Sheet feeding device and image formation device

Abstract

To reduce a contact noise when a sheet enters a separation nip from a pickup roller.SOLUTION: A sheet feeding device includes: a pickup roller 2 that feeds a sheet supported by a feeding cassette 5; a feed roller 3 that transports the sheet fed by the pickup roller 2; a retard roller 4 that contacts the feed roller 3 to form a separation nip and separates the sheets one by one; and a nip sensor 24 that detects that the leading edge of the sheet fed by the pickup roller 2 has reached the separation nip. If the leading edge of the sheet has not reached the separation nip when feeding by the pickup roller 2 starts, the control unit starts feeding the sheet with the feeding speed by the pickup roller 2 as the first speed, and after the leading edge of the sheet reaches the separation nip, increases the transport speed by the feed roller 3 to a second speed that is faster than the first speed and transports the sheet.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a sheet feeding device that feeds a sheet, and an image forming apparatus to which the sheet feeding device is applied. [Background technology]

[0002] Conventionally, image forming apparatuses using an electrophotographic method, such as copying machines, printers, and facsimiles, have been widely used that have a sheet feeding device that feeds sheets to an image forming section. As such a sheet feeding device, one that has a separation roller and a retard roller to prevent double feeding of sheets fed from a pickup roller is known (see Patent Document 1). In this sheet feeding device, a nip sensor is provided in a separation nip where the separation roller and the retard roller contact each other. If the nip sensor detects the leading edge of a sheet within a predetermined time from the start of sheet feeding, the sheet is fed at a second conveying speed that is slower than the first conveying speed. In this way, this sheet feeding device feeds back sheet position information in the feeding section to reduce the variation in the sheet interval between the preceding sheet and the succeeding sheet, thereby improving productivity. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-1878 A Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, there has been an increasing demand for faster and quieter image formation in image forming devices used in offices. However, in the sheet feeding device described in the above-mentioned Patent Document 1, the feeding speed increases with the increase in image formation speed, and there is a problem that the contact noise when the sheet enters the separation nip from the pickup roller may become louder.

[0005] SUMMARY OF THE DISCLOSURE An object of the present invention is to provide a sheet feeding device and an image forming apparatus that can reduce the contact noise generated when a sheet enters a separation nip from a pickup roller. [Means for solving the problem]

[0006] One aspect of the present invention is a sheet feeding device comprising a support section that supports a stack of sheets, a feeding section that feeds sheets supported by the support section, a transport section that transports the sheets fed by the feeding section, a separation section that contacts the transport section to form a separation nip and separates the sheets fed by the feeding section one by one, a first sensor that detects that a leading edge of a sheet fed by the feeding section has reached the separation nip, a pair of transport rollers that are arranged downstream of the transport section in the sheet transport direction and transport the sheets transported by the transport section, a second sensor that detects that a leading edge of a sheet transported by the transport section has reached the pair of transport rollers, and a control section that controls the feeding section and the transport section, wherein the control section starts feeding the sheet at a feeding speed by the feeding section as a first speed if the leading edge of the sheet has not reached the separation nip when feeding by the feeding section begins, and then increases the transport speed by the transport section to a second speed faster than the first speed and transports the sheet after the leading edge of the sheet reaches the separation nip.

[0007] Another aspect of the present invention is an image forming apparatus including the above-mentioned sheet feeding device and an image forming section that forms an image on the sheet fed by the sheet feeding device. Effect of the Invention

