Image forming apparatus

Abstract

The present invention provides an image forming apparatus that prevents jamming from occurring on the sheet. [Solution] When the cut front cover 203 is opened during cut printing which involves cutting the sheet S with the cutter 10, the rotation of the first discharge roller 85 and the second discharge roller 86 is stopped, and the transport path guided by the flapper 88 is switched from the first discharge path 201A to the second discharge path 201B, while the pressure roller 62, transport roller 36 and third discharge roller 87 continue to rotate, so that the sheet S to be printed is discharged to the outside of the device body 20 from the second discharge path 201B instead of the first discharge path 201A to which it was originally guided.

Description

Technical Field

[0001] The present invention relates to an image forming apparatus provided with a cutter for cutting a sheet.

Background Art

[0002] Conventionally, as an image forming apparatus for printing an image on a sheet as a printing object, an image forming apparatus provided with a cutter for cutting a sheet on which an image has been formed is known.

[0003] For example, in Japanese Unexamined Patent Application Publication No. 2023-19469, after an image is formed, a pair of discharge rollers arranged downstream in the sheet conveyance direction of the sheet rotate forward, so that the sheet is discharged toward a cutting device and conveyed to a cutting position and stopped, and the stopped sheet is cut with a cutting blade extending in the sheet width direction intersecting the conveyance direction. Then, it is disclosed that the sheet after cutting is discharged to a discharge tray by a pair of discharge rollers and stacked. Here, in the image forming apparatus described in the above patent document, as a discharge path for discharging the sheet after an image is formed, only one discharge path provided with a cutting device is provided.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Generally, image forming apparatuses are equipped with a retractable cover to allow for the replacement or inspection of internal components, or to remove jammed sheets in the transport path. Users can access the inside of the apparatus by opening the cover. On the other hand, if the cover is opened for any reason during printing, the image forming apparatus stops printing and ejects the sheet that was to be printed. In this case, as described in the above-mentioned patent document, the sheet must be ejected from an ejection path equipped with a cutting device, which presents a problem in that there is a higher possibility of sheet jamming compared to image forming apparatuses without a cutting device.

[0006] The present invention aims to solve the problems of the conventional invention and provides an image forming apparatus that has a first discharge path for discharging the sheet to the outside of the apparatus body via the cutter position, and a second discharge path for discharging the sheet to the outside of the apparatus body without passing through the cutter position, and prevents jamming of the sheet by discharging the sheet to the outside of the apparatus body via the second discharge path when the cover is opened during printing. [Means for solving the problem]

[0007] To achieve the above objective, the image forming apparatus according to the present invention includes: an image forming unit for forming a developer image on a sheet; a fixing unit having a heating roller for heating the sheet and a pressure roller for nipping the sheet between itself and the heating roller, for fixing the developer image formed on the sheet; a cutter positioned downstream of the fixing unit in the sheet transport direction in a transport path through which the sheet is transported passing the image forming unit and the fixing unit, for cutting the sheet on which the developer image has been fixed; and an apparatus body having the transport path, the apparatus body having a first discharge path for discharging the sheet to the outside of the apparatus body via the cutter position as part of the transport path, and a second discharge path for discharging the sheet to the outside of the apparatus body without passing through the cutter position. The device comprises a flapper that guides the sheet to either the first discharge path or the second discharge path, a first discharge roller and a second discharge roller arranged in the first discharge path, a third discharge roller arranged in the second discharge path, a transport roller arranged in the transport path upstream of the flapper in the sheet transport direction, and a cutter and a cover that covers the first discharge path. When the cover is opened during printing, which involves cutting the sheet with the cutter, the first and second discharge rollers stop rotating, the flapper switches from the first discharge path to the second discharge path, and the pressure roller, the transport roller and the third discharge roller rotate to discharge the sheet from the second discharge path to the outside of the device body. [Effects of the Invention]

[0008] The image forming apparatus according to the present invention having the above configuration includes a first discharge path for discharging the sheet to the outside of the apparatus body via the cutter position, and a second discharge path for discharging the sheet to the outside of the apparatus body without passing through the cutter position. When the cover is opened during printing, the sheet can be discharged to the outside of the apparatus body via the second discharge path. As a result, jams in the sheet being discharged when printing is stopped can be prevented. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram illustrating the configuration of the MFP, which is the first embodiment. [Figure 2] This is a perspective view showing the general configuration of the cutter in an MFP (Multi-Function Processor). [Figure 3] This is a block diagram showing the control configuration of the MFP. [Figure 4] This diagram shows in detail the drivers and circuits on the main board, which receive operating voltage from the low-voltage power supply board. [Figure 5] This diagram shows the mode of cutting off the operating voltage. [Figure 6] This flowchart shows the procedure for printing and cutting a sheet on one side. [Figure 7] This flowchart shows the detailed steps of the image formation process. [Figure 8] This flowchart shows the detailed procedure for the sheet cutting process. [Modes for carrying out the invention]

[0010] The first and second embodiments of the image forming apparatus according to this application, which are implemented as an MFP (Multi-Function Peripheral, also known as a multifunction device), will be described below with reference to the drawings.

[0011] <First Embodiment> First, the overall configuration of the MFP1 according to the first embodiment will be described. Figure 1 shows the schematic configuration of the MFP1 according to the first embodiment. In the following description, the front-to-back direction and the up-and-down direction are as indicated on the paper.

[0012] [Overall configuration of the MFP] Figure 1 is a cross-sectional view showing the schematic configuration of an MFP1 according to the first embodiment. The MFP1 is an example of an image forming apparatus and has printing, copying, and scanning functions. The MFP1 may also have a fax function added to these functions.

[0013] The MFP1 includes an image forming main body 2 and an image reading unit 9. The image forming main body 2 uses the electrophotographic method and has a function of forming an image on a sheet S. As an example, the image forming main body 2 has a function of forming a monochrome image on the sheet S. The present disclosure is not limited to this. For example, the image forming main body 2 may have a function of forming a full-color image on the sheet S.

[0014] The image reading unit 9 reads an image formed on a medium such as a sheet, and has an image reading sensor such as a CCD (Charge Coupled Device) method or a CIS (Contact Image Sensor) method, and a moving mechanism for moving the image reading sensor. The image reading unit 9 reads an image formed on the medium under the control of the ASIC 105 (see FIG. 3).

[0015] The image forming main body 2 includes a device main body 20, a conveyance 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". Hereinafter, the device main body 20 is also simply referred to as the "main body 20".

[0016] 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 conveyance path 201, a re-conveyance path 202, and a cut front cover 203. The front cover 21 is attached to the front surface of the main body 20 in an openable and closable state. The supply tray 31 is attached to the lower part of the main body 20 in a detachable state. The sheet S is placed on the supply tray 31. The sheet S is a standard sheet such as A4 size. The sheet S is, for example, a paper medium such as plain paper or thick paper, but is not limited thereto, and may be an OHP film. The discharge tray 22 is provided at the upper part of the main body 20, and the sheet S on which the developer image is formed is placed on the discharge tray 22.

[0017] The transport path 201 is a path for transporting the sheet S placed on the supply tray 31 in the transport 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 the path through which the sheet S passes through the process unit 4 and the fuser 6. The transport path 201 branches into the first discharge path 201A and the second discharge path 201B from branching position D1, which is the downstream end position of the first path 201C.

[0018] The first discharge path 201A is a path for discharging the sheet S from branching position D1, through cutter position SP, to the outside of the main body 20 of the apparatus. The second discharge path 201B is a path for discharging the sheet S from branching position D1, without passing through cutter position SP where the cutter 10 is located, to the outside of the main body 20 of the apparatus. Therefore, the sheet S transported via the process unit 4 and the fuser 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.

[0019] Still, the switching of the discharge path of the sheet S between the first discharge path 201A and the second discharge path 201B is performed by the flapper 88. Specifically, the discharge path is switched by switching the position of the flapper 88 between the position 88A which is the first position and the position 88B which is the second position. More specifically, the first position 88A is a position for guiding the sheet S conveyed by the conveying roller 36 to the first discharge path 201A. The state where the flapper 88 is in the first position 88A is also referred to as the first state. In the first state where the flapper 88 is in the first position 88A, the sheet S is guided to the first discharge path 201A. On the other hand, the second position 88B is a position for guiding the sheet S conveyed by the conveying roller 36 to the second discharge path 201B. The state where the flapper 88 is in the second position 88B is also referred to as the second state. In the second state where the flapper 88 is in the second position 88B, the sheet S is guided to the second discharge path 201B. Still, the position of the flapper 88 is switched via a cam mechanism with the flapper solenoid 89 as a drive source, and in printing accompanied by cutting of the sheet S, the sheet S is discharged with the flapper 88 in the first position 88A. On the other hand, in printing for a standard-size sheet S that is not cut, the sheet S is discharged with the flapper 88 in the second position 88B. However, even when cutting is performed, in double-sided printing, it becomes the second position 88B during the first single-sided printing. Also, as will be described later, even in printing accompanied by cutting of the sheet S, in the case where a situation occurs where printing is aborted such as the cut front cover 203 being opened midway, it may switch to the second position 88B. Still, the details of the operation of the flapper 88 will be described later again.

