Patent Application
20200095080
The present invention relates to a sheet feeding apparatus configured to feed sheets and an image forming system equipped with the same.
There are many varieties of recording media that can be used to form images in an image forming apparatus such as a copying machine or a printer. Examples of such recording media including OHT (Overhead Transparency) sheets, tracing paper, art paper and coated paper are coated paper, which are characterized in having a smooth surface through which gas is not easily passed. If a plurality of such sheets having a smooth surface through which gas is not easily passed are stored in a sheet feeding unit under a high humidity environment, the sheets tend to be attached to each other, and multi feed in which the sheets are conveyed in an overlapped state may occur. A technique is proposed where air is blown from an air blow unit to the sheets stored in the sheet feeding unit, thereby solving the problem of attaching of sheets (refer to Japanese Patent Application Laid-Open Publication No. 2014-16386).
However, in a state where hot air is blown to separate the sheets as in the air blow unit disclosed in Japanese Patent Application Laid-Open Publication No. 2014-16386, the moisture content of sheet may be reduced excessively if the blowing time of warm air to the sheets to be fed is too long. Especially if the sheets stored in the sheet feeding unit are long-sized sheets, the blowing time of warm air tends to be extended. Excessive reduction of moisture content of the sheet leads to deterioration of image quality, such as blanking of toner image, and causes creases to be formed on the sheet while fixing the toner image on the sheet at the fixing unit, which may cause deterioration of quality of the product.
According to a first aspect of the present invention, a sheet feeding apparatus includes a sheet supporting portion configured to support a plurality of sheets, a sheet feeding portion configured to feed a sheet supported on the sheet supporting portion in a sheet feeding direction, an air blow unit including an air blower configured to blow air, an opening portion through which air blown from the air blower is blown out, a duct configured to form a flow path through which air flows between the air blower and the opening portion, an adjustment portion arranged to oppose to an upper surface of the duct and the opening portion and configured to vary an opening dimension in a height direction between the upper surface and the adjustment portion, the air blow unit being configured to separate a plurality of sheets, including an uppermost sheet, among the sheets supported on the sheet supporting portion by air blowing out from the opening portion, a drive source configured to drive the adjustment portion, and a control unit configured to execute, in a state where a length of the sheet supported on the sheet supporting portion in the sheet feeding direction is a first length, a first mode in which the drive source is controlled such that the opening dimension is set to a first dimension, and to execute, in a state where the length of the sheet supported on the sheet supporting portion in the sheet feeding direction is a second length that is longer than the first length, a second mode in which the drive source is controlled such that the opening dimension is set to a second dimension that is smaller than the first dimension.
Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
A first embodiment according to a present invention will be described. In the following description, up, down, right, left, front and rear directions are illustrated based on a state in which a printer 100 serving as an image forming apparatus is viewed approximately from a front side, in other words, viewpoint of
The printer 100 is a laser beam printer adopting an electrophotographic system. The printer 100 includes, as illustrated in
An image forming unit 120 constitutes a so-called four-drum full color image forming unit including a laser scanner 122, four process cartridges 123 and an intermediate transfer portion 130. The process cartridges 123 form toner images of respective colors, which are yellow (Y), magenta (M), cyan (C) and black (K). The respective process cartridges 123 include a photosensitive drum 5, a developing unit 6, a charging unit 7, a cleaner 8 and so on. Toner cartridges 121 respectively storing color toner of each color are detachably attached to the apparatus body 110 at an area above the image forming unit 120.
The intermediate transfer portion 130 includes an intermediate transfer belt 9d serving as an intermediate transfer body, primary transfer rollers 10Y, 10M, 10C and 10K, a drive roller 9a, a tension roller 9b, and a secondary transfer inner roller 9c. The intermediate transfer belt 9d is wound around and supported by rollers including the drive roller 9a, the tension roller 9b and the secondary transfer inner roller 9c, and in a state where the drive roller 9a is driven to rotate, the intermediate transfer belt 9d is rotated in a direction of arrow D1 illustrated in
The primary transfer rollers 10Y, 10M, 10C and 10K are arranged to contact an inner circumferential surface of the intermediate transfer belt 9d at positions opposed to the photosensitive drums 5 of the respective colors. Primary transfer portions are formed between respective photosensitive drums 5 and the intermediate transfer belt 9d. Further, a secondary transfer outer roller 11 is arranged at a position opposed to the secondary transfer inner roller 9c with the intermediate transfer belt 9d interposed therebetween. The secondary transfer outer roller 11 is in contact with an outer circumferential surface of the intermediate transfer belt 9d. The intermediate transfer belt 9d and the secondary transfer outer roller 11 constitute a secondary transfer portion.
