JP5771899B2 - Stapler driving device, stapler driving method, post-processing device, and image forming apparatus - Google Patents

Description

  The present invention relates to a stapler driving device, a stapler driving method, a post-processing device, and an image forming apparatus.

  A post-processing apparatus may be connected to a subsequent stage of an image forming apparatus such as a printer that prints images or characters on paper. This post-processing device is equipped with a puncher that punches holes in the paper, a stapler that staples a stack of multiple sheets of paper with staples, and a paper folding machine that folds the paper, depending on the user's usage. Is done.

  Focusing on the stapler, a DC motor is mounted on the stapler, and a stapling operation is performed in which a staple is inserted into the sheet bundle and bent by a driving force generated by the rotation of the DC motor.

JP 2008-174382 A

  An object of the present invention is to suppress operation noise while securing productivity of stapling operation.

The stapler driving device according to claim 1 is:
A power supply unit that includes a motor and supplies power to a motor of a stapler that performs a stapling operation in which a staple is inserted into a bundle of a plurality of stacked recording media and bent by a driving force generated by the rotation of the motor;
At a time point before the specific operation point included in the stapling operation, the power supply unit supplies the first power to the motor, and at a time point after the operation point, A power control unit that causes the power supply unit to supply a second power lower than the first power toward the motor;
A stapler driving device including a braking unit that applies braking to the motor after the time of the operation portion.

The stapler driving device according to claim 2 is:
The motor is a DC motor;
The braking unit applies the braking by short-circuiting the motor.

The stapler driving device according to claim 3 is:
The motor is a DC motor;
The power supply unit supplies the pulse-width-modulated power to the output ratio based on an instruction from the power control unit toward the motor,
The power control unit instructs the power supply unit to output a first output ratio at a time point before the operation point, and at a time point after the operation point, the power supply unit A second output ratio smaller than the first output ratio is indicated.

The stapler driving method of claim 4 comprises:
A specific operation point included in the stapling operation of the stapler that includes a motor and performs a stapling operation in which a staple is inserted into a bundle of a plurality of stacked recording media and bent by a driving force generated by the rotation of the motor. At an earlier time point, the first electric power is supplied to the motor, and at a time point after the operation point, a second electric power lower than the first electric power is supplied to the motor. A first process to supply;
And a second step of braking the motor after the time of the operating portion.

The post-processing device according to claim 5 comprises:
A bundle forming unit that receives a recording medium from an image forming apparatus that forms an image on the recording medium, and forms a bundle by stacking a plurality of the recording media;
A stapler that includes a motor and performs a stapling operation that inserts and staples staples into the bundle with a driving force generated by the rotation of the motor;
A power supply unit for supplying power to the motor of the stapler;
At a time point before the specific operation point included in the stapling operation, the power supply unit supplies the first power to the motor, and at a time point after the operation point, A power control unit that causes the power supply unit to supply a second power lower than the first power toward the motor;
A post-processing device including a braking unit that applies braking to the motor after the time of the operation portion.

An image forming apparatus according to claim 6 is provided.
An image forming unit that forms an image on a recording medium;
A bundle forming unit that receives a recording medium from the image forming unit and forms a bundle by stacking a plurality of the recording media;
A stapler that includes a motor and performs a stapling operation that inserts and staples staples into the bundle with a driving force generated by the rotation of the motor;
A power supply unit for supplying power to the motor of the stapler;
At a time point before the specific operation point included in the stapling operation, the power supply unit supplies the first power to the motor, and at a time point after the operation point, A power control unit that causes the power supply unit to supply a second power lower than the first power toward the motor;
An image forming apparatus including a braking unit that applies braking to the motor after the time of the operation portion.

  According to the stapler driving device of the first aspect, the operation noise is suppressed while securing the productivity of the stapling operation.

  According to the stapler driving device of the second aspect, braking to the motor is accurately and easily applied.

  According to the stapler driving device of the third aspect, the power supplied to the DC motor can be controlled accurately and easily.

  According to the stapler driving method of the fourth aspect, as in the first aspect, the operation noise is suppressed while ensuring the productivity of the staple operation.

  According to the post-processing apparatus of the fifth aspect, the operation sound is suppressed while ensuring the productivity of the post-processing including the stapling operation.

  According to the image forming apparatus of the sixth aspect, the operation sound is suppressed while ensuring the productivity of the processing including the image formation and the stapling operation.

1 is an overall configuration diagram of a print system. It is operation | movement explanatory drawing of the mechanism around the stapler of the post-processing apparatus shown in FIG. It is a perspective view which shows the guide member in which two rails were formed. 1 is an overall configuration diagram of a printing system in which a copying machine and a post-processing apparatus are connected. It is the schematic diagram which showed the driving force transmission mechanism and sensor of a stapler. It is explanatory drawing of the operation mechanism of the pressing member with which the stapler was equipped. It is the figure which showed the positional relationship of a light-shielding plate and HP sensor. It is the figure which showed the shape of the staple. It is a top view which shows the state by which the needle plate was abutted by the needle stopper. FIG. 6 is a side view showing a state in which the staple needle is abutted against the needle stopper. It is a figure which shows operation | movement of the member in the 1st step of the staple operation by a stapler. It is a figure which shows operation | movement of the member in the 2nd step of the staple operation by a stapler. It is a figure which shows operation | movement of the member in the 3rd step of the staple operation by a stapler. It is a figure which shows operation | movement of the member in the 4th step of the staple operation by a stapler. It is a figure which shows operation | movement of the member in the 5th step of the staple operation by a stapler. It is a figure which shows operation | movement of the member in the 5th step of the staple operation by a stapler. It is a figure which shows operation | movement of the member in the 6th step of the staple operation by a stapler. It is a figure which shows operation | movement of the member in the 7th step of the staple operation by a stapler. It is a figure which shows operation | movement of the member in the 8th step of the staple operation by a stapler. It is a figure which shows operation | movement of the member in the 9th step of the staple operation by a stapler. It is the figure which showed the operation | movement sound waveform in each process which comprises a series of staple operations. It is a block diagram of the control circuit which bears the operation control of the stapler in the post-processing device. FIG. 23 is a control block diagram of the DC motor shown in FIG. 22. It is a figure which shows the circuit structure of the motor drive part shown in FIG. It is a figure which shows a response | compatibility with four motor control signals input into a motor drive part, and operation | movement of a DC motor. It is a control conceptual diagram. It is a figure which shows the motor control signal which applies a brake with respect to a DC motor after changing the duty from 100%-> 75%-> 50% from the start of rotation, and changing a duty. It is a figure which shows a response | compatibility with four motor control signals input into a motor drive part, and operation | movement of a DC motor in the timing of A shown in FIG. It is a figure which shows a response | compatibility with four motor control signals input into a motor drive part, and the operation | movement of a DC motor in the timing of B shown in FIG. It is a figure which shows a response | compatibility with four motor control signals input into a motor drive part, and the operation | movement of a DC motor in the timing of C shown in FIG.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is an overall configuration diagram of a printing system.