[0020] The re-conveying path 202 is for conveying the sheet S having a developer image formed on one surface in the direction opposite to the conveying direction and then conveying it again toward the process unit 4, that is, for conveying the sheet S with one side printed when double-sided printing is performed, again toward the process unit 4. The re-conveying path 202 is a path that starts from the connection position D2 on the downstream side in the conveying direction from the branch position D1 on the first discharge path 201A and ends at the merging position J on the upstream side in the conveying direction of the pre-registration sensor SE1 in the conveying path 201. Note that the connection position D2 which is the starting point of the re-conveying path 202 may be a position on the downstream side of the fixing unit.

[0021] The conveying mechanism 3 includes a pickup roller 33, a separation roller 34, a registration roller 35, a conveying roller 36, a first discharge roller 85, a second discharge roller 86, a third discharge roller 87, a flapper 88, re-conveying rollers 38, 39, a main motor 108 (see Figure 3), a cut discharge motor 122 (see Figure 3), and a normal discharge motor 124 (see Figure 3).

[0022] The pickup roller 33 picks up the sheets S in the supply tray 31 that have been pushed upward by the sheet pressing 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.

[0023] The registration roller 35 is positioned upstream of the process section 4 in the transport path 201. The registration roller 35 aligns the direction of the front end of the sheet S and then transports the sheet S toward the process section 4. In the following description, the front end of the sheet S refers to the front end of the sheet S in the transport direction, and the rear end of the sheet S refers to the rear end of the sheet S in the transport direction. The transport roller 36 is positioned upstream of the flapper 88 in the transport path 201 in the sheet transport direction and transports the sheet S after it has passed through the fuser 6 toward the first discharge roller 85 or the third discharge roller 87.

[0024] The first discharge roller 85 and the second discharge roller 86 are located in the first discharge path 201A. The first discharge roller 85 is located upstream of the cutter position SP where the cutter 10 is located, and the second discharge roller 86 is located downstream of the cutter position SP.

[0025] The first discharge roller 85 rotates due to the driving force from the cut discharge motor 122 (see Figure 3). The first driven roller 85A is positioned opposite the first discharge roller 85 across the first discharge path 201A. The first driven roller 85A rotates in conjunction with the rotation of the first discharge roller 85. The second discharge roller 86 also rotates due to the driving force from the cut discharge motor 122. The second driven roller 86A is positioned opposite the second discharge roller 86 across the first discharge path 201A. The second driven roller 86A rotates in conjunction with the rotation of the second discharge roller 86.

[0026] The first discharge roller 85 and the second discharge roller 86 discharge the sheet S to the discharge tray 22 by rotating in a way that conveys the sheet S in the conveying direction. The rotation that conveys the sheet S in the conveying direction corresponds to a counterclockwise rotation when viewed from the left side with the left-right axis of the main body 20.

[0027] Meanwhile, the third discharge roller 87 is located in the second discharge path 201B. The third discharge roller 87 is normally rotated by a driving force from the discharge motor 124 (see Figure 3). A third driven roller 87A is located opposite the third discharge roller 87 across the second discharge path 201B. The third driven roller 87A rotates in conjunction with the rotation of the third discharge roller 87. The third discharge roller 87 discharges the sheet S to the discharge tray 22 by rotating in a direction that transports the sheet S in the transport direction. The third discharge roller 87 also transports the sheet S to the re-transport path 202 by rotating in the opposite direction to the rotation that transports the sheet S in the transport direction. The rotation in the opposite direction 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 axis of the main body 20.

[0028] Retransport rollers 38 and 39 are arranged in the retransport path 202. The retransport rollers 38 and 39 transport the sheet S that has been transported in the retransport path 202 toward the process section 4. By retransporting the sheet S, on which an image has been formed on one side, toward the process section 4 via the retransport path 202 using the retransport rollers 38 and 39, it is possible to form an image on both sides of the sheet S.

[0029] The process unit 4 forms an image on the sheet S and is housed within the main body 20. The image is a developer image. The process unit 4 includes a drum cartridge 5 and a laser unit 7. The drum cartridge 5 includes a photoreceptor drum 51, a toner storage unit 57, a supply roller 56, a developer 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 in accordance with the rotation of the registration roller 35 and transports the sheet S together with the registration roller 35.

[0030] The photoreceptor drum 51 is driven by the main motor 108 (see Figure 3) to rotate in a way that transports the sheet S in the transport direction, thereby transporting the sheet S. The rotation of the photoreceptor drum 51 that transports the sheet S in the transport direction is a clockwise rotation when viewed from the left side, with the left-right axis of the main body 20 as the axis. The toner storage section 57 contains toner. The supply roller 56 supplies the toner from the toner storage section 57 to the developing roller 55. The charger 52 is a Scorotron type charger that uniformly charges the surface of the photoreceptor drum 51. The charger 52 may also be a charging roller.

[0031] A transfer roller 53 is positioned opposite the photoreceptor drum 51. The transfer roller 53 forms a transfer nip TN between itself and the photoreceptor drum 51 in the transport path 201. A transfer belt may be used instead of the transfer roller 53.

[0032] The main body 20 has a laser unit 7 at its upper interior. The laser unit 7 includes a polygon mirror 131 (see Figure 3), a laser light-emitting unit 132 (see Figure 3), a polygon motor 133 (see Figure 3), lenses and reflectors (not shown), etc. The laser unit 7 exposes the surface of the photoreceptor drum 51 by rapidly scanning the surface of the photoreceptor drum 51 with laser light based on image data emitted from the laser light-emitting unit 132. The dashed line in Figure 1 shows the laser light irradiated from the laser light-emitting unit 132.

[0033] The surface of the photoreceptor drum 51 is exposed by the laser unit 7, forming an electrostatic latent image based on the image data. The developing roller 55 supplies toner to the electrostatic latent image formed on the surface of the photoreceptor drum 51, thereby forming a toner image on the surface of the photoreceptor drum 51.

[0034] A transfer voltage is applied to the transfer roller 53. The transfer roller 53 transports the sheet S between itself and the photoreceptor drum 51, thereby transferring the toner image formed on the surface of the photoreceptor drum 51 to the sheet S as it passes through the transfer nip TN. In this way, an image is formed on the sheet S.

[0035] A fuser 6 is located downstream of the process section 4 in the transport path 201. The fuser 6 has a heating roller 61, a pressure roller 62, and a heater 63. The heating roller 61 heats the sheet S. The pressure roller 62 forms a nip N with the heating roller 61 and pressurizes the sheet S. Note that the fuser 6 is an example of a "fusing section". The pressure roller 62 rotates to transport the sheet S in the transport direction by the driving force of the main motor 108. The rotation of the pressure roller 62 to transport the sheet S in the transport direction is counterclockwise when viewed from the left side with the left-right direction of the main body 20 as the axis. The heater 63 is, for example, a halogen heater and heats the heating roller 61.

[0036] The fuser 6 heats the sheet S with the heating roller 61 and rotates the pressure roller 62, thereby pressurizing and transporting the sheet S with the heating roller 61 and pressure roller 62, and fixing the developer image formed on the sheet S by the process unit 4 to the sheet S. However, in the fuser 6, the heating roller 61 may be rotated instead of the pressure roller 62.

[0037] The fuser 6 is configured to include a heating roller 61, a pressure roller 62, and a heater 63, but is not limited to this configuration. For example, the fuser 6 may also have a 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.

[0038] Furthermore, the fuser 6 may have a substrate on which a heating pattern is formed, a belt that rotates around the substrate, and a pressure roller, with the substrate and belt in contact with the pressure roller. Alternatively, the fuser 6 may have a heating roller, a heater, and a pressure belt.

[0039] In the first discharge path 201A, a cutter 10 is positioned between the first discharge roller 85 and the second discharge roller 86. The cutter 10 is positioned downstream of the fuser 6 in the direction of sheet S transport. The MFP1 stops the rotation of the first discharge roller 85 and the second discharge roller 86 so that the cutting position on sheet S reaches the cutter position SP. With the rotation of the first discharge roller 85 and the second discharge roller 86 stopped, the MFP1 cuts the sheet S using the cutter 10.