A sheet feeding unit 240 includes cassettes 150 and 220 on which sheets P are supported, and a manual feed tray 210. The cassettes 150 and 220 are arranged at a lower portion of the apparatus body 110, for example, and are configured to be inserted to the apparatus body 110 in a detachable manner. The manual feed tray 210 is arranged at a right side of the apparatus body 110.
In a state where the printer 100 receives a command to start image forming operation, the photosensitive drum 5 rotates, and a surface of the photosensitive drum 5 is charged uniformly by the charging unit 7. Then, the laser scanner 122 modulates and outputs a laser beam based on an image data entered from an input interface or an external computer. The laser scanner 122 outputs laser beams and scans the surface of the respective photosensitive drums 5, thereby forming electrostatic latent images based on image data on the surface of the respective photosensitive drums 5. That is, electrostatic latent images of yellow (Y), magenta (M), cyan (C) and black (K) are sequentially formed on the photosensitive drums 5 of the respective process cartridges 123. The formed electrostatic latent images of yellow, magenta, cyan and black are visualized by toner supplied from the developing unit 6, and form yellow, magenta, cyan and black toner images. By having transfer voltage applied to the primary transfer rollers 10Y, 10M, 10C and 10K, the yellow, magenta, cyan and black toner images formed on the respective photosensitive drums 5 are sequentially transferred in a superposed manner to the intermediate transfer belt 9d. Thereby, a full-color toner image is formed on the intermediate transfer belt 9d. The toner remaining on the respective photosensitive drums 5 after the toner images are transferred is collected by the cleaner 8.
Meanwhile in the printer 100, in parallel with the image forming operation, the sheet P is picked up by the sheet feeding unit 240 from a selected storage location of the sheet P and is fed to the image forming unit 120. In the case of the printer 100 illustrated in
If the cassette 150 is selected as the storage location of the sheet P, the sheets P stored in the cassette 150 are sent by a pickup roller 151 and are separated one by one by a feed roller 22 and a separation roller 21. The sheet P separated one by one is conveyed by conveyance roller pairs 153, 154 and 155 arranged on a conveyance path 20 to a registration roller pair 161. A leading edge of the sheet P being conveyed to the registration roller pair 161 is abutted against a nip of the registration roller pair 161, by which skewing of the sheet is corrected. Thereafter, the sheet P is conveyed to the secondary transfer portion at a matched timing with the toner image borne on the intermediate transfer belt 9d. The toner image borne on the intermediate transfer belt 9d is transferred collectively to the sheet P by a secondary transfer bias applied to the secondary transfer outer roller 11. The sheet P to which the toner image has been transferred is conveyed to a fixing unit 170, and the sheet P is subjected to heat and pressure by a fixing roller 171 and a pressure roller 172. Thereby, the toner image on the sheet P is fixed to the sheet P.
In a state where image formation to the sheet P has been completed, the sheet P on which the toner image has been fixed is conveyed to a conveyance path 231, the conveyance destination being switched by the switching member 173. If the sheet discharge tray 200 is selected as a discharge destination, the sheet P conveyed to the conveyance path 231 is guided through the conveyance path 231 to a sheet discharge path 180 by a switching member 174 arranged on the conveyance path 231. The sheet P guided to the sheet discharge path 180 is discharged by a sheet discharge roller pair 12 arranged on the sheet discharge path 180 to the sheet discharge tray 200. Further, if the sheet discharge tray 27 is selected as a sheet discharge destination, the sheet P conveyed to the conveyance path 231 is guided by the switching member 174 through the conveyance path 231 to a sheet discharge path 181. The sheet P having been guided to the sheet discharge path 181 is discharged by a sheet discharge roller pair 13 arranged on the sheet discharge path 181 to the sheet discharge tray 27.
