Image forming device

Abstract

To provide an image forming device that can surely discharge a sheet having an image formed thereon, with good accuracy.SOLUTION: A complex machine 1 is provided with: a process part 4; a cutter 10; a device main body 20 that has a first discharge path 201A that does not pass on a cutter position SP and a second discharge path 201B that passes on the cutter position; a first discharge roller 87 arranged on the first discharge path; a second discharge roller 86 arranged on the second discharge path; a third discharge roller 85 arranged closer to an upstream side than the second discharge roller; a discharge sensor SE3 arranged on the first discharge path; a sheet sensor SE4 arranged on the second discharge path; and a CPU 101. When instructed to cut a sheet, the CPU executes pre-cutting stop processing for stopping the sheet at the cutter position and discharging stop processing for rotating and then stopping the second discharge roller, on the basis of a detected result by the sheet sensor.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus. [Background technology]

[0002] Conventionally, as described in Patent Document 1, for example, there is known an image forming apparatus having a cutting device for cutting a sheet on which an image is formed. This cutting device is provided with a pair of entrance rollers, a pair of registration rollers, a pair of discharge rollers, etc. as sheet conveying means. In addition, this cutting device is provided with an entrance sensor that detects the entrance of a sheet and an exit sensor that detects the exit of a sheet. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-37867 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the image forming device described in Patent Document 1, it was not clear which sensor in the image forming device should be used as a reference for determining the timing to stop the sheet for cutting and the timing to stop the discharge rollers, which resulted in problems such as instability in the accuracy of the sheet cutting position and discharge accuracy.

[0005] SUMMARY OF THE INVENTION In view of the above problems, the present invention provides an image forming apparatus that can accurately and reliably discharge sheets on which images have been formed. [Means for solving the problem]

[0006] (1) To achieve the above-mentioned object, according to one aspect of the present disclosure, there is provided an image forming apparatus, the image forming apparatus including: an image forming unit that forms an image on a sheet, a heating rotator, and a pressure rotator that forms a nip between the heating rotator and the fixing unit, and that fixes the image formed on the sheet to the sheet; a cutter that is disposed at a cutter position downstream of the fixing unit in a sheet conveyance direction along a conveyance path along which the sheet is conveyed after passing through the image forming unit and the fixing unit, and that is capable of cutting the sheet in a direction intersecting the conveyance direction; and an apparatus main body having the conveyance path, the apparatus main body including: a first path along which the sheet passes through the image forming unit and the fixing unit; a first discharge path for discharging the sheet from a branch position that is a downstream end position of the first path in the conveyance direction to the outside of the apparatus main body without passing through the cutter position; and a second discharge path for discharging the sheet from the branch position to the outside of the apparatus main body via the cutter position. the control unit is configured to perform a pre-cutting stop process, when an instruction to cut the sheet is received, by controlling the driving of the conveying unit to stop the sheet at the cutter position, and a discharge stop process, when an instruction to cut the sheet is received, by rotating the second discharge roller and then stopping the second discharge roller in order to discharge the cut sheet outside the device body, based on the detection result of the second sensor.

[0007] According to this aspect of the image forming apparatus, the pre-cutting stop process, which stops the sheet at the cutter position, is performed based on the detection result of the second sensor located on the second discharge path, which is closer to the cutter position than the first sensor. This allows the sheet to be stopped at the cutter position with high accuracy. Furthermore, the discharge stop process, which stops the second discharge roller after rotating, is also performed based on the detection result of the second sensor, allowing the sheet to be reliably discharged from the device body via the second discharge path. Furthermore, because the timing for stopping the rotation of the second discharge roller is optimal, it is possible to reduce noise caused by the second discharge roller continuing to rotate unnecessarily after the sheet is discharged, and reduce wasted power consumption for driving the second discharge roller.

[0008] (2) In the image forming apparatus of the above aspect, when cutting of the sheet is not instructed, the control unit may determine the timing to stop rotation of the first discharge roller, which is driven to rotate in order to discharge the sheet, based on the detection result by the first sensor.

[0009] In this image forming apparatus, the timing for stopping the rotation of the first discharge rollers arranged on the first discharge path is determined based on the detection results of the first sensor arranged on the first path from the fixing unit to the branch position or on the first discharge path. That is, the timing for stopping the rotation of the first discharge rollers is determined based on the detection results of the first sensor arranged upstream of the second sensor arranged on the second discharge path, rather than the second sensor arranged on the second discharge path. This allows the sheet to be reliably discharged from the first discharge path to the outside of the apparatus body. Furthermore, because the timing for stopping the rotation of the first discharge rollers is appropriate, it is possible to reduce noise caused by the first discharge rollers continuing to rotate unnecessarily after the sheet is discharged, as well as the wasted power consumed by driving the second discharge rollers.

[0010] (3) In the image forming apparatus of the above aspect, the second discharge roller may be disposed downstream of the cutter position in the conveying direction. According to the image forming apparatus of this aspect, the cut sheet that has passed the cutter position can be easily discharged.

[0011] (4) In the image forming apparatus of the above aspect, the first sensor may be disposed on the first path from the fixing unit to the branch position. According to the image forming apparatus of this aspect, the first sensor can detect whether the sheet has passed through the fixing unit, regardless of whether a cutting instruction has been issued.

[0012] (5) In the image forming apparatus of the above aspect, the control unit may stop conveying the sheet if the first sensor still detects the sheet after a predetermined time has elapsed since the first sensor detected the sheet.

[0013] According to the image forming apparatus of this aspect, when an abnormality occurs, such as when the sheet remains stuck in the fixing unit, it can be determined that a jam has occurred, and the conveyance of the sheet can be stopped.

[0014] (6) In the image forming apparatus of the above aspect, the length of the conveying path from the nip to the cutter position may be longer than half the length of the cuttable sheet in the conveying direction.

[0015] In this image forming apparatus, when the sheet is cut at the cutter position, the sheet is no longer sandwiched in the nip of the fixing unit, so that it is possible to prevent heat from being applied to the sheet from the heating rotor while the rotation of the pressure rotor is stopped, and it is also unnecessary to control the temperature of the fixing unit.

[0016] (7) In the image forming apparatus of the above aspect, the control unit may determine the amount of rotation of the second discharge roller from the time when the second sensor detects the rear end of the sheet in the conveying direction based on information about the length of the sheet in the conveying direction during the discharge stop processing.

[0017] According to this type of image forming device, the detection of the rear end of the sheet is used as the trigger, and the conveying distance after detection is shorter than when the detection of the front end is used as the trigger, so the sheet can be discharged more accurately and reliably.

[0018] (8) In the image forming apparatus of the above form, the apparatus may further include a second path that is different from the first path and transports the sheet from downstream of the fixing unit to a position on the first path upstream of the image forming unit, and the first discharge roller may rotate in one direction to discharge the sheet to the outside and rotate in the other direction to transport the sheet to the second path, and when double-sided printing is instructed, the control unit may rotate the first discharge roller in one direction and then in the other direction based on the detection result of the first sensor to transport the sheet to the second path.

[0019] According to the image forming apparatus of this aspect, the same first sensor can be used to determine the timing of paper discharge via the first discharge path and the timing of conveyance to the second path for double-sided printing, which simplifies the apparatus configuration.

[0020] (9) In the image forming apparatus of the above aspect, the apparatus may further include a flapper that guides the sheet to either the first discharge path or the second discharge path, and the first sensor may be located upstream of the flapper in the conveying direction.

[0021] According to the image forming apparatus of this aspect, the sheet transport path can be switched between the first discharge path and the second discharge path with a simple configuration.

[0022] (10) In the image forming apparatus of the above aspect, the apparatus may further include a third discharge roller as the conveying unit, which is arranged on the second discharge path upstream of the cutter position in the conveying direction, and a motor that drives the first discharge roller, the second discharge roller, and the third discharge roller. When cutting of the sheet is instructed, the control unit may determine the timing to stop the rotation of the motor to stop the sheet at the cutter position and the timing to stop the rotation of the motor that has been rotated to discharge the sheet based on the detection result by the second sensor.When cutting of the sheet is not instructed, the control unit may determine the timing to stop the rotation of the motor that has been rotated to discharge the sheet based on the detection result by the first sensor.

[0023] According to this image forming apparatus, in a configuration in which one motor drives three discharge rollers, the information from the first and second sensors can be selectively used to appropriately control the timing at which each discharge roller stops, which means that the sheet can be stopped at the cutter position with high accuracy and the sheet can be reliably discharged from the discharge path.

[0024] (11) In the image forming apparatus of the above aspect, when cutting of the sheet is instructed, the control unit may, in the pre-cutting stop processing, stop the rotation of the motor at a timing when the amount of rotation of the motor from the timing when the leading end of the sheet is detected by the second sensor reaches a first predetermined amount, thereby stopping the sheet at the cutter position to cut the sheet, and in the discharge stop processing, stop the rotation of the motor that has been rotated to transport the cut sheet at a timing when the amount of rotation of the motor from the timing when the trailing end of the sheet downstream after cutting is detected by the second sensor reaches a second predetermined amount, thereby discharging the sheet.

[0025] According to the image forming apparatus of this aspect, the first predetermined amount and the second predetermined amount are appropriately set based on, for example, sheet size information, thereby facilitating motor control and enabling the sheet to be discharged reliably.

[0026] (12) In the image forming apparatus of the above aspect, when cutting of the sheet is not instructed, the control unit may stop the rotation of the motor that has been driven to rotate to transport the sheet and discharge the sheet at a timing when the amount of rotation of the motor from the timing when the rear end of the sheet is detected by the first sensor reaches a third predetermined amount.