[0008] According to the present invention, it is possible to reduce the contact noise generated when the sheet enters the separation nip from the pickup roller. [Brief description of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view showing an image forming apparatus according to an embodiment; [Diagram 2] FIG. 2 is a control block diagram showing a control system of the image forming apparatus according to the embodiment. [Diagram 3] 2 is a cross-sectional view showing a cassette feeding section of the image forming apparatus according to the embodiment; [Figure 4] 2 is a plan view showing a cassette feeding section of the image forming apparatus according to the embodiment; FIG. [Diagram 5] 10 is a time chart showing a conveying position of a sheet in a case where a leading edge of the sheet is not detected by a nip sensor at a feeding start reference time in the image forming apparatus according to the embodiment. [Figure 6] 11 is a time chart showing a conveying position when conveyance of a sheet is delayed in a case where a leading edge of the sheet is not detected by a nip sensor at a feed start reference time in the image forming apparatus according to the embodiment; [Figure 7] 10 is a time chart showing a conveying position of a sheet in a case where a leading edge of the sheet is detected by a nip sensor at a feeding start reference time in the image forming apparatus according to the embodiment. [Figure 8] 5 is a flowchart showing a processing procedure when feeding a sheet in the image forming apparatus according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The present embodiment will be described below with reference to the drawings. First, the schematic configuration of an image forming apparatus 1 according to this embodiment will be described with reference to Figs. 1 and 2. Fig. 1 is a cross-sectional view showing the schematic configuration of the image forming apparatus 1 according to this embodiment, and Fig. 2 is a block diagram of a control system. The image forming apparatus 1 is a tandem type intermediate transfer type laser beam printer that utilizes an electrophotographic process. The image forming apparatus 1 can form and output a full-color or monochrome image corresponding to print image data output from a host device 900 connected to a control unit 100 on a sheet S, which is a recording medium.

[0011] 2, the control unit 100 is a control means for controlling the overall operation of the image forming apparatus 1, and transmits and receives information to and from the host device 900 and the operation unit 730. The control unit 100 also performs signal processing and sequence control for various process devices. Here, the host device 900 is a personal computer, an image scanner, a facsimile, or the like.

[0012] The control unit 100 has a CPU, a RAM, and a ROM, and controls each unit in the image forming apparatus 1. The CPU outputs an output signal to each electric component to operate the electric component at a desired timing and with a required amount of control based on the detection signals input from each sensor and the information stored in the ROM. Therefore, it is the CPU that actually controls the electric components. The ROM and RAM store information data required for controlling each unit, and the CPU reads the information data stored in the ROM and writes it to the RAM. The control unit 100 controls the pickup roller 2 and feed roller 3 of the cassette feeding unit 230 described later.

[0013] 1, the image forming apparatus 1 has an image forming apparatus main body 201A and an image forming section 201B that forms an image on a sheet S. An image reading device 202 that is installed substantially horizontally is provided above the image forming apparatus main body 201A. A discharge space V for discharging sheets is formed between the image reading device 202 and the image forming apparatus main body 201A.

[0014] The cassette feeding section 230 is an example of a sheet feeding device, and feeds a sheet S from a feeding cassette 5 which is a sheet storage means for storing the sheet S. The cassette feeding section 230 has a pickup roller 2, and a separation roller pair 6 consisting of a feed roller 3 and a retard roller 4 for separating the sheet S sent out from the pickup roller 2. The cassette feeding section 230 will be described later.

[0015] Moreover, the manual feed unit 500 feeds the sheet S from the manual feed tray 10, which is a means for holding the sheet S. The manual feed unit 500 is an example of a manual feed tray into which a sheet can be manually fed, and similarly to the cassette feed unit 230, has a pickup roller 502, which is a sheet feeding means, and a separation roller pair for separating the sheet S sent out from the pickup roller 502. The separation roller pair is made up of a feed roller 503 and a retard roller 504.

[0016] The image forming section 201B forms an image on a sheet fed by the cassette feeding section 230. The image forming section 201B is of a four-drum full-color type, and has a laser scanner 210 and four process cartridges 211 that form toner images of four colors, yellow (Y), magenta (M), cyan (C), and black (K). Here, each process cartridge 211 is provided with a photosensitive drum 212, a charger 213 as a charging means, and a developer 214 as a developing means. The image forming section 201B also has a secondary transfer section 218 and a fixing section 201E disposed above the process cartridges 211. A toner cartridge 215 supplies toner to the developer 214.