[0040] Figure 2 shows the schematic configuration of the cutter 10. As shown in Figure 2, the cutter 10 includes a cutter frame 11, a slide rail 12, a fixed blade 13, a sheet passage section 14, a movable 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 extending in the axial direction formed on the cutter frame 11. The fixed blade 13 is a flat, plate-shaped blade extending in the axial direction and fixed to the cutter frame 11. The sheet passage section 14 is a space formed on the cutter frame 11 through which a sheet S passes. In this embodiment, the sheet passage section 14 is formed between the slide rail 12 and the fixed blade 13. The movable blade 15 is a disc-shaped blade and is rotatably supported by the slide holder 16.

[0041] The slide holder 16 engages with the slide rail 12 and is mounted on the cutter frame 11 so as to be slidable along the slide rail 12. When the cutter motor 106 is driven forward, the slide holder 16 slides from one side to the other in the axial direction, and when the cutter motor 106 is driven in reverse, the slide holder 16 slides from the other side to the one side in the axial direction. The slide holder 16 is movable from the initial position FP, shown by a solid line in Figure 2, to the completion position KP, shown by a dashed line. The slide holder 16, to which the movable blade 15 is fixed, is movable in the cutting direction intersecting the transport direction at the cutter position SP. That is, the cutter 10 can cut the sheet S in an intersecting direction that intersects the transport direction of the sheet S. The cutting direction is either from the initial position FP towards the completion position KP, or from the completion position KP towards the initial position FP.

[0042] When the sheet S is in the cutter position SP, the slide holder 16 moves along the slide rail 12 to the completion position KP, and one sheet S is sandwiched between the fixed blade 13 and the movable blade 15 and cut into two sheets. After cutting the sheet S, the MFP1 rotates the first discharge roller 85 and the second discharge roller 86 for a predetermined time to discharge the two sheets S into the discharge tray 22.

[0043] Furthermore, the MFP1 is configured to cut A4 and letter-sized sheets S at the center of the sheet in the transport direction using the cutter 10. In other words, the length of the transport path 201 from the nip N to the cutter position SP in Figure 1 is designed to be longer than half the dimensions of the A4-sized sheet S in the transport direction (297 mm) (148.5 mm).

[0044] With this configuration, when cutting an A4 or letter-sized sheet S at the cutter position SP with the rotation of the first discharge roller 85 and the second discharge roller 86 stopped, the rear end of the sheet S passes through the nip N of the fuser 6. If the rotation of the first discharge roller 85 and the second discharge roller 86 is stopped in order to cut the sheet S at the cutter position SP while the sheet S is held between the nip N of the fuser 6, the rotation of the pressure roller 62 must also be stopped. However, if the rotation of the pressure roller 62 is stopped while the sheet S is held between the nip N of the fuser 6, heat will be locally applied to the same spot on the sheet S from the heating roller 61. Therefore, when cutting the sheet S at the cutter position SP with the rotation of the first discharge roller 85 and the second discharge roller 86 stopped, the rear end of the sheet S must pass through the nip N of the fuser 6.

[0045] Furthermore, the length of the transport path 201 from the nip of the transport roller 36 to the cutter position SP in Figure 1 is designed to be longer than half the dimension (148.5 mm) of the A4-sized sheet S in the transport direction (297 mm).

[0046] With this configuration, when cutting the sheet S at the cutter position SP with the rotation of the first discharge roller 85 and the second discharge roller 86 stopped, the rear end of the sheet S passes through the nip of the conveyor roller 36. When cutting the sheet S at the cutter position SP with the rotation of the first discharge roller 85 and the second discharge roller 86 stopped, if the nip N of the conveyor roller 36 or the pressure roller 62 is rotating with the sheet S in between, there is a risk that the sheet S will bend into an accordion shape between the first discharge roller 85 and the conveyor roller 36. Therefore, with the above configuration, it is possible to stop the sheet S at the cutter position SP without bending into an accordion shape by only stopping the rotation of the first discharge roller 85 and the second discharge roller 86, without stopping the rotation of the conveyor roller 36 or the fuser 6.

[0047] Furthermore, the length of the second discharge path 201B is designed to be shorter than the length of the first discharge path 201A. This is to allow the sheet S to be quickly discharged outside the main body 20 of the device when it is not cut after image formation. The second discharge roller 86 is positioned further forward in the front-to-back direction than the third discharge roller 87. This ensures that there is space to move the cutter position SP away from the fuser 6. In addition, the shorter sheet S after cutting can be discharged further forward from the second discharge roller 86, making it easier for the user to access the discharged sheet S.

[0048] Furthermore, the distance between the first discharge roller 85 and the second discharge roller 86 is designed to be shorter than half the length of the letter-sized sheet S in the transport direction (279.4 mm) (139.7 mm). This is to allow the sheet S, after being cut by the cutter 10, to be transported between the first discharge roller 85 and the second discharge roller 86. Conversely, sheets S that are less than twice the length of the distance between the first discharge roller 85 and the second discharge roller 86 are configured not to accept a cutting instruction.

[0049] Furthermore, above the first discharge path 201A of the main body 20, a cut front cover 203 is provided that covers the cutter 10 and the first discharge path 201A as described above. The cut front cover 203 can be manually opened and closed by the user in the vertical direction, and a cut front cover switch 203a is also provided to detect when the cut front cover 203 is opened. The user can then remove the jammed sheet S in the first discharge path 201A by opening and closing the cut front cover 203. In addition, when the cut front cover 203 is opened during printing that involves cutting a sheet, as described later, the MFP1 stops the rotation of the first discharge roller 85 and the second discharge roller 86, and further switches the transport path guided by the flapper 88 from the first discharge path 201A to the second discharge path 201B, and rotates the pressure roller 62, transport roller 36 and third discharge roller 87 to discharge the sheet S from the second discharge path 201B to the outside of the main body of the device. The cut front cover 203 is an example of a "cover".

[0050] [Electrical configuration of MFP1] Next, the electrical configuration of MFP1 will be explained using Figure 3. Figure 3 shows the electrical configuration of MFP1. Note that Figure 3 mainly shows the components necessary for explaining the first embodiment, and other components of MFP1 are omitted.

[0051] As shown in Figure 3, the MFP1 contains multiple circuit boards, including a main board 100 and a low-voltage power supply board 110. Each circuit board is connected to the others via a harness. Although not shown in the figure, a main motor board and a high-voltage power supply board are also present.

[0052] The low-voltage power supply board 110 has an AC-DC conversion circuit that receives an AC voltage supplied by the commercial power supply, for example AC100V, and converts this AC100V into a DC voltage, for example DC24V, using the AC-DC conversion circuit. The low-voltage power supply board 110 outputs the generated DC24V to the main board 100 via the harness.

[0053] The main board 100 has a DC-DC conversion circuit that either supplies the DC24V input from the low-voltage power supply board 110 directly to each driver and circuit, or converts it to a lower voltage, such as DC3.3V, using the DC-DC conversion circuit, and then supplies it to the various electronic components mounted on the main board 100. However, if there are electronic components that are driven by other DC voltage values, such as DC5V, multiple DC-DC conversion circuits may be provided to generate DC1.8V, DC5V, etc., in addition to DC3.3V.

[0054] Here, Figure 4 shows in detail the drivers and circuits of the main board 100, which is supplied with DC24V input from the low-voltage power supply board 110 as its operating voltage, as well as the motors and solenoids connected to those drivers and circuits, from the control configuration of Figure 3.

[0055] As shown in Figure 4, the main board 100 inputs DC24V from the low-voltage power supply board 110 as the first operating voltage to the cutter motor driver 118, and the cutter motor driver 118 also supplies power to the cutter motor 106 based on the signal from the ASIC 105.

[0056] The main board 100 inputs DC24V from the low-voltage power supply board 110 as a second operating voltage to the flapper switching circuit 119, and the flapper switching circuit 119 also supplies power to the flapper solenoid 89 based on the signal from the ASIC 105.

[0057] The main board 100 inputs DC24V from the low-voltage power supply board 110 as a third operating voltage to the stepping motor driver 121, and the stepping motor driver 121 also supplies power to the cut-off motor 122 based on the signal from the ASIC 105.

[0058] The main board 100 inputs DC24V from the low-voltage power supply board 110 as the operating voltage to the stepping motor driver 123, and the stepping motor driver 123 also supplies power to the normal discharge motor 124 based on the signal from the ASIC 105.

[0059] Although not shown in Figure 4, the main board 100 also inputs the DC24V from the low-voltage power supply board 110 as the operating voltage to the motor drivers 115 and 116, and the motor driver 116 also supplies power to the main motor 108 based on the signal from the ASIC 105 (Figure 3).