[0027] According to the image forming apparatus of this aspect, by appropriately setting the third predetermined amount based on, for example, sheet size information, motor control becomes easy and the sheet can be reliably discharged. [Brief explanation of the drawings]

[0028] [Figure 1] 1 is a cross-sectional view showing a schematic configuration of a multifunction peripheral according to a first embodiment of the present invention. [Figure 2] 2 is a perspective view showing a schematic configuration of a cutter included in the multifunction peripheral of FIG. 1. FIG. [Figure 3] FIG. 2 is a block diagram showing a control configuration of the multifunction peripheral of FIG. [Figure 4] 10 is a flowchart showing the procedure of a sheet single-sided printing cutting process. [Figure 5] 10 is a flowchart showing a detailed procedure of an image forming process. [Figure 6] 10 is a flowchart showing a detailed procedure of a sheet cutting process. [Figure 7] 10 is a flowchart showing a detailed procedure of a sheet conveying step number determination process. [Figure 8] 10 is a flowchart showing the procedure of a sheet double-sided printing cutting process. [Figure 9] 10 is a flowchart showing a detailed procedure of a sheet reversing process. [Figure 10]10 is a flowchart showing a detailed procedure of the image forming process (second side). [Figure 11] 10 is a flowchart showing the procedure of normal processing for single-sided printing on a sheet. [Figure 12] 10 is a flowchart showing the procedure of normal sheet double-sided printing processing. DETAILED DESCRIPTION OF THE INVENTION

[0029] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. First Embodiment A multifunction peripheral 1 according to a first embodiment of the present invention will be described with reference to FIGS. [Overall configuration of MFP 1] FIG. 1 is a cross-sectional view showing the schematic configuration of a multi-function peripheral (MFP) 1 according to a first embodiment of the present invention. The multi-function peripheral 1 is an example of an image forming device, and has functions such as printing, copying, and scanning. Note that a multi-function peripheral may also have a fax function in addition to these functions. For ease of explanation, the up-down direction and front-rear direction of the multi-function peripheral 1 are defined below as indicated by the arrows in FIG. 1. Furthermore, the left side of the paper is defined as this side, and the right side of the paper is defined as the other side.

[0030] The multifunction device 1 includes an image forming main body unit 2 and an image reading unit 9. The image forming main body unit 2 is an electrophotographic type and has a function of forming an image on a sheet S. The image forming main body unit 2 has a function of forming a monochrome image on a sheet S, but the present disclosure is not limited to this, and the image forming main body unit 2 may have a function of forming a full-color image on a sheet S, for example.

[0031] The image reading unit 9 reads an image formed on a medium such as paper, and includes an image reading sensor such as a CCD (Charge Coupled Device) type or a CIS (Contact Image Sensor) type, and a movement mechanism for moving the image reading sensor. The image reading unit 9 reads the image formed on the medium under the control of the ASIC 105 (see FIG. 3).

[0032] The image forming main body 2 includes an apparatus main body 20, a conveying mechanism 3, a process unit 4, a fixing unit 6, and a cutter 10. The process unit 4 corresponds to an example of an "image forming unit." Note that hereinafter, the apparatus main body 20 may also be simply referred to as the "main body 20."

[0033] The main body 20 is formed in a substantially rectangular parallelepiped shape and has a front cover 21, a supply tray 31, a discharge tray 22, a conveying path 201, and a re-conveying path 202. The re-conveying path 202 corresponds to an example of a "second path." The front cover 21 is attached to the front of the main body 20 in an openable and closable manner. The supply tray 31 is attached to the bottom of the main body 20 in a detachable manner. A sheet S is placed on the supply tray 31. The sheet S is a standard size sheet such as A4 size. The sheet S is, for example, a paper medium such as plain paper or cardboard, but is not limited to these, and may also be an OHP film. The discharge tray 22 is provided on the top of the main body 20, and a sheet S on which an image has been formed is placed on the discharge tray 22.

[0034] The conveying path 201 is a path for conveying the sheet S placed on the supply tray 31 in a conveying direction toward the discharge tray 22 via the process unit 4, and includes a first path 201C, a first discharge path 201A, and a second discharge path 201B. The first path 201C is a path through which the sheet S passes through the process unit 4 and the fixing unit 6. The conveying path 201 branches into the first discharge path 201A and the second discharge path 201B from a branch position D1, which is the downstream end position of the first path 201C.

[0035] The first discharge path 201A is a path for discharging the sheet S from the branch position D1 to the outside of the apparatus body 20 without passing through the cutter position SP where the cutter 10 is arranged. The second discharge path 201B is a path for discharging the sheet S from the branch position D1 to the outside of the apparatus body 20 via the cutter position SP. Therefore, the sheet S conveyed via the process unit 4 and the fixing unit 6 is either discharged to the discharge tray 22 via the first discharge path 201A or discharged to the discharge tray 22 via the second discharge path 201B.

[0036] The re-conveying path 202 is a path for conveying the sheet S, on one side of which an image has been formed, in the opposite direction to the conveying direction, again toward the process unit 4. The re-conveying path 202 is a path that starts from a connection position D2 on the second discharge path 201B, which is downstream in the conveying direction from the branching position D1, and ends at a junction position J on the conveying path 201, which is upstream in the conveying direction of the pre-registration sensor SE1. Note that the connection position D2, which is the start point of the re-conveying path 202, may be any position downstream of the fixing unit.

[0037] The conveying mechanism 3 has a pickup roller 33, a separation roller 34, a registration roller 35, a conveying roller 36, a first discharge roller 87, a second discharge roller 86, a third discharge roller 85, a flapper 88, re-conveying rollers 38 and 39, a main motor 108 (see FIG. 3), and a discharge motor 109 (see FIG. 3). The third discharge roller 85 corresponds to an example of a "conveying section."

[0038] The pickup roller 33 picks up the sheets S in the supply tray 31 that have been pushed upward by the sheet pressure plate 32, and transports them toward the transport path 201. The separation roller 34 separates the sheets S picked up by the pickup roller 33 one by one.

[0039] The registration rollers 35 are disposed upstream of the process unit 4 on the conveying path 201. The registration rollers 35 align the direction of the leading edge of the sheet S, and then convey the sheet S toward the process unit 4. In the following description, the leading edge of the sheet S means the leading edge of the sheet S in the conveying direction, and the trailing edge of the sheet S means the trailing edge of the sheet S in the conveying direction. The conveying rollers 36 convey the sheet S after it has passed through the fixing unit 6 toward the first discharge rollers 87 or the third discharge rollers 85.

[0040] The third discharge roller 85 and the second discharge roller 86 are disposed on the second discharge path 201B. The third discharge roller 85 is disposed at a position upstream of the cutter position SP where the cutter 10 is disposed, and the second discharge roller 86 is disposed at a position downstream of the cutter position SP.

[0041] The third discharge roller 85 is rotated by the driving force from the discharge motor 109 (see FIG. 3). A third driven roller 85A is disposed at a position opposite the third discharge roller 85 across the second discharge path 201B. The third driven roller 85A is rotated in accordance with the rotation of the third discharge roller 85. The second discharge roller 86 is also rotated by the driving force from the discharge motor 109. A second driven roller 86A is disposed at a position opposite the second discharge roller 86 across the second discharge path 201B. The second driven roller 86A is rotated in accordance with the rotation of the second discharge roller 86.

[0042] The third discharge roller 85 and the second discharge roller 86 rotate to transport the sheet S in the transport direction, thereby discharging the sheet S onto the discharge tray 22. The rotation to transport the sheet S in the transport direction corresponds to a counterclockwise rotation when viewed from the left side, with the left-right direction of the main body 20 as an axis.

[0043] On the other hand, the first discharge roller 87 is disposed on the first discharge path 201A. The first discharge roller 87 is rotated by a driving force from a discharge motor 109 (see FIG. 3). A first driven roller 87A is disposed at a position facing the first discharge roller 87 across the first discharge path 201A. The first driven roller 87A is rotated in accordance with the rotation of the first discharge roller 87. The first discharge roller 87 rotates to transport the sheet S in the transport direction, thereby discharging the sheet S onto the discharge tray 22. The first discharge roller 87 also rotates in a direction opposite to the rotation that transports the sheet S in the transport direction, thereby transporting the sheet S to the re-conveyance path 202. The rotation in the direction opposite to the rotation that transports the sheet S in the transport direction corresponds to a clockwise rotation when viewed from the left side, with the left-right direction of the main body 20 as an axis.

[0044] Re-conveying rollers 38 and 39 are arranged on the re-conveying path 202. The re-conveying rollers 38 and 39 convey the sheet S conveyed to the re-conveying path 202 toward the process unit 4. The re-conveying rollers 38 and 39 re-convey the sheet S, on one side of which an image has been formed, toward the process unit 4 via the re-conveying path 202, thereby making it possible to form images on both sides of the sheet S.

[0045] The process unit 4 forms an image on the sheet S and is housed within the main body 20. The process unit 4 has a drum cartridge 5 and a laser unit 7. The drum cartridge 5 has a photosensitive drum 51, a toner storage unit 57, a supply roller 56, a developing roller 55, a charger 52, a transfer roller 53, and a pinch roller 54. The drum cartridge 5 can be removed from the main body 20 by opening the front cover 21. The pinch roller 54 of the drum cartridge 5 faces the registration roller 35. The pinch roller 54 rotates following the rotation of the registration roller 35 and transports the sheet S together with the registration roller 35.

[0046] The photosensitive drum 51 is rotated by a driving force from a main motor 108 (see FIG. 3) to transport the sheet S in the transport direction, thereby transporting the sheet S in the transport direction. The photosensitive drum 51 rotates clockwise when viewed from the left, with the left-right direction of the main body 20 as its axis. Toner is stored in the toner storage section 57. The supply roller 56 supplies the toner in the toner storage section 57 to the developing roller 55. The charger 52 is a scorotron type charger, and uniformly charges the surface of the photosensitive drum 51. The charger 52 may be a charging roller.

