the rotary blade are integrated. The blowing nozzle 511a is formed to guide the air from the fan 511b and blow the air to the side end of the sheet bundle on the lifting plate 514. The blowing nozzle 511a opens at the limiting surface (the surface facing the side end of the sheet bundle) of the side end limiting plate 511.

[0059] Similarly, the air blowing portion 512A includes a fan 512b and a blowing nozzle 512a. The fan 512b is a unit in which a rotary blade that generates an air flow and a fan motor that rotates the rotary blade are integrated. The blowing nozzle 512a is formed to guide the air from the fan 512b and blow the air to the other side end of the sheet stack on the lifting plate 514. The blowing nozzle 512a opens at the limiting surface (the surface facing the side end of the sheet stack) of the side end limiting plate 512.

[0060] Furthermore, the side end restriction plates 511 and 512 are provided with holding plates 511 c and 512 c for restricting the sheet S blown with air from floating up and passing over the side end restriction plates 511 and 512 in the vicinity of the opening portions of the blowing nozzles 511 a and 512 a .

[0061] The fans 511 b and 512 b may be, for example, sirocco fans or propeller fans (axial flow fans). The air blowing portions 511A and 512A may be disposed as separate units that are not incorporated in the side end restriction plates 511 and 512 .

[0062] Control system for image forming system Next, we will refer to Figure 2 The configuration of a control system in the image forming apparatus 200 is described. Figure 2 is a block diagram illustrating a control system of the image forming system according to the present embodiment.

[0063] The control section 100 according to the present embodiment is provided, for example, in the printer 201. The control section 100 is a control circuit including a CPU 101 that executes a program for controlling the image forming apparatus, and a ROM 102 and a RAM 103 as a storage unit storing programs and data for controlling the image forming apparatus. The control section 100 is a controller or a control means that controls the operation of the entire image forming apparatus 200 including the extension feeder 500. The image forming apparatus 200 may include a sub-control section mounted on the extension feeder 500 so as to control each unit of the extension feeder 500 based on a command from the control section 100.

[0064] The control section 100 is connected to the host device and the operation unit 730, and performs signal processing, sequence control, etc. on various processing devices while exchanging information with the host device 900 and the operation unit. Note that the host device 900 is an external device such as a personal computer, an image scanner, or a facsimile machine.

[0065] Furthermore, the control portion 100 is electrically connected to the above-mentioned fans 511 b and 512 b , the feed sensor 505 , various motors ( 520 , 521 , 610 , 611 , 612 ), various high voltage power supplies ( 600 , 601 , 602 ), and an environment sensor 620 .

[0066] The feeding motor 520 is a driving source for driving the feeding unit 506. The conveying motor 521 is a driving source for driving the traction roller pair 504. The charging power source 600 is a power source for generating power to be applied to the charger 213 ( Figure 1 ) of the charging voltage. The developing power supply 601 is a circuit for generating a charging voltage to be applied to the developing roller 214a ( Figure 1 The primary transfer power supply 602 is a circuit for generating a developing voltage to be applied to each primary transfer roller 219 ( Figure 1 ) of the primary transfer voltage. The drum drive motor 610 is a drive source or a drive portion that rotationally drives each photosensitive drum 212. The belt drive motor 611 is a drive roller 216a ( Figure 1 ) is a driving source. The developing drive motor 612 is a driving source for rotating the developing roller 214a ( Figure 1 The environment sensor 620 is an example of an environment detection portion or an environment detection member that detects an environmental condition of an environment in which the image forming apparatus 200 is installed, and detects, for example, the temperature and humidity of air entering into a housing of the image forming apparatus 200.

[0067] During the execution of the image forming operation, the drum drive motor 610 and the belt drive motor 611 rotationally drive each photosensitive drum 212 and the intermediate transfer belt 216 at a predetermined rotation speed (peripheral speed). The predetermined rotation speed is the length of the toner image created by the image forming portion 201B per unit time in the sub-scanning direction, and is referred to as a process speed.

[0068] Operation during air blowing Next, we will refer to Figure 4 The state of the sheets S in the case where air is blown toward the sheet bundle by the air blowing portions 511A and 512A is described. Figure 4 A state in which the air blowing portions 511A and 512A perform an operation of blowing air toward a sheet bundle (hereinafter, referred to as “air blowing operation”) in the extension feeder 500 according to the present embodiment is illustrated.

[0069] like Figure 4 As shown in FIG. 1 , the air sent from the fans 511b and 512b of the air blowing parts 511A and 512A flows along the blowing nozzles 511a and 512a as indicated by arrows A1 and A2, and is blown to the side surface of the sheet stack. Then, the air enters the gap between several sheets to several tens of sheets located above the sheet stack, and the sheet stack S floats. The retaining plates 511c and 512c suppress excessive floating of the sheet stack S.

[0070] By making the sheets S float by air to reduce the adhesive force between the sheets (loosen the sheet bundle), the feeding of the sheets S becomes easier. For example, in the case of the sheets S having smooth surface characteristics (such as coated paper), the feeding of the pickup roller 501 may not be performed normally because the adhesive force between the sheets is strong. Specifically, even if the pickup roller 501 applies a conveying force to the uppermost sheet S, the uppermost sheet S may not be in close contact with the lower sheets S. Since the adhesive force between the sheets is reduced by loosening the sheet bundle by blowing air, the pickup roller 501 easily feeds the uppermost sheet S.

[0071] Hereinafter, driving the fans 511b and 512b to blow air toward the sheet bundle is referred to as an "air blowing operation" or an air loosening operation. The air blowing operation is an example of an adjustment operation for adjusting a condition related to sheet feeding. The air blowing operation of the present embodiment is performed so as to weaken (reduce) the adhesive force between sheets, which is a condition related to sheet feeding, to an extent that stable feeding of the feeding unit 506 becomes possible.

[0072] The air loosening portions 511A and 512A described in the present embodiment are examples of an air loosening mechanism that loosens sheets using air, and an air loosening mechanism having another configuration may be used. For example, an air loosening mechanism that blows air toward the tip end of a sheet bundle (the downstream end in the sheet feeding direction) may be used instead of or in addition to the air blowing portions 511A and 512A that blow air toward the side ends (ends in the sheet width direction) of the sheet bundle.

[0073] Basic workflow of printing jobs Next, we will refer to Figure 5 The basic flow of a print job according to the present embodiment is described. Figure 5 4 is a flowchart illustrating an example of control related to control of a print job in a case where the sheet S is fed from the extension feeder 500 . Figure 5 The control content shown in is the basis of the control in each example described below.

[0074] If a print job (also referred to simply as a "job") is input, the control section 100 starts the following processing (S201). A print job or an image forming job is a series of tasks for forming an image on each sheet S while conveying the sheets S one by one in the image forming apparatus and outputting a product. Assume that the number of sheets S on which images are formed in the print job (the number of sheets required) is set by the operation unit 730 ( Figure 1 ) or a screen operation in the host device or is specified in advance by the user when inputting a print job. The print job includes the above-mentioned image forming operation, the preparation operation before starting the image forming operation, and the post-processing operation after completing the image forming operation. The image forming operation includes the feeding operation of the sheet feeding section feeding one sheet S and the operation of the image forming section 201B forming an image on the sheet S. As described below, the air blowing operation may be performed as a part of the preparation operation before the image forming operation of the first sheet of the print job is started, or may be performed after the image forming operation of the first sheet is started.

[0075] If the execution of the print job is started, the control part 100 performs the air blowing operation (Sα). Specifically, in the extension feeder 500, if the fans 511b and 512b of the air blowing parts 511A and 512A are driven based on the command from the control part 100 (S202), the air blowing operation is started. If a predetermined time has passed from the start of the driving of the fans 511b and 512b ("Yes" in S203), the driving of the fans 511b and 512b is stopped (S204), and the air blowing operation ends. By performing the air blowing operation, the sheet stack is loosened. That is, several to several tens of sheets S above the sheet stack on the lifting plate 514 float up, and the adhesive force between the sheets is reduced.