Meanwhile, in a state where images are formed on both sides of the sheet P, the sheet P on which an image has been formed on a first side is guided by the switching member 173 to a reverse conveyance path 17. The sheet P guided to the reverse conveyance path 17 is temporarily conveyed to a reverse conveyance path 16 by conveyance roller pairs 14 and 15. After the sheet P has been conveyed to the reverse conveyance path 16, the conveyance roller pair 15 is reversed, and the sheet P is conveyed to a duplex conveyance path 18 by the conveyance roller pair 15 rotated in reverse rotation and a switching member 175. The sheet P having been conveyed to the duplex conveyance path 18 is further conveyed from the duplex conveyance path 18 to the conveyance path 20 by a conveyance roller pair 19, and thereafter conveyed to the registration roller pair 161. Then, similar to forming an image to the first side described earlier, image is formed on a second side of the sheet P.
Next, the sheet feed deck 250 will be described in detail. As illustrated in
The storage cabinet 506 is capable of storing a long sheet whose length in a sheet feeding direction denoted by arrow D2 (refer to
Further, the sheet feed deck 250 includes a pickup roller 501 configured to feed an uppermost sheet supported on the lifter 507, and a feed roller 502 and a separation roller 503 configured to separate the fed sheets P one by one and conveying the same. The sheet P having been separated one by one by the feed roller 502 and the separation roller 503 is drawn into the printer 100 by draw-in rollers 504 and 505 provided in the printer 100. The pickup roller 501, the feed roller 502, the separation roller 503 and the draw-in rollers 504 and 505 are formed so that the outer circumferential surfaces thereof that come in contact with the sheet P are formed of a material having a high friction coefficient, such as rubber.
The lifting mechanism 530 includes, as illustrated in
Further, a sheet presence detection sensor 601, a sheet height detection sensor 602, a sheet feed sensor 603, a bottom position detection sensor 604 and a replenishment position detection sensor 605 are arranged in the sheet feed deck 250. Further, a storage cabinet open/close detection sensor 608 for detecting the opening/closing of the storage cabinet 506 and an environment sensor 614 (refer to
Now, the sheet presence detection sensor 601 is a sensor that detects the presence of the sheet P supported on the lifter 507, and for example, it is arranged close to the pickup roller 501 serving as a sheet feeding portion. The sheet height detection sensor 602 is a sensor that detects whether an uppermost surface of the sheet P supported on the lifter 507 is positioned at a feed position in which the sheet can be fed by the pickup roller 501, and for example, it is arranged near the pickup roller 501. The sheet feed sensor 603 is a sensor that detects that the sheet P supported on the lifter 507, that is, the sheet P stored in the sheet feed deck 250, has passed a predetermined position, such as an exit through which the sheet P is fed from the sheet feed deck 250 (hereinafter referred to as “sheet feed port”). The sheet feed sensor 603 is arranged near the sheet feed port, for example, and it enables to detect that the leading edge and the trailing edge of the sheet P in the sheet feeding direction has passed the sheet feed port.
The bottom position detection sensor 604 and the replenishment position detection sensor 605 detect the position of the lifter 507 in a stacking direction. The bottom position detection sensor 604 is a sensor arranged at a lower portion of the storage cabinet 506 to detect that the lifter 507 is at a lowermost position in the storage cabinet 506. The replenishment position detection sensor 605 is a sensor arranged below the separation roller 503 and detects that a remaining amount of sheets P supported on the lifter 507 has been reduced based on the position of the lifter 507 in the stacking direction. The environment sensor 614 is a sensor that detects an environmental condition inside the storage cabinet 506, that is, the environmental condition including a temperature (atmospheric temperature) and humidity of ambient atmosphere of the sheet P supported on the lifter 507.