  The printing system 1A shown in FIG. 1 includes a printer 10, a paper transport device 20, and a post-processing device 30.

  The printer 10 is an electrophotographic printer that receives an image signal from a host device (not shown) and forms an image based on the image signal on a sheet. An outline will be described.

  The printer 10 is provided with four paper storage units 111. Each paper storage unit 111 stores paper PP having a different paper type, size, and orientation (portrait and landscape). . Information on the paper type, size, and orientation of the paper stored in each paper storage unit 111 is set in advance and stored in the main body control unit 120. When a print command is received from the host device, the paper PP is taken out by the take-out roll 112 from the paper storage unit 111 that stores the paper corresponding to the command, and the taken-out paper PP is supplied by the supply roll 113 and the transport roll 114. The leading edge of the paper is conveyed to the adjustment roll 115.

  On the other hand, the exposure device 121 exposes each photoconductor 122 arranged for each color of C, M, Y, and K, and forms an electrostatic latent image on each photoconductor 122. The electrostatic latent image formed on each photoconductor 122 is developed with each color toner by a developing device (not shown) to form a toner image, and each color toner image is stretched by a tension roll 124 by the action of the transfer roll 125. The toner images of the respective colors are transferred so as to overlap each other on the intermediate transfer belt 123 that circulates in the direction of the arrow A in a suspended state.

  The paper PP having the leading end reaching the adjustment roll 115 is sent to the secondary transfer position T in accordance with the toner image on the intermediate transfer belt 123 and the time, and the secondary transfer roll 116 acts on the intermediate transfer belt 123. The toner image is transferred to the paper PP. The paper PP that has received the transfer of the toner image is further conveyed, heated and pressurized by the fixing roll 117, and the toner image on the paper is fixed to the paper PP, and a fixed image is formed on the paper PP. The fixed sheet PP is further conveyed by the conveyance roll 118, and is discharged onto the sheet discharge table 119 of the printer 10 when the sheet conveying apparatus 20 is not present.

  In this printing system 1A, since the paper transport device 20 is installed on the paper discharge table 119, the paper PP discharged from the printer 10 is inherited by the paper transport device 20, and the transport roll in the paper transport device 20 is used. 21 is further transported by the post-processing apparatus 30. The post-processing measure 30 will be described later.

  A command for each job is input to the printer 10 from the host device. Specifically, as an example, when the image signal for 10 sheets and the paper on which the image based on each image signal is formed are 1 to 10 pages, the paper of 1 to 10 pages is regarded as one sheet bundle, An instruction is issued such that ten sheets of paper bundles are created by binding with a staple needle for each paper bundle. For example, in the case of this example, the paper PP is sequentially taken out from the paper storage unit 111 that stores the paper according to the dimensions of the image, and the first page image and the second page are taken out to each paper PP taken out in order. ,..., The 10th page image, the 1st page image, the 2nd page image,..., The 10th page image are sequentially printed for a total of 10 bundles (100 sheets). . The printed paper is sequentially sent to the post-processing device 30 via the paper transport device 20.

  The post-processing device 30 includes a puncher 31 and a stapler 32, and a sheet processing control unit 35 that controls operation of the puncher 31 and communication with the printer 10. The paper taken into the post-processing device 30 is transported by the transport roll 131, and when it is instructed to form punch holes at the edges of the paper, the puncher 31 is activated, and the paper with punch holes is further formed. The paper is conveyed and discharged onto the paper tray 136. The paper tray 136 is movable up and down between a position indicated by a solid line and a position indicated by a broken line in FIG. 1, and descends in accordance with the total thickness of the sheets sequentially stacked on the paper tray 136.

  When the stapler 32 provided in the post-processing device 30 is instructed to bind the sheet bundle, the stapling operation by the stapler 32 is executed as follows.

  FIG. 2 is an operation explanatory view of a mechanism around the stapler of the post-processing device 30 shown in FIG.

  Here, a fixed plate 137 on which a sheet is placed and a movable plate 135 that can move forward and backward in the direction of arrow XX ′ are provided. In FIG. 2, the movable plate 135 has advanced in the direction of the arrow X. Further, here, a paper discharge roll 132 and a counter roll 133 are provided. The paper discharge roll 132 is movable up and down in the direction of arrow YY ′ shown in FIG. When the paper discharge roll 132 is lowered, the paper is sandwiched between the paper discharge roll 132 and the opposing roll 133, and is rotated to discharge the paper onto the paper tray 136 shown in FIG. Here, the paper discharge roll 132 is in a position raised in the arrow Y direction. Further, a paddle 134 and a lateral support plate 139 are provided here. The paddle 134 rotates in the direction of arrow B and plays a role of pushing the paper toward the stapler 32 side. The sheet pushed toward the stapler 32 is abutted against the abutting wall 138. Further, the lateral support plate 139 receives the contact of the paper struck in the horizontal direction by a striking plate (not shown) disposed so as to sandwich the paper from the left and right sides of the lateral support plate 139, and the paper It plays a role to align the horizontal position of.

  The paper that has passed through the arrangement area of the puncher 31 shown in FIG. 1 proceeds along the paper conveyance path P1 shown in FIG. At this time, the paper discharge roll 132 is in a position raised in the arrow Y direction, and the movable plate 135 is in the state of being advanced in the arrow X direction. The paper that has traveled along the paper transport path P1 is placed across the fixed plate 137 and the movable plate 135, and is abutted against the abutting wall 138 by the paddle 134 and at the same time the horizontal receiving plate 139 by a striking plate (not shown). In this way, positioning is performed both vertically and horizontally. The above operation is repeated while the number of sheets forming one sheet bundle (10 sheets in the above example) is sent, so that a plurality of sheets forming one sheet bundle are vertically and horizontally positioned. Are stacked together. The plurality of stacked sheets are bound by a stapler 32 into one sheet bundle. A staple 33 having two protrusions 331 is attached to the stapler 32, and the two protrusions 331 of the legs 33 are provided on the guide member 34 and extend in a direction perpendicular to the paper surface of FIG. Each of the rails 342 enters a groove 341 formed in the rail 342. The stapler 32 is guided by the two rails 342 and is movable in a direction perpendicular to the paper surface of FIG. Therefore, when the bundle of sheets is bound by the stapler 32, the sheet bundle is guided by the rail 342 and moved, for example, at a designated portion of the bundle of sheets such as two places near the center or one corner.