[0076] The predetermined time is the time length (hereinafter referred to as the air blowing time) for blowing air to the sheet stack by the air blowing operation. The air blowing time is the time length of the air blowing operation as an example of the adjustment operation. The air blowing time in the present embodiment is the time length from the start of the driving of the fans 511b and 511b (the start of the energization of the fan motor) to the stop of the driving of the fans 511b and 512b (the interruption of the energization of the fan motor). Since the fans 511b and 512b are driven from the rotation stop state, it is expected that the time until the rotation speed (rotation speed) of the fans 511b and 512 reaches the desired rotation speed and the time until the floating of the sheet S is stabilized are regarded as the air blowing time. For example, the predetermined time is set to 10 seconds. The predetermined time can be set to different values ​​according to the material of the sheet S (especially, whether the material has high smoothness, such as coated paper) and / or size.

[0077] After the air blowing operation, a feeding operation (S205) is performed. The feeding operation is a series of operations of feeding one sheet S toward the image forming portion 201B by the feeding unit 506 as a sheet feeding portion. In the present embodiment, a series of operations from starting the driving of the feeding unit 506 by the feeding motor 520 in a state where the pickup roller 501 is in contact with the uppermost sheet S until the feeding sensor 505 detects the trailing edge of the sheet S is referred to as a "feeding operation".

[0078] Specifically, in the extension feeder 500, the feeding unit 506 is driven by the feeding motor 520 in a state where the pickup roller 501 is abutted against the topmost sheet S based on the start command (S205) of the feeding operation from the control portion 100. Therefore, the sheet S is fed out from the storage device 510 by the pickup roller 501, and the sheet S is separated by the feeding roller 502 and the retard roller 503. The sheet S having passed through the separation nip portion between the feeding roller 502 and the retard roller 503 is further conveyed and delivered to the printer body 201A by the traction roller pair 504 driven by the conveying motor 521. In addition, in the process of conveying the sheet S from the separation nip portion to the traction roller pair 504, the leading end and the trailing edge of the sheet S are detected by the feeding sensor 505.

[0079] From the start of the print job until the number of sheets S fed by the feeding operation (S205) (hereinafter, the number of sheets fed after the start of the job is referred to as the number of sheets fed after the start of the job) reaches the required number of sheets for the print job (i.e., when S206 is "No"), the feeding operation is repeated for each sheet S. If the number of sheets S fed from the extension feeder 500 reaches the required number of sheets in the print job ("Yes" in S206), the control section 100 ends the processing (S207).

[0080] In the present embodiment, the air blowing operation (Sα) is not performed while the feeding operation (S205) is performed. This is to reduce the possibility of skew feeding of the sheet S due to the simultaneous performance of the feeding operation and the air blowing operation. Specifically, if the sheet S floats due to the air, the sheet S may be bent, and the side ends of the sheet S may be separated from the side end restriction plates 511 and 512. In this case, the skew feeding suppression effect of the side end restriction plates 511 and 512 on the sheet S is reduced, and therefore, skew feeding may occur in the sheet S. If the skew feeding amount of the fed sheet S (the inclination of the front end of the sheet with respect to the width direction of the sheet) is large, the skew feeding cannot be sufficiently corrected by the skew feeding correction using the registration roller pair 240, and the image may be tilted. Therefore, in the present embodiment, the air blowing operation is not performed while the feeding operation is performed.

[0081] While the feeding operation (S205) is repeatedly performed, the sheets S floated by the air blowing operation (Sα) fall due to gravity, and the air between the sheets gradually escapes. That is, the sheet bundle gradually returns to the state before the air blowing operation is performed (the state in which the adhesive force between the sheets is strong). In addition, if the number of sheets in the sheet bundle stacked on the lifting plate 514 is large, it is difficult to loosen all the sheets S in the sheet bundle in one air blowing operation.

[0082] Therefore, in the present embodiment, whenever the number of sheets S fed by the feeding operation (S205) from the start of the print job (i.e., the number of sheets fed after the start of the job) increases by a predetermined number, the feeding operation is temporarily stopped and the air blowing operation (Sα) is performed. That is, before the number of sheets fed after the start of the job reaches the required number of sheets for the print job (“No” in S206), if the number of sheets fed after the start of the job increases by a predetermined number from the end of the previous air blowing operation (“Yes” in S208), the control section 100 performs the air blowing operation. The control section 100 does not perform the air blowing operation until the number of sheets fed after the start of the job increases by a predetermined number from the previous air blowing operation (“No” in S208).

[0083] The "predetermined number of sheets" is set to the number of sheets S that can be loosened by one air blowing operation. In other words, the "predetermined number of sheets" indicates the number of sheets S that can be fed without performing the air blowing operation again after performing the air blowing operation.

[0084] The predetermined number of sheets is set to, for example, 10 sheets. In this case, if the required number of sheets of the print job is 10 sheets or less, after the air blowing operation (Sα) is performed before the first sheet S is fed, 10 sheets S are fed without performing the air blowing operation again. On the other hand, if the required number of sheets of the print job is 50, after the air blowing operation (Sα) is performed before the first sheet S is fed, the air blowing operation (Sα) is performed once each time the number of sheets fed after the start of the job increases by 10 sheets. Therefore, the air blowing operation (Sα) is performed five times in total until the print job is completed.

[0085] If the feeding operation is repeated without performing the air blowing operation (Sα) (No in S208), the feeding operation of the next sheet is started at a predetermined interval (sheet interval) after the previous sheet feeding operation is completed. If the air blowing operation (Sα) is performed (Yes in S208), the time from the completion of the feeding operation of the previous sheet to the start of the feeding operation of the next sheet (the sheet fed first after the air blowing operation) may be longer than the predetermined interval.

[0086] As described above, in the present embodiment, if a print job of a required number of sheets larger than a predetermined number of sheets is performed, the feeding operation is temporarily stopped and the air blowing operation (Sα) is performed, and the feeding operation is resumed after the air blowing operation (Sα) is performed. In other words, in the case of performing a job of forming images on a number of sheets larger than a predetermined number of sheets, the control section is configured to stop the feeding operation after a predetermined number of sheets are fed by the sheet feeding section, perform an adjustment operation for adjusting a condition related to the feeding of sheets, and resume the feeding operation after performing the adjustment operation.

[0087] Meanwhile, during the execution of the print job, the image forming portion 201B is usually continuously driven. However, if the image forming portion 201B is continuously driven while the feeding operation is temporarily stopped and the air blowing operation is performed, the amount of wear of the photosensitive drum 212 relative to the cumulative number of printed sheets of the image forming apparatus 200 may increase.

[0088] That is, since the sheet S is not fed to the image forming portion 201B while the feeding operation is interrupted to perform the air blowing operation, the creation of the toner image to be formed on the sheet S in the image forming portion 201B is also stopped. As described above, since the time during which the image forming portion 201B is driven becomes longer even if the toner image is not generated, the amount of wear of the photosensitive drum 212 relative to the cumulative number of printed sheets increases. That is, the amount of wear of the photosensitive drum 212 relative to the cumulative number of printed sheets of the image forming apparatus 200 increases compared to the case where the air blowing operation is not performed or the case where the air blowing operation is performed simultaneously with the feeding operation without stopping the feeding operation. Therefore, the number of printable sheets on the photosensitive drum 212 (the cumulative number of printed sheets requiring replacement of the cartridge) can be reduced compared to the case where the air blowing operation is not performed. Furthermore, if the photosensitive drum 212 is part of the process cartridges 211Y to 211K, the printable sheet number of the process cartridges (the cumulative print sheet number requiring cartridge replacement) can be smaller than that without performing the air blowing operation.

[0089] The wear rate of the photosensitive drum 212 varies due to various factors. For example, the photosensitive drum 212 is worn by the cleaning blade 231 ( Figure 1) and wears due to friction with the intermediate transfer belt 216. If a charging voltage is applied to the charger 213, the surface of the photosensitive drum 212 deteriorates due to discharge between the charger 213 and the photosensitive drum 212, and wear of the photosensitive drum 212 is promoted. Although the cause of wear of the photosensitive drum 212 varies depending on the specific configuration of the image forming portion 201B, basically, wear of the photosensitive drum 212 progresses during the period when the image forming portion 201B is driven. Even in a configuration in which the cleaning blade 231 is not provided, the photosensitive drum 212 may also wear due to friction with the intermediate transfer belt 216 or the like.

[0090] Therefore, in each example of the present embodiment described below, if the air blowing operation is performed during the execution of the print job, processing such as temporarily stopping the drive of the image forming part 201B is performed. Therefore, the progress of the wear of the photosensitive drum 212 can be suppressed when the feeding operation is interrupted to perform the air blowing operation.