Further, as illustrated in
An air blow unit 620 for blowing separation air for separating sheets to a plurality of sheets including the uppermost sheet among the sheets from the uppermost sheet to the lowermost sheet stored in a stacked manner in the storage cabinet 506 is arranged on the side regulating plate 610a, as illustrated in
The warm air blowing portion 620a includes a fan 611a serving as an air blower, an air heater 613 serving as a heater, a shutter 615a serving as an adjustment portion and a swing member, and an opening portion 612a from which warm air 24a serving as the separation air is blown out. An air intake duct 618 and an exhaust duct 617a are respectively connected to an air intake side and an exhaust side of the fan 611a. The air heater 613 is arranged inside the air intake duct 618. The shutter 615a serving as an adjustment portion is arranged near the opening portion 612a at an exit portion of the exhaust duct 617a serving as a duct, and is configured to enable a height of a flow path FP formed within the exhaust duct 617a to be adjusted within a range of height of the exhaust duct 617a.
More specifically, the shutter 615a is arranged to oppose to an upper surface 619 of the exhaust duct 617a, as illustrated in
The cool air blowing portion 620b includes, as illustrated in
Further, the opening portion 612a at the warm air blowing portion 620a and the opening portion 612b at the cool air blowing portion 620b are arranged to correspond to a height of the pickup roller 501 (refer to
According to the sheet feed deck 250 configured as above, long sheets can be stored in the storage cabinet 506, and the portion of the trailing edge in the sheet feeding direction of the sheet P stored in the storage cabinet 506 is determined by moving the trailing edge regulating plate 2. Further, both ends of the sheet P in the width direction are positioned by moving the side regulating plates 610a and 610b. The exhaust duct 617a illustrated in
The control unit 700 controls the image forming operation in the image forming system 800 (refer to
The storage cabinet control unit 320 is connected in a manner capable of telecommunicating with an interface that receives input of command, a timer, various sensors, and various components composed of devices being the target of control. The above-mentioned interface includes the storage cabinet open/close button 510 that receives input of an open command and a close command of the storage cabinet 506 (refer to
Next, a relationship among moisture content of the sheet P (hereinafter referred to as “moisture content of sheet”), multi feed of the sheet P and creases on the sheet P (hereinafter referred to as “paper creases”) that occur when the toner image is fixed in the fixing unit 170 (refer to
At first, a relationship between the moisture content of sheet and the warm air blowing time will be described. The graph illustrated in
Regarding
As illustrated in
Next, with reference to
Next, we will describe a result of experiment performed by the present inventors regarding the relationship among moisture content Wp of sheet, the multi feed and the generation of paper creases on the sheet P. The present experiment was performed in a room with an atmospheric temperature of 30 [° C.] and a humidity of 80 [%], and the type, grammage [g/m2] and size of the sheet P being used are, respectively, the same as the type, the grammage [g/m2] and the size of the sheet P being used to acquire the results of
As a result of the experiment, the present inventors have obtained knowledge that the moisture content Wp of the sheet should be reduced to 7.4 [%] or lower to relieve the attachments of sheets and feed the sheets P without causing multi feed. The range of the moisture content Wp of the sheet enabling to prevent multi feed of the sheet P (Wp≤7.4 [%]) is range R1 illustrated in
Further, the present inventors have also obtained knowledge that if the moisture content Wp of sheet is reduced to 4.2 [%] or lower, paper creases may be formed on the sheet P during fixing of toner image at the fixing unit 170 (refer to
Next, with reference to
However, as the wind speed increases, the behavior of the sheet P becomes unstable, and the contact between the sheet P and the pickup roller 501 (refer to
In the present description, the following conditions (1) to (3) are presupposed. (1) If a job for feeding k number of sheets P (wherein k is a natural number) is entered, warm air 24a (refer to
At first, we will focus on the stacking direction of the sheet P being fed. If the above presuppositions (1) through (3) are satisfied, if a job to feed sheets P is received, the sheets P positioned from the first to the twentieth sheets among all the sheets from the uppermost sheet to the lowermost sheet stacked and stored in the storage cabinet 506 are separated by the warm air 24a. Each time a sheet P is fed, the uppermost sheet is fed and each sheet moves up closer to the top. Therefore, if k represents 20 sheets or less, the sheet P receiving the blow of warm air 24a the longest before being fed is the kth sheet from the uppermost sheet. The sheet P which is the 21st sheet at the time the feeding of sheets P is started will not receive blow of warm air 24a at the time the feeding of sheets P is started, but it receives blow of warm air 24a after it has become the 20th sheet, and continues receiving blow until it is fed. Therefore, the warm air blowing time for the 21st sheet to the kth sheet is the same as the warm air blowing time of the sheet P that is positioned as the 20th sheet at the time feeding has been started.