[0017] The secondary transfer unit 218 includes a transfer belt 216 wound around a drive roller 216a and a tension roller 216b. A primary transfer roller 219 is provided on the inside of the transfer belt 216, which contacts the transfer belt 216 at a position facing the photosensitive drum 212. The transfer belt 216 is rotated in the direction of an arrow by a drive roller 216a driven by a drive unit (not shown). A secondary transfer roller 217 that transfers a color image formed on the transfer belt 216 to a sheet S is provided at a position facing the drive roller 216a of the secondary transfer unit 218.

[0018] A fixing section 201E is disposed above the secondary transfer roller 217, and a first discharge roller pair 225a, a second discharge roller pair 225b, and a double-sided reversing section 201F are disposed above the fixing section 201E. The double-sided reversing section 201F is provided with a reversing roller pair 222 that can rotate forward and backward, and a re-conveying path R that conveys the sheet S, on one side of which an image has been formed, back to the image forming section 201B. An operation section 730 that accepts operations from a user is provided on the upper portion of the image forming apparatus 1. A touch panel type having both a display function and an input function is adopted as the operation section 730.

[0019] Next, an image forming operation of the image forming apparatus 1 will be described. First, when the image forming apparatus 1 receives image data of an original to be printed, the image information is subjected to image processing, converted into an electric signal, and transmitted to a laser scanner 210 of the image forming unit 201B. In the image forming unit 201B, the surface of the photosensitive drum 212, the surface of which is uniformly charged to a predetermined polarity and potential by a charger 213, is sequentially exposed to a laser. As a result, electrostatic latent images of yellow, magenta, cyan, and black are sequentially formed on the photosensitive drum of each process cartridge 211, respectively.

[0020] Thereafter, the electrostatic latent images are developed and visualized with toner of each color, and the toner images of each color on each photosensitive drum are transferred in order onto the transfer belt 216 in a superimposed manner by a primary transfer bias applied to a primary transfer roller 219. As a result, a toner image is formed on the transfer belt 216.

[0021] In parallel with this toner image forming operation, the sheets S are conveyed one by one by the cassette feeding section 230 or the manual feeding section 500 to the registration roller pair 240, and skew is corrected by the registration roller pair 240. After the skew is corrected, the sheets S are conveyed by the registration roller pair 240 to the secondary transfer section 218, and the toner images are transferred all at once onto the sheets S by a secondary transfer bias applied to the secondary transfer roller 217 in the secondary transfer section 218.

[0022] Next, the sheet S onto which the toner image has been transferred is transported to the fixing section 201E, where the toners of the various colors melt and mix under heat and pressure in a roller nip section formed by the pressure roller 220a and the heating roller 220b, and are fixed as a color image on the sheet S. The sheet S onto which the image has been fixed is discharged into the discharge space V by a first discharge roller pair 225a or a second discharge roller pair 225b provided downstream of the fixing section 201E, and is stacked on a discharge tray 223 protruding from the bottom surface of the discharge space V. When images are formed on both sides of the sheet S, after the images are fixed, the sheet S is transported to a re-conveyance path R by a reversing roller pair 222, and is transported again to the image forming section 201B.

[0023] [Sheet Feeding Device] Next, the cassette feeding section 230 for feeding sheets will be described with reference to Figs. 3 and 4. The cassette feeding section 230 has a pickup roller 2 that picks up the sheets S stacked in a feeding cassette 5, a feed roller 3 that conveys the picked up sheets, and a retard roller 4 that faces the pickup roller 2 and separates a plurality of sheets into one sheet. The feed roller 3 and the retard roller 4 function as a separation roller pair 6 that separates and conveys the sheets one by one. The feed roller 3 is an example of a conveying section, and conveys the sheets fed by the pickup roller 2. The retard roller 4 is an example of a separating section, and contacts the feed roller 3 to form a separation nip and separates the sheets fed by the pickup roller 2 one by one.