  The stapling operation itself by the stapler 32 will be described later.

  In synchronism with the binding of the sheet bundle by the stapler 32, the sheet discharge roll 132 descends in the direction of the arrow Y ′ and the sheet bundle is sandwiched between the opposing roll 133, and the movable plate 135 moves in the direction of the arrow X ′. Retreat to. When the binding operation to the sheet bundle is completed, the sheet bundle is discharged onto the sheet receiving plate 136 by the rotation of the sheet discharge roll 132.

  While the above binding operation is being performed, adjustment between the printer 10 and the post-processing device 30 prevents the next sheet from being further conveyed from the printer 10 (see FIG. 1). The printing operation is interrupted. If the interruption time is long, the productivity of printing and sheet bundles will be reduced. For this reason, it is desired to increase the speed of the stapling operation, but if the speed of the stapling operation is increased, a loud operation sound is generated.

  Therefore, in the present embodiment, control is performed to suppress both the decrease in productivity and the generation of operation sound with a good balance. This control method will be described later.

  FIG. 3 is a perspective view showing a guide member on which two rails are formed.

  Grooves 341 are respectively formed in the two rails 342 of the guide member 34, and the protrusion 331 of the foot 33 shown in FIG. 2 enters the groove 341 to guide the movement of the stapler 32. These rails 342 as a whole extend in a direction perpendicular to the paper surface of FIG. 2 but have curved shapes near both ends. This is because when corners of the sheet bundle are bound, corners of the sheet are bound obliquely with respect to the sheet.

  Here, the post-processing device 30 described with reference to FIGS. 1 to 3 can be connected not only to the printer having the form shown in FIG. 1 but also to another form of printer. Here, a copier including a configuration of another form of printer will be described.

  FIG. 4 is an overall configuration diagram of a printing system in which a copying machine and a post-processing apparatus are connected.

  The print system 1B is composed of a copying machine 40 and a post-processing device 30. The post-processing device 30 is the same as the post-processing device 30 shown in FIG. 1, and here, the same reference numerals as those shown in FIG.

  The copying machine 40 shown in FIG. 4 includes an image reading unit 41, an operation panel 42, and an image forming unit 43.

  The image reading unit 41 includes a transparent document table 411 that reads a document image, and a main body unit 412 that accommodates an optical scanning system including a lamp, a mirror, and the like (not shown). A document is placed on document platen 411 so that the document image is in contact with document platen 411. The document image is read by scanning with an optical scanning system, and an image signal representing the document image is generated. The generated image signal is stored in a memory in the main body control unit 450.

  The operation panel 42 accepts user operations. Here, various operations such as various settings, image reading and image formation start instructions are performed. Various instructions on the operation panel 42 are also stored in the main body control unit 450.

  The image forming unit 43 is an electrophotographic printer that forms an image on a sheet based on the image signal stored in the main body control unit 450.

  The image forming unit 43 is provided with three paper storage units 431. Each paper storage unit 431 stores paper PP having a different paper type, size, and orientation (vertical placement, horizontal placement). ing. Information on the paper type, dimensions, and orientation of the paper stored in the paper storage unit 431 is set in advance by operating the operation panel 42 and stored in the main body control unit 450. When a print command is received from the operation panel 42, the paper PP is taken out by the take-out roll 432 from the paper storage unit 431 in which the paper corresponding to the command is stored, and the taken-out paper PP is supplied to the supply roll 433 and the transport roll 434. Is conveyed along the sheet conveyance path R1, and the leading edge of the sheet reaches the adjustment roll 435.

  On the other hand, the exposure device 435 exposes each photoconductor 436 arranged for each color of C, M, Y, and K, and forms an electrostatic latent image on each photoconductor 436. The electrostatic latent image formed on each photoconductor 436 is developed with each color toner by a developing device (not shown) to form a toner image, and each color toner image is stretched by a tension roll 438 by the action of the transfer roll 437. The toner images of the respective colors are transferred so as to overlap each other on the intermediate transfer belt 439 that circulates in the direction of the arrow A in a suspended state.

  The paper PP having the leading end reaching the adjustment roll 435 is sent to the secondary transfer position T in accordance with the toner image on the intermediate transfer belt 439, and the secondary transfer roll 440 acts on the intermediate transfer belt 439. The toner image is transferred to the paper PP. The paper PP to which the toner image has been transferred is further transported by the transport belt 441, and the toner image on the paper is fixed to the paper PP by being heated and pressed by the fixing device 442 by the roll 442a and the belt 442b. A fixed image is formed on the PP. In the case of single-sided printing, the fixed sheet PP proceeds along the sheet conveyance path R2, the sheet correction unit 435 corrects the curve of the sheet, is further conveyed, and is discharged from the copying machine 40. The paper discharged from the copying machine 40 is passed on to the post-processing device 30 connected to the subsequent stage.

  When printing on both sides of the paper is designated, the paper after the image on the first side fixed by the fixing device 442 is conveyed along the paper conveyance path R3, and further reaches the paper conveyance path R4. Thereafter, the transport direction is reversed, and this time, the paper travels along the paper transport path R5 and further proceeds along the paper transport path R1. At this time, the paper is taken out of the paper storage unit 431 and is reversed from the front and back when the paper travels on the paper transport path R1. An image is formed on the second surface of the paper that has advanced to the paper conveyance paths R5 and R1 in the same manner as described above, and is discharged from the copier 40 through the paper conveyance path R2, and is then sent to the post-processing device 30. inherited.

  In this copying machine 40, designation is performed in units of one job by operating the operation panel 42. Specifically, as an example, an instruction is input to create 10 bundles of copy images in which 10 image images sequentially read by the image reading unit 41 are 1 to 10 pages. For example, in the case of this example, the paper PP is sequentially taken out from the paper storage unit 431 in which the paper according to the dimensions of the image is stored, and the first page image and the second page are taken out to each paper 3 taken out in order. , ..., 10th page image, 1st page image, 2nd page image, ..., 10th page image in total in the order of 10 bundles (100 sheets). It is done sequentially. However, one-sided printing is described here as an example. The printed sheets are sequentially sent to the post-processing device 30.