[0091] Example 1 The control of the image forming apparatus 200 according to Example 1 will be described. In Example 1, in the case where the feeding operation is temporarily stopped and the air blowing operation is performed during the execution of the print job, the operation of the image forming part 201B is temporarily stopped. In addition, the execution suitability and execution time (air blowing time) of the air blowing operation are changed according to the type of the sheet S to be fed and the environmental conditions of the installation site of the image forming apparatus 200.

[0092] First, description will be given of whether to perform the air blowing operation according to the kind of the sheet S. It is assumed that the type of the sheet S is set in advance by the user through a screen operation of the operation unit 730 or the like when inputting a print job.

[0093] In Example 1, if the type of sheet S used in the print job is a sheet with a weak adhesive force between sheets, the air blowing operation is not performed. An example of a sheet with a weak adhesive force between sheets is ordinary paper. By not performing the air blowing operation on a sheet with a weak adhesive force between sheets, that is, a sheet that is relatively easy to separate even without performing the air blowing operation, productivity can be improved. On the other hand, in Example 1, if the type of sheet S used in the print job is a sheet with a strong adhesive force between sheets, the air blowing operation is performed. An example of a sheet with a strong adhesive force between sheets is coated paper and waterproof paper.

[0094] Next, the setting of the air blowing time according to the environmental conditions will be described. In Example 1, the control part changes the time length of the air blowing operation according to the environmental conditions detected by the environmental detection part. In Example 1, the air blowing time is determined based on the temperature and humidity detected by the environmental sensor 620. That is, the environmental condition in Example 1 is a combination of temperature and humidity (hereinafter collectively referred to as temperature and humidity information). As the environmental condition, only one of the temperature and humidity may be used. The humidity may be relative humidity or absolute humidity (absolute moisture content).

[0095] Figure 6 An example of setting criteria for air blowing time according to temperature and humidity information is shown. Figure 6 As shown in , environmental conditions are divided into three sections (1) to (3) according to the values ​​of temperature and humidity, and different air blowing times are set between sections (1) to (3). Section (3) is an environment where the amount of moisture in the atmosphere is large, and the adhesion between sheets tends to be strong due to the moisture. Therefore, if the temperature and humidity information corresponds to section (3), it is preferable to set the air blowing time to be long and loosen the sheet bundle more reliably. On the other hand, section (1) is an environment where the amount of moisture in the atmosphere is small, and the adhesion between sheets is unlikely to be strong. Therefore, if the temperature and humidity information corresponds to section (1), it is preferable to set the air blowing time to be short to enhance the productivity of the image forming device 200. Section (2) is an environment where the amount of moisture in the atmosphere is medium. Therefore, if the temperature and humidity information corresponds to section (2), it is preferable to set the air blowing time to a value between sections (1) and (3) in order to balance the separability and productivity.

[0096] In Example 1, if the temperature and humidity information corresponds to section (1), the air blowing time is set to 5 seconds, if the temperature and humidity information corresponds to section (2), the air blowing time is set to 10 seconds, and if the temperature and humidity information corresponds to section (3), the air blowing time is set to 30 seconds.

[0097] The above is merely an example, and the number of divisions of the environmental conditions, the boundary position, etc. may be changed appropriately. In addition, for example, in an environment where the amount of moisture in the atmosphere is small, the air blowing operation may not be performed.

[0098] Print job control method in Example 1 If a print job is input, the control section 100 starts the following processing (S301). If the execution of the print job is started, the control section 100 determines the air blowing time based on the temperature and humidity information and performs the air blowing operation (Sα). Specifically, in the extension feeder 500, if the fans 511b and 512b of the air blowing sections 511A and 512A are driven based on a command from the control section 100, the air blowing operation is started (S302). If a predetermined time has passed since the driving of the fans 511b and 512b ("Yes" in S303), the driving of the fans 511b and 512b is stopped (S304), and the air blowing operation ends. The predetermined time in S303 is the air blowing time determined based on the temperature and humidity information. By performing the air blowing operation, the sheet bundle is loosened.

[0099] After the air blowing operation, the control section 100 starts the operation of the image forming section 201B (S305). In the present embodiment, the "operation of the image forming section 201B" means rotating the photosensitive drum 212 and the intermediate transfer belt 216 at the process speed, and applying a charging voltage, a developing voltage, and a primary transfer voltage having voltage values ​​at the time of image formation. In other words, in the present embodiment, the "operation of the image forming section 201B" means starting various motors and various high voltage power supplies up to a predetermined rotation speed or output voltage, and an operating state in which a toner image can be created if exposure by the exposure unit 210 is started based on a video signal.

[0100] Specifically, the control section 100 activates various motors (drum drive motor 610, belt drive motor 611, and development drive motor 612) and various high voltage power sources (charging power source 600, development power source 601, and primary transfer power source 602). If activation of each element of the image forming section 201B is completed, the control section 100 causes one sheet S to be fed by a feeding operation (S306). Thereafter, an image is formed on the fed sheet S by the image forming section 201B.

[0101] The control section 100 repeatedly performs the feeding operation (S306) until the number of sheets fed after the job starts reaches the number of sheets required for the print job (i.e., when S307 is "No"). If the number of sheets fed after the job starts reaches the number of sheets required for the print job ("Yes" in S306), the control section 100 ends the processing (S314).

[0102] When the feeding operation (S306) is repeatedly performed, the control part 100 temporarily stops the feeding operation and performs the air blowing operation (Sα) when the number of sheets fed after each job start increases by a predetermined number. That is, before the number of sheets fed after the job start reaches the required number of sheets for the print job (“No” in S307), if the number of sheets fed after the job start increases by a predetermined number from the end of the previous air blowing operation (“Yes” in S308), the control part 100 performs the air blowing operation. The control part 100 does not perform the air blowing operation until the number of sheets fed after the job start increases by a predetermined number from the previous air blowing operation (“No” in S308). The predetermined number of sheets is, for example, 10, but it can be set to a different value depending on the type of sheet S.

[0103] The control content in the case of performing the air blowing operation in the middle of the print job instead of performing the air blowing operation at the start of the print job (S302 to S304) is different depending on the length of the air blowing time determined based on the temperature and humidity information. The middle of the print job is a period after at least one sheet S is fed after the start of the print job. That is, Figure 7 The process in the case of "YES" in S308 is branched according to the length of the air blowing time.

[0104] In the case where the air blowing operation is performed in the middle of the print job, if the air blowing time is long (“Yes” in S309 ), then the air blowing operation is performed. Figure 7 Specifically, if the value of the air blowing time is greater than or equal to a predetermined threshold value, it is determined that the air blowing time is long. The threshold value is, for example, 10 seconds. In this case, if the temperature and humidity information corresponds to section (2) (the air blowing time is 10 seconds) or section (3) (the air blowing time is 30 seconds), it is determined that the air blowing time is long.

[0105] That is, if the air blowing time is long, the control section 100 stops the operation of the image forming section 201B (S310), and then performs the air blowing operation (Sα). Specifically, the control section 100 stops various motors (drum drive motor 610, belt drive motor 611, and development drive motor 612), various high voltage power supplies (charging power supply 600, development power supply 601, and primary transfer power supply 602), and the exposure unit 210 in a predetermined order. In the extension feeder 500, the driving of the fans 511b and 512b of the air blowing sections 511A and 512A is started based on a command from the control section 100 (S311), thereby starting the air blowing operation. If a predetermined time has passed from the start of the driving of the fans 511b and 512b ("Yes" in S312), the driving of the fans 511b and 512b is stopped (S313), and the air blowing operation ends. The predetermined time in S312 is the air blowing time determined based on the temperature and humidity information. By performing the air blowing operation, the sheet bundle is loosened again.

[0106] If the air blowing operation is finished, the control section 100 restarts the operation of the image forming section 201B (S305). That is, the control section 100 starts various motors (drum drive motor 610, belt drive motor 611 and development drive motor 612), various high voltage power supplies (charging power supply 600, development power supply 601 and primary transfer power supply 602) and exposure unit 210. If the start-up of each element of the image forming section 201B is completed, the control section 100 restarts the feeding operation (S306). The processing after S306 is the same as described above.

[0107] On the other hand, in the case where the air blowing operation is performed in the middle of the print job, if the air blowing time is short (No in S309), then the air blowing operation is performed. Fig. 9 In Example 1, if the value of the air blowing time is less than a predetermined threshold value, it is determined that the air blowing time is short. The threshold value is, for example, 10 seconds. In this case, if the temperature and humidity information corresponds to segment (1) (the air blowing time is 5 seconds), it is determined that the air blowing time is short.