[0060] Furthermore, on / off circuits 126 to 129, consisting of FETs, transistors, resistors, etc., are connected to the terminals of the ASIC105 via signal lines. Here, the first on / off circuit 126 is a circuit that switches whether or not to supply the first operating voltage, DC24V, from the low-voltage power supply board 110 to the cutter motor driver 118. Specifically, when the ASIC105 outputs H from its terminals, the drain-source of the FET in the on / off circuit 126 turns on, and DC24V from the low-voltage power supply board 110 is supplied to the cutter motor driver 118. Conversely, when the ASIC105 outputs L from its terminals, the drain-source of the FET in the on / off circuit 126 turns off, and the supply of DC24V from the low-voltage power supply board 110 to the cutter motor driver 118 stops, that is, the first operating voltage is cut off. In addition, a cut front cover switch 203a, which detects the opening and closing of the cut front cover 203, is also connected to the on / off circuit 126 via a signal line. The on / off circuit 126 has a circuit configuration that, when the cut front cover switch 203a is off, i.e., the cut front cover 203 is open, even if a high (H) is output from the terminals of the ASIC 105, the DC 24V supplied from the low-voltage power supply board 110 to the cutter motor driver 118 is forcibly stopped, as shown in Figure 5, i.e., the first operating voltage is cut off. In other words, the on / off circuit 126 is a circuit that cuts off the first operating voltage in response to the control signal from the ASIC 105 and the opening of the cut front cover 203. Therefore, it is possible to control the first operating voltage supplied to the cutter motor driver 118 by sending a signal from the ASIC 105 to the on / off circuit 126, and it is also possible to instantly cut it off in hardware without control by the ASIC 105 when the cut front cover 203 is opened.

[0061] The second on / off circuit 127 is a circuit that switches whether or not to supply the second operating voltage, DC24V, from the low-voltage power supply board 110 to the flapper switching circuit 119. Specifically, when the ASIC 105 outputs H from its terminal, the drain-source connection of the FET in the on / off circuit 127 turns on, and DC24V from the low-voltage power supply board 110 is supplied to the flapper switching circuit 119. Conversely, when the ASIC 105 outputs L from its terminal, the drain-source connection of the FET in the on / off circuit 127 turns off, and the supply of DC24V from the low-voltage power supply board 110 to the flapper switching circuit 119 stops, i.e., the second operating voltage is cut off. The on / off circuit 127 is also connected via a signal line to the cut-off front cover switch 203a, which detects the opening and closing of the cut-off front cover 203. The on / off circuit 127 has a circuit configuration that, when the cut front cover switch 203a is off, i.e., the cut front cover 203 is open, even if a high (H) is output from the terminals of the ASIC 105, forcibly stops the supply of DC24V from the low-voltage power supply board 110 to the flapper switching circuit 119, as shown in Figure 5, i.e., the second operating voltage is cut off. In other words, the on / off circuit 127 is a circuit that cuts off the second operating voltage in conjunction with the control signal from the ASIC 105 and the opening of the cut front cover 203. Therefore, it is possible to control the second operating voltage supplied to the flapper switching circuit 119 by sending a signal from the ASIC 105 to the on / off circuit 127, and it is also possible to instantly cut it off in hardware without control by the ASIC 105 when the cut front cover 203 is opened.

[0062] The third on / off circuit 128 is a circuit that switches whether or not to supply the third operating voltage, DC24V, from the low-voltage power supply board 110 to the stepping motor driver 121. Specifically, when the ASIC 105 outputs H from its terminal, the drain-source of the FET in the on / off circuit 128 turns on, and DC24V from the low-voltage power supply board 110 is supplied to the stepping motor driver 121. Conversely, when the ASIC 105 outputs L from its terminal, the drain-source of the FET in the on / off circuit 128 turns off, and the supply of DC24V from the low-voltage power supply board 110 to the stepping motor driver 121 stops, i.e., the third operating voltage is cut off. The on / off circuit 128 is also connected via a signal line to the cut-off front cover switch 203a, which detects the opening and closing of the cut-off front cover 203. The on / off circuit 128 has a circuit configuration that, when the cut front cover switch 203a is off, i.e., the cut front cover 203 is open, even if a high (H) is output from the terminals of the ASIC 105, the DC24V supplied from the low-voltage power supply board 110 to the stepping motor driver 121 is forcibly stopped, as shown in Figure 5, i.e., the third operating voltage is cut off. In other words, the on / off circuit 128 is a circuit that cuts off the third operating voltage in conjunction with the control signal from the ASIC 105 and the opening of the cut front cover 203. Therefore, it is possible to control the third operating voltage supplied to the stepping motor driver 121 by sending a signal from the ASIC 105 to the on / off circuit 128, and it is also possible to instantly cut it off in hardware without control by the ASIC 105 when the cut front cover 203 is opened.

[0063] The fourth on / off circuit 129 is a circuit that switches whether or not to supply DC24V, the operating voltage from the low-voltage power supply board 110, to the stepping motor driver 123. Specifically, when the ASIC 105 outputs H from its terminal, the drain-source connection of the FET in the on / off circuit 129 turns on, and DC24V from the low-voltage power supply board 110 is supplied to the stepping motor driver 123. Conversely, when the ASIC 105 outputs L from its terminal, the drain-source connection of the FET in the on / off circuit 129 turns off, and the supply of DC24V from the low-voltage power supply board 110 to the stepping motor driver 123 stops, i.e., the operating voltage is cut off. However, the on / off circuit 129 is not connected to the cut-off front cover switch 203a, which detects the opening and closing of the cut-off front cover 203. Therefore, the supply of operating voltage to the stepping motor driver 123 continues even if the cut-off front cover 203 is opened when the ASIC 105 is outputting H from its terminal.

[0064] Furthermore, the supply of operating voltage to motor drivers 115 and 116 continues even if the cut front cover 203 is opened, as long as the ASIC 105 outputs a high voltage from its terminals.

[0065] The main board 100 also includes an ASIC 105, a ROM 102, a RAM 103, an NVRAM 104, motor drivers 115 and 116 for driving various motors, stepping motor drivers 121 and 123, a cutter motor driver 118 for controlling the rotation of the cutter motor 106, and a flapper switching circuit 119 for controlling the power supply state to the flapper solenoid 89. In addition, a front register sensor SE1, a back register sensor SE2, a paper ejection sensor SE3, a sheet sensor SE4, an operation panel PA, a communication interface (I / F) 130, a flapper solenoid 89, and various motors are connected to it.

[0066] The ASIC105 is equipped with a CPU101. The CPU101 performs overall control over all parts of the MFP1. The CPU101 and ASIC105 are considered an example of a "control unit". In the following description, the CPU101 is described as the main operator in the example of a control unit, but the ASIC105 as a whole may be used as the main operator, or the CPU101 and ASIC105 may work together to perform each operation. The ASIC105 is electrically connected to the ROM102, RAM103, NVRAM104, pre-cash register sensor SE1, post-cash register sensor SE2, paper ejection sensor SE3, sheet sensor SE4, operation panel PA, communication I / F130, fuser 6, and laser unit 7.

[0067] ROM102 stores various control programs and settings for controlling the MFP1. The sheet single-sided printing and cutting process (Figure 6), described later, is included in the above control program.

[0068] RAM103 is used as a work area from which various control programs are read, and as a storage area for temporarily storing image data included in the job. The CPU101 controls each part of the MFP1 while storing the processing results in RAM103 or NVRAM104 according to the control programs read from ROM102 and signals output from various sensors.

[0069] The control panel PA includes, for example, a touch panel with an integrated touchpad and display, and a key button section. The control panel PA receives user input and outputs the received information to the ASIC105. By operating the control panel PA, the user can, for example, configure various settings related to the MFP1. They can also issue instructions for executing copy and scan functions.

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

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

[0072] Furthermore, the CPU 101 transmits driving force to the re-transport rollers 38 and 39 by driving the main motor 108 in the forward direction via the motor driver 116. The transmitted driving force causes the re-transport rollers 38 and 39 to rotate in a manner that transports the sheet S toward the process section 4. The rotation of the re-transport rollers 38 and 39 in a manner that transports the sheet S toward the process section 4 is a clockwise rotation when viewed from the left side with the left-right axis of the main body 20.

[0073] On the other hand, even when the CPU 101 reverses the drive of the main motor 108, driving force is transmitted to the re-transport rollers 38 and 39. Due to the transmitted driving force, the re-transport rollers 38 and 39 rotate to transport the sheet S toward the process section 4.