[0024] The feeding cassette 5 has a sheet storage section for storing the sheets S, a side regulating plate and a rear end regulating plate for regulating the position of the stored sheets, and a middle plate for raising the stored sheets to a position where they can be fed. The feeding cassette 5 is an example of a support section, and supports a stack of sheets.

[0025] The pickup roller 2 rotates while being pressed against the sheet surface, thereby sending the sheet S to a pair of separation rollers 6. The pickup roller 2 is an example of a feeding section, and feeds a sheet supported by a feeding cassette 5.

[0026] The drive transmission force (limit value) of the torque limiter (not shown) is set to be greater than the friction force generated between the sheets due to the friction coefficient of the sheets used. Also, the drive transmission force (limit value) of the torque limiter (not shown) is set to be smaller than the friction force due to the friction coefficient between the sheet and the feed roller 3. Therefore, when only one sheet S enters the separation nip between the feed roller 3 and the retard roller 4, which are the separation roller pair 6, or when no sheet S is entered, the retard roller 4 rotates together with the feed roller 3. Also, when two or more sheets S enter the separation nip, the retard roller 4 rotates in the opposite direction to the sheet feeding direction indicated by the arrow F, and separates the sheets S one by one.

[0027] The retard roller 4 rotates around the retard roller holder shaft 27 as a rotation center, and is pressed toward the feed roller 3. The sheet sent out by the feed roller 3 is delivered to a pull-out roller pair 29, and is further transported to a registration roller pair 240 downstream of the sheet transport path. The pull-out roller pair 29 is an example of a transport roller pair, and is disposed downstream of the feed roller 3 in the sheet transport direction, and transports the sheet transported by the feed roller 3. In this embodiment, a feed motor 231 (see FIG. 2) is provided as a drive unit that drives the pickup roller 2 and the feed roller 3. That is, the pickup roller 2 and the feed roller 3 are configured to rotate synchronously.

[0028] The nip sensor 24 is disposed at a position where it can detect the leading edge of the sheet near the nip area between the feed roller 3 and the retard roller 4. The nip sensor 24 is an example of a first sensor, and detects that the leading edge of the sheet fed by the pickup roller 2 has reached the separation nip of the separation roller pair 6.

[0029] As shown in FIG. 4, the feed roller 3 and the retard roller 4 are disposed at approximately the center in the sheet width direction perpendicular to the sheet conveying direction. The nip sensor 24 is disposed at a position overlapping the nip area of ​​the feed roller 3 and the retard roller 4 in the sheet conveying direction, and at a position not overlapping the arrangement area of ​​the feed roller 3 and the retard roller 4 in the sheet width direction. That is, the nip sensor 24 is disposed at a position offset from the roller pair in the axial direction of the shafts holding the feed roller 3 and the retard roller 4, respectively, in the sheet width direction. Thus, in this embodiment, the nip sensor 24 is disposed so that at least a part of it overlaps with the feed roller 3 when viewed from the width direction intersecting the sheet conveying direction. In this embodiment, the nip sensor 24 is disposed downstream of the separation nip in the sheet conveying direction. When the nip sensor 24 detects the leading edge of the sheet, the control unit 100 determines that the leading edge of the sheet has reached the separation nip. The position of the nip sensor 24 is not limited to the downstream of the separation nip in the sheet transport direction, but may be coincident with the separation nip or may be disposed upstream of the separation nip in the sheet transport direction.

[0030] The feed roller 3 and the retard roller 4 are removably attached to a cantilevered support shaft, and the nip sensor 24 is disposed at a position spaced from the end of the support shaft in the direction in which the roller members are removed by at least the length L of the roller members. This allows the feed roller 3 and the retard roller 4 to be easily replaced without the nip sensor 24 getting in the way.