  The main body control unit 450 is responsible for storing image signals, storing commands by operating the operation panel 42, controlling the entire copying machine 40, and communicating with the post-processing device 30. The main body control unit 450 is also responsible for adjustments in operation with the post-processing device 30.

  The copier 40 can also receive an image signal in place of image reading by the image reading unit 41 and a command in place of operation of the operation panel 42 from the host device. In this case, an image is formed on the sheet in accordance with a command from the host device. The main body controller 450 is also responsible for communication with the host device.

  Here, the printer 10 shown in FIG. 1 and the copier 40 shown in FIG. 4 are shown as devices to which the post-processing device 30 is connected. However, the post-processing device 30 is not limited to the printer 10 or the copier 40, and The present invention is not limited to the electrophotographic method, and may be configured to be connectable to a printer of another print method such as an ink jet printer.

  Next, the operation of the stapler itself will be described.

  FIG. 5 is a schematic diagram illustrating a driving force transmission mechanism and a sensor of the stapler.

  The stapler 32 has a pressing member 328. The stapler 32 is provided with a DC motor 321. When the DC motor 321 rotates, the presser member 328 rotates in the direction of arrow DD ′.

  The driving force transmission mechanism from the DC motor 321 to the presser member 328 is as follows. When the DC motor 321 rotates, the driving force is transmitted in the order of the gear 322, the relay gear 323, and the driving gear 324, and the driving shaft 325 rotates. After the description of FIGS. 6 and 7, the description will return to FIG. 5 again.

  FIG. 6 is an explanatory diagram of an operation mechanism of a pressing member provided in the stapler.

  The presser member 328 moves up and down between an upper position shown in FIG. 6A and a lower position shown in FIG. 6B by rotating around the rotation center 328a. Here, a drive cam 326 is attached to the drive shaft 325, and the presser member 328 moves up and down via a relay cam 327 that rotates about a rotation center 327a. When the drive shaft 325 rotates once, the presser member reciprocates once, and one stapling operation ends.

  Further, the light shielding plate 51 is attached to the drive shaft 325 at a position different from the drive cam 326 in the axial direction (direction perpendicular to the paper surface of FIG. 6). The light shielding plate 51 is fixed to the drive shaft 325 and rotates by the same rotation angle at the same speed in synchronization with the rotation of the drive cam 326. An HP (home position) sensor 52 is provided in the vicinity of the light shielding plate 51.

  FIG. 7 is a diagram showing the positional relationship between the light shielding plate and the HP sensor.

  The HP sensor 52 is a photoelectric sensor that projects and receives light, and is fixed at a position where the rotating light-shielding plate 51 passes so as to block light projection and reception by the HP sensor 52. The HP sensor 52 outputs an L level signal while the light shielding plate 51 is passing, and outputs an H level signal when the light shielding plate 51 is separated from the HP sensor 52. Since the light shielding plate 51 rotates together with the rotation of the drive shaft 325, the rotation position of the drive shaft 325 is detected by the HP sensor 52. Here, this sensor is used to detect the initial position of the drive shaft 325.

  After the electric power is supplied to the DC motor 321 and the stapler 32 starts the stapling operation, the HP sensor 52 indicates that the drive shaft 325 rotates once and returns to the initial position even after a certain threshold time (for example, 500 msec) elapses. If it is not detected in step (3), it is considered that the stapling operation is defective, the rotation of the DC motor 321 is stopped, and the DC motor 321 is reversed. When the DC motor 321 is reversed, the HP sensor 52 monitors whether the drive shaft 325 returns to the initial position within a certain threshold time (for example, 200 msec). Although the processing contents differ depending on whether or not the HP sensor 52 detects that the drive shaft 325 has returned to the initial position within the threshold time due to the reverse rotation of the DC motor 321, error processing is performed in either case.

  Returning to FIG. 5, various sensors provided in the stapler 32 will be described.

  The stapler 32 is provided with a sensor 53 and a sensor 54 in addition to the HP sensor 52. The sensor 53 is a sensor that detects whether or not a staple needle (described later) is in a state in which a staple operation for binding a sheet bundle can be performed. The sensor 54 is a sensor that detects that the remaining number of staples has decreased.

  FIG. 8 is a diagram showing the shape of the staple needle.

  The staple needle 61 has a linear shape, and as shown in FIG. 8A, the linear staple needles 61 are arranged in a single plate shape and bonded so that they do not easily fall apart. 60 is formed. Here, as for the staple needle 61 in use, only the leading two staple needles 61 a and 61 b are bent in a direction in which both end portions thereof are erected at right angles from the needle plate 60.

  As shown in FIG. 8B, the left and right tip portions of the staple needle 61 are formed in a tapered shape so that the thickness becomes thinner toward the tip, facilitating insertion into the sheet bundle.

  FIG. 9 is a plan view showing a state in which the needle plate is abutted against the needle stopper. The staple stopper 62 has a first stopper 62a against which both ends of the linear staple needle 61 before being bent are abutted, and a leading staple needle 61a among the two staple needles 61a and 61b which are bent. And a second stopper 62b to be applied. A guide member 63 is placed on the needle plate 60. The leading end portion of the guide member 63 has a size that enters the inside of the two staple needles 61a and 61b that are bent.

  FIG. 10 is a side view showing a state in which the staple needle is abutted against the needle stopper.

  The guide member 63 is formed with an inclined surface 63a so as to cover the upper part of the bent staple needle 61a and expose the lower part. The guide member 63 is urged in the direction of arrow E shown in FIG.

  The stapler 32 further includes a needle push-up member 71 having a thickness substantially the same as the width of one staple needle 61 and a needle bending member 72 having a similar thickness. The needle push-up member 71 is disposed immediately below the folded leading staple needle 61a, and the needle bending member 72 is disposed directly below the third staple needle 61 from the leading end, that is, directly below the leading staple needle that has not yet been folded. Has been.

  When the DC motor 321 (see FIG. 5) provided in the stapler 32 rotates and the drive shaft 325 rotates, the needle push-up member 71 pushes up the staple needle 61a at the tip in the arrow G direction and inserts it into a sheet bundle (not shown). At the time of this push-up, the guide member 63 is pushed back by the thickness of one staple needle 61 in the direction of arrow F shown in FIG. 10B against the spring bias. Then, by the needle bending member 72 that has been raised following the staple pushed up by the needle push-up member 71, the leading staple needle that has not been bent is bent with the leading end portion of the guide member 63 as a guide. The needle push-up member 71 and the needle bending member 72 are lowered to the initial position shown in FIG. 10A when the binding operation for one bundle of sheets by the staple needle 61a pushed up by the needle push-up member 71 is completed.