Next, operation control of the shutters 615a and 615b will be described. Since the shutters 615a and 615b are operated similarly, in the following description, the operation control of only the shutter 615a will be described. The shutter 615a can be operated according to a first mode illustrated in
That is, in a first mode where the normal-sized sheet which is a sheet having a first length is fed, the shutter 615a swings with angle θ1 set as a maximum swing angle. Then, in the opened position B, an opening dimension where the shutter 615a is positioned becomes a first dimension h1. That is, in a state where the control unit 700 executes the first mode, the swing angle θ1 of the shutter 615a from the closed position where the opening dimension is set to the first dimension h1 becomes maximum. The closed position is a position where the opening dimension h becomes minimum.
Further, in the second mode, the shutter 615a swings between the closed position A and an intermediate position C, as illustrated in
That is, in the second mode for feeding a long sheet having a second length that is longer than the first length, the shutter 615a swings with angle θ2 set as the maximum swing angle. Then, in the intermediate position C, the opening dimension at which the shutter 615a is positioned is set to a second dimension h2 that is smaller than the first dimension h1 (h2<h1). That is, in a state where the control unit 700 executes the second mode, the swing angle θ2 from the closed position where the opening dimension is the second dimension h2 becomes the maximum swing angle for the shutter 615a. As described, by operating the shutter 615a by a first mode and a second mode, the opening dimension h can be varied, and the height of the air blown toward the sheet P stacked on the lifter 507 can be varied. For example, in the first mode, air can be blown to the top 20 sheets including the uppermost sheet of all the sheets P stacked on the lifter 507. Further, in the second mode, air can be blown to the top 10 sheets including the uppermost sheet of all the sheets P stacked on the lifter 507.
Curved lines C13 and C16 in
By comparing the curved lines C13 and C14 illustrated in
If the above-mentioned presuppositions (1) through (3) are satisfied, the sheet feed time of the first sheet P is varied according to the sheet length, since it is proportional to the sheet length. Further, the warm air blowing time to one sheet P is elongated as the length of sheet feed time of the sheet P is elongated. That is, the warm air blowing time to one sheet P is longer if the sheet P being fed is the long sheet compared to the case where the sheet P being fed is the normal-sized sheet. Further, by referring to the curved lines C13 and C14 of
Therefore, in a state where the long sheet is fed, excessive drop of moisture content of sheet tends to occur compared to the case where a normal-sized sheet is fed, and product quality deterioration due to the excessive drop of moisture content of sheet tends to occur. Therefore, according to the present embodiment, as described later, sheet feed control is performed, and the operation mode of the shutters 615a and 615b is controlled so that the warm air blowing time to the sheet P becomes equivalent in cases where a long sheet is fed and where a normal-sized sheet is fed.
That is, if a normal-sized sheet is fed, the shutters 615a and 615b are operated in a first mode. In a state where the shutter 615a is operated by a first mode, the opening dimension h is relatively large, so that a large number of sheets receive blow of the warm air 24a, according to which sheets can be separated preferably. Meanwhile, upon feeding long sheets, the shutters 615a and 615b are operated in a second mode. In a state where the shutter 615a is operated in a second mode, the opening dimension h is relatively small, so that the number of sheets to which the warm air 24a is blown is reduced. Therefore, even if the sheet length is long, the total time during which the warm air 24a is blown to the sheet being fed can be suppressed, and as shown by the curved lines C15 and C18 of
Next, with reference to the flowcharts of
Next, the control unit 700 determines whether the storage position of the sheet being fed is the sheet feed deck 250 based on sheet attribute information selected by the user in step S1 (step S2). If the storage position of the sheet being fed is not the sheet feed deck 250 (step S2: NO), the present processing is ended.