[0047] A transfer roller 53 is disposed at a position facing the photosensitive drum 51. The transfer roller 53 forms a transfer nip TN between itself and the photosensitive drum 51 on the transport path 201. Note that a transfer belt may be used instead of the transfer roller 53.

[0048] The main body 20 has a laser unit 7 at an upper portion thereof. The laser unit 7 has a polygon mirror 131 (see FIG. 3), a laser emission unit 132 (see FIG. 3), a polygon motor 133 (see FIG. 3), a lens, a reflecting mirror, etc. (not shown). The laser unit 7 exposes the surface of the photosensitive drum 51 by scanning the surface of the photosensitive drum 51 at high speed with a laser beam (see the two-dot chain line in FIG. 1) based on image data emitted from the laser emission unit 132.

[0049] An electrostatic latent image based on image data is formed on the surface of the photosensitive drum 51 by exposing it to light with the laser unit 7. The developing roller 55 supplies toner to the electrostatic latent image formed on the surface of the photosensitive drum 51, thereby forming a toner image on the surface of the photosensitive drum 51.

[0050] A transfer voltage is applied to the transfer roller 53. The transfer roller 53 transports the sheet S between itself and the photosensitive drum 51, thereby transferring the toner image formed on the surface of the photosensitive drum 51 onto the sheet S passing through the transfer nip TN. In this way, an image is formed on the sheet S.

[0051] The fixing unit 6 is disposed downstream of the process unit 4 on the conveying path 201. The fixing unit 6 includes a heating roller 61, a pressure roller 62, and a heater 63. The heating roller 61 is an example of a heating rotator and heats the sheet S. The pressure roller 62 is an example of a pressure rotator and forms a nip N between the heating roller 61 and the pressure roller 62 to pressurize the sheet S. The fixing unit 6 corresponds to an example of a "fixing unit." The pressure roller 62 rotates by the driving force of the main motor 108 to convey the sheet S in the conveying direction. The pressure roller 62 rotates counterclockwise as viewed from the left side, with the left-right direction of the main body 20 as its axis to convey the sheet S in the conveying direction. The heater 63 is, for example, a halogen heater and heats the heating roller 61.

[0052] The fixing device 6 heats the sheet S with the heating roller 61 and rotates the pressure roller 62, thereby conveying the sheet S while applying pressure with the heating roller 61 and the pressure roller 62, thereby fixing the image formed on the sheet S by the process unit 4 to the sheet S.

[0053] Although the fixing device 6 has been described as including the heating roller 61, the pressure roller 62, and the heater 63, the invention is not limited to this. For example, the fixing device 6 may have a configuration including the heater 63, a nip plate that receives radiant heat from the heater 63, a heating belt that rotates around the nip plate, and a pressure roller.

[0054] The fixing unit 6 may also have a substrate on which a heat generating pattern is formed, a belt that rotates around the substrate, and a pressure roller, with the substrate and belt contacting the pressure roller.The fixing unit 6 may also have a heating roller, a heater, and a pressure belt.

[0055] A cutter 10 is disposed between the third discharge roller 85 and the second discharge roller 86 on the second discharge path 201B. The cutter 10 is disposed downstream of the fixing unit 6 in the conveyance direction of the sheet S. The multifunction device 1 stops the rotation of the third discharge roller 85 and the second discharge roller 86 so that the cutting position on the sheet S reaches the cutter position SP. With the rotation of the third discharge roller 85 and the second discharge roller 86 stopped, the multifunction device 1 cuts the sheet S using the cutter 10.

[0056] FIG. 2 shows a schematic configuration of the cutter 10. As shown in FIG. 2, the cutter 10 has a cutter frame 11, a slide rail 12, a fixed blade 13, a sheet passing section 14, a moving blade 15, a slide holder 16, and a cutter motor 106. The cutter frame 11 extends in the axial direction. The slide rail 12 is a rail formed on the cutter frame 11 and extending in the axial direction. The fixed blade 13 is a flat blade fixed to the cutter frame 11 and extending in the axial direction. The sheet passing section 14 is a space formed in the cutter frame 11 through which the sheet S passes. In this embodiment, the sheet passing section 14 is formed between the slide rail 12 and the fixed blade 13. The moving blade 15 is a disc-shaped blade and is rotatably supported by the slide holder 16.

[0057] The slide holder 16 engages with the slide rail 12 and is attached to the cutter frame 11 so as to be slidable along the slide rail 12. When the cutter motor 106 is driven in the forward direction, the slide holder 16 slides from one axial side (e.g., the right side wall of the main body 20) to the other axial side (e.g., the left side wall of the main body 20). When the cutter motor 106 is driven in the reverse direction, the slide holder 16 slides from the other axial side to one axial side. The slide holder 16 is movable from an initial position FP indicated by a solid line in FIG. 2 to a completion position KP indicated by a dashed line. The slide holder 16, to which the movable blade 15 is fixed, is movable at the cutter position SP in a cutting direction intersecting the conveyance direction of the sheet S. That is, the cutter 10 can cut the sheet S in a direction intersecting the conveyance direction of the sheet S. The cutting direction is a direction from the initial position FP toward the completion position KP or a direction from the completion position KP toward the initial position FP.

[0058] When the sheet S is at the cutter position SP and the slide holder 16 moves along the slide rail 12 to the completion position KP, the single sheet S is sandwiched between the fixed blade 13 and the movable blade 15 and cut into two pieces. After the sheet S is cut, the multifunction device 1 rotates the third discharge roller 85 and the second discharge roller 86 for a predetermined time, thereby discharging the two cut sheets S onto the discharge tray 22.

[0059] The multifunction device 1 is configured so that A4 and letter-sized sheets S can be cut at the center of the sheet in the conveying direction by the cutter 10. In other words, the length of the conveying path 201 from the nip N to the cutter position SP in Fig. 1 is designed to be longer than half (148.5 mm) of the dimension (297 mm) of an A4-sized sheet S in the conveying direction.

[0060] With this configuration, when an A4-sized or letter-sized sheet S is cut at cutter position SP with the rotation of the third discharge roller 85 and the second discharge roller 86 stopped, the trailing edge of the sheet S passes through the nip N of the fuser 6. When the rotation of the third discharge roller 85 and the second discharge roller 86 is stopped to cut the sheet S at cutter position SP with the sheet S sandwiched in the nip N of the fuser 6, the rotation of the pressure roller 62 must be stopped. However, if the rotation of the pressure roller 62 stops with the sheet S sandwiched in the nip N of the fuser 6, heat is applied locally from the heating roller 61 to the same location on the sheet S. Therefore, when the rotation of the third discharge roller 85 and the second discharge roller 86 is stopped and the sheet S is cut at cutter position SP, the trailing edge of the sheet S must pass through the nip N of the fuser 6.

[0061] Furthermore, the length of the conveying path 201 from the nip of the roller 36 to the cutter position SP in FIG. 1 is designed to be longer than half (148.5 mm) of the dimension (297 mm) of an A4 size sheet S in the conveying direction.

[0062] With this configuration, when the sheet S is cut at the cutter position SP with the rotation of the third discharge roller 85 and the second discharge roller 86 stopped, the trailing edge of the sheet S passes through the nip of the roller 36. If the nip N of the roller 36 and the pressure roller 62 is rotating while the sheet S is pinched when the sheet S is cut at the cutter position SP with the rotation of the third discharge roller 85 and the second discharge roller 86 stopped, the sheet S may bend like an accordion between the third discharge roller 85 and the roller 36. Therefore, with the above configuration, it is possible to stop the sheet S at the cutter position SP without the sheet S bending like an accordion by simply stopping the rotation of the third discharge roller 85 and the second discharge roller 86 without stopping the rotation of the roller 36 or the fixing unit 6.

[0063] The length of the first discharge path 201A is designed to be shorter than the length of the second discharge path 201B. This is to quickly discharge the sheet S outside the apparatus main body 20 when the sheet S after image formation is not cut. The second discharge roller 86 is positioned forward in the front-to-rear direction than the first discharge roller 87. This makes it possible to ensure a space for separating the cutter position SP from the fixing unit 6. Furthermore, since the short cut sheet S discharged from the second discharge roller 86 can be discharged further forward, the user can more easily access the discharged sheet S.

[0064] The distance between the third discharge roller 85 and the second discharge roller 86 is designed to be shorter (139.7 mm) than half the dimension (279.4 mm) of a letter-sized sheet S in the conveying direction. This is to enable the sheet S after being cut by the cutter 10 to be conveyed between the third discharge roller 85 and the second discharge roller 86. Conversely, a cutting instruction is not accepted for a sheet S whose length is less than twice the distance between the third discharge roller 85 and the second discharge roller 86.

[0065] [Control configuration of MFP 1] Next, the control configuration of the multifunction device 1 will be described with reference to Fig. 3. As shown in Fig. 3, the multifunction device 1 further includes an ASIC 105, a ROM 102, a RAM 103, an NVRAM 104, a pre-registration sensor SE1, a post-registration sensor SE2, a discharge sensor SE3, a sheet sensor SE4, an operation panel PA, a communication interface (I / F) 130, and a flapper solenoid 89. The ASIC 105, the ROM 102, the RAM 103, and the NVRAM 104 are mounted on a main board 100.