  FIG. 11 to FIG. 20 are diagrams illustrating the operation of the member in each step of the staple operation by the stapler. As described above, the stapler 32 is provided with the DC motor 321 (see FIG. 5), and the drive shaft 325 is rotated by the rotation of the DC motor 321. The rotation of the drive shaft 325 causes each of the operations related to the stapling operation. The members operate in coordination.

  FIG. 11 shows an initial state immediately after the needle plate 60 is loaded on the stapler. A plurality of needle plates 60 are accommodated in a stacked manner. Here, in addition to the needle stopper 62, the needle push-up member 71, the needle bending member 72, which are composed of the first stopper 62a and the second stopper 62b described with reference to FIGS. 73 is shown. The leaf spring 73 plays a role of feeding the lowermost needle plate 60a of the stacked needle plates 60 to the needle stopper 62 side. Also shown here are a needle bending member 74, a presser member 75, and an upper member 76, which are components constituting the presser member 328 shown in FIG. The needle folding member 74 plays a role of bending both ends of the staple needle penetrating the paper bundle and pressing them against the paper bundle, and the presser member 75 plays a role of pressing the needle folding member 74 from above. ing. The upper member 76 plays a role of pressing the sheet bundle from above.

  FIG. 12 shows the next step in the state shown in FIG.

  Here, the lowermost needle plate 60a is pushed and moved in the direction of arrow H by the leaf spring 73, both ends of the tip of the needle plate 60a are abutted against the first stopper 62a, and the upper member 76 is further bent. The member 74 and the presser member 75 are moved downward in the direction of arrow I while remaining on the top. The upper member 76 is formed with a groove 761 into which the needle bending member 74 is inserted. The lower part of the upper member 76 causes the needle bending member 74 to move relative to the upper member 76 so that the groove 761 is formed. It appears.

  Next, as shown in FIG. 13, the needle push-up member 71 rises in the direction of arrow J. At this stage, there is no staple needle 61a (see FIG. 9) abutted against the second stopper 62b. Therefore, the needle push-up member 71 is idle. As the needle push-up member 71 is raised, the needle bending member 72 is also raised, and both ends of the leading staple needle 61 abutted against the first stopper 62a are bent at right angles to the needle plate 60a. At this time, the leaf spring 73 continues to urge the needle plate 60a in the arrow H direction.

  Next, as shown in FIG. 14, the presser member 75 is lowered in the direction of the arrow K, and the needle folding member 74 is pushed into the groove 761. At this stage, there is no staple needle, and the punching is performed. The leaf spring 73 once moves backward.

  Next, as shown in FIG. 15, the upper member 76 rises in the arrow L direction together with the needle bending member 74 and the pressing member 75, and the needle pushing up member 71 and the needle bending member 72 are lowered in the arrow M direction. The staple plate 61a is pushed by the leaf spring 73 and the first staple needle 61a that is bent rubs through the first stopper 62a, and the second staple needle 61b that is not yet bent from the first is the first staple needle 61b. The state is abutted against the stopper 62a.

  Next, when the steps of FIGS. 13 to 15 are repeated again, the leading two staple needles 61a and 61b are bent this time, and the leading staple needle 61a becomes the second stopper 62b as shown in FIG. It will be in a state of being hit.

  The sensor 53 shown in FIG. 5 is a sensor that detects that the leading staple needle 61a of the needle plate 60a bent as described above is in contact with the second stopper 62b. When this state is detected by the sensor 53, the actual stapling operation for binding the sheet bundle can be executed.

  Here, the idle driving operation shown in FIGS. 13 to 15 is repeated up to 13 times. This is because the feeding of the needle plate 60a by the leaf spring 73 may fail. If the sensor 53 does not detect the presence of the leading staple 61a even after repeating the steps of FIGS. 13 to 13 13 times, error processing is executed.

  FIG. 16 shows a state at the start of actual stapling operation.

  Here, the leading two staple needles 61a and 61b of the needle plate 60a are bent, and the leading staple needle 61a is abutted against the second stopper 62b. FIG. 16 also shows a sheet bundle PS scheduled to be stapled.

  Next, as shown in FIG. 17, the leaf spring 73 pushes the needle plate 60a in the arrow N direction to push the needle plate 60a against the needle stopper 62, and the upper member 76 descends in the arrow O direction to raise the sheet bundle PS. It can be pressed from. At this time, a groove 761 is formed.

  Next, as shown in FIG. 18, the needle push-up member 71 rises in the direction of the arrow P, and the sheet bundle PS is penetrated by the leading staple needle 61a. The needle bending member 72 is also raised, and the both side portions of the two adjacent straight leading staple needles 61 are bent upward.

  Next, as shown in FIG. 19, the presser member 75 is lowered in the direction of the arrow Q, the needle bending member 74 is pushed into the groove 761, and both ends of the staple needle 61a are bent inward. The groove 761 is formed slightly obliquely so that both ends of the staple needle 61a bent inward do not collide with each other.

  Next, as shown in FIG. 20, the upper member 76 rises in the direction of arrow R, and accordingly, the needle folding member 74 and the presser member 75 also rise together with the upper member 76. In addition, the needle push-up member 71 and the needle bending member 72 are lowered in the arrow S direction. The needle plate 60a is pushed by the leaf spring 73, and the next leading staple is abutted against the second stopper 62b.

  Thereafter, the sheet bundle PS bound by the staple needle is discharged to the outside of the post-processing device 30 as described with reference to FIG.

  The above steps of FIGS. 16 to 20 are repeated, and the sheet bundle PS bound by the staple needle 61 is sequentially formed.

  Another sensor 54 shown in FIG. 5 is a sensor that detects that the number of remaining staples 61 has decreased as a result of consuming the staples 61 as described above. When the remaining staple needles 61 are low, a warning is given to the user.

  FIG. 21 is a diagram showing an operation sound waveform in each process constituting a series of stapling operations. FIG. 21 also shows the light shielding plate 51 and the HP sensor 52. In this figure, the rotation direction of the light shielding plate 51 is counterclockwise.

  Here, a series of stapling operations are divided into a starting step T1, a binding step T2, and a return step T3. In the present embodiment, the time length t1 of the starting process T1 is fixed at t1 = 50 msec. Further, the boundary between the binding process T2 and the return process T3 can be known from the change in the output of the HP sensor 52. Further, the end timing (that is, the initial state) of the return process T3 can be known from the output change of the HP sensor 52.