[0074] The cut discharge motor 122 transmits driving force to the first discharge roller 85 and the second discharge roller 86. Meanwhile, the normal discharge motor 124 transmits driving force to the third discharge roller 87. When the CPU 101 drives the cut discharge motor 122 in the forward direction via the stepping motor driver 121, the forward rotation of the cut discharge motor 122 causes the first discharge roller 85 and the second discharge roller 86 to rotate in a way that transports the sheet S in the transport direction. In other words, the stepping motor driver 121 corresponds to a cut discharge motor driver that controls the rotation of the cut discharge motor 122. Meanwhile, when the CPU 101 drives the normal discharge motor 124 in the forward direction via the stepping motor driver 123, the forward rotation of the normal discharge motor 124 causes the third discharge roller 87 to rotate in a way that transports the sheet S in the transport direction. In other words, the stepping motor driver 123 corresponds to a driver that controls the rotation of the normal discharge motor 124. In the first discharge roller 85, the second discharge roller 86, and the third discharge roller 87, the rotation that conveys the sheet S in the conveying direction is counterclockwise when viewed from the left side with the left-right axis of the main body 20.

[0075] As a result, the sheet S is discharged to the discharge tray 22 via the first discharge path 201A or the second discharge path 201B. On the other hand, when the CPU 101 reverses the drive of the normal discharge motor 124, the third discharge roller 87 rotates in the opposite direction to the conveying direction of the sheet S. In the case of the third discharge roller 87, rotation in the opposite direction to the conveying direction of the sheet S means clockwise rotation when viewed from the left side with the left-right axis of the main body 20. As a result, the sheet S being conveyed in the second discharge path 201B is conveyed in the opposite direction to the conveying direction, and the sheet S is conveyed towards the re-conveying path 202.

[0076] The CPU 101 controls the drive of the cutter motor 106 via the cutter motor driver 118. The cutter motor 106 is a DC brush motor. The cutter motor 106 is not limited to a DC brush motor; it may also be a DC brushless motor. The forward rotation of the cutter motor 106 causes the slide holder 16 to move the movable blade 15 in the width direction of the sheet S, and the sheet S is cut. The encoder 113 is attached to the rotation axis 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 obtains 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, that is, the position of the movable blade 15 in the axial direction.

[0077] The CPU 101 controls the flapper 88 via the flapper switching circuit 119. Specifically, the ASIC 105 and the flapper switching circuit 119 are connected by a signal line, and either an on (=H) or off (=L) control signal is input to the flapper switching circuit 119 from the output port of the ASIC 105 depending on the current state of the MFP1. The flapper switching circuit 119 then cuts off the operating voltage based on the input control signal, and is able to switch whether or not power is supplied to the flapper solenoid 89. This switches the position of the flapper 88 between a first position 88A and a second position 88B. The first position 88A is the position that guides the sheet S conveyed by the conveyor roller 36 to the first discharge path 201A. The second position 88B is the position that guides the sheet S conveyed by the conveyor roller 36 to the second discharge path 201B. Furthermore, the second position 88B is also the position that guides the sheet S located in the second discharge path 201B to the re-transport path 202, and also the position that guides the sheet S to be discharged in the event that printing is stopped during printing that involves cutting the sheet S.

[0078] When the MFP1 is powered on and no current is flowing through the coil of the flapper solenoid 89, the flapper 88 is in the second position 88B, which is the second state in which the sheet is guided to the second discharge path 201B. On the other hand, when current is flowing through the coil of the flapper solenoid 89, the flapper 88 is in the first position 88A, which is the first state in which the sheet is guided to the first discharge path 201A. In order for the flapper 88 to maintain the first state in the first position 88A, current must continue to flow through the coil of the flapper solenoid 89. Therefore, for example, if the cut front cover 203 is opened while the flapper is in the first state, the operating voltage supplied to the flapper switching circuit 119 is interrupted as described above (Figures 4 and 5), the power supply to the flapper solenoid 89 is also stopped, and the state is forcibly changed from the first state to the second state without receiving a control signal from the ASIC 105. In other words, at the timing when the drive voltage supplied to the flapper switching circuit 119 is interrupted, the transport path guided by the flapper 88 switches from the first discharge path 201A to the second discharge path 201B.

[0079] The pre-register sensor SE1 is positioned upstream of the registration roller 35 in the transport path 201 (see Figure 1) and is a sensor that detects when the sheet S passes. The pre-register sensor SE1 can be a sensor with an actuator that swings when the sheet S comes into contact with it, or an optical sensor, etc. The pre-register sensor SE1 outputs an ON signal when the sheet S is passing and an OFF signal when the sheet S is not passing. The detection signal from the pre-register sensor SE1 is output to the ASIC105.

[0080] The post-registration sensor SE2 is positioned upstream of the fuser 6 in the transport path 201, specifically between the registration roller 35 and the transfer roller 53 (see Figure 1), and is a sensor that detects when the sheet S passes through. The post-registration sensor SE2 has the same configuration as the pre-registration sensor SE1. The detection signal from the post-registration sensor SE2 is output to the ASIC 105.

[0081] The paper ejection sensor SE3 is positioned downstream of the fuser 6 in the sheet transport direction and upstream of the flapper 88 in the sheet transport direction in the transport path 201 (see Figure 1), and detects when a sheet S passes through. The paper ejection sensor SE3 has the same configuration as the pre-cash register sensor SE1. The detection signal from the paper ejection sensor SE3 is output to the ASIC105.

[0082] The sheet sensor SE4 is positioned between the cutter position SP and the second discharge roller 86 (see Figure 1) and detects the passage of the sheet S. The sheet sensor SE4 has the same configuration as the pre-cash register sensor SE1. The detection signal from the sheet sensor SE4 is output to the ASIC 105. Note that the distance from the sheet sensor SE4 to the nip N in the transport direction is greater than the distance from the paper discharge sensor SE3 to the nip N in the transport direction.

[0083] The communication interface 130 is connected to a network such as a LAN and enables connection to external devices such as a PC with a driver for the MFP1 installed. The CPU 101 can receive print jobs via the communication interface 130. A print job includes various information necessary for forming an image on the sheet S, such as image data for image formation, the size and type of the sheet S used for image formation, and information on whether or not to cut the sheet S.

[0084] [Effects of MFP1 in the First Embodiment] In the MFP1 according to the first embodiment having the above configuration, when the cut front cover 203 is opened during cut printing which involves cutting the sheet S with the cutter 10, the third operating voltage supplied from the low-voltage power supply board 110 to the stepping motor driver 121 by the on / off circuit 128 is cut off, as shown in Figures 4 and 5. As a result, the power supply to the cut discharge motor 122 is also stopped, and the first discharge roller 85 and the second discharge roller 86 stop rotating. Furthermore, the second operating voltage supplied from the low-voltage power supply board 110 to the flapper switching circuit 119 by the on / off circuit 127 is also cut off, and power is no longer supplied to the coil of the flapper solenoid 89, so the flapper 88 switches from the first position 88A to the second position 88B, and the transport path guided by the flapper 88 also switches from the first discharge path 201A to the second discharge path 201B. On the other hand, even when the cut front cover 203 is opened, the supply of operating voltage to the motor driver 116 and the stepping motor driver 123 is not interrupted. As a result, the pressure roller 62, the transport roller 36, and the third discharge roller 87 continue to rotate, and the sheet S that was to be printed is discharged to the outside of the device body 20 via the second discharge path 201B instead of the first discharge path 201A to which it is normally guided.

[0085] In this case, if a cover on the main body 20 of the device, such as the cut front cover 203, is opened for any reason while cut printing is being performed, the MFP1 stops printing and ejects the sheet S that was to be printed. However, in conventional image forming apparatus capable of cut printing, the sheet S is ejected from an ejection path where the cutter 10 is located, which made it highly likely that the sheet S would jam. In contrast, in the MFP1 of the first embodiment, the sheet S can be ejected to the outside of the main body 20 of the device from the second ejection path 201B instead of the first ejection path 201A where the cutter 10 is located. As a result, it is possible to prevent the sheet S from jamming when printing is stopped.

[0086] Furthermore, in the MFP1 according to the first embodiment, the first, second, and third operating voltages supplied to the cutter motor driver 118, the flapper switching circuit 119, and the stepping motor driver 121 by the on / off circuits 126 to 128 are shut off by hardware without waiting for instructions from the ASIC 105 when the cut front cover 203 is opened. Therefore, when the cut front cover 203 is opened, the first, second, and third operating voltages can be shut off as quickly as possible.