[0031] The pull-out sensor 26 is provided downstream of the nip sensor 24 in the sheet conveying direction, and is disposed closer to the center in the sheet width direction than the nip sensor 24. The pull-out sensor 26 is disposed upstream of the registration roller pair 240 in the sheet conveying path. The pull-out sensor 26 is an example of a second sensor, and detects that the leading edge of the sheet conveyed by the feed roller 3 has reached the pull-out roller pair 29. In this embodiment, the control unit 100 adjusts the conveying speed by the pull-out roller pair 29 based on the timing when the pull-out sensor 26 detects the leading edge of the sheet. The control unit 100 also starts feeding by the pickup roller 2 based on the timing when the pull-out sensor 26 detects the trailing edge of the sheet.

[0032] [Feed section operation] Next, the control of the cassette feeding section 230 having the nip sensor 24 will be described with reference to Figs. 5 to 8. Figs. 5 to 7 are time charts showing the change in the sheet position over time, with the horizontal axis representing time (t) and the vertical axis representing distance (position), with the sheet leading edge position F and the sheet trailing edge position R. Fig. 8 is a flowchart showing these processing procedures.

[0033] As shown in FIG. 5 and FIG. 8, the control unit 100 receives a feeding start command from the upper side and starts the feeding process at a feeding start reference time (t=0) (step S1). When the control unit 100 determines that the nip sensor 24 does not detect a sheet (step S2; NO), it sets the sheet conveying speed to a low first speed V1 and starts feeding (step S3). Here, if the sheet feeding speed is increased to improve productivity, there is a risk that the contact sound of the leading edge of the sheet against the separation roller pair 6 will become louder. Therefore, in this embodiment, the first speed V1 is set to a speed that suppresses the contact sound when the leading edge of the sheet contacts the separation roller pair 6. The specific value of the first speed V1 varies depending on many factors such as the type of sheet and the material and configuration of the separation unit. Here, it is assumed that the control unit 100 determines that the sheet feeding speed from the start of feeding by the pickup roller 2 until the sheet reaches the separation nip is the first speed V1 based on the detection by the nip sensor 24 (step S4; NO).

[0034] On the other hand, if the sheet feeding speed is slowed down, the productivity decreases. Therefore, in this embodiment, when the leading edge of the sheet is detected by the nip sensor 24 (t1), the rotation speed of the feed roller 3 is increased at that timing to increase the sheet conveying speed to a high second speed V2 (step S5), and the sheet is conveyed (step S6). This makes it possible to suppress the decrease in productivity.

[0035] In this manner, if the leading edge of the sheet has not yet reached the separation nip when feeding by the pickup roller 2 is started, the control unit 100 starts feeding the sheet with the feeding speed by the pickup roller 2 set to the first speed V1. After the leading edge of the sheet reaches the separation nip, the control unit 100 increases the conveying speed by the feed roller 3 to the second speed V2, which is faster than the first speed V1, and conveys the sheet.

[0036] Next, a case where the actual sheet conveying speed is slower than the control value due to slippage or the like will be described with reference to Figs. 6 and 8. In Fig. 6, the actual sheet position is indicated by a dashed line with respect to the sheet position as a command value for control indicated by a solid line. The actual sheet speed is assumed to be a third speed V3 slower than the first speed V1 for control. In this case, the sheet conveying speed is increased from the third speed V3 to a fourth speed V4 at the timing (t2) when the leading edge of the sheet is detected by the nip sensor 24. At this time, the fourth speed V4 is set to be greater than the third speed V3 in order to make up for the delay (Δt=t2-t1) relative to the arrival time (t1) at the nip sensor 24 for control. In addition, by setting the fourth speed V4 to the maximum speed in advance, it is possible to prevent loss of synchronism of a drive source (not shown).