  The starting process T1 is a time of 50 msec from the time when the power supply to the DC motor 321 (see FIG. 5) is started in the initial state shown in FIG. The binding process T2 is a process that continues to the state of FIG. 19 following the start process T1. The return step T3 is a step for performing the operation described with reference to FIG.

  Here, the time length of the starting process T1 is represented by t1, the time length of the binding process T2 is represented by t2, and the time length of the return process T3 is represented by t3.

  FIG. 22 is a block diagram of a control circuit responsible for operation control of the stapler in the post-processing apparatus.

  Here, it is assumed that the post-processing device 30 is connected to the printer 10 shown in FIG.

  Here, a CPU 351, a RAM 352, a motor driving unit 353, and an oscillator 354 are shown. These are some of the components in the sheet processing control unit 35 shown in FIG.

  Also shown here are the DC motor 321, the stapling mechanism 39 including the various mechanical elements described above, and the HP sensor 52 as components of the stapler 32.

  Various data (to be described later) stored in a non-volatile memory (not shown) is transferred to the RAM 352 when the power of the post-processing device 30 is turned on, and a stapler operation control program operating on the CPU 351 is also loaded on the RAM 352. . The CPU 351 receives information from the printer 10 such as the type of paper (paper type) used for the current print, the number of sheets per bundle (number of staples), the number of sheets bundle, and the like. In the present embodiment, these pieces of information are not used for motor control, but are used for forming a sheet bundle. The CPU 351 also receives the output signal of the HP sensor 52, and the CPU 351 recognizes that the stapler 32 is in the initial state and that it is at the timing of switching from the binding process T2 to the return process T3.

  In the motor drive unit 353, the pulse width modulation power with the duty instructed by the CPU 351 is generated. The oscillator 354 generates a clock signal for generating pulse width modulation power (PWM power) in the motor driving unit 353.

  Here, PWM is a technique for modulating power into a periodic pulse-like waveform. The pulse height in the modulated waveform is equal to the rated voltage of the DC motor 321. The ratio of the pulse width to the pulse period in the modulated waveform is the ratio of the effective output to the rated output. This ratio is referred to as PWM power duty (output ratio). By adjusting this duty, the effective output of PWM power is adjusted between 0 and the rated power.

  The PWM power generated by the motor drive unit 353 is supplied to the DC motor 321, and the DC motor 321 rotates with the supplied PWM power. Here, the DC motor 321 rotates at a rotational speed approximately along the duty of the PWM power supplied to the DC motor 321.

  Here, the CPU 351, the motor drive unit 353, and the DC motor 321 shown in FIG. 22 will be described in detail with reference to FIGS.

  FIG. 23 is a control block diagram of the DC motor 321 shown in FIG. 22, and FIG. 24 is a diagram showing a circuit configuration of the motor drive unit 353 shown in FIG.

  As shown in FIG. 23, four motor control signals are input from the CPU 351 to the motor driving unit 353. As shown in FIG. 24, the motor drive unit 353 has an H-bridge circuit composed of four FETs (field effect transistors). Of the four FETs, the upper left FET in FIG. 24 is referred to as FET 1, the lower left FET is referred to as FET 2, the upper right FET is referred to as FET 3, and the lower right FET is referred to as FET 4.

  The FETs 1 and 3 are FETs that are turned on when an L-level motor control signal is input and are turned OFF when an H-level motor control signal is input. The FET2 and FET4 are FETs that are turned on when an H-level motor control signal is input and are turned OFF when an L-level motor control signal is input.

  Of the four motor control signals input from the CPU 351 to the motor drive unit 353, the first motor control signal is input to the FET1, the second motor control signal is input to the FET2, and the third motor control signal is input to the FET3. The fourth motor control signal is input to the FET 4.

  FIG. 25 is a diagram illustrating the correspondence between the four motor control signals input to the motor drive unit 353 and the operation of the DC motor 321.

  As shown in FIG. 25, when the first motor control signal and the third motor control signal are H level motor control signals, and the second motor control signal and the fourth motor control signal are L level motor control signals, All of FET1 to FET4 are turned off. At this time, both terminals of the DC motor 321 are released, and the DC motor 321 becomes free.

  Further, when the first motor control signal and the second motor control signal are L level motor control signals, and when the third motor control signal and the fourth motor control signal are H level motor control signals, FET1 and FET4 are ON. State, and FET2 and FET3 are turned off. At this time, a current flows through the DC motor 321 from the left to the right in FIG. 24, and the DC motor 321 rotates CW (clockwise rotation).

  Further, when the first motor control signal and the second motor control signal are H level motor control signals, and when the third motor control signal and the fourth motor control signal are L level motor control signals, FET2 and FET3 are turned on. State, and FET1 and FET4 are turned off. At this time, a current flows through the DC motor 321 from right to left in FIG. 24, and the DC motor 321 rotates CCW (reverses counterclockwise).

  Further, when all of the first motor control signal to the fourth motor control signal are H level motor control signals, FET2 and FET4 are turned on, and FET1 and FET3 are turned off. At this time, both terminals of the DC motor 321 become ground, and a short circuit brake is applied to the DC motor 321.

  When the first motor control signal, the second motor control signal, and the fourth motor control signal are L level motor control signals, and when the third motor control signal is H level motor control signals, the FET 1 is in an ON state, And FET2-FET4 will be in an OFF state. At this time, the ground side terminal of the DC motor 321 is released, and the DC motor 321 becomes free.

  When the first motor control signal is an H level motor control signal and the second motor control signal to the fourth motor control signal are L level motor control signals, the FET 3 is in an ON state, and the FET 4 of the FET 1 and the FET 2 Is turned off. At this time, the ground side terminal of the DC motor 321 is released, and the DC motor 321 becomes free.

  Further, when the first motor control signal, the third motor control signal, and the fourth motor control signal are L level motor control signals, and the second motor control signal is an H level motor control signal, FET1 to FET3 are turned on. And the FET 4 is turned off. At this time, the power supply side terminal of the DC motor 321 is released, and the DC motor 321 becomes free.

  Further, when the first motor control signal to the third motor control signal are L level motor control signals and the fourth motor control signal is H level motor control signal, the FET 4 of the FET 1 and the FET 3 is in the ON state, and the FET 2 Is turned off. At this time, the power supply side terminal of the DC motor 321 is released, and the DC motor 321 becomes free.

  The DC motor 321 operates by any combination of the above eight motor control signal combinations described with reference to FIG.