[0108] That is, if the air blowing time is short, the control section 100 performs the air blowing operation (Sα) without stopping the operation of the image forming section 201B. Specifically, the control section 100 performs the air blowing operation (Sα) while operating various motors (drum drive motor 610, belt drive motor 611, and development drive motor 612) and various high voltage power supplies (charging power supply 600, development power supply 601, and primary transfer power supply 602). In the extension feeder 500, the driving of the fans 511b and 512b of the air blowing sections 511A and 512A is started based on a command from the control section 100 (S411), thereby starting the air blowing operation. If a predetermined time has passed from the start of the driving of the fans 511b and 512b ("Yes" in S412), the driving of the fans 511b and 512b is stopped (S413), and the air blowing operation ends. The predetermined time in S412 is the air blowing time determined based on the temperature and humidity information. By performing the air blowing operation, the sheet bundle is loosened again.

[0109] If the air blowing operation ends, the control portion 100 restarts the feeding operation ( Figure 7 That is, unlike the case where the air blowing time is long (S310 to S313), since the operation of the image forming part 201B is not stopped, the control part 100 can restart the feeding operation immediately after the air blowing operation ends. The processing after S306 is the same as described above.

[0110] Operation status of the image forming section Will refer to Figure 8 The sequence diagram and reference Figure 7 The flow chart describes the operation state of the image forming part 201B in the case where the air blowing time is long.

[0111] If the execution of the print job is started (S301), the air blowing operation is performed at a predetermined air blowing time (Sα, S302 to S304). After the air blowing operation is performed, the operation of the image forming part 201B is started (S305). First, the drum drive motor 610 is started (OFF→ON), and after the drum drive motor 610 is started (that is, after the rotation speed of the photosensitive drum 212 is stabilized at the process speed), various high voltage power supplies and the developing drive motor 612 are sequentially started (OFF→ON). Specifically, the application of voltage or the driving of the motor is started in the order of the charging power supply 600, the developing power supply 601, the developing drive motor 612, and the primary transfer power supply 602. After the output voltages of the various high voltage power supplies and the rotation speed of the developing drive motor 612 are stabilized, the exposure by the exposure unit 210 is started. Note that the ON / OFF of the belt drive motor 611 is synchronized with the ON / OFF of the drum drive motor 610. On the other hand, if the driving of the feeding motor 520 is started (OFF→ON) after the operation of the image forming portion 201B is started, the feeding operation is started, and the sheets S are fed one by one (S306). The image forming portion 201B forms an image on the fed sheet S.

[0112] Note that the start timing of the feeding operation (start of driving of the feeding motor 520) may be before or after the start timing of exposure of the exposure unit 210. The before and after of the start timing of the feeding operation and the start timing of exposure also vary according to the magnitude relationship between the length of the sheet conveying path from the feeding unit 506 to the secondary transfer portion 201D and the path length from the exposure position in the image forming portion 201B to the secondary transfer portion 201D. For example, if the former length is longer than the latter path length, exposure of the exposure unit 210 may be started after the start of the feeding operation. The path length from the exposure position to the secondary transfer portion 201D is the sum of the outer peripheral length of the photosensitive drum 212 from the exposure position to the corresponding primary transfer portion and the outer peripheral length of the intermediate transfer belt 216 from the primary transfer portion to the secondary transfer portion 201D.

[0113] If a predetermined number of sheets S counted from the start of the print job are fed and the exposure operation for forming an image on the sheet S is completed, the operations of various high voltage power supplies and various motors are sequentially stopped (S310). If the predetermined number of last sheets S are fed, the feeding motor 520 is stopped to perform an air blowing operation.

[0114] Then, in a state where the image forming portion 201B and the feeding motor 520 are stopped, an air blowing operation is performed for a predetermined air blowing time (Sα, S311 to S313). After the air blowing operation is performed, the operation of the image forming portion 201B is resumed (S305), and the feeding operation is resumed (S306). Thereafter, each time a predetermined number of sheets S are fed from the end of the previous air blowing operation, the operation of the image forming portion 201B and the feeding operation are stopped, and after the air blowing operation is performed, the operation of the image forming portion 201B and the feeding operation are resumed.

[0115] As described above, in Example 1, if the air blowing operation is performed, the rotation of the photosensitive drum 212 is stopped. In other words, in Example 1, if the air blowing operation is performed, the rotation speed of the photosensitive drum 212 is reduced to 0 mm / sec. Therefore, even in the case where the air blowing operation is performed, the increase in the cumulative rotation amount of the photosensitive drum 212 relative to the cumulative number of printed sheets of the image forming apparatus 200 is suppressed compared to the case where the photosensitive drum 212 is continuously driven to rotate at the process speed. Therefore, the wear of the photosensitive drum 212 caused by the friction with the cleaning blade 231 and the like can be reduced. That is, according to this example, an image forming apparatus configured to suppress the reduction in the number of printable sheets of the photosensitive member can be provided.

[0116] As described in Example 2 described later, if the air blowing operation is performed, similar advantages can be obtained even if the rotation of the photosensitive drum 212 is changed to a predetermined speed (second speed) lower than the process speed (first speed) without stopping the rotation. In other words, when the adjustment operation is performed, the control portion performs a mode of stopping the rotation of the photosensitive member or changing the rotation speed of the photosensitive member from the first speed (which is the rotation speed of the photosensitive member in the case where the image forming portion forms an image on a sheet) to the second speed lower than the first speed. Therefore, it is possible to provide an image forming apparatus configured to suppress a reduction in the number of printable sheets of the photosensitive member.

[0117] In Example 1, if the air blowing operation is performed, the application of the charging voltage is stopped. In other words, in Example 1, if the air blowing operation is performed, the voltage applied to the charger 213 by the charging power source 600 is reduced to 0V. Therefore, even in the case where the air blowing operation is performed, the increase in the cumulative time of applying the charging voltage to the charger 213 relative to the cumulative number of printed sheets of the image forming apparatus 200 is reduced compared to the case where the charger 213 continues to be applied with the charging voltage having the same voltage value as the voltage value at the time of image formation. Therefore, the degradation of the surface of the photosensitive drum 212 due to discharge can be suppressed, and the acceleration of the wear of the photosensitive drum 212 due to the surface degradation can be suppressed. That is, according to this example, an image forming apparatus configured to suppress a reduction in the number of printable sheets of the photosensitive member can be provided.

[0118] As described in Example 3 described later, if the air blowing operation is performed, the same advantage can be obtained even if the application of the charging voltage is not stopped and the charging voltage is changed to a predetermined voltage value (second voltage value) lower than the value of the charging voltage (first voltage value) when the image is formed. In other words, if the adjustment operation is performed, the control portion performs a mode in which the voltage applied to the charging unit by the voltage applying unit is changed from the first voltage value (which is the value of the voltage applied to the charging unit by the voltage applying unit in the case where the image forming portion forms an image on the sheet) to the second voltage value lower than the first voltage value. Therefore, an image forming apparatus configured to suppress a reduction in the number of printable sheets of a photosensitive member can be provided.

[0119] In Example 1, if the air blowing operation is performed, the rotation of the photosensitive drum 212 is stopped, and the application of the charging voltage is stopped. Therefore, it is possible to provide an image forming apparatus configured to further suppress a reduction in the number of printable sheets of a photosensitive member.

[0120] Next, we will refer to Fig.10 The sequence diagram and reference Figure 7 and Fig. 9 The flow chart of FIG. 1 describes the operation state of the image forming part 201B in the case where the air blowing time is short. The operation from the start of the print job (S301) to the feeding of a predetermined number of sheets S is the same as that of FIG. 1 except that the air blowing time is different. Figure 8 The sequence diagram is the same as

[0121] If a predetermined number of sheets S are fed from the start of the print job, the air blowing operation is performed with a predetermined air blowing time (Sα, S411 to S413). Figure 8 ), the air blowing operation is performed in a state where the operation of the image forming part 201B is not stopped.

[0122] Then, after the air blowing operation is performed, the feeding operation is resumed (S306). In addition, the exposure of the exposure unit 210 is resumed, and an image is formed on each fed sheet S. Thereafter, each time a predetermined number of sheets S are fed from the previous air blowing operation, the feeding operation is stopped, and the feeding operation is resumed after the air blowing operation is performed.