[0087] Furthermore, the flapper solenoid 89 is a solenoid that is in a first state when power is maintained by the flapper switching circuit 119, and in a second state when power is not maintained by the flapper switching circuit 119. At the timing when the drive voltage supplied to the flapper switching circuit 119 is cut off, the transport path guided by the flapper 88 switches from the first discharge path 201A to the second discharge path 201B. Therefore, when the cut front cover 203 is opened, the transport path guided by the flapper 88 can be switched from the first discharge path 201A to the second discharge path 201B as quickly as possible without waiting for control by the ASIC 105.

[0088] <Second Embodiment> Next, the MFP according to the second embodiment will be described with reference to Figures 6 to 8. In the following description, the same reference numerals as those used in the configuration of the MFP1 according to the first embodiment in Figures 1 to 5 indicate the same or corresponding parts as those in the configuration of the MFP1, etc., according to the first embodiment.

[0089] The schematic configuration of the MFP according to this second embodiment is substantially the same as that of the MFP1 according to the first embodiment. Furthermore, the various control processes are also substantially the same as those of the MFP1 according to the first embodiment.

[0090] However, the MFP1 according to the first embodiment shuts off the first, second, and third operating voltages by a hardware configuration without waiting for control from the ASIC105 when the cut front cover 203 is opened, and discharges the sheet S to be printed to the outside of the device body 20 from the second discharge path 201B, whereas the MFP1 according to the second embodiment differs in that it performs the above function by control from the ASIC105. In other words, in the MFP1 according to the second embodiment, the operating voltages to the cutter motor driver 118, flapper switching circuit 119, and stepping motor driver 121 are shut off by a control signal from the ASIC105, so the hardware configuration for shutting off the operating voltage by the cut front cover switch 203a described in Figures 4 and 5 is unnecessary.

[0091] The control processes performed in the MFP1 according to the second embodiment are described below.

[0092] [Control processing by the control unit] In the second embodiment, the CPU 101 of the MFP1's ASIC 105 will be used to explain, in particular, the single-sided sheet printing and cutting process, based on Figure 6. Figure 6 is a flowchart illustrating the printing process, which is one of the main processes executed after the MFP1 is powered on, and specifically involves single-sided printing and cutting the printed sheet S with a cutter 10. This process is executed when the MFP1 receives a request for single-sided printing and cutting the printed sheet S with a cutter 10 from an external device such as a PC via the operation panel PA or the communication I / F 130. The processes shown in the flowchart in Figure 6 are stored in the MFP1's memory and executed by the CPU 101. The CPU 101 is an example of a control unit.

[0093] First, in step 1 (hereinafter abbreviated as S), the CPU 101 turns on the heater 63 and controls the heater 63 so that the heating roller 61 reaches the target temperature.

[0094] Next, in S2, the CPU 101 drives the main motor 108 in the forward direction. When the main motor 108 is driven in the forward direction, the output of the main motor 108 transmits driving force to the transport roller 36, pressure roller 62, photoreceptor drum 51, developing roller 55, pickup roller 33, and registration roller 35 (Figure 3). Then, the transport roller 36, pressure roller 62, photoreceptor drum 51, developing roller 55, pickup roller 33, and registration roller 35 rotate to transport the sheet S in the transport direction.

[0095] Subsequently, in S3, the CPU 101 sends a control signal to the flapper switching circuit 119, switching the flapper 88 from the second position 88B to the first position 88A.

[0096] As described above, immediately after powering on the MFP1 and before the start of the printing process, the flapper 88 is initially in the second position 88B, which guides the sheet S to the second discharge path 201B. The process in S3 switches the flapper 88 from the second position 88B to the first position 88A. As a result, the flapper 88 then guides the sheet S, which has been conveyed by the transport roller 36, to the first discharge path 201A where the cutter 10 is located.

[0097] The CPU 101, the flapper switching circuit 119, and the on / off circuit 127 are connected by signal lines. Depending on the current state of the MFP1, either an on (=H) or off (=L) control signal is input to the on / off circuit 127 from the output port of the CPU 101. Based on the input control signal, the on / off circuit 127 switches the on / off state of the second operating voltage supplied to the flapper switching circuit 119, and also switches whether or not power is supplied to the flapper solenoid 89. When no current flows through the coil of the flapper solenoid 89 immediately after the MFP1 is powered on, the flapper 88 is in the second position 88B. In order to maintain the state in the first position 88A, it is necessary to keep current flowing through the coil of the flapper solenoid 89.

[0098] Next, in S4, the CPU 101 executes the image formation process described below. The image formation process forms an image on the sheet S. However, if the cut front cover 203 is opened during printing, as described below, printing is stopped at that point and the sheet S that was to be printed is ejected. Details will be described later.

[0099] Subsequently, in S5, the CPU 101 performs the sheet cutting process described later, following the image formation process (S4). In the sheet cutting process, the sheet S after image formation is cut by the cutter 10 in the first discharge path 201A. However, if the cut front cover 203 is opened during the cutting process, as described later, the cutting process is stopped at that point and an error is displayed. Details will be described later.

[0100] After the sheet S has been cut, the cut discharge motor 122 is driven in the forward direction, and the first discharge roller 85 and the second discharge roller 86 rotate in conjunction with the forward rotation of the cut discharge motor, and the sheet S cut by the cutter 10 is conveyed toward the discharge tray 22 by the first discharge roller 85 and the second discharge roller 86.

[0101] Subsequently, in S6, the CPU 101 determines whether or not there is printing for the next sheet in the currently running job. In this determination, if there is printing for the next sheet (S6: YES), the cutter 10 is returned to the initial position FP (S7). More specifically, the CPU 101 reverses the cutter motor 106 to move the slide holder 16 from the completion position KP towards the initial position FP, and stops the cutter motor 106 when the cutter 10 reaches the initial position FP. Then, the CPU 101 returns the process to S4 and continues to execute the processes from S4 onwards. Here, when the single-sided sheet printing and cutting process is performed consecutively on the next sheet S, the switching control of the flapper 88 is not performed. This is because, in the process of S3, the flapper 88 has already been switched to the first position 88A, and that state is maintained. Therefore, when printing and cutting continuously, it is not necessary to switch the flapper 88 each time.

[0102] On the other hand, if there is no printing required for the next sheet (S6:NO), the process proceeds to S8.

[0103] In S8, the CPU 101 sends a control signal to the flapper switching circuit 119 to switch the flapper 88 from the first position 88A to the second position 88B. Specifically, the flapper 88 is switched from the first position 88A to the second position 88B by controlling the power supply to the coil of the flapper solenoid 89 to be turned off.

[0104] Next, in S9, the CPU 101 reverses the cutter motor 106 to move the slide holder 16 from the completed position KP towards the initial position FP. Then, in the same manner as in S7, the CPU 101 waits until the slide holder 16 reaches the initial position FP, and stops the cutter motor 106 when the slide holder 16 reaches the initial position FP (S10).

[0105] Next, in S11, the CPU 101 turns off the heater 63 and stops the main motor 108 (S12), and then terminates the single-sided sheet printing and cutting process.

[0106] Note that the order of operations S8 to S12 may be changed. Also, if the final sheet has been printed and instructions for the next job have been received, the heater 63 may not be turned off in S11, and the main motor 108 may be kept rotating forward while the next job is executed.

[0107] Next, the image formation process of S4 will be explained based on Figure 7. Figure 7 is a flowchart of the image formation process.

[0108] First, in S21, the CPU 101 transmits a pickup command. The pickup roller 33, driven by the main motor 108, picks up the sheets S in the supply tray 31 that have been pushed upward by the sheet pressing 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.

[0109] Next, in S22, the CPU 101 starts forming an image on the sheet S after the post-register sensor SE2 detects the front edge of the sheet S (S22: Yes) (S23). The image data to be printed is received from an external device such as a PC via the communication I / F 130, along with the print instruction. The surface of the photoreceptor drum 51 is exposed by the laser unit 7 to form an electrostatic latent image based on the image data, and the developing roller 55 supplies toner to the electrostatic latent image formed on the surface of the photoreceptor drum 51, thereby forming a toner image on the surface of the photoreceptor drum 51. Then, the transfer roller 53 transports the sheet S between itself and the photoreceptor drum 51, transferring the toner image formed on the surface of the photoreceptor drum 51 to the sheet S as it passes through the transfer nip TN. In this way, an image is formed on the sheet S. After that, the developer image formed on the sheet S by the process unit 4 is fixed to the sheet S using the fuser 6.