  Here, the case where the DC motor 321 is rotated by the PWM power will be described by taking, for example, the case where the DC motor 321 rotates CW. A PWM signal is input to the fourth motor control signal in a state in which the first motor control signal and the second motor control signal are L level motor control signals and the third motor control signal is H level motor control signal. For example, when the ratio of the H level motor control signal is 75% (a PWM signal with a duty of 75%), this PWM signal has 75% of the unit time for supplying power to the motor and 25% for supplying power to the motor. The motor rotation speed can be reduced by entering a state in which the current is not supplied (one-side terminal released state) and a current limit close to the duty ratio is applied on average.

  FIG. 26 is a conceptual diagram of control.

  The control to be performed here is to adjust the duty for each process. The starting step T1 is a step of starting the rotation of the DC motor 321 and requires a large amount of power, and is fixed at a duty of 100% here. The time length t1 of the starting process T1 is fixed at t1 = 50 msec as described above.

  In the next binding step T2, the duty is adjusted and the operation noise is suppressed. When the duty is lowered, the rotational speed of the DC motor 321 is reduced. However, not only the rotational speed is reduced but also the driving force is reduced. Therefore, the duty of the binding step T2 is determined to be a minimum duty that ensures a driving force that does not cause a binding failure. Here, as an example, the duty is 75%.

  In the next return process T3, the duty is adjusted and the operation noise is suppressed. Even in this return step T3, if the driving force is excessively reduced, the return operation may be defective. Therefore, the duty of the return process T3 is determined to be a minimum duty that ensures a driving force that does not cause a failure of the return operation. Here, as an example, the duty is 50%.

  Here, when the duty is changed, for example, due to factors such as the inertia of the drive system and the force of the assist spring (not shown) of the stapler, the actual rotational speed of the DC motor 321 changes to the duty with a time delay. I know I will follow. In order to ensure the productivity of the stapling operation, it is necessary for the DC motor 321 to maintain the number of rotations corresponding to the preceding duty exactly until the duty change timing. However, in order to accurately suppress the operation sound, it is necessary that the DC motor 321 quickly decelerates to the rotational speed corresponding to the duty of the subsequent stage after the duty change timing has passed. Therefore, here, control is performed such that braking is applied to the DC motor 321 after the duty is changed.

  Below, the control algorithm for suppressing the operation sound in the binding process T2 and the return process T3 will be described.

  FIG. 27 is a diagram showing a motor control signal for changing the duty from 100% → 75% → 50% from the start of rotation and braking the DC motor 321 after the time when the duty is changed.

  Here, an example in which the DC motor 321 rotates CW is shown.

  In the starting step T1, the first motor control signal and the second motor control signal among the four motor control signals input from the CPU 351 to the motor drive unit 353 are set to the L level motor control signal, and the third motor control signal The fourth motor control signal is an H level motor control signal. As a result, FET1 and FET4 are turned on and FET2 and FET3 are turned off, and the DC motor 321 rotates CW with a duty of 100%.

  In the binding step T2, a PWM signal having a duty of 75% is input to the fourth motor control signal among the four motor control signals input from the CPU 351 to the motor driving unit 353. This PWM signal is a signal in which the ratio of the motor control signal of H level is 75%, 75% of the unit time is a time during which power is supplied to the motor, and 25% is a state where power is not supplied to the motor (one side Terminal release state).

  In the binding step T2, the short-circuit brake signal is superimposed on the 2-pulse PWM signal after the duty change. The number of pulses is variable and can be adjusted so as to obtain desired motor rotation characteristics.

  Here, the timing of A, B, and C shown in FIG. 27 in the binding step T2 will be described in detail.

  FIG. 28 is a diagram illustrating the correspondence between the four motor control signals input to the motor driving unit 353 and the operation of the DC motor 321 at the timing A shown in FIG.

  In the timing A shown in FIG. 27 in the binding process T2, the first motor control signal, the second motor control signal, and the fourth motor control signal among the four motor control signals input from the CPU 351 to the motor driving unit 353. Is an L level motor control signal, and the third motor control signal is an H level motor control signal. As a result, FET1 is turned on and FET2 to FET4 are turned off, the ground side terminal of the DC motor 321 is released, and the DC motor 321 becomes free. That is, in this state, since a circuit is not formed between the terminals of the DC motor 321, neither driving torque nor braking torque is generated in the DC motor 321. Therefore, the motor shaft of the DC motor 321 can be freely rotated, and continues to rotate due to the inertia of the drive system, so that the rotational speed slowly decreases.

  FIG. 29 is a diagram showing the correspondence between the four motor control signals input to the motor drive unit 353 and the operation of the DC motor 321 at the timing B shown in FIG.

  At the timing B shown in FIG. 27 in the binding process T2, all of the first motor control signal to the fourth motor control signal among the four motor control signals input from the CPU 351 to the motor driving unit 353 are at the H level. It is a motor control signal. As a result, FET2 and FET4 are turned on, FET1 and FET3 are turned off, both terminals of the DC motor 321 are grounded, and a short circuit brake is applied to the DC motor 321. That is, this state is a state where both terminals of the DC motor 321 are grounded, and a strong braking torque is generated from the characteristics of the DC motor 321. For this reason, the rotation of the DC motor 321 is braked, and it is possible to decelerate faster to a desired rotational speed. If this control state is taken for a long time, the brake will be overworked and may fall below the desired rotational speed (in this example, 75% duty). Therefore, fine speed control is realized by generating a short-circuit brake for an extremely short time as in this example.

  FIG. 30 is a diagram illustrating a correspondence between the four motor control signals input to the motor driving unit 353 and the operation of the DC motor 321 at the timing C illustrated in FIG.

  At the timing C shown in FIG. 27 in the binding process T2, the first motor control signal and the second motor control signal among the four motor control signals input from the CPU 351 to the motor drive unit 353 are L level motor control. The third motor control signal and the fourth motor control signal are H level motor control signals. As a result, FET1 and FET4 are turned on, and FET2 and FET3 are turned off, and current flows from the left to the right in FIG. 24 in the DC motor 321, and the DC motor 321 rotates CW (clockwise forward rotation). . That is, this state is normal CW drive, and in combination with timing B, pseudo torque control is realized.

  Returning to FIG. 27, the return process T3 will be described.

  In the return step T3, a PWM signal having a duty of 50% is input to the fourth motor control signal among the four motor control signals input from the CPU 351 to the motor drive unit 353. This PWM signal is a signal in which the ratio of the H level motor control signal is 50%, 50% of the unit time is the time during which power is supplied to the motor, and 50% is in the state where power is not supplied to the motor (one side Terminal release state).

  In the return step T3, the short-circuit brake signal is superimposed on the two-pulse PWM signal after the duty change, as in the above-described binding step T2. The number of pulses is variable and can be adjusted so as to obtain desired motor rotation characteristics.