[0066] ASIC 105 is equipped with a CPU 101. CPU 101 performs overall control of each unit of multifunction peripheral 1. CPU 101 and ASIC 105 correspond to an example of a "control unit." In the following description, CPU 101 will be described as an operating entity as an example of a control unit, but the entire ASIC 105 may be substituted for the operating entity, or CPU 101 and ASIC 105 may cooperate to perform each operation. ASIC 105 is electrically connected to ROM 102, RAM 103, NVRAM 104, pre-registration sensor SE1, post-registration sensor SE2, discharge sensor SE3, sheet sensor SE4, operation panel PA, communication I / F 130, fuser 6, and laser unit 7.

[0067] The ROM 102 stores various control programs and various settings for controlling the multifunction device 1. The control programs include a single-sided sheet printing and cutting process, a double-sided sheet printing and cutting process, a single-sided sheet printing normal process, and a double-sided sheet printing normal process, which will be described later with reference to FIGS.

[0068] The RAM 103 is used as a working area from which various control programs are read and as a storage area for temporarily storing image data included in a job. The CPU 101 controls each part of the multifunction peripheral 1 in accordance with the control programs read from the ROM 102 and signals output from various sensors, while storing the processing results in the RAM 103 or the NVRAM 104.

[0069] The operation panel PA has, for example, a touch panel in which a touchpad and a display are integrally formed, and a key button section. The operation panel PA accepts user operations and outputs the accepted information to the ASIC 105. For example, by operating the operation panel PA, the user can instruct the multifunction device 1 to cut the sheet S after image formation.

[0070] The main motor 108 outputs a driving force to the pickup roller 33, the registration roller 35, the conveyance roller 36, the re-conveyance rollers 38 and 39, the pressure roller 62, and the drum cartridge 5. When the main motor 108 is driven in the forward direction, the output of the main motor 108 transmits a driving force to the conveyance roller 36, the pressure roller 62, the photosensitive drum 51, the developing roller 55, the pickup roller 33, and the registration roller 35. Then, the conveyance roller 36, the pressure roller 62, the photosensitive drum 51, the developing roller 55, the pickup roller 33, and the registration roller 35 rotate to convey the sheet S in the conveyance direction.

[0071] On the other hand, even if the main motor 108 is driven in the reverse direction, the driving force is not transmitted to the conveying roller 36, the pressure roller 62, the drum cartridge 5, the pickup roller 33, and the registration roller 35.

[0072] Furthermore, the CPU 101 drives the main motor 108 in the forward direction to transmit a driving force to the re-conveying rollers 38 and 39. The transmitted driving force causes the re-conveying rollers 38 and 39 to rotate to transport the sheet S toward the process unit 4. The rotation of the re-conveying rollers 38 and 39 to transport the sheet S toward the process unit 4 is a clockwise rotation when viewed from the left side, with the left-right direction of the main body 20 as an axis.

[0073] On the other hand, even when the CPU 101 drives the main motor 108 in the reverse direction, the driving force is transmitted to the re-conveying rollers 38 and 39. The transmitted driving force causes the re-conveying rollers 38 and 39 to rotate so as to convey the sheet S toward the process unit 4.

[0074] The discharge motor 109 transmits driving force to the first discharge roller 87, the second discharge roller 86, and the third discharge roller 85. The discharge motor 109 is an example of a "motor." The CPU 101 drives the discharge motor 109 to rotate in the forward direction. By driving the discharge motor 109 in the forward direction, the first discharge roller 87, the second discharge roller 86, and the third discharge roller 85 rotate to transport the sheet S in the transport direction. The rotation of the first discharge roller 87, the second discharge roller 86, and the third discharge roller 85 to transport the sheet S in the transport direction is a counterclockwise rotation when viewed from the left side, with the left-right direction of the main body 20 as an axis.

[0075] As a result, the sheet S is discharged onto the discharge tray 22 via the first discharge path 201A or the second discharge path 201B. Meanwhile, the CPU 101 drives the discharge motor 109 in the reverse direction. The first discharge rollers 87 rotate in the direction opposite to the conveying direction of the sheet S. For the first discharge rollers 87, the rotation in the direction opposite to the conveying direction of the sheet S means clockwise rotation as viewed from the left side, with the left-right direction of the main body 20 as an axis. As a result, the sheet S being conveyed along the first discharge path 201A is conveyed in the direction opposite to the conveying direction, and the sheet S is conveyed toward the re-conveyance path 202.

[0076] The CPU 101 controls the drive of the cutter motor 106. The cutter motor 106 is a DC brush motor. The cutter motor 106 is not limited to a DC brush motor and may be a DC brushless motor. When the cutter motor 106 is driven in the forward direction, the slide holder 16 moves the moving blade 15 in the width direction of the sheet S, thereby cutting the sheet S. The encoder 113 is attached to the rotation shaft of the cutter motor 106 and outputs a signal corresponding to the rotation of the cutter motor 106. The CPU 101 receives the signal output from the encoder 113 and acquires the rotation direction, rotation position, and rotation speed of the cutter motor 106 based on the received signal. This allows the CPU 101 to know the position of the slide holder 16 on the slide rail 12, i.e., the position of the moving blade 15 in the axial direction.

[0077] The CPU 101 controls the flapper 88. By switching the direction of current flowing through the flapper solenoid 89, the position of the flapper 88 is switched between a first position (position 88A indicated by a two-dot chain line in FIG. 1) and a second position (position 88B indicated by a solid line in FIG. 1). The first position 88A is a position where the sheet S conveyed by the conveying rollers 36 is guided to the first discharge path 201A. The first position 88A is also a position where the sheet S on the first discharge path 201A is guided to the re-conveyance path 202. The second position 88B is a position where the sheet S conveyed by the conveying rollers 36 is guided to the second discharge path 201B.

[0078] The pre-registration sensor SE1 is disposed upstream of the registration rollers 35 on the conveying path 201 (see FIG. 1), and is a sensor that detects the passage of the sheet S. The pre-registration sensor SE1 may be a sensor having an actuator that oscillates when the sheet S comes into contact with it, or an optical sensor. The pre-registration sensor SE1 outputs an ON signal when the sheet S is passing, and outputs an OFF signal when the sheet S is not passing. The detection signal by the pre-registration sensor SE1 is output to the ASIC 105.

[0079] The post-registration sensor SE2 is disposed upstream of the fixing unit 6 on the conveying path 201, specifically between the registration roller 35 and the transfer roller 53 (see FIG. 1), and is a sensor that detects the passage of the sheet S. The post-registration sensor SE2 has the same configuration as the pre-registration sensor SE1. A detection signal by the post-registration sensor SE2 is output to the ASIC 105.

[0080] The discharge sensor SE3 is disposed between the fixing unit 6 and the conveying rollers 36 on the conveying path 201 (see FIG. 1), and detects the passage of the sheet S. The discharge sensor SE3 has the same configuration as the pre-registration sensor SE1. A detection signal from the discharge sensor SE3 is output to the ASIC 105. The discharge sensor SE3 corresponds to an example of a "first sensor."

[0081] Sheet sensor SE4 is disposed between cutter position SP and second discharge roller 86 (see FIG. 1) and detects the passage of sheet S. Sheet sensor SE4 has the same configuration as pre-registration sensor SE1. A detection signal from sheet sensor SE4 is output to ASIC 105. Sheet sensor SE4 is an example of a "second sensor." Note that the distance in the conveying direction from sheet sensor SE4 to nip N is greater than the distance in the conveying direction from discharge sensor SE3 to nip N.

[0082] The communication I / F 130 is connected to a network such as a LAN, and enables connection to an external device such as a PC incorporating a driver for the multifunction device 1. The CPU 101 can receive a print job via the communication I / F 130. The print job includes various information required to form an image on the sheet S, such as image data for image formation, the size and type of the sheet S to be used for image formation, and information on whether or not to cut the sheet S.

[0083] <Single-sided printing and cutting process> Next, each printing process performed by the multifunction device 1 described above will be explained in order. The printing processes of this embodiment can be broadly classified into four types. The multifunction device 1 executes the following printing processes: single-sided sheet printing and cutting process, double-sided sheet printing and cutting process, single-sided sheet normal processing, and double-sided sheet normal processing. FIG. 4 shows the procedure for the single-sided sheet printing and cutting process executed by the ASIC 105, particularly the CPU 101. This single-sided sheet printing and cutting process is initiated when the multifunction device 1 receives a print job or print command that includes an instruction to print (form an image) on one side of the sheet S and an instruction to cut the sheet S that has been printed on one side. Hereinafter, in the explanation of each process, steps will be abbreviated as "S."

[0084] 4, first, the CPU 101 turns on the heater 63 (S10) and controls the heater 63 so that the heating roller 61 reaches the target temperature. Next, the CPU 101 drives the main motor 108 in the forward direction (S12), and then switches the flapper 88 to the second position 88B (S14).

[0085] 4, the flapper 88 is initially located at the first position 88A. The process of S14 switches the flapper 88 from the first position 88A to the second position 88B. This causes the flapper 88 to guide the sheet S conveyed by the conveyance roller 36 to the second discharge path 201B where the cutter 10 is provided.

[0086] Then, CPU 101 executes image forming processing (S20). Fig. 5 shows detailed procedures of the image forming processing. In Fig. 5, first, CPU 101 executes a pickup command (S40). As a result, the driving force of main motor 108 is transmitted to pickup roller 33, so that sheet S in supply tray 31 is picked up and conveyed toward conveying path 201.