[0110] Subsequently, when the paper discharge sensor SE3 detects the front end of the sheet S that has passed between the heating roller 61 and the pressure roller 62 of the fuser unit 6 (S24: Yes), it sends control signals to the on / off circuits 128 and 129, thereby cutting off the operating voltage to the stepping motor driver 123 and stopping the normal discharge motor 124. However, the operating voltage to the stepping motor driver 121 is not cut off, and the cut discharge motor 122 is driven in the forward direction (S25). Since the main motor 108 has already been driven in S2, the pressure roller 62 and the transport roller 36 are rotating, and the rotation of the pressure roller 62, the transport roller 36, the first discharge roller 85 and the second discharge roller 86 transports the sheet S, which has been guided from the transport path 201 to the first discharge path 201A, in the transport direction.

[0111] Then, after a predetermined time has elapsed (S26: Yes), the image formation process is terminated (S27).

[0112] On the other hand, if the post-registration sensor SE2 detects that the cut front cover 203 has been opened by the cut front cover switch 203a before detecting the front end of the seat S (S22: No, S28: Yes), the system proceeds to S29 without starting image formation.

[0113] In S29, the CPU 101 sends a control signal to the flapper switching circuit 119 to switch the flapper 88 from the first position 88A to the second position 88B. Specifically, the flapper 88 is switched from the first position 88A to the second position 88B by controlling the power supply to the coil of the flapper solenoid 89 to be turned off. As a result, the flapper 88 then guides the sheet S conveyed by the conveyor roller 36 to the second discharge path 201B, which is not equipped with a cutter 10.

[0114] Subsequently, in S30, the CPU 101 sends control signals to the on / off circuits 128 and 129, thereby cutting off the operating voltage to the stepping motor driver 121 and stopping the cut-off discharge motor 122. However, the operating voltage to the stepping motor driver 123 is not cut off, and the normal discharge motor 124 is driven in the forward direction. Since the main motor 108 has already been driven in S2, the pressure roller 62 and the transport roller 36 are rotating, and the rotation of the pressure roller 62, the transport roller 36 and the third discharge roller 87 transports the sheet S, which has been guided from the transport path 201 to the second discharge path 201B, in the transport direction.

[0115] As a result, the sheet S is discharged from the second discharge path 201B to the outside of the device body 20 without image formation occurring. From S30 onward, the sheet cutting process (S5) is not performed, and the motor is stopped after the sheet is discharged to terminate the process.

[0116] On the other hand, if the cut front cover 203 is opened by the cut front cover switch 203a after image formation has started but before the paper ejection sensor SE3 detects the front end of the sheet S that has passed between the heating roller 61 and the pressure roller 62 of the fuser 6 (S24: No, S31: Yes), the started image formation continues while the system proceeds to S32. However, image formation may be forcibly terminated at the moment the system detects that the cut front cover 203 has been opened.

[0117] In S32, the CPU 101 sends a control signal to the flapper switching circuit 119 to switch the flapper 88 from the first position 88A to the second position 88B. Specifically, the flapper 88 is switched from the first position 88A to the second position 88B by controlling the power supply to the coil of the flapper solenoid 89 to be turned off. As a result, the flapper 88 then guides the sheet S conveyed by the conveyor roller 36 to the second discharge path 201B, which is not equipped with a cutter 10.

[0118] Subsequently, the paper discharge sensor SE3 determines whether it has detected the leading edge of the sheet S that has passed between the heating roller 61 and the pressure roller 62 of the fuser unit 6 (S33). If it has detected it (S33: Yes), the process proceeds to S34. In S34, the CPU 101 sends control signals to the on / off circuits 128 and 129 to cut off the operating voltage to the stepping motor driver 121, stopping the cut-off discharge motor 122. However, it does not cut off the operating voltage to the stepping motor driver 123, allowing the normal discharge motor 124 to rotate in the forward direction. Since the main motor 108 has already been driven in S2, the pressure roller 62 and the transport roller 36 are rotating. The rotation of the pressure roller 62, the transport roller 36, and the third discharge roller 87 transports the sheet S, which has been guided from the transport path 201 to the second discharge path 201B, in the transport direction.

[0119] In other words, if the cut front cover 203 is opened before the paper discharge sensor SE3 detects the front edge of the sheet S, the image-formed sheet S is guided to the second discharge path 201B, which does not pass through the cutter position SP, instead of the first discharge path 201A, which passes through the cutter position SP. After the image formation is complete, the sheet S is discharged from the second discharge path 201B to the outside of the device body 20. In this case, the sheet cutting process (S5) is not performed.

[0120] On the other hand, if the cut front cover 203 is opened after the paper output sensor SE3 has detected the front edge of the sheet S, the switching of the transport path from the first discharge path 201A to the second discharge path 201B cannot be completed in time, so the flapper 88 does not switch from the first position and the normal image forming process (S21~S27) is performed. The image-formed sheet S is then guided to the first discharge path 201A via the cutter position SP, but after that, the transport of the sheet S is stopped in the sheet cutting process (S8) described later, and an error is displayed (S50, S51).

[0121] Next, the sheet cutting process in S5 will be explained based on Figure 8. Figure 8 is a flowchart of the sheet cutting process.

[0122] First, in S41, the CPU 101 determines whether the sheet S being transported along the first discharge path 201A by the first discharge roller 85 and the second discharge roller 86 has reached the sheet stop position. The sheet stop position is, for example, the position where the center of the sheet S reaches the cutter position SP of the cutter 10 when the sheet S is cut in the center in the transport direction. The CPU 101 determines whether the sheet S has reached the sheet stop position by counting the number of steps of the cut discharge motor 122, triggered by the detection of the front end of the sheet S by the sheet sensor SE4. Specifically, the CPU 101 determines that the sheet S has reached the sheet stop position when the amount of rotation of the cut discharge motor 122 from the time the front end of the sheet S is detected by the sheet sensor SE4 reaches a first predetermined amount. Here, the "first predetermined amount" is a value determined based on the length information of the sheet S in the transport direction. This length information will hereafter also simply be called "sheet size information". Specifically, sheet size information is information such as "A4 size" or "letter size". Sheet size information can be obtained by reading it from the information set as the paper size in the print job.

[0123] Then, when it is determined that the sheet S being transported along the first discharge path 201A has reached the sheet stopping position (S41: Yes), the cut discharge motor 122 is temporarily stopped (S42).

[0124] Then, in S43, the CPU 101 drives the cutter motor 106 in the forward direction, moving the slide holder 16 from the initial position FP to the completion position KP. As a result, the cutter motor 106 slides the slide holder 16 from one side to the other in the axial direction, so the slide holder 16 starts moving from the initial position FP, shown by the solid line in Figure 2, to the completion position KP, shown by the dashed line. With the sheet S sandwiched between the movable blade 15 and the fixed blade 13 supported by the slide holder 16, the slide holder 16 moves, and the sheet S is cut in the axial direction.

[0125] Subsequently, the CPU 101 waits until the slide holder 16 reaches the completion position KP (S44: Yes), and then stops the cutter motor 106 (S45). This completes the cutting of the sheet S by the cutter 10.

[0126] Next, in S46, the CPU 101 restarts the cut discharge motor 122, which had been stopped. As the cut discharge motor rotates forward, the first discharge roller 85 and the second discharge roller 86 rotate, and the sheet S cut by the cutter 10 is conveyed toward the discharge tray 22 by the first discharge roller 85 and the second discharge roller 86.

[0127] Subsequently, in S47, the CPU 101 determines whether or not the sheet S has been discharged from the device body 20. If it is determined that the sheet S has been discharged from the device body 20 (S47: YES), the CPU 101 stops driving the cut discharge motor 122 and the normal discharge motor 124 (S48). The process then proceeds to S6.

[0128] On the other hand, if the cut front cover 203 is detected to have been opened by the cut front cover switch 203a before the sheet S being transported along the first discharge path 201A reaches the sheet stopping position (S41: No, S49: Yes), then all motors involved in sheet transport, including the main motor 108, the cut discharge motor 122, and the normal discharge motor 124, are stopped at that point (S50). That is, the operating voltage to the motor driver 116, the stepping motor driver 121, and the stepping motor driver 123 is cut off. As a result, the sheet S is not cut by the cutter 10, and its transport is stopped, causing it to remain within the transport path. Consequently, the sheet S cannot be automatically discharged from the device, but at least jams within the transport path can be prevented.

[0129] Subsequently, in S51, the CPU 101 displays an error on the MFP1's display, informing the user that the printing process has terminated abnormally, that the sheet S is still in the transport path and needs to be manually removed from the device.