If the storage position of the sheet being fed is the sheet feed deck 250 (step S2: YES), the control unit 700 acquires environment information including the atmospheric temperature and humidity in the storage cabinet 506 by the environment sensor 614 arranged in the storage cabinet 506 (step S3). Then, the control unit 700 determines whether initial separation processing of the sheet bundle by warm air 24 is necessary based on the acquired environment information and the sheet attribute information (step S4).
In a state where initial separation processing is determined necessary (step S4: YES), the initial separation processing is performed (step S5). Detailed processing of the initial separation processing will be illustrated in the flowchart of
The setting table of the heater temperature illustrated in
As the atmospheric temperature detected by the environment sensor 614 becomes higher, or as the humidity becomes higher, the heater temperature of the air heater 613 is set to a higher temperature. If the heater temperature is set to “OFF”, power to the air heater 613 is not supplied, so that the air heater 613 is set to a temperature close to outer atmospheric temperature. For example, if the atmospheric temperature detected by the environment sensor 614 is the first temperature, that is 20 [° C.] or higher and less than 30 [° C.], and the humidity is the first humidity, that is 40 [%] or higher and less than 60 [%], the air heater 613 is set to the first heater temperature, that is, 60 [° C.]. Further, if the atmospheric temperature detected by the environment sensor 614 is the second temperature, that is, 30 [° C.] or higher, and the humidity is the second humidity, that is, 60 [%] or higher, the air heater 613 is set to the second heater temperature, that is, 90 [° C.], higher than the first heater temperature.
Similarly, the setting table of the fan output illustrated in
As the atmospheric temperature detected by the environment sensor 614 increases, or as the humidity increases, the fan output of the fans 611a and 611b is set to a higher output. The output of the fans 611a and 611b is changed, for example, by changing the rotational speed of the fans 611a and 611b, that is, changing the number of rotations per unit time.
For example, if the atmospheric temperature detected by the environment sensor 614 is the third temperature, that is, 20 [° C.] or higher and less than 30 [° C.], and the humidity is the third humidity, that is 40 [%] or higher and less than 60 [%], the fan output is set to the first rotational speed, that is, 40 [%]. Further, if the atmospheric temperature detected by the environment sensor 614 is the fourth temperature, that is, 30 [° C.] or higher, and the humidity is the fourth humidity, that is, 60 [%] or higher, the fan output is set to the second rotational speed, that is, 60 [%], faster than the first rotational speed.
After the heater temperature and the fan output have been determined in this manner, the control unit 700 starts blowing separation air to the sheet P supported on the lifter 507 by the air blow unit 620 (step S502). Then, after a predetermined time set in advance has elapsed from the start of blowing of separation air, the control unit 700 stops blowing separation air from the air blow unit 620 is stopped (steps S503 and S504). In this state, the shutters 615a and 615b operate based on a first mode. As described, by blowing separation air to the sheets P before feeding sheets, the attachment of sheets stacked on the lifter 507 can be solved, and multi feed by the pickup roller 501 can be reduced.
Next, the control unit 700 determines whether the sheet P being fed is a long sheet or not (step S505). If the sheet P being fed is not a long sheet (step S505: NO), the initial separation processing is ended. If the sheet P being fed is a long sheet (step S505: YES), as illustrated in
Then, the control unit 700 receives change of shutter operation control from the user (step S507). In a state where the user presses the “shutter operation control change” button 311 (step S507: YES), the control unit 700 changes the shutters 615a and 615b from the first mode to the second mode (step S508) and ends the initial separation processing. If the user presses an “OK” button without pressing the “shutter operation control change” button 311 (step S507: NO), the control unit 700 ends the initial separation processing without changing the shutters 615a and 615b from the first mode.
In a state where the initial separation processing is ended, as illustrated in
If a trailing edge of a final sheet of the job is detected by the sheet feed sensor 603, the control unit 700 determines that separation of the sheet P is no longer necessary, and stops the output of separation air from the air blow unit 620 (steps S11 and S12). Thereby, the job and the sheet feed control are completed (step S13). The blowing of separation air by the air blow unit 620 is performed at least from before the feeding of the first sheet of the job is started to the feeding of the final sheet of the job is started.