[0087] Next, CPU 101 waits until post-registration sensor SE2 switches from off to on (S42: NO). As described above, post-registration sensor SE2 is disposed between registration roller 35 and transfer roller 53 on conveyance path 201, and outputs an on signal when sheet S is passing through and an off signal when sheet S is not passing through. Therefore, in S42, CPU 101 waits until post-registration sensor SE2 detects the leading edge of sheet S. Then, when post-registration sensor SE2 detects the leading edge of sheet S (S42: YES), CPU 101 starts image formation on sheet S (S44). Note that image formation may be started triggered by something other than post-registration sensor SE2 detecting the leading edge of sheet S. It is sufficient that image formation is performed so that the toner image formed by photosensitive drum 51 is correctly transferred to the image formation position on sheet S.

[0088] Next, CPU 101 waits until discharge sensor SE3 switches from off to on (S46: NO). As described above, discharge sensor SE3 is disposed between fuser 6 and conveyance rollers 36 on conveyance path 201, and outputs an on signal when sheet S is passing through, and outputs an off signal when sheet S is not passing through. Therefore, in S46, CPU 101 waits until discharge sensor SE3 detects the leading edge of sheet S. Then, when discharge sensor SE3 detects the leading edge of sheet S (S46: YES), CPU 101 drives discharge motor 109 to rotate forward (S48). As discharge motor 109 is driven to rotate forward, third discharge roller 85 and second discharge roller 86 convey sheet S present on second discharge path 201B in the conveyance direction.

[0089] CPU 101 determines whether discharge sensor SE3 has been switched off. If it is determined that discharge sensor SE3 has been switched off (S50: YES), image formation is terminated (S54), and the image formation process is terminated. If discharge sensor SE3 remains on and it cannot be determined that it has been switched off (S50: NO), CPU 101 determines whether a predetermined time has elapsed since discharge sensor SE3 was turned on. If CPU 101 determines that the predetermined time has not elapsed (S51: NO), it returns to the determination of S50. If CPU 101 determines that the predetermined time has elapsed (S51: YES), it stops conveying sheet S (S53), and the series of printing processes is terminated.

[0090] Here, the "predetermined time" in S51 is, for example, the time required for the discharge sensor SE3 to detect the leading edge of the sheet S in the conveying direction and for the trailing edge of the sheet S to pass through the discharge sensor SE3. Therefore, after the predetermined time has elapsed, the discharge sensor SE3 should have switched from on to off. However, if the discharge sensor SE3 has not switched off and is detecting the sheet S, it can be determined that the sheet S is in a jammed state on the first path 201C.

[0091] When stopping the conveyance of the sheet S (S53), specifically, the CPU 101 stops the discharge motor 109, the main motor 108, and other devices. Examples of other devices include the process unit 4 and the fixing unit 6. At this time, it is preferable that the CPU 101 displays on the operation panel PA a notification screen (not shown) that notifies the user that a jam has occurred and information indicating where the jam has occurred.

[0092] Returning to FIG. 4, after the image forming process (S20), the CPU 101 executes a sheet cutting process (S22). FIG. 6 shows the detailed procedure of the sheet cutting process. In FIG. 6, first, the CPU 101 waits until the sheet sensor SE4 switches from off to on (S60: NO). Then, the CPU 101 waits until the sheet S conveyed by the third discharge roller 85 and the second discharge roller 86 reaches a sheet stop position (S61: NO). The sheet stop position is, for example, when the sheet S is cut at the center in the conveyance direction, the position where the center of the sheet S reaches the cutter position SP of the cutter 10. Note that the position where the center of the sheet S reaches the cutter position SP of the cutter 10 is the position after the sheet S has passed through the fixing unit 6, and the trailing edge of the sheet S is not nipped by the fixing unit 6.

[0093] The CPU 101 determines whether the sheet S has reached the sheet stop position by counting the number of steps of the discharge motor 109 when the sheet sensor SE4 detects the leading edge of the sheet S. Specifically, the CPU 101 stops the discharge motor 109 when the amount of rotation of the discharge motor 109 from the time the sheet sensor SE4 detects the leading edge of the sheet S reaches a first predetermined amount. Here, the "first predetermined amount" is a value determined based on information about the length of the sheet S in the conveyance direction (hereinafter simply referred to as "sheet size information"). Specifically, the sheet size information is information such as "A4 size" or "letter size." The sheet size information can be obtained by reading it from the information set as the paper size by the print job.

[0094] 7 shows a detailed procedure for determining the number of sheet conveyance steps based on a set sheet length. In FIG. 7, CPU 101 acquires sheet size information included in a print job or a print command (S75). Then, CPU 101 acquires the number of steps of discharge motor 109 required for the "cutting position of sheet S when sheet sensor SE4 changes from off to on" corresponding to the acquired sheet size information to reach "cutter position SP" (S76), and then terminates the process for determining the number of sheet conveyance steps based on a set sheet length. More specifically, for each sheet size, ROM 102, NVRAM 104, or the like stores the number of steps of discharge motor 109 required for the "cutting position of sheet S when sheet sensor SE4 changes from off to on" to reach "cutter position SP." For example, if the sheet size information is A4, CPU 101 acquires the stored number of steps corresponding to A4 from ROM 102 or NVRAM 104.

[0095] In the process of S76, the CPU 101 acquires the number of steps of the discharge motor 109 required for the cutting position of the sheet S, i.e., the center position, to reach the cutter position SP when the sheet sensor SE4 changes from off to on, i.e., when the leading edge of the sheet S is detected. Note that this number of steps is a fixed value according to the sheet size of the sheet S, so the number of steps associated with the sheet size information may be stored in advance in the NVRAM 104, for example, as a factory setting. In this case, in S76, the CPU 101 reads out and acquires the number of steps corresponding to the sheet size information acquired in S75 from the NVRAM 104.

[0096] The sheet size information may be obtained based on the set sheet length as described above, or may be measured using the output from the pre-registration sensor SE1 or the post-registration sensor SE2. For example, the sheet size information can be obtained by calculation using the conveying speed and the time from when the leading edge of the sheet S is detected by the pre-registration sensor SE1 or the post-registration sensor SE2 to when the trailing edge of the sheet S is detected.

[0097] As described above in detail, by using the sheet size information, it is possible to obtain in advance how much the discharge motor 109 must rotate after the sheet sensor SE4 detects the leading edge of the sheet S until the center of the sheet S reaches the cutter position SP. Whether the amount of rotation of the discharge motor 109 has reached the first predetermined amount can be determined by counting the number of steps of the discharge motor 109 as described above. Alternatively, it may be determined by counting a predetermined time.

[0098] Referring again to FIG. 6, after the sheet sensor SE4 is turned on (S60: YES), when the sheet S reaches the sheet stop position (S61: YES), the CPU 101 stops driving the discharge motor 109 (S62). That is, the rotation of the third discharge roller 85 and the second discharge roller 86 is stopped. The process in S62 corresponds to an example of a "pre-cutting stop process." If the sheet sensor SE4 remains off (S60: NO) and it is determined that a predetermined time has elapsed (S77: YES), the CPU 101 determines that the sheet S has jammed in the conveying path 201, and stops the discharge motor 109 and the main motor 108, thereby stopping the conveyance of the sheet S (S78). The predetermined time is counted from the time when the discharge sensor SE3 is turned on, and is set as the time required for the leading edge of the sheet S to reach the position of the sheet sensor SE4. Instead of the predetermined time, the determination may be made based on the number of rotation steps of the main motor 108.

[0099] Thereafter, the CPU 101 drives the cutter motor 106 in the forward direction to move (on the outward path) the slide holder 16 from the initial position FP toward the completion position KP (S64). As a result, the cutter motor 106 slides the slide holder 16 from one side (for example, the right side wall of the main body 20) to the other side (for example, the left side wall of the main body 20) in the axial direction, so that the slide holder 16 starts moving from the initial position FP indicated by the solid line in Fig. 2 toward the completion position KP (on the outward path) indicated by the dashed line. As the slide holder 16 moves with the sheet S sandwiched between the movable blade 15 and the fixed blade 13 supported by the slide holder 16, the sheet S is cut in the axial direction.

[0100] Next, the CPU 101 waits until the slide holder 16 reaches the completion position KP (S66: NO). The CPU 101 determines whether the slide holder 16 has reached the completion position KP based on the output signal from the encoder 113. When the slide holder 16 has reached the completion position KP (S66: YES), the CPU 101 stops the cutter motor 106 (S68) in the same manner as in S18 (see FIG. 4) above. This completes the cutting of the sheet S by the cutter 10.

[0101] Next, the CPU 101 drives the discharge motor 109 to rotate in the forward direction (S70). As the discharge motor 109 rotates in the forward direction, the third discharge roller 85 and the second discharge roller 86 rotate, and the sheet S cut by the cutter 10 is conveyed by the third discharge roller 85 and the second discharge roller 86 toward the discharge tray 22.

[0102] Then, CPU 101 waits until sheet sensor SE4 switches from on to off (S71: NO). Furthermore, CPU 101 waits until discharge of the cut sheet S is completed by third discharge roller 85 and second discharge roller 86 (S72: NO). Here, CPU 101 determines whether discharge is completed by counting the number of steps of discharge motor 109, triggered by sheet sensor SE4 detecting the trailing edge of cut sheet S on the downstream side (S71: YES). Specifically, CPU 101 stops discharge motor 109 when the amount of rotation of discharge motor 109 from the time when sheet sensor SE4 detects the trailing edge of cut sheet S on the downstream side reaches a second predetermined amount.

[0103] Here, the "second predetermined amount" is a value determined based on sheet size information. By using the sheet size information and the distance between the sheet sensor SE4 and the second discharge roller 86, it is possible to obtain in advance how much the discharge motor 109 should rotate after the sheet sensor SE4 detects the trailing edge of the cut downstream sheet S until the trailing edge of the cut downstream sheet S passes the second discharge roller 86. The second predetermined amount is set to a value equal to or greater than the value required for the trailing edge of the cut downstream sheet S to completely pass the second discharge roller 86.