[0130] [Effects of the MFP1 in the second embodiment] As described in detail above, in the MFP1 according to the second embodiment, when the cut front cover 203 is opened during cut printing which involves cutting the sheet S by the cutter 10, the CPU 101 detects that the cut front cover 203 has been opened by the cut front cover switch 203a and cuts off the third operating voltage supplied from the low-voltage power supply board 110 to the stepping motor driver 121 (S30, S34). As a result, power to the cut discharge motor 122 is stopped, and the rotation of the first discharge roller 85 and the second discharge roller 86 is also stopped. Furthermore, the CPU 101 also cuts off the second operating voltage supplied from the low-voltage power supply board 110 to the flapper switching circuit 119, causing the flapper 88 to switch from the first position 88A to the second position 88B (S29, S32), and the transport path guided by the flapper 88 also switches from the first discharge path 201A to the second discharge path 201B. On the other hand, even when the cut front cover 203 is opened, the supply of operating voltage to the motor driver 116 and the stepping motor driver 123 is not interrupted (S2, S30, S34). As a result, the pressure roller 62, the transport roller 36, and the third discharge roller 87 continue to rotate, and the sheet S that was to be printed is discharged to the outside of the device body 20 via the second discharge path 201B instead of the first discharge path 201A to which it is normally guided.

[0131] In this case, if a cover on the main body 20 of the device, such as the cut front cover 203, is opened for any reason while cut printing is being performed, the MFP1 stops printing and ejects the sheet S that was to be printed. However, in conventional image forming apparatus capable of cut printing, the sheet S is ejected from an ejection path where the cutter 10 is located, which made it highly likely that the sheet S would jam. In contrast, in the MFP1 of the second embodiment, the sheet S can be ejected to the outside of the main body 20 of the device from the second ejection path 201B instead of the first ejection path 201A where the cutter 10 is located, as described above. As a result, it is possible to prevent the sheet S from jamming when printing is stopped.

[0132] Furthermore, when the CPU 101 detects the opening of the cut front cover 203 during cut printing which involves cutting the sheet S with the cutter 10, and the CPU 101 detects the opening of the cut front cover 203 before the detection of the leading edge of the sheet S by the paper discharge sensor SE3 (S24: NO, S31: YES), it switches the transport path guided by the flapper 88 from the first discharge path 201A to the second discharge path 201B (S32). On the other hand, if the CPU 101 detects the opening of the cut front cover 203 after the detection of the leading edge of the sheet S by the paper discharge sensor SE3 (S41: NO, S49: Yes), it stops the main motor 108 without switching the transport path guided by the flapper 88 from the first discharge path 201A to the second discharge path 201B (S50). In other words, if there is a high probability that the leading edge of the sheet S is ahead of the flapper 88 when the cut front cover 203 is opened, it is difficult to discharge the sheet S to the outside of the device via the second discharge path 201B, so the main motor 108 is stopped to stop the discharge of the sheet S. As a result, the sheet S cannot be automatically discharged from the device, but at least jams in the transport path can be prevented.

[0133] It should be noted that the present invention is not limited to the embodiments described above, and various improvements and modifications are possible without departing from the spirit of the invention. For example, in the above embodiment, the cut front cover 203, one of the covers provided by the main body of the device 20, is targeted, and if the cut front cover 203 is opened during cut printing, the sheet S that was to be printed is discharged to the outside of the main body of the device 20 from the second discharge path 201B instead of the first discharge path 201A to which it is normally guided. However, the same processing may be performed not only for the cut front cover 203, but also when other covers that cause the printing to be stopped are opened.

[0134] Furthermore, although Figure 6 illustrates a printing process where single-sided printing is performed and the printed sheet S is cut by a cutter 10, the process is basically the same for double-sided printing where the printed sheet S is cut by a cutter 10, with the only difference being that a sheet reversal process is inserted after single-sided printing.

[0135] Furthermore, in the above embodiment, the main motor 108 that supplies driving force to the pressure roller 62 and the transport roller 36, the cut discharge motor 122 that supplies driving force to the first discharge roller 85 and the second discharge roller 86, and the normal discharge motor 124 that supplies driving force to the third discharge roller 87 are all three types of motors used to provide driving force to each roller. However, it is not necessarily required to use three types of motors to supply driving force to each roller, and it is also possible to supply driving force with a common motor.

[0136] Furthermore, in the above embodiment, a multifunction device equipped with a printer function, as well as a fax function, a copier function, and a scanner function, is used as an example of an image forming apparatus. However, a printer equipped with only a printer function may also be used. [Explanation of Symbols]

[0137] 1…MFP (Image Forming Processor), 2…Image Forming Main Unit (Device Body), 6…Fuser (Fuser Unit), 10…Cutter, 85…First Ejection Roller, 86…Second Ejection Roller, 87…Third Ejection Roller, 88…Flapper, 89…Flapper Solenoid, 105…ASIC, 108…Main Motor, 118…Cutter Motor Driver, 119…Flapper Switching Circuit, 121…Stepping Motor Driver, 122…Cut Ejection Motor, 124…Normal Ejection Motor, 126~129…On / Off Circuit, 201A…First Ejection Path, 201B…Second Ejection Path, S…Sheet, SE1…Pre-Cash Register Sensor, SE2…Post-Cash Register Sensor, SE3…Paper Ejection Sensor

Claims

1. An image forming unit that forms a developer image on a sheet, A fixing unit comprising a heating roller for heating the sheet and a pressure roller for nipping the sheet between itself and the heating roller, for fixing the developer image formed on the sheet, A cutter positioned downstream of the fixing unit in the sheet transport direction from the image forming unit and the fixing unit in the transport path through which the sheet is transported, cuts the sheet on which the developer image has been fixed, A device body having the aforementioned transport path, wherein the device body includes a first discharge path for discharging the sheet to the outside of the device body via the cutter position as part of the transport path, and a second discharge path for discharging the sheet to the outside of the device body without passing through the cutter position, A flapper that guides the sheet to either the first discharge path or the second discharge path, The first discharge roller and the second discharge roller are arranged in the first discharge path, A third discharge roller arranged in the second discharge path, A conveying roller arranged in the conveying path upstream of the flapper in the sheet conveying direction, The cutter and the cover covering the first discharge path are provided, When the cover is opened during printing, which involves cutting the sheet with the cutter, The first discharge roller and the second discharge roller stop rotating, The flapper switches from the first discharge path to the second discharge path. The pressure roller, the transport roller, and the third discharge roller rotate to discharge the sheet from the second discharge path to the outside of the device body. An image forming apparatus characterized by the following:

2. A main motor that supplies driving force to the pressure roller and the conveying roller, A cut-off discharge motor that supplies driving force to the first discharge roller and the second discharge roller, The image forming apparatus according to claim 1, further comprising a conventional discharge motor that supplies driving force to the third discharge roller.

3. A cutter motor for driving the aforementioned cutter, A cutter motor driver that controls the rotation of the cutter motor and operates according to a first operating voltage, A flapper solenoid that switches the flapper to either a first state in which the sheet is guided to the first discharge path, or a second state in which the sheet is guided to the second discharge path, A switching circuit that controls the current supply to the flapper solenoid and operates according to a second operating voltage, A cut-off discharge motor driver that controls the rotation of the cut-off discharge motor and operates according to a third operating voltage, The image forming apparatus according to claim 2, further comprising the cutter motor driver, the switching circuit, and an on / off circuit that cuts off the first operating voltage, the second operating voltage, and the third operating voltage supplied to the cut discharge motor driver when the cover is opened.

4. The flapper solenoid is a solenoid that is in the first state when power is maintained by the switching circuit, and in the second state when power is not maintained by the switching circuit. The image forming apparatus according to claim 3, characterized in that the transport path guided by the flapper switches from the first discharge path to the second discharge path at the timing when the drive voltage supplied to the switching circuit by the on / off circuit is interrupted.

5. Control unit and The system includes a cover switch that detects when the cover is opened, The control unit, The image forming apparatus according to claim 3, characterized in that when it is detected that the cover has been opened, the on / off circuit controls the supply of the first operating voltage, the second operating voltage, and the third operating voltage to the cutter motor driver, the switching circuit, and the cut discharge motor driver to be cut off.

6. Control unit and A cover switch that detects when the cover is opened, The transport path includes a paper discharge sensor located downstream of the fixing unit in the sheet transport direction and upstream of the flapper in the sheet transport direction, which detects the passage of the sheet. The control unit, When the opening of the cover is detected during printing, which involves cutting the sheet with the cutter, If the opening of the cover is detected before the leading edge of the sheet is detected by the paper discharge sensor, the transport path guided by the flapper is switched from the first discharge path to the second discharge path, The image forming apparatus according to claim 2, characterized in that, after the leading edge of the sheet is detected by the paper discharge sensor, if the opening of the cover is detected, the main motor is stopped without switching the transport path guided by the flapper from the first discharge path to the second discharge path.

Images