In the above-described explanation of sheet feed control, the change of shutter operation control is received in a state where the “shutter operation control change” button 311 displayed on the display operation unit 310 is pressed, but the present invention is not restricted thereto. For example, the change of shutter operation control can be received automatically at a point of time when the control unit 700 acquires the sheet attribute information of the sheet P (refer to
As described, in a state where a long sheet is fed, the operation mode of the shutters 615a and 615b can be changed to the second mode to narrow the opening dimension h, by which the number of sheets to which the warm air 24a is blown can be reduced. Thereby, even if the sheet length is long, the total time during which the warm air 24a is blown to the sheets being fed can be suppressed, and excessive reduction of moisture content of the sheet can be prevented. Thereby, paper creases transfer failures can be reduced, and the quality of the product can be improved.
Next, a second embodiment of the present invention will be described. The second embodiment differs from the first embodiment in the contents of the initial separation processing, but it does not differ in points other than the initial separation processing. Therefore, in the present embodiment, the configurations and processing steps that do not differ from those of the first embodiment are either not shown or are denoted with the same reference numbers, and the same descriptions as the first embodiment are omitted.
In the present embodiment, in a state where the operation mode of the shutters 615a and 615b is changed, the influence of variation of pressure loss that occurs in the flow path is considered. For example, in a state where the operation mode of the shutters 615a and 615b is changed from the first mode (refer to
Therefore, according to the initial separation processing of the present embodiment, as illustrated in
According to the above-described operation, variation of sheet separation ability of separation air can be suppressed before and after change of operation mode of the shutters 615a and 615b. Therefore, the sheets can be separated preferably regardless of the selected operation mode of the shutters 615a and 615b.
The present invention is not restricted to the embodiments described above and can be implemented in various embodiments other than the examples described above. Various elements can be omitted, replaced or changed within the scope of the present invention. For examples, the dimensions, materials, shapes and relative arrangements of components can be altered if necessary, to apply the present invention according to the configuration and various conditions of the apparatus.
In all the embodiments described above, the sheet P stacked on the lifter 507 is fed by the pickup roller 501, but the present invention is not limited thereto. For example, the sheets stacked on the lifter 507 can be fed by attaching the sheet using negative pressure or electrostatic force. Further, the present invention is not limited to a configuration where air is blown from rotating fans 611a and 611b, and the present invention can also be configured to send air from an air blow portion such as a bellows pump.
In all the embodiments described above, the shutter 615a (refer to
In all the embodiments described above, an example where the printer 100 (refer to
In all the embodiments described above, an example where the opening portions 612a and 612b (refer to
The printer 100 adopting an electrophotographic system was described as an example of the image forming apparatus in all the embodiments described above, but the present invention can be applied to an inkjet-type image forming apparatus that forms an image on a sheet by discharging ink from nozzles.
Embodiment(s) of the present invention can also be realized by a computer of a system or apparatus that reads out and executes computer executable instructions (e.g., one or more programs) recorded on a storage medium (which may also be referred to more fully as a ‘non-transitory computer-readable storage medium’) to perform the functions of one or more of the above-described embodiment(s) and/or that includes one or more circuits (e.g., application specific integrated circuit (ASIC)) for performing the functions of one or more of the above-described embodiment(s), and by a method performed by the computer of the system or apparatus by, for example, reading out and executing the computer executable instructions from the storage medium to perform the functions of one or more of the above-described embodiment(s) and/or controlling the one or more circuits to perform the functions of one or more of the above-described embodiment(s). The computer may comprise one or more processors (e.g., central processing unit (CPU), micro processing unit (MPU)) and may include a network of separate computers or separate processors to read out and execute the computer executable instructions. The computer executable instructions may be provided to the computer, for example, from a network or the storage medium. The storage medium may include, for example, one or more of a hard disk, a random-access memory (RAM), a read only memory (ROM), a storage of distributed computing systems, an optical disk (such as a compact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™), a flash memory device, a memory card, and the like.
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.
This application claims the benefit of Japanese Patent Application No. 2018-181032, filed Sep. 26, 2018, which is hereby incorporated by reference herein in its entirety.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2018-181032 | Sep 2018 | JP | national |