[0123] As described above, in this example, if the air blowing time is short, the air blowing operation is performed without stopping the operation of the image forming part 201B. Therefore, if the benefit of stopping the operation of the image forming part 201B is small, the influence of stopping the operation of the image forming part 201B can be reduced. Since the cleaning blade 231 rubs each photosensitive drum 212 to mechanically scrape off the attached substances, if the friction between the cleaning blade and the photosensitive drum 212 increases and the cleaning blade 231 rotates, the function of removing the toner is impaired. Therefore, if the air blowing time is short, the process of forming the toner image for supply on the photosensitive drum 212 at the timing of performing the air blowing operation without stopping the operation of the image forming part 201B and supplying the toner as a lubricant to the cleaning blade 231 can be performed in parallel. Thus, the rolling up of the cleaning blade 231 can be suppressed.

[0124] Relationship between the length of air blowing time and stop of the image forming portion Will refer to Fig.11A and Fig. 11B The detailed reason why the air blowing operation is performed without stopping the operation of the image forming section 201B when the air blowing time is short and the reference to the air blowing time of whether to stop the operation of the image forming section 201B are described.

[0125] Fig.11A : is a graph illustrating the relationship between the length of the air blowing time (horizontal axis) and the reduction rate of the number of printable sheets of the photosensitive drum 212 (vertical axis). Fig. 11B is a graph illustrating the relationship between the length of the air blowing time (horizontal axis) and the reduction rate (vertical axis) of the productivity of the image forming apparatus 200. The horizontal axis in each graph represents the time length of one air blowing operation. Fig.11A The vertical axis in represents the reduction degree of the number of printable sheets of the photosensitive drum 212 when the air blowing operation is performed, with the number of printable sheets of the photosensitive drum 212 when the air blowing operation is not performed as a reference (100%). The "number of printable sheets of the photosensitive drum 212" represents the cumulative number of printed sheets that can output images without image defects due to wear of the photosensitive drum 212 when a durability test of repeatedly performing an image forming operation of forming a predetermined test image on a sheet S is performed from a state where the photosensitive drum 212 is new. Fig. 11B The vertical axis in represents the degree of reduction in productivity when the air blowing operation is performed, with the productivity (the number of printed sheets per unit time in a continuous print job) of the image forming apparatus 200 when the air blowing operation is not performed (100%) as a reference.

[0126] Fig.11A and Fig. 11B Based on the result of executing a print job in which coated paper was used as the sheet S, the air blowing operation was performed once every time 10 sheets of coated paper were fed, and images were formed on a total of 500 sheets of coated paper. Fig.11A and Fig. 11B The solid line in shows the result in the case where the operation of the image forming section 201B is stopped while the air blowing operation is performed, and the dotted line shows the result in the case where the operation of the image forming section 201B is not stopped while the air blowing operation is performed.

[0127] like Fig.11A and Fig. 11B As indicated by the dotted line in , if the operation of the image forming portion 201B is not stopped while the air blowing operation is performed, the reduction rate of the number of printable sheets and the productivity become larger as the air blowing time becomes longer. The reason why the reduction rate of the number of printable sheets increases according to the length of the air blowing time is that although the toner image is not created as described above, as the period during which the image forming portion 201B is driven becomes longer, the amount of wear of the photosensitive drum 212 relative to the cumulative number of printed sheets increases. The reason why the reduction rate of productivity increases according to the length of the air blowing time is that if the air blowing operation is performed, the feeding operation is stopped, and thus the feeding interval of the sheets (sheet interval) becomes longer compared to the case where the feeding operation is repeated without performing the air blowing operation.

[0128] like Fig.11A As indicated by the solid line in , if the operation of the image forming portion 201B is stopped while the air blowing operation is being performed, the rate of reduction in the number of printable sheets becomes substantially constant regardless of the length of the air blowing time. This is because, since the rotation of the photosensitive drum 212 is stopped while the air blowing operation is being performed, even if the air blowing time becomes longer, the period during which the image forming portion 201B is driven although no toner image is created does not become longer. On the other hand, the number of printable sheets decreases compared to the case where the air blowing operation is not performed because a period during which the photosensitive drum 212 is rotationally driven occurs although no toner image is created while the air blowing operation is being performed. That is, if the operation of the image forming portion 201B is stopped before the start of the air blowing operation and if the operation of the image forming portion 201B is resumed after the end of the air blowing operation, there is a period during which the photosensitive drum 212 is rotationally driven although no toner image is created.

[0129] exist Fig.11A , if the area where the air blowing time is 10 seconds or longer is observed, it can be seen that the case (solid line) in which the operation of the image forming portion 201B is stopped while the air blowing operation is performed is more favorable. That is, if the air blowing time is 10 seconds or longer, the reduction rate of the number of printable sheets on the photosensitive drum 212 is lower in the case (solid line) in which the operation of the image forming portion 201B is stopped while the air blowing operation is performed than in the case (dashed line) in which the operation of the image forming portion 201B is not stopped. This means that if the air blowing time is long, the rotation amount of each photosensitive drum 212 during the execution of the air blowing operation exceeds the increase in the rotation amount of each photosensitive drum 212 accompanying the stop and restart of the operation of the image forming portion 201B.

[0130] On the other hand, if the air blowing time is less than 10 seconds, the reduction rate of the number of printable sheets on the photosensitive drum 212 is more significant in the case where the operation of the image forming portion 201B is stopped while the air blowing operation is being performed (solid line) than in the case where the operation of the image forming portion 201B is not stopped (dashed line). This means that if the air blowing time is short, the rotation amount of each photosensitive drum 212 during the execution of the air blowing operation decreases below the increase in the rotation amount of each photosensitive drum 212 accompanying the stop and restart of the operation of the image forming portion 201B.

[0131] like Fig. 11B As shown in , regardless of the length of the air blowing time, the productivity in the case where the operation of the image forming portion 201B is stopped when the air blowing operation is performed (solid line) is lower than the productivity in the case where the operation of the image forming portion 201B is not stopped when the air blowing operation is performed (dashed line). However, as the air blowing time becomes shorter, the ratio (X / Y) between the reduction rate X of the productivity indicated by the solid line and the reduction rate Y of the productivity indicated by the dashed line becomes more significant. This is because a period for stopping and restarting the operation of the image forming portion 201B is required before and after the start of the air blowing operation. In addition, as the air blowing time becomes shorter, the ratio of the period for stopping and restarting the operation of the image forming portion 201B increases in the period from the stop of the feeding operation to the restart of the feeding operation after the air blowing operation is performed.

[0132] According to the above results, if the air blowing time is long, it is preferable to stop the operation of the image forming portion 201B while the air blowing operation is being performed from the viewpoint of suppressing a decrease in the number of printable sheets of the photosensitive drum 212. Furthermore, if the air blowing time is long, even if the operation of the image forming portion 201B is stopped while the air blowing operation is being performed, the influence on the decrease in productivity of the image forming apparatus 200 is relatively small.

[0133] On the other hand, if the air blowing time is short, it is preferable not to stop the operation of the image forming part 201B while performing the air blowing operation from the viewpoint of suppressing a decrease in the number of printable sheets of the photosensitive drum 212 and a decrease in productivity of the image forming apparatus 200.

[0134] Therefore, in Example 1, if the air blowing time is less than 10 seconds, the operation of the image forming portion 201B is not stopped while the air blowing operation is performed, and if the air blowing time is 10 seconds or longer, the operation of the image forming portion 201B is stopped while the air blowing operation is performed. Therefore, in a configuration in which the length of the air blowing time can be changed according to environmental conditions and the like, the number of printable sheets and productivity can be achieved at a high level.

[0135] Note that the threshold value of the air blowing time for whether to stop the operation of the image forming portion 201B when the air blowing operation is performed is not limited to the above value (10 seconds). In addition, in this example, the configuration of changing the air blowing time based on the temperature and humidity information as an example of the environmental conditions has been exemplified, but the above control can also be applied to the case where the air blowing time is changed according to other conditions (for example, the material and size of the sheet S).