[0037] That is, after executing steps S1 to S3, the control unit 100 judges whether the sheet feeding speed from when the pickup roller 2 starts feeding until the sheet reaches the separation nip is slower than the first speed V1 by the detection of the nip sensor 24 (step S4). When the control unit 100 judges that the sheet feeding speed is, for example, the third speed V3, which is slower than the first speed V1 (step S4; YES), the control unit 100 increases the conveying speed by the feed roller 3 to a fourth speed V4, which is faster than the second speed V2 (step S7). The feed roller 3 conveys the sheet at this fourth speed (step S6). This makes it possible to make up for the delay in the arrival time (t1) at the nip sensor 24 in terms of control, thereby suppressing the variation in the sheet interval.

[0038] Next, as shown in FIG. 7, a case where the nip sensor 24 detects a sheet at the reference feed start time (t=0) will be described. For example, a following sheet may be conveyed downstream of the separation nip by being pulled by a preceding sheet, and the nip sensor 24 detects the sheet when the sheet starts to be fed. In this case, as shown in FIG. 7 and FIG. 8, the control unit 100 receives a feed start command from the upper side and starts the feeding process at the reference feed start time (t=0) (step S1). If the control unit 100 determines that the nip sensor 24 detects a sheet (step S2; YES), it delays the feed start time to t3 (step 8). Furthermore, it starts conveying at a fifth speed V5 faster than the first speed V1 (step S6). In this way, if the leading edge of the sheet has reached the separation nip when the pickup roller 2 starts feeding, the control unit 100 starts conveying the sheet at a conveying speed by the feed roller 3 at a fifth speed V5 faster than the first speed V1. The fifth speed V5 may be, for example, the same as the second speed V2.

[0039] Here, when the nip sensor 24 detects a sheet at the reference feeding start time (t=0), the position of the sheet is unknown, and therefore, if the sheet is conveyed at a normal conveying speed from the pull-out roller pair 29, there is a possibility that the sheet interval will vary. Therefore, it is desirable to adjust the conveying speed of the pull-out roller pair 29 based on the timing at which the pull-out sensor 26 detects the leading edge of the sheet.

[0040] As shown by the solid line in FIG. 7, the control unit 100 assumes that the leading edge of the sheet has reached the separation nip when the pickup roller 2 starts feeding, and that the distance from the separation nip to the leading edge of the sheet is a first distance. In this case, the control unit 100 sets the conveying speed by the pull-off roller pair 29 to a sixth speed V6 after the leading edge of the sheet reaches the pull-off roller pair 29. Also, as shown by the dashed line in FIG. 7, the control unit 100 assumes that the leading edge of the sheet has reached the separation nip when the pickup roller 2 starts feeding, and that the distance from the separation nip to the leading edge of the sheet is a second distance longer than the first distance. In this case, the control unit 100 sets the conveying speed by the pull-off roller pair 29 to a seventh speed V7 slower than the sixth speed V6 after the leading edge of the sheet reaches the pull-off roller pair 29. This can reduce the variation in the sheet interval downstream of the pull-off roller pair 29.

[0041] As described above, according to the cassette feeding unit 230 of the present embodiment, the control unit 100 starts feeding the sheet by setting the feeding speed by the pickup roller 2 to the first speed V1. As a result, the first speed V1 can be set to a speed that suppresses the abutment sound when the leading edge of the sheet abuts against the separation roller pair 6, and the abutment sound can be suppressed. Then, after the leading edge of the sheet reaches the separation nip, the conveying speed by the feed roller 3 is increased to the second speed V2 faster than the first speed V1 and conveyed. As a result, even if the conveying speed is low until the separation roller pair 6 is reached, the speed can be increased after the separation roller pair 6 is reached, so that a decrease in productivity can be suppressed. In this way, a device that suppresses the entry sound of the separation nip by reducing the feeding speed up to the separation nip and that can realize high speed and quietness can be provided by responding to the high speed by increasing the speed based on the nip sensor 24.