[0104] Whether the rotation amount of the discharge motor 109 has reached the second predetermined amount can be determined by counting the number of steps of the discharge motor 109, similar to the determination of whether the rotation amount has reached the first predetermined amount. Alternatively, it may be determined by counting a predetermined time. In this case, the CPU 101 determines the rotation time of the second discharge rollers 86 from the time when the sheet sensor SE4 detects the trailing edge of the cut downstream sheet S so that the rotation amount of the discharge motor 109 is equal to or greater than the first predetermined amount. In other words, the CPU 101 determines the rotation time of the second discharge rollers 86 from the time when the sheet sensor SE4 detects the trailing edge of the cut downstream sheet S, based on the sheet size information.

[0105] When the discharge of the cut sheet S is completed (S72: YES), the CPU 101 stops the driving of the discharge motor 109 (S74), in the same manner as in S62 above. That is, the rotation of the third discharge roller 85 and the second discharge roller 86 is stopped. The process in S74 corresponds to an example of a "discharge stop process." After the process in S74, the sheet cutting process ends.

[0106] Returning to FIG. 4, the CPU 101 determines whether the job being executed includes printing of a next sheet (S24). If the determination indicates that a next sheet is to be printed (S24: YES), the CPU 101 returns the cutter 10 to the initial position FP (S26). More specifically, the CPU 101 reverses the cutter motor 106 to move the slide holder 16 from the completion position KP toward the initial position FP (returning path), and stops the cutter motor 106 when the cutter 10 reaches the initial position FP. The CPU 101 then returns the process to S20 and continues executing the processes from S20 onward. Here, when the sheet single-sided printing and cutting process is to be continued for the next sheet S, switching control of the flapper 88 is not performed. This is because the flapper 88 has already been switched to the second position 88B in the process of S14 and is maintained in that state. This is convenient when printing and cutting continuously because it is not necessary to switch the flapper 88 each time.

[0107] On the other hand, if the next sheet is not to be printed (S24: NO), the CPU 101 switches the flapper 88 to the first position 88A (S28). By the processing of S28, the flapper 88 is switched from the second position 88B to the first position 88A.

[0108] Next, the CPU 101 drives the cutter motor 106 in the reverse direction to move the slide holder 16 from the completion position KP toward the initial position FP (returning) (S30). Then, similar to S16 above, the CPU 101 waits until the slide holder 16 reaches the initial position FP (S32: NO), and when the slide holder 16 reaches the initial position FP (S32: YES), the CPU 101 stops the cutter motor 106 (S34) similar to S18 above.

[0109] Next, the CPU 101 turns off the heater 63 (S36) and stops the main motor 108 (S38), and then ends the sheet single-sided printing and cutting process.

[0110] The order of the processes of S28 to S38 may be reversed. Also, if the job being executed in S24 has finished printing the final sheet and an instruction for the next job has been issued, after the processes of S28 to S34 have been performed, the next job may be executed with the heater 63 still on and the main motor 108 rotating forward.

[0111] <Double-sided printing and cutting of sheets> Next, the sheet double-sided printing and cutting process will be described. Figure 8 shows the procedure of the sheet double-sided printing and cutting process executed by the ASIC 105, particularly the CPU 101. This sheet double-sided printing and cutting process is started when the multifunction device 1 receives a print job or print command that includes an instruction to print (form an image) on both sides of the sheet S and an instruction to cut the double-sided printed sheet S. Figure 8 is configured by partially modifying the sheet single-sided printing and cutting process in Figure 4, so in Figure 8, processes that are the same as those in Figure 4 are assigned the same reference numerals and their description will be omitted as appropriate.

[0112] As described above, before the process of FIG. 8 is started, the flapper 88 is at the first position 88A as an initial position, where it guides the sheet S toward the first discharge path 201A.

[0113] The CPU 101 executes the processes of S10, S12, and S20. The CPU 101 uses the conveying mechanism 3 to convey the sheet S toward the first discharge path 201A. The image forming process of S20 indicates a process of forming an image on the first side of the sheet S. Then, the CPU 101 executes the sheet inversion process (S80). FIG. 9 shows the detailed procedure of the sheet inversion process. In FIG. 9, first, the CPU 101 waits until the sheet S reaches the inversion position (S90: NO). The CPU 101 executes this process by determining whether the sheet S has reached the inversion position. The CPU 101 determines whether the trailing edge of the sheet S in the conveying direction has reached the inversion position by determining whether a predetermined time has elapsed since the discharge sensor SE3 detected the leading edge of the sheet S in the conveying direction.

[0114] Then, when the sheet S reaches the reversal position (S90: YES), the CPU 101 drives the discharge motor 109 to rotate in the reverse direction (S92). In other words, the CPU 101 "rotates the first discharge rollers 87 in one direction and then in the other direction based on the detection result of the discharge sensor SE3, in order to transport the sheet S to the re-conveyance path 202, when double-sided printing is instructed." As the discharge motor 109 is driven in the reverse direction, the first discharge rollers 87 rotate in the opposite direction to the rotation that transports the sheet S in the transport direction, and the sheet S is transported toward the re-conveyance path 202. The sheet S transported to the re-conveyance path 202 is transported toward the process unit 4 by the re-conveyance rollers 38 and 39.

[0115] As in S42 (see FIG. 5), the CPU 101 waits until the post-registration sensor SE2 switches from off to on (S94: NO). Then, when the post-registration sensor SE2 detects the leading edge of the sheet S (S94: YES), the CPU 101 ends the sheet reversing process.

[0116] 8, the CPU 101 switches the flapper 88 to the second position 88B (S82) in the same manner as in S14 (see FIG. 4) described above. As a result, the flapper 88 is switched to the second position 88B, and the cutter motor 106 is driven to rotate in the reverse direction. Therefore, the flapper 88 guides the sheet S conveyed by the conveyance roller 36 to the second discharge path 201B on which the cutter 10 is provided. Then, the CPU 101 executes the image forming process (second side) (S86).

[0117] 10 shows detailed steps of the image formation process (second side) for forming an image on the second side of the sheet S transported via the re-conveyance path 202. The image formation process (second side) is configured by omitting the processes of S40 and S42 included in the image formation process of FIG. 5. Therefore, in the process of FIG. 10, the same processes as those included in the image formation process of FIG. 5 are given the same reference numerals, and their description will be omitted. The image formation process (second side) is configured by omitting the processes of S40 and S42 included in the image formation process of FIG. 5 because the sheet S to be printed is a sheet S that has been printed on its first side via the re-conveyance path 202, so there is no need to pick up a new sheet S from the supply tray 31, and because the process of S42 has already been performed in S94 (see FIG. 9), there is no need to perform it again.

[0118] Returning to Fig. 8, the CPU 101 executes the process of S18 in Fig. 4. In the sheet cutting process of S18, the sheet S having images formed on both the first and second sides is cut by the cutter 10.

[0119] Next, the CPU 101 switches the flapper 88 from the second position 88B to the first position 88A (S88) in the same manner as in S28 (see FIG. 4) described above. This switches the flapper 88 to the first position 88A. Therefore, the flapper 88 guides the sheet S conveyed by the conveying roller 36 to the first discharge path 201A where the cutter 10 is not provided.

[0120] If it is determined in S24 that the job being executed includes printing of the next sheet (S24: YES), the CPU 101 returns the cutter 10 to the initial position FP (S26). Thereafter, the CPU 101 returns the process to S20 and continues to execute the processes from S20 onwards.

[0121] On the other hand, if it is determined in S24 that the job being executed does not include printing of the next sheet (S24: NO), CPU 101 executes the same processes of S30 to S38 as those of S30 to S38 in FIG. 4, and then ends the sheet double-sided printing and cutting process.

[0122] <Normal processing for single-sided printing on sheets> Next, the normal single-sided sheet printing process will be described. Fig. 11 shows the procedure for the normal single-sided sheet printing process executed by the ASIC 105, particularly the CPU 101. This normal single-sided sheet printing process is started when the multifunction device 1 receives a print job or print command that includes an instruction to print (form an image) on one side of the sheet S, but does not include an instruction to cut the sheet S. In this embodiment, "normal process" means that after an image is printed on the sheet S based on the print job or print command, the sheet S is discharged to the discharge tray 22 without being cut.

[0123] 11 is configured by partially modifying the sheet single-sided printing and cutting process of Fig. 4, so in Fig. 11, the same processes as those in Fig. 4 are given the same reference numerals and their explanations will be omitted as appropriate. As described above, before the process of Fig. 11 starts to be executed, the flapper 88 is in the first position 88A as its initial position, and is in a position to guide the sheet S toward the first discharge path 201A.

[0124] The CPU 101 executes the processes of S10, S12, and S20. Thereafter, the CPU 101 waits until the discharge of the sheet S is completed (S81: NO). Here, the CPU 101 determines whether the discharge is completed by counting the number of steps of the discharge motor 109, triggered by the detection of the trailing edge of the sheet S by the discharge sensor SE3. That is, when an instruction to cut the sheet S has not been issued, the timing to stop the rotation of the discharge motor 109, which has been driven to rotate in order to discharge the sheet S, is determined based on the detection result by the discharge sensor SE3. In other words, the timing to stop the rotation of the first discharge roller 87 is determined based on the detection result by the discharge sensor SE3.

[0125] Specifically, the CPU 101 stops the discharge motor 109 when the amount of rotation of the discharge motor 109 from the time when the discharge sensor SE3 detects the trailing edge of the sheet S after the image forming process reaches a third predetermined amount. The "time when the trailing edge of the sheet S after the image forming process is detected" is the time when the discharge sensor SE3 turns off in S50 of Fig. 5. The "third predetermined amount" is a value determined based on the sheet size information.