  With the control algorithm described above, the DC motor 321 rotates at a rotational speed that accurately follows the motor control signal. As a result, a stapling operation in which driving force is ensured and operation sound is small is realized.

  In the embodiment described above, information such as the type of paper (paper type), the number of sheets per bundle (number of staples), and the number of sheets is not used for motor control but is used for forming a sheet bundle. However, since the duty and the rotational speed of the DC motor are not necessarily in a one-to-one relationship, it is known that the duty varies greatly depending on the individual difference of the stapler and the paper type and number of sheets to be bound. Information such as the number of staples may be used for motor control.

DESCRIPTION OF SYMBOLS 1A, 1B Print system 10 Printer 20 Paper conveyance apparatus 30 Post-processing apparatus 31 Puncher 32 Stapler 33 Foot part 34 Guide member 35 Paper processing control part 39 Staple mechanism 40 Copying machine 41 Image reading part 42 Operation panel 43 Image formation part 51 Light-shielding plate 52 HP (Home Position) Sensor 53, 53a, 54 Sensor 60, 60a Needle Plate 61, 61a, 61b Staple Needle 62, 62a, 62b Needle Stopper 63 Guide Member 71 Needle Push-Up Member 72 Needle Bending Member 73 Plate Spring 74 Needle Bending Member 75 Pressing member 76 Upper member 111,431 Paper storage portion 112,432 Take-out roll 113,433 Supply roll 114,118,121,131,434,21 Conveyance roll 115,435 Adjustment roll 116,440 Secondary transfer roller 117 Fixing roll 119 Paper discharge table 120,450 Main body control unit 134 Padra 135 Movable plate 136 Paper receiving plate 137 Fixed plate 138 Abutting wall 139 DC plate 321 Gear 323 Relay gear 324 Drive gear 325 Drive shaft 326 Drive Cam 327 Relay cam 327a, 328a Center of rotation 328 Presser member 331 Protrusion 341, 761 Groove 342 Rail 351 CPU
352 RAM
353 Motor drive unit 354 Oscillator PP Paper PS Paper bundle R1, R2, R3, R4, R5 Paper transport path

Claims (5)

A DC motor for a stapler that includes a DC motor having a terminal for receiving power supply, and executes a stapling operation in which a staple is inserted into a bundle of a plurality of stacked recording media and bent by a driving force generated by the rotation of the motor. A power supply unit for supplying power to the terminal via the terminal;
At a time point before a specific operation point included in the stapling operation, the power supply unit supplies the first power to the motor, and at a time point after the operation point, A power control unit that causes the power supply unit to supply a second power lower than the first power toward the motor;
After the time of the operation location, the first state in which the terminal is released to make the rotation of the DC motor free, the second state in which the terminal of the DC motor is grounded, and the second power A third state in which electric power for rotating the DC motor in the same direction as the rotation direction of the DC motor is supplied from the power supply unit to the DC motor, and the terminal is released to free the rotation of the DC motor. A stapler drive device comprising: a braking unit that applies a brake to the DC motor by causing a fourth state to be generated and a fifth state in which the terminal of the DC motor is grounded in this order. . The power supply unit supplies the pulse width-modulated power to an output ratio based on an instruction from the power control unit toward the DC motor;
The power control unit instructs the power supply unit to output a first output ratio at a time point before the operation point, and at a time point after the operation point, the power supply unit 2. The stapler driving device according to claim 1, wherein the second output ratio is smaller than the first output ratio. For stapling operation in a stapler that includes a DC motor having a terminal for receiving power supply, and executes a stapling operation in which a staple is inserted into a bundle of a plurality of stacked recording media and bent by a driving force generated by the rotation of the motor The first electric power is supplied to the DC motor at a time point before the specific operation point included, and the first electric power is supplied to the DC motor at a time point after the operation point. A first step of supplying a second power lower than the first power;
After the time of the operation location, the first state in which the terminal is released to make the rotation of the DC motor free, the second state in which the terminal of the DC motor is grounded, and the second power A third state in which electric power for rotating the DC motor in the same direction as the rotation direction of the DC motor is supplied from the power supply unit to the DC motor, and the terminal is released to free the rotation of the DC motor. A stapler driving method comprising: a second process of causing a brake to be applied to the DC motor by causing a fourth state to be generated and a fifth state to ground the terminal of the DC motor in this order. . A bundle forming unit that receives a recording medium from an image forming apparatus that forms an image on the recording medium, and forms a bundle by stacking a plurality of the recording media;
A stapler that includes a DC motor having a terminal for receiving power supply, and that performs a stapling operation of inserting and bending a staple into the bundle with a driving force generated by the rotation of the DC motor;
A power supply unit that supplies power to the stapler motor via the terminal;
At a time point before a specific operation point included in the stapling operation, the power supply unit supplies the first power to the motor, and at a time point after the operation point, A power control unit that causes the power supply unit to supply a second power lower than the first power toward the motor;
After the time of the operation location, the first state in which the terminal is released to make the rotation of the DC motor free, the second state in which the terminal of the DC motor is grounded, and the second power A third state in which electric power for rotating the DC motor in the same direction as the rotation direction of the DC motor is supplied from the power supply unit to the DC motor, and the terminal is released to free the rotation of the DC motor. A post-processing device, comprising: a braking unit that brakes the DC motor by causing a fourth state to occur and a fifth state in which the terminal of the DC motor is grounded in this order. . An image forming unit that forms an image on a recording medium;
A bundle forming unit that receives a recording medium from the image forming unit and forms a bundle by stacking a plurality of the recording media;
A stapler that includes a DC motor having a terminal for receiving power supply, and that performs a stapling operation of inserting and bending a staple into the bundle with a driving force generated by the rotation of the DC motor;
A power supply unit that supplies power to the stapler motor via the terminal;
At a time point before a specific operation point included in the stapling operation, the power supply unit supplies the first power to the motor, and at a time point after the operation point, A power control unit that causes the power supply unit to supply a second power lower than the first power toward the motor;
After the time of the operation location, the first state in which the terminal is released to make the rotation of the DC motor free, the second state in which the terminal of the DC motor is grounded, and the second power A third state in which electric power for rotating the DC motor in the same direction as the rotation direction of the DC motor is supplied from the power supply unit to the DC motor, and the terminal is released to free the rotation of the DC motor. An image forming apparatus, comprising: a braking unit that applies a brake to the DC motor by causing a fourth state to occur and a fifth state in which the terminal of the DC motor is grounded in this order.

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