[0136] As described above, in Example 1, whether to stop or decelerate the rotation of the photosensitive drum 212 when performing the air blowing operation is changed according to the length of the air blowing time. In other words, the mode is the first mode, and the control part performs the first mode in which the time length of the adjustment operation is the first length, and if the time length of the adjustment operation is the second length shorter than the first length, the second mode in which the rotation speed of the photosensitive member is maintained at the first speed of the adjustment operation is performed. The case where the time length of the adjustment operation is the first length is, for example, the case where the air blowing time is 30 seconds. The case where the time length of the adjustment operation is the second length is, for example, the case where the air blowing time is 5 seconds. Thus, the number of printable sheets and productivity can be achieved at a high level.

[0137] In Example 1, whether to stop applying the charging voltage or to lower the voltage value when performing the air blowing operation is changed according to the length of the air blowing time. In other words, the mode is the first mode, and if the time length of the adjustment operation is the first length, the control part executes the first mode when performing the adjustment operation, and if the time length of the adjustment operation is the second length shorter than the first length, the control part executes the second mode in which the voltage applied by the voltage applying unit to the charging unit is maintained at the first voltage value when performing the adjustment operation. Thus, the number of printable sheets and productivity can be achieved at a high level.

[0138] Modifications Note that, in Example 1, a method of stopping the rotation of the photosensitive drum 212 and stopping the application of the charging voltage when the air blowing operation is performed is described, but only one of the rotation stop and the application stop of the charging voltage may be performed for the photosensitive drum 212. Therefore, at least compared with a configuration in which the photosensitive drum 212 continues to rotate at the process speed even during the execution of the air blowing operation and a charging voltage having the same voltage value as that at the time of image formation is applied, the wear of the photosensitive drum 212 can be reduced.

[0139] If the application of the charging voltage is continued in the state where the photosensitive drum 212 is stopped, the surface of the photosensitive drum 212 is locally deteriorated by continuing to receive the discharge of the charger 213, which may cause image defects. Therefore, in order to obtain an image with better image quality, if the application of the charging voltage is not stopped when the air blowing operation is performed, it is preferable to stop the rotation of the photosensitive drum 212 or decelerate the rotation of the photosensitive drum 212 as in Example 2.

[0140] Example 2 An image forming apparatus according to Example 2 will be described. In Example 1, a method of stopping the rotation of the photosensitive drum 212 when the air blowing operation is performed is described, but in Example 2, when the air blowing operation is performed, the rotation of the photosensitive drum 212 is decelerated without being stopped. Hereinafter, unless otherwise specified, elements denoted by the same reference numerals as those in Example 1 are assumed to have substantially the same configuration and operation as those described in Example 1, and portions different from those in Example 1 will be mainly described.

[0141] Will refer to Fig.12 Describe the print job control method in Example 2. Fig.12 The contents of S301 to S309, S314, and S411 to S413 in Example 1 ( Figure 7 and Fig. 9 ) are the same, so their description will be omitted.

[0142] Similar to Example 1, while repeatedly performing the feeding operation (S306), the control section 100 temporarily stops the feeding operation and performs the air blowing operation (Sα) every time the number of sheets fed after the start of the job increases by a predetermined number. That is, before the number of sheets fed after the start of the job reaches the required number of sheets for the print job (“No” in S307), if the number of sheets fed after the start of the job increases by a predetermined number from the end of the previous air blowing operation (“Yes” in S308), the control section 100 performs the air blowing operation.

[0143] In the case where the air blowing operation is performed in the middle of the print job, if the air blowing time is long (“Yes” in S309 ), then the air blowing operation is performed. Fig.12Specifically, if the value of the air blowing time is greater than or equal to a predetermined threshold, it is determined that the air blowing time is long. The threshold is, for example, 10 seconds.

[0144] In the case where the air blowing operation is performed in the middle of a print job, if the air blowing time is long, the rotation speed of the photosensitive drum 212 is decelerated to a speed lower than the process speed (in Fig.12 and Fig.13 In other words, when the adjustment operation is performed, the control portion executes a mode of stopping the rotation of the photosensitive member or changing the rotation speed of the photosensitive member from a first speed (i.e., the rotation speed of the photosensitive member in the case where the image forming portion forms an image on the sheet) to a second speed slower than the first speed. After the rotation speed of the photosensitive drum 212 is reduced to the speed B, the air blowing operation (Sα, S511 to S513) is performed. After the air blowing operation is completed, the rotation speed of the photosensitive drum 212 is re-accelerated to the process speed.

[0145] Specifically, in the case of "Yes" in S309, the control section 100 sends a command to the drum drive motor 610 to change the rotation speed (peripheral speed) of the photosensitive drum 212 from the process speed (speed A) to a predetermined speed (speed B) lower than the process speed (S510). It is assumed that the values ​​of the process speed (speed A) and the predetermined speed (speed B) are predetermined and stored in a storage unit (e.g., Figure 2 In the extension feeder 500, based on the command from the control section 100, the driving of the fans 511b and 512b of the air blowing sections 511A and 512A is started (S511), thereby starting the air blowing operation. If a predetermined time (air blowing time) has passed since the driving of the fans 511b and 512b ("Yes" in S512), the driving of the fans 511b and 512b is stopped (S513), and the air blowing operation is terminated.

[0146] If the air blowing operation is completed, the control section 100 sends a command to the drum drive motor 610 to change the rotation speed of the photosensitive drum 212 from the predetermined speed (speed B) to the process speed (speed A) (S514). After the rotation speed of the photosensitive drum 212 is stabilized at the process speed (speed A), the control section 100 restarts the feeding operation (S306).

[0147] Will refer to Fig.13 The sequence diagram and reference Fig.12The flow chart of FIG. 1 describes the operation state of the image forming portion 201B in the case where the air blowing time is long in Example 2. The operation from the start of the print job (S301) to the feeding of a predetermined number of sheets S is similar to the operation of FIG. Figure 8 The operations are the same as in the sequence diagram.

[0148] If a predetermined number of sheets S counted from the start of the print job are fed, the photosensitive drum 212 is decelerated from the process speed (speed A) to the predetermined speed (speed B) so as to perform the air blowing operation (S510). Then, in a state where the photosensitive drum 212 is rotationally driven at the predetermined speed (speed B), the air blowing operation is performed at a predetermined air blowing time (Sα, S511 to S513). After the air blowing operation is performed, the photosensitive drum 212 is accelerated from the predetermined speed (speed B) to the process speed (speed A) (S514). In addition, the driving of the feeding motor 520 is started, and the feeding operation is resumed (S306). Thereafter, each time a predetermined number of sheets S are fed from the end of the previous air blowing operation, the rotation speed of the photosensitive drum 212 is decelerated to the predetermined speed, and after the air blowing operation is performed, the rotation speed of the photosensitive drum 212 is accelerated to the process speed.

[0149] As described above, in Example 2, if the air blowing operation is performed, the rotation of the photosensitive drum 212 is decelerated to a predetermined speed lower than the process speed. Therefore, even in the case where the air blowing operation is performed, the increase in the cumulative rotation amount of the photosensitive drum 212 relative to the cumulative number of printed sheets of the image forming apparatus 200 is suppressed compared to the case where the photosensitive drum 212 is continuously rotationally driven at the process speed. Therefore, the wear of the photosensitive drum 212 due to the friction with the cleaning blade 231 and the like can be reduced. That is, according to this example, an image forming apparatus configured to suppress a reduction in the number of printable sheets of the photosensitive member can be provided.

[0150] In Example 2, the voltage output of various high voltage power supplies is not stopped (OFF) when performing the air blowing operation. Therefore, compared with Example 1, the downtime of the image forming apparatus 200 associated with performing the air blowing operation can be shortened, and the productivity of the image forming apparatus 200 can be improved.

[0151] Modifications In Example 2, if the air blowing operation is performed, the application of the charging voltage to the charger 213 can be stopped (OFF). Therefore, the degradation of the surface of the photosensitive drum 212 due to the discharge of the charger 213 during the execution of the air blowing operation can be suppressed, and the acceleration of the wear of the photosensitive drum 212 due to the degradation of the surface can be suppressed. That is, according to this modification, compared with Example 2, it is possible to provide an image forming apparatus configured to further suppress an increase in the amount of wear of the photosensitive member.

[0152] Example 3 An image forming apparatus according to Example 3 will be described. In Example 1, a method of stopping application of a charging voltage to the charger 213 when performing an air blowing operation was described, but in Example 3, when performing an air blowing operation, a voltage value is reduced without stopping application of the charging voltage. Hereinafter, unless otherwise specified, elements denoted by the same reference numerals as those in Example 1 are assumed to have substantially the same configuration and operation as those described in Example 1, and portions different from those in Example 1 will be mainly described.