[0042] In the above embodiment, the case where the sheet feeding device is applied to the cassette feeding section 230 has been described, but the present invention is not limited to this, and may be applied to, for example, the manual feeding section 500 or the ADF. [Explanation of symbols]

[0043] 1...image forming apparatus, 2...pickup roller (feeding section), 3...feed roller (conveying section), 4...retard roller (separating section), 5...feed cassette (support section), 24...nip sensor (first sensor), 26...pulling sensor (second sensor), 29...pulling roller pair (conveying roller pair), 201B...image forming section, 230...cassette feeding section (sheet feeding device)

Claims

1. a support portion for supporting the sheet stack; a feeding section that feeds the sheet supported by the supporting section; a conveying section that conveys the sheet fed by the feeding section; a separation unit that comes into contact with the conveying unit to form a separation nip and separates the sheets fed by the feeding unit one by one; a first sensor that detects that a leading edge of the sheet fed by the feeding section has reached the separation nip; a pair of conveying rollers disposed downstream of the conveying unit in a sheet conveying direction, the pair of conveying rollers conveying the sheet conveyed by the conveying unit; a second sensor that detects that a leading edge of the sheet conveyed by the conveying unit has reached the pair of conveying rollers; A control unit that controls the feeding unit and the conveying unit, When the leading edge of the sheet has not yet reached the separation nip when feeding by the feeding unit is started, the control unit starts feeding of the sheet by setting a feeding speed by the feeding unit to a first speed, and after the leading edge of the sheet reaches the separation nip, increases the conveying speed by the conveying unit to a second speed faster than the first speed and conveys the sheet. A sheet feeding device comprising:

2. When the control unit determines, based on detection by the first sensor, that a sheet feeding speed from when feeding by the feeding unit starts until when the sheet reaches the separation nip is a third speed that is slower than the first speed, the control unit increases a conveying speed by the conveying unit to a fourth speed that is faster than the second speed and conveys the sheet.

2. The sheet feeding apparatus according to claim 1, wherein the sheet feeding apparatus comprises:

3. when the leading edge of the sheet has reached the separation nip when the feeding unit starts feeding, the control unit starts conveying the sheet at a conveying speed by the conveying unit at a fifth speed that is faster than the first speed.

2. The sheet feeding apparatus according to claim 1, wherein the sheet feeding apparatus comprises:

4. The control unit is when the leading edge of the sheet has reached the separation nip when the feeding unit starts feeding, and the distance from the separation nip to the leading edge of the sheet is a first distance, after the leading edge of the sheet has reached the conveying roller pair, a conveying speed by the conveying roller pair is set to a sixth speed; when the leading edge of the sheet has reached the separation nip when the feeding section starts feeding, and the distance from the separation nip to the leading edge of the sheet is a second distance longer than the first distance, after the leading edge of the sheet has reached the pair of conveying rollers, the conveying speed by the pair of conveying rollers is set to a seventh speed slower than the sixth speed.

4. The sheet feeding apparatus according to claim 3,

5. the control unit adjusts a conveying speed of the conveying roller pair based on a timing at which the second sensor detects the leading edge of the sheet.

2. The sheet feeding apparatus according to claim 1, wherein the sheet feeding apparatus comprises:

6. The control unit starts feeding by the feeding unit based on a timing when the second sensor detects the rear end of the sheet.

2. The sheet feeding apparatus according to claim 1, wherein the sheet feeding apparatus comprises:

7. the first sensor is disposed so as to at least partially overlap with the conveying unit when viewed from a width direction intersecting the sheet conveying direction; 2. The sheet feeding apparatus according to claim 1, wherein the sheet feeding apparatus comprises:

8. the first sensor is located downstream of the separation nip in the sheet conveying direction, the control unit determines that the leading edge of the sheet has reached the separation nip when the first sensor detects the leading edge of the sheet.

8. The sheet feeding apparatus according to claim 7,

9. A drive unit that drives the feeding unit and the conveying unit is provided.

2. The sheet feeding apparatus according to claim 1, wherein the sheet feeding apparatus comprises:

10. A sheet feeding device according to any one of claims 1 to 9, an image forming unit that forms an image on the sheet fed by the sheet feeding device, 1. An image forming apparatus comprising:

Images