[0126] By using the sheet size information and the distance from the discharge sensor SE3 to the first discharge roller 87, it is possible to previously obtain how much further the discharge motor 109 must rotate after the discharge sensor SE3 detects the trailing edge of the sheet S after image formation processing so that the trailing edge of the sheet S passes the first discharge roller 87. The third predetermined amount is set to a value equal to or greater than the value required for the trailing edge of the sheet S after image formation processing to completely pass the first discharge roller 87. Whether the rotation amount of the discharge motor 109 has reached the third predetermined amount can be determined by counting the number of steps of the discharge motor 109, similar to the determination of whether the first predetermined amount has been reached. Alternatively, it may be determined by counting a predetermined time. In this case, the CPU 101 determines the rotation time of the first discharge roller 87 after the discharge sensor SE3 detects the trailing edge of the sheet S after image formation processing so that the rotation amount of the discharge motor 109 is equal to or greater than the third predetermined amount.

[0127] Then, when the discharge of the sheet S is completed (S81: YES), the CPU 101 stops driving the discharge motor 109 (S83). After that, the CPU 101 executes the processes of S24, S36, and S38, and then ends the normal sheet single-sided printing process.

[0128] <Normal sheet double-sided printing process> Next, the normal sheet double-sided printing process will be described. Fig. 12 shows the procedure of the normal sheet double-sided printing process executed by the ASIC 105, particularly the CPU 101. This normal sheet double-sided printing process is started when the multifunction device 1 receives a print job or print command that includes an instruction to print (form an image) on both sides of the sheet S, but does not include an instruction to cut the sheet S.

[0129] 12 is configured by combining and partially modifying the normal sheet single-sided printing process of Fig. 11 and the sheet double-sided printing cutting process of Fig. 8, so in Fig. 12, the same processes as those in Fig. 8 and Fig. 11 are given the same reference numerals and their explanations will be omitted as appropriate. Before the process of Fig. 12 starts, the flapper 88 is in the first position 88A as its initial position, where it guides the sheet S toward the first discharge path 201A.

[0130] The CPU 101 sequentially executes the processes of S10, S12, S20, S80, and S86. Through the processes up to this point, images are formed on both the front and back sides of the sheet S. Thereafter, the CPU 101 sequentially executes the processes of S81, S83, S24, S36, and S38, and then ends the normal sheet duplex printing process. As with the normal sheet single-sided printing process, in the normal sheet duplex printing process, the timing to stop the rotation of the discharge motor 109 (first discharge roller 87), which has been driven to rotate in order to discharge the sheet S, is determined based on the detection result of the discharge sensor SE3.

[0131] The multifunction device 1 of the first embodiment has the above-described structure, and thereby provides the following functions and effects.

[0132] (1) In the sheet single-sided printing cutting process and sheet double-sided printing cutting process, which are processes instructed to cut the sheet S, the CPU 101 of the multifunction device 1 of the first embodiment executes a pre-cutting stop process that stops the sheet S at the cutter position SP to cut the sheet S by controlling the drive of the third discharge roller 85, and an ejection stop process that stops the second discharge roller 86 after rotating it to eject the cut sheet S outside the device main body 20, based on the detection results of the sheet sensor SE4.

[0133] That is, the pre-cutting stop process, which stops the sheet S at the cutter position SP, is performed based on the detection result of the sheet sensor SE4, which is located on the second discharge path 201B and closer to the cutter position SP. This allows the sheet S to be stopped accurately at the cutter position SP. Furthermore, the discharge stop process, which stops the second discharge rollers 86 after rotating, is also performed based on the detection result of the sheet sensor SE4, so the sheet S can be reliably discharged to the outside of the apparatus body 20 through the second discharge path 201B. Furthermore, because the timing for stopping the rotation of the second discharge rollers 86 is appropriate, it is possible to reduce noise caused by the second discharge rollers 86 continuing to rotate unnecessarily after the sheet S is discharged, and to reduce wasted power consumption by the discharge motor 109.

[0134] (2) In the multifunction device 1 of the first embodiment described above, in the normal sheet single-sided printing process and normal sheet double-sided printing process, which are processes in which cutting of the sheet S is not instructed, the CPU 101 determines the timing to stop the rotation of the first discharge roller 87, which is driven to rotate in order to discharge the sheet S, based on the detection result by the discharge sensor SE3.

[0135] That is, the timing to stop rotation of the first discharge roller 87 arranged on the first discharge path 201A is determined based on the detection result by the discharge sensor SE3 arranged on the first path 201C from the fixing unit to the branch position D1, so the sheet S can be reliably discharged from the first discharge path 201A to the outside of the apparatus main body 20. Furthermore, because the timing to stop rotation of the first discharge roller 87 is appropriate, it is possible to suppress noise caused by the first discharge roller 87 continuing to rotate unnecessarily after the sheet S is discharged, and to suppress wasted power consumption of the discharge motor 109.

[0136] (3) In the multifunction peripheral 1 of the first embodiment, the second discharge rollers 86 are disposed downstream of the cutter position SP in the transport direction. Therefore, the cut sheet S that has passed through the cutter position SP can be easily discharged.

[0137] (4) In the multifunction device 1 of the first embodiment, the discharge sensor SE3 is disposed on the first path 201C from the fixing unit to the branch position D1. Therefore, the discharge sensor SE3 can detect whether the sheet S has passed through the fixing unit, regardless of whether a cutting command is issued.

[0138] (5) If the discharge sensor SE3 detects the sheet S even after a predetermined time has elapsed since the discharge sensor SE3 detected the sheet S, the CPU 101 of the multifunction peripheral 1 of the first embodiment stops the conveyance of the sheet S (S53). Therefore, when an abnormality occurs, such as the sheet S remaining stuck in the fixing unit, it can be determined that a jam has occurred, and the conveyance of the sheet S can be stopped.

[0139] (6) In the multifunction peripheral 1 of the first embodiment, the length of the conveying path 201 from the nip N to the cutter position SP is longer than half the length of the cuttable sheet S in the conveying direction. Therefore, when cutting the sheet S at the cutter position SP, the state in which the sheet S is sandwiched in the nip N of the fixing unit 6 is released, so that it is possible to prevent heat from being applied to the sheet S from the heating roller 61 while the pressure roller 62 is stopped from rotating. In addition, there is no need for control such as changing the temperature of the fixing unit 6.

[0140] In this embodiment, the length is the length in the transport direction from the downstream end of the nip N of the fixing device 6 in the transport direction to the fixed blade 13 of the cutter 10, but it may also be, for example, the length in the transport direction from the downstream end of the outer periphery of the pressure roller 62 or heating roller 61 of the fixing device 6 in the transport direction to the fixed blade 13 of the cutter 10.

[0141] (7) In the multifunction peripheral 1 of the first embodiment, the CPU 101 determines the rotation amount of the second discharge roller 86 from the timing when the sheet sensor SE4 detects the trailing edge of the cut downstream sheet S, based on the sheet size information. In this way, by using the detection of the trailing edge of the sheet S as the trigger, the conveying distance after detection is shorter than when the detection of the leading edge is used as the trigger, for example, and therefore the sheet S can be discharged more accurately and reliably.

[0142] (8) In the multifunction peripheral 1 of the first embodiment, when double-sided printing is instructed, the CPU 101 rotates the first discharge roller 87 in one direction (forward rotation) and then in the other direction (reverse rotation) based on the detection result of the discharge sensor SE3 in order to transport the sheet S to the re-conveyance path 202. This allows the same discharge sensor SE3 to be used for both the timing of discharge via the first discharge path 201A and the timing of transport to the re-conveyance path 202 for second-side printing, simplifying the device configuration.

[0143] (9) The multifunction peripheral 1 of the first embodiment includes a flapper 88 that guides the sheet S to either the first discharge path 201A or the second discharge path 201B, and the discharge sensor SE3 is located upstream in the conveyance direction of the flapper 88. Therefore, with a simple configuration, the conveyance path of the sheet S can be switched between the first discharge path 201A and the second discharge path 201B.

[0144] (10) The multifunction peripheral 1 of the first embodiment described above includes a third discharge roller 85 disposed upstream of the cutter position SP in the conveying direction as a conveying unit that conveys the sheet S to the second discharge path 201B. The multifunction peripheral 1 further includes a discharge motor 109 that drives the first discharge roller 87, the second discharge roller 86, and the third discharge roller 85. Therefore, in a configuration in which one motor drives the three discharge rollers 85, 86, and 87, the timing for stopping each of the discharge rollers 85, 86, and 87 can be appropriately controlled by selectively using information from two different sensors SE3 and SE4. That is, the sheet S can be stopped at the cutter position SP with high accuracy, and the sheet S can be reliably discharged from the discharge path 201A or 201B.

[0145] (11) In the multifunction peripheral 1 of the first embodiment, when cutting of the sheet S is instructed, the CPU 101 stops the discharge motor 109 when the amount of rotation of the discharge motor 109 from the time when the leading edge of the sheet S is detected by the sheet sensor SE4 reaches a first predetermined amount. Furthermore, the CPU 101 stops the discharge motor 109 when the amount of rotation of the discharge motor 109 from the time when the trailing edge of the sheet S downstream after cutting is detected by the sheet sensor SE4 reaches a second predetermined amount. Therefore, by appropriately setting the first predetermined amount and the second predetermined amount based on the sheet size information, motor control becomes easier and the sheet S can be reliably discharged.