[0153] Will refer to Fig.14 The print job control method in Example 3 is described. Fig.14 The contents of S301 to S309, S314, and S411 to S413 in Example 1 ( Figure 7 and Fig. 9 ) are the same, so their description will be omitted.

[0154] Similar to Example 1, while repeatedly performing the feeding operation (S306), the control section 100 temporarily stops the feeding operation and performs the air blowing operation (Sα) every time the number of sheets fed after the start of the job increases by a predetermined number. That is, before the number of sheets fed after the start of the job reaches the required number of sheets for the print job (“No” in S307), if the number of sheets fed after the start of the job increases by a predetermined number from the end of the previous air blowing operation (“Yes” in S308), the control section 100 performs the air blowing operation.

[0155] In the case where the air blowing operation is performed in the middle of the print job, if the air blowing time is long (“Yes” in S309 ), then the air blowing operation is performed. Fig.14 Specifically, if the value of the air blowing time is greater than or equal to a predetermined threshold, it is determined that the air blowing time is long. The threshold is, for example, 10 seconds.

[0156] In the case where the air blowing operation is performed in the middle of the print job, if the air blowing time is long, the output voltages of the various high voltage power supplies are set to predetermined voltage values ​​lower than the voltage values ​​in the case where the image forming operation is performed (hereinafter referred to as "setting A"). Hereinafter, the predetermined voltage value lower than the voltage value (setting A) when the image forming operation is performed is referred to as "setting B". In other words, if the adjustment operation is performed, the control portion performs a mode in which the voltage applied to the charging unit by the voltage applying unit is changed from a first voltage value (i.e., a voltage value applied to the charging unit by the voltage applying unit in the case where the image forming portion forms an image on a sheet) to a second voltage value lower than the first voltage value. After the output voltages of the various high voltage power supplies are reduced to the predetermined voltage value (setting B), the air blowing operation is performed (Sα, S611 to S613). After the air blowing operation ends, the output voltages of the various high voltage power supplies are increased to the voltage value (setting A) when the image forming operation is performed.

[0157] Specifically, in the case of "yes" in S309, the control section 100 changes the output voltages of the various high voltage power supplies from the voltage values ​​(setting A) when the image forming operation is performed to the predetermined voltage values ​​(setting B) (S610). As a result, the output voltages (charging voltage, developing voltage, and primary transfer voltage) of the charging power supply 600, the developing power supply 601, and the primary transfer power supply 602 are each lowered to the predetermined voltage values ​​(setting B). Assume that the voltage value (setting A) when the image forming operation is performed and the predetermined voltage value (setting B) are predetermined and stored in a storage unit (e.g., Figure 2 ROM 102 in the image forming operation. Note that the values ​​of the charging voltage, the developing voltage, and the primary transfer voltage when performing the image forming operation (setting A) may be different from each other. In addition, the values ​​of the charging voltage, the developing voltage, and the primary transfer voltage when performing the air blowing operation (setting B) may be different from each other.

[0158] In the extension feeder 500, based on the command from the control section 100, the driving of the fans 511b and 512b (S611) of the air blowing sections 511A and 512A is started, thereby starting the air blowing operation. If a predetermined time (air blowing time) has passed since the driving of the fans 511b and 512b ("Yes" in S612), the driving of the fans 511b and 512b is stopped (S613), and the air blowing operation is terminated.

[0159] If the air blowing operation is finished, the control section 100 changes the output voltages of the various high voltage power supplies from the predetermined voltage value (setting B) to the voltage value (setting A) in the case of performing the image forming operation. Therefore, the charging voltage, the developing voltage, and the primary transfer voltage each rise to the voltage value (setting A) when the image forming operation is performed (S614). After the charging voltage, the developing voltage, and the primary transfer voltage are stabilized at the voltage value (setting A) when the image forming operation is performed, the control section 100 restarts the feeding operation (S306).

[0160] In Example 3, the reference Fig.15 The sequence diagram and reference Fig.14 The flow chart of FIG. 10 describes the operation state of the image forming part 201B in the case where the air blowing time is long. The operation from the start of the print job (S301) to the feeding of a predetermined number of sheets S is similar to the operation of FIG. Figure 8 The same as in the sequence diagram.

[0161] If a predetermined number of sheets S are fed from the start of the print job, the output voltages (charging voltage, developing voltage, and primary transfer voltage) of the various high-voltage power supplies are reduced from the voltage value (setting A) when the image forming operation is performed to the predetermined voltage value (setting B) (S610). Then, in a state where the output voltages of the various high-voltage power supplies are reduced to the predetermined voltage value (setting B), the air blowing operation is performed for a predetermined air blowing time (Sα, S611 to S613). After the air blowing operation is performed, if the image forming operation is performed again, the output voltages of the various high-voltage power supplies are increased to the voltage value (setting A) (S614). In addition, the driving of the feeding motor 520 is started, and the feeding operation is resumed (S306). Thereafter, each time a predetermined number of sheets S are fed from the previous air blowing operation, the output voltages of the various high-voltage power supplies are reduced to the predetermined voltage value (setting B), and after the air blowing operation is performed, the output voltages of the various high-voltage power supplies are increased to the original voltage value (setting A).

[0162] As described above, in Example 3, if the air blowing operation is performed, the voltage value of the charging voltage applied to the charger 213 is lowered compared to the voltage value at the time of image formation. Therefore, compared to the case where the charger 213 continues to apply the charging voltage having the same voltage value as at the time of image formation even when the air blowing operation is performed, an increase in the cumulative time during which the charging voltage at the time of image formation is applied to the charger 213 relative to the cumulative number of printed sheets of the image forming apparatus is suppressed. Therefore, the degradation of the surface of the photosensitive drum 212 due to discharge can be suppressed, and the acceleration of the wear of the photosensitive drum 212 due to the degradation of the surface can be suppressed. That is, according to this example, an image forming apparatus configured to suppress a reduction in the number of printable sheets of the photosensitive member can be provided.

[0163] In Example 3, the rotation of the photosensitive drum 212 is not stopped or decelerated when the air blowing operation is performed. Therefore, compared with Example 1, the downtime of the image forming apparatus 200 associated with the air blowing operation can be shortened, and the productivity of the image forming apparatus 200 can be improved.

[0164] Modifications In Example 3, in the case where the air blowing operation is performed, the rotation of the photosensitive drum 212 can be stopped, or the rotation speed of the photosensitive drum 212 can be reduced. Therefore, the rotation amount of the photosensitive drum 212 can be reduced while the air blowing operation is performed. That is, according to this modification, compared with Example 3, it is possible to provide an image forming apparatus configured to further suppress an increase in the amount of wear of the photosensitive member.

[0165] Other Modifications In each of the above-described embodiments, the image forming apparatus 200 configured to perform the air blowing operation has been described as an example of an “adjustment operation”, but the “adjustment operation” may be another operation. For example, in an image forming apparatus including a plurality of sheet feeding portions, the “adjustment operation” may be an operation of automatically switching the supply source of sheets to another sheet feeding portion when sheets are exhausted in the sheet feeding portion being used during execution of a print job. In this case, for example, in the sheet feeding portion whose supply source has been switched, the rotation of the photosensitive drum 212 may be stopped, or the charging voltage may be stopped during the waiting time until the preparation for feeding is completed. In this case, the predetermined number of sheets is the number of sheets stacked on the sheet feeding portion to be used first. In addition, the “adjustment operation” may be, for example, a cooling period set to avoid overheating of each roller and the feeding motor of the feeding unit.

[0166] In each of the above-described embodiments, the configuration in which the air blowing portions 511A and 512A as the air loosening mechanism are provided in the extension feeder 500 has been exemplified. The air loosening mechanism is not limited to the extension feeder 500, and may be provided in another sheet feeding module (e.g., Figure 1 In this case, if the feeding operation is stopped and the air blowing operation is performed during the execution of a print job in which the sheet S is fed from the manual feeding portion 235 or the cassette feeding portion 230 provided with the air release mechanism, the control described in each embodiment can be applied.

[0167] In each of the above-described embodiments, a configuration has been described in which a mode (first mode) in which the photosensitive drum 212 and the like are stopped while the air blowing operation is performed and a mode (second mode) in which the photosensitive drum 212 and the like are not stopped while the air blowing operation is performed are selectively performed according to the length of the air blowing time. Without being limited thereto, for example, in the case where the air blowing operation is performed while the length of the air blowing time is fixed, the operation may be performed in a mode in which the photosensitive drum 212 is stopped while the air blowing operation is performed.