[0146] (12) In the multifunction peripheral 1 of the first embodiment, when cutting of the sheet S is not instructed, the CPU 101 stops the discharge motor 109 when the amount of rotation of the discharge motor 109 reaches a third predetermined amount from the time when the discharge sensor SE3 detects the rear end of the sheet S after image formation processing. Therefore, by appropriately setting the third predetermined amount based on sheet size information, motor control becomes easier and the sheet S can be reliably discharged.

[0147] <Other embodiments> In the multifunction peripheral 1 of the first embodiment, the third discharge rollers 85 are used as an example of a conveying unit, but the conveying unit may be configured with a separate member other than a roller pair, such as a conveying belt. Furthermore, the third discharge rollers 85 as a conveying unit need only be located downstream of the second discharge rollers 86 and be able to convey the sheet S, and their location is not limited to being on the second discharge path 201B. For example, they may be located downstream of the branch position D1.

[0148] In the multifunction device 1 of the first embodiment, the sheet sensor SE4 is disposed between the cutter position SP and the second discharge roller 86. However, as long as the sheet sensor SE4 can detect that the sheet S passes near the cutter position SP, the sheet sensor SE4 may be disposed between the third discharge roller 85 and the cutter position SP.

[0149] In the multifunction device 1 of the first embodiment, the discharge sensor SE3 may be disposed on the first discharge path 201A.

[0150] In the multifunction peripheral 1 of the first embodiment, the discharge motor 109 is configured to drive the three discharge rollers 85, 86, and 87, but each of the discharge rollers 85, 86, and 87 may be driven by a separate motor. Also, in a configuration in which one discharge motor 109 drives three discharge rollers 85, 86, and 87 as in the first embodiment, the first discharge roller 87 may be rotated in the forward direction by the discharge motor 109 in order to rotate the first discharge roller 87 in the direction in which the sheet S is discharged, and the second discharge roller 86 and the third discharge roller 85 may be rotated in the reverse direction by the discharge motor 109 in order to rotate the second discharge roller 86 and the third discharge roller 85 in the direction in which the sheet S is discharged.

[0151] In the multifunction peripheral 1 of the first embodiment, the discharge stop process in S74 stops the second discharge roller 86 and the third discharge roller 85 by stopping one discharge motor 109. However, this is not limited to this. For example, the third discharge roller 85 may be driven by a motor separate from that for the second discharge roller 86, thereby stopping the third discharge roller 85 before stopping the second discharge roller 86, or the third discharge roller 85 may continue to rotate. In S72 and S74, the CPU 101 may stop the motor driving the second discharge roller 86 when the motor reaches the second predetermined amount so that the amount of rotation of the second discharge roller 86 that discharges the sheet S onto the discharge tray 22 is at least the amount of rotation required to completely discharge the sheet S.

[0152] In the multifunction peripheral 1 of the first embodiment, the pre-cutting stopping process stops one discharge motor 109, thereby stopping the second discharge roller 86 and the third discharge roller 85 in S62. However, this is not limiting. For example, if the transport unit has other rollers between the third discharge roller 85 and the second discharge roller 86, and the third discharge roller 85 and other rollers are driven by a motor separate from the motor used to drive the second discharge roller 86, the other motor may be stopped so that at least the cutting position on the sheet S reaches the cutter position SP, and the second discharge roller 86 may be stopped or rotating.

[0153] In the first embodiment, the multifunction peripheral 1 is given as an example of an image forming apparatus, but the image forming apparatus is not limited to the multifunction peripheral 1 and may be a standalone printer or copier. In each of the above embodiments, the multifunction peripheral 1 having the fixing unit 6 is given, but the image forming apparatus may be an inkjet printer.

[0154] The present invention is not limited to the above-described embodiments and can be realized in various configurations without departing from the spirit of the present invention. For example, the technical features in each embodiment corresponding to the technical features in the form described in the Summary of the Invention section can be appropriately replaced or combined to solve some or all of the above-described problems or achieve some or all of the above-described effects. Furthermore, if a technical feature is not described as essential in this specification, it can be appropriately deleted. [Explanation of symbols]

[0155] 1...multifunction device (image forming apparatus), 2...image forming main body section, 3...conveying mechanism, 4...processing section (image forming section), 6...fixing device (fixing section), 10...cutter, 20...main body (device main body), 61...heating roller (heating rotating body), 62...pressure roller (pressure rotating body), 63...heater, 85...third discharge roller (conveying section), 86...second discharge roller, 87...first discharge roller, 88...flapper, 101...CPU (control section), 102...ROM, 103...RAM, 104...NVRAM, 105...ASIC, 106...cutter motor, 108...main motor, 109...discharge motor, 201...conveying path, 201A...first discharge path, 201B...second discharge path, 201C...first path, 202...re-conveying path (second path), D1...branching position, S...sheet, SP...cutter position, SE1...pre-registration sensor, SE2...post-registration sensor, SE3...discharge sensor (first sensor), SE4...sheet sensor (second sensor).

Claims

1. an image forming unit that forms an image on a sheet; a fixing unit including a heating rotor and a pressure rotor that forms a nip between the heating rotor and the pressure rotor, and that fixes the image formed on the sheet to the sheet; a cutter that is arranged at a cutter position downstream of the fixing unit in a conveyance direction of the sheet in a conveyance path along which the sheet is conveyed after passing through the image forming unit and the fixing unit, and that is capable of cutting the sheet in a cross direction that intersects with the conveyance direction; an apparatus main body having the transport path, the apparatus main body having: a first path that is a path through which the sheet passes through the image forming unit and the fixing unit; a first discharge path for discharging the sheet from a branching position that is a downstream end position of the first path in the transport direction to the outside of the apparatus main body without passing through the cutter position; and a second discharge path for discharging the sheet from the branching position via the cutter position to the outside of the apparatus main body; a first discharge roller disposed in the first discharge path and configured to discharge the sheet; a second discharge roller disposed in the second discharge path and configured to discharge the sheet; a conveying section disposed upstream of the second discharge roller; a first sensor disposed on the first path from the fixing unit to the branch position or on the first discharge path, and configured to detect the presence or absence of the sheet; a second sensor disposed on the second discharge path and configured to detect the presence or absence of the sheet; a control unit, The control unit When cutting of the sheet is instructed, an image forming apparatus is characterized in that it performs a pre-cutting stop process that stops the sheet at the cutter position to cut the sheet by controlling the drive of the conveying unit, and an ejection stop process that stops the second ejection roller after rotating it to eject the cut sheet outside the device main body, based on the detection result by the second sensor.

2. The control unit 2. The image forming apparatus according to claim 1, characterized in that, when cutting of the sheet is not instructed, the timing for stopping rotation of the first discharge roller, which is driven to rotate in order to discharge the sheet, is determined based on the detection result by the first sensor.

3. 3. The image forming apparatus according to claim 1, wherein the second discharge roller is disposed downstream of the cutter position in the transport direction.

4. 3. The image forming apparatus according to claim 1, wherein the first sensor is disposed on the first path from the fixing unit to the branch position.

5. The control unit 5. The image forming apparatus according to claim 4, wherein if the first sensor detects the sheet even after a predetermined time has elapsed since the first sensor detected the sheet, conveyance of the sheet is stopped.

6. 3. The image forming apparatus according to claim 1, wherein the length of the conveying path from the nip to the cutter position is longer than half the length of the cuttable sheet in the conveying direction.

7. The control unit 3. The image forming apparatus of claim 1, wherein in the discharge stop processing, the amount of rotation of the second discharge roller from the time when the second sensor detects the rear end of the sheet in the conveying direction is determined based on information on the length of the sheet in the conveying direction.

8. a second path that is different from the first path and that transports the sheet from a downstream side of the fixing unit to a position on the first path that is upstream of the image forming unit, the first discharge roller rotates in one direction to discharge the sheet to the outside, and rotates in the other direction to convey the sheet to the second path; The control unit 3. The image forming apparatus according to claim 1, wherein when double-sided printing is instructed, the first discharge roller is rotated in one direction and then in the other direction based on the detection result by the first sensor in order to transport the sheet to the second path.

9. a flapper that guides the sheet to one of the first discharge path and the second discharge path, 5. The image forming apparatus according to claim 4, wherein the first sensor is located upstream of the flapper in the transport direction.

10. a third discharge roller as the conveying unit, the third discharge roller being disposed on the second discharge path and upstream of the cutter position in the conveying direction; a motor that drives the first discharge roller, the second discharge roller, and the third discharge roller; The control unit When an instruction to cut the sheet is given, a timing to stop the rotation of the motor to stop the sheet at the cutter position and a timing to stop the rotation of the motor that has been rotationally driven to discharge the sheet are determined based on the detection result by the second sensor; 4. The image forming apparatus according to claim 3, wherein when cutting of the sheet is not instructed, the timing for stopping the rotation of the motor that has been driven to rotate in order to discharge the sheet is determined based on the detection result by the first sensor.

11. The control unit 11. The image forming apparatus of claim 10, wherein, when cutting of the sheet is instructed, in the pre-cutting stop processing, the rotation of the motor is stopped at a timing when the amount of rotation of the motor from the timing when the leading edge of the sheet is detected by the second sensor reaches a first predetermined amount, and the sheet is stopped at the cutter position to cut the sheet, and in the discharge stop processing, the rotation of the motor that has been driven to rotate to transport the cut sheet is stopped at a timing when the amount of rotation of the motor from the timing when the trailing edge of the sheet downstream after cutting is detected by the second sensor reaches a second predetermined amount, and the sheet is discharged.

12. The control unit 11. The image forming apparatus of claim 10, characterized in that, when cutting of the sheet is not instructed, the rotation of the motor, which has been driven to rotate in order to transport the sheet, is stopped at the timing when the rotation amount of the motor from the timing when the rear end of the sheet is detected by the first sensor reaches a third predetermined amount, and the sheet is discharged.

Images