[0168] In each of the above-described embodiments, as the image forming portion, the image forming portion 201B as an intermediate transfer tandem type electrophotographic mechanism is exemplified. The image forming portion is not limited thereto, and may be, for example, a direct transfer type in which a toner image formed on a photosensitive member is directly transferred onto a sheet S without passing through an intermediate transfer member. The image forming portion may include only one photosensitive member and form a monochrome image using one type of toner.

[0169] Other embodiments The present invention can also be implemented by the following process: a program for implementing one or more functions of the above-mentioned embodiments is supplied to a system or device via a network or storage medium, and one or more processors in a computer of the system or device read and execute the program. The present invention can also be implemented by a circuit (e.g., ASIC) that implements one or more functions.

[0170] The embodiment(s) of the present invention may also be implemented by a computer of a system or device that reads out and executes computer executable instructions (e.g., one or more programs) recorded on a storage medium (which may also be more completely referred to as a "non-transitory computer-readable storage medium") to perform the functions of one or more of the above-mentioned embodiment(s) and / or includes one or more circuits (e.g., application-specific integrated circuits (ASICs)) for performing the functions of one or more of the above-mentioned embodiment(s), and by a method executed by a computer of a system or device, for example, by reading out and executing computer executable instructions from a storage medium to perform the functions of one or more of the above-mentioned embodiment(s) and / or controlling one or more circuits to perform the functions of one or more of the above-mentioned embodiment(s). The computer may include one or more processors (e.g., a central processing unit (CPU), a microprocessing unit (MPU)), and may include a network of separate computers or separate processors to read out and execute computer executable instructions. Computer executable instructions may be provided to the computer, for example, from a network or a storage medium. The storage medium may include, for example, a hard disk, a random access memory (RAM), a read-only memory (ROM), a storage device of a distributed computing system, an optical disk (such as a compact disk (CD), a digital versatile disk (DVD), or a Blu-ray disk (BD)) TM ), flash memory devices, memory cards, etc.

[0171] Other embodiments The embodiments of the present invention may also be implemented by providing software (program) for executing the functions of the above-mentioned embodiments to a system or device via a network or various storage media, and a computer or a central processing unit (CPU) or a microprocessing unit (MPU) of the system or device reads and executes the program.

[0172] While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments.The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims

1. An image forming device, the image forming device being configured to form an image on a sheet, the image forming device comprising: an image forming section including: a rotatable image bearing member; a charging unit configured to charge the image bearing member; an exposure unit configured to expose the image bearing member charged by the charging unit to form an electrostatic latent image on the image bearing member; and a developing unit configured to develop the electrostatic latent image formed on the image bearing member using a developer; a driving portion configured to rotationally drive the image bearing member; a sheet material supporting portion configured to support a sheet material; a sheet blowing portion configured to perform a blowing operation of blowing air toward the sheet supported on the sheet supporting portion; a sheet feeding portion configured to perform a feeding operation of feeding a sheet supported on the sheet supporting portion; and a control section configured to execute a mode in which, after a sheet fed by the sheet feeding section passes through a transfer position and before a subsequent sheet fed by the sheet feeding section passes through the transfer position, the blowing operation is performed in a state in which the feeding operation is stopped, and a toner image formed by the image forming section is transferred to the sheet at the transfer position, in a predetermined period of time, wherein The control section is configured to control the driving section to stop rotation of the image bearing member during the mode.

2. The image forming apparatus according to claim 1, wherein The control portion is configured to control the driving portion to stop the rotation of the image bearing member during the mode, if a time for which the sheet blowing portion performs the blowing operation in the predetermined period is equal to or longer than a predetermined time.

3. The image forming apparatus according to claim 2, wherein The control portion is configured to execute the mode without stopping the rotation of the image bearing member during the mode, if a time during which the sheet blowing portion performs the blowing operation in the predetermined period is less than the predetermined time.

4. The image forming apparatus according to claim 1, wherein The control portion is configured to execute the mode without stopping the rotation of the image bearing member during the mode, if a time during which the sheet blowing portion performs the blowing operation in the predetermined period is less than a predetermined time.

5. The image forming apparatus according to claim 1 or 2, further comprising: A detection part, the detection part is configured to detect the ambient humidity, wherein The sheet blowing portion is configured to: (i) perform the blowing operation for a first time in the predetermined period when the ambient humidity detected by the detection portion is a first humidity, and (ii) perform the blowing operation for a second time in the predetermined period when the ambient humidity detected by the detection portion is a second humidity higher than the first humidity, the second time being longer than the first time.

6. The image forming apparatus according to claim 1 or 2, wherein The sheet blowing portion is configured to perform the blowing operation in the predetermined period if the sheet supported on the sheet supporting portion is a predetermined sheet.

7. The image forming apparatus according to claim 1 or 2, further comprising: An image forming device body, the image forming device body comprising an image forming part, wherein The sheet supporting portion is a manual feed tray provided on a side of the image forming apparatus main body.

8. An image forming apparatus, the image forming apparatus being configured to form an image on a sheet, the image forming apparatus comprising: an image forming section including: a rotatable image bearing member; a charging unit configured to charge the image bearing member; an exposure unit configured to expose the image bearing member charged by the charging unit to form an electrostatic latent image on the image bearing member; and a developing unit configured to develop the electrostatic latent image formed on the image bearing member using a developer; a driving portion configured to rotationally drive the image bearing member; a sheet material supporting portion configured to support a sheet material; a sheet blowing portion configured to perform a blowing operation of blowing air toward the sheet supported on the sheet supporting portion; a sheet feeding portion configured to perform a feeding operation of feeding a sheet supported on the sheet supporting portion; and a control section configured to execute a mode in which, after a sheet fed by the sheet feeding section passes through a transfer position and before a subsequent sheet fed by the sheet feeding section passes through the transfer position, the blowing operation is performed in a state in which the feeding operation is stopped, and a toner image formed by the image forming section is transferred to the sheet at the transfer position, in a predetermined period of time, wherein The control section is configured to control the driving section during the mode so that a rotation speed of the image bearing member during the mode is slower than a rotation speed of the image bearing member during formation of an image on a sheet.

9. The image forming apparatus according to claim 8, wherein The control part is configured to control the driving part so that the rotation speed of the image bearing member during the mode is slower than the rotation speed of the image bearing member during the formation of the image on the sheet, when the time for the sheet blowing part to perform the blowing operation in the predetermined time period is a predetermined time or longer.

10. The image forming apparatus according to claim 9, wherein The control part is configured to control the driving part so that the rotation speed of the image bearing member during the mode is maintained at the rotation speed of the image bearing member during the formation of the image on the sheet when the time for the sheet blowing part to perform the blowing operation in the predetermined time period is less than the predetermined time.

11. The image forming apparatus according to claim 8, wherein The control part is configured to control the driving part so that the rotation speed of the image bearing member during the mode is maintained at the rotation speed of the image bearing member during the formation of the image on the sheet when the time for the sheet blowing part to perform the blowing operation in the predetermined time period is less than a predetermined time.

12. The image forming apparatus according to claim 8 or 9, further comprising: a voltage applying unit configured to apply a voltage to the charging unit, wherein A voltage value of a voltage applied to the charging unit by the voltage applying unit during the mode is smaller than a voltage value of a voltage applied to the charging unit by the voltage applying unit during formation of an image on a sheet.

13. The image forming apparatus according to claim 8 or 9, further comprising: A detection part, the detection part is configured to detect the ambient humidity, wherein The sheet blowing portion is configured to: (i) perform the blowing operation for a first time in the predetermined period when the ambient humidity detected by the detection portion is a first humidity, and (ii) perform the blowing operation for a second time in the predetermined period when the ambient humidity detected by the detection portion is a second humidity higher than the first humidity, the second time being longer than the first time.

14. The image forming apparatus according to claim 8 or 9, wherein The sheet blowing portion is configured to perform the blowing operation in the predetermined period if the sheet supported on the sheet supporting portion is a predetermined sheet.

15. The image forming apparatus according to claim 8 or 9, further comprising: An image forming device body, the image forming device body comprising an image forming part, wherein The sheet supporting portion is a manual feed tray provided on a side of the image forming apparatus main body.

Images