JP7366614B2 - Image forming device and image forming system - Google Patents

Description

The present invention relates to an image forming system equipped with a cutting device that cuts sheets.

An image forming system is known in which a sheet cutting device is arranged downstream of an image forming device such as a copying machine or a printer, and the sheet cutting device cuts the margin portion of a sheet on which an image has been formed to perform marginless printing. . Patent Document 1 describes an image forming system that includes a cutting unit that performs cutting processing on a sheet on which an image has been formed according to a preset cutting amount.

Japanese Patent Application Publication No. 2014-83803

In an image forming system that requires high-quality products, it is required to perform cutting processing with high precision. Particularly, when cutting a margin portion to produce a borderless printed matter, it is undesirable for the margin to remain after cutting.

An object of the present invention is to suppress deviation of the cutting position of a sheet cut by a sheet cutting device.

An image forming apparatus according to one aspect of the present invention includes: an image forming unit that forms an image on a sheet; a detection unit that is provided in a sheet conveying path and detects a leading edge and a trailing edge of the sheet being conveyed; a cutting unit that performs cutting processing on the sheet on which an image has been formed by the unit; a length in the transport direction of the sheet calculated based on information detected by the detection unit; and preset margin information of the sheet. an image forming apparatus, comprising: a control means for calculating a distance from a leading edge position of the sheet to a cutting position of the sheet by the cutting means, based on the above.
has.

According to the present invention, it is possible to suppress a shift in the cutting position of a sheet cut by a sheet cutting device.

Overall configuration diagram of image forming system Configuration diagram of sheet cutting device Perspective view of tip/rear end cutter section Side view of top and bottom cutter part Block diagram showing the control configuration of the image forming system Flowchart showing the flow of operation of the image forming system Diagram showing the relationship between sheets and images formed on them

Hereinafter, exemplary embodiments for carrying out the present invention will be described with reference to the drawings.

FIG. 1 schematically shows the overall configuration of an image forming system 100 according to this embodiment. As shown in the figure, the image forming system 100 is composed of an image forming apparatus A0, and a sheet cutting apparatus B0 and a sheet processing apparatus C0 provided side by side. The image forming apparatus A0 includes an image forming unit A1, which is the main body of the apparatus, and a scanner unit A2 and a feeder unit A3, which constitute an image reading device.

(1. Image forming device)
The image forming unit A1 is equipped with an image forming section A11, which is an electrophotographic unit using a tandem intermediate transfer method, as an image forming means of this embodiment. The image forming unit A11 forms yellow, magenta, cyan, and black toner images on the four photoreceptors 1Y, 1M, 1C, and 1K by an electrophotographic process, and transfers them to a recording material via an intermediate transfer member. Recording materials include paper such as plain paper and thick paper, plastic films, cloth, sheet materials with surface treatments such as coated paper, sheet materials with special shapes such as envelopes and index paper, etc., of different sizes and materials. Various sheets can be used.

A primary charger 221, an exposure device 218, a developing device 223, a transfer charger 220, and a cleaner device 222 are arranged around each of the photoreceptors 1Y to 1K. The primary charger 221 uniformly charges the surfaces of the photoreceptors 1Y to 1K, and the exposure device 218 charges the photoreceptors 1Y to 1K based on a signal sent from the control unit of the image forming apparatus A0 based on the image data to be printed. is exposed to light to write an electrostatic latent image on the surface of the photoreceptor. The developing device 223 supplies toner of each color to the photoreceptors 1Y to 1K, and visualizes the electrostatic latent image as a toner image. The toner images of each color developed by the developing device 223 and carried on the photoreceptors 1Y to 1K are multiple-transferred to a transfer belt 226 as an intermediate transfer body by the transfer charger 220, and the toner images of the four colors are superimposed. A full-color toner image is formed. The cleaner device 222 removes deposits such as untransferred toner that remains on the photoreceptors 1Y to 1K without being transferred to the transfer belt 226. Further, the surfaces of the photoreceptors 1Y to 1K are prepared for the next electrophotographic process by having charges removed by a static eliminator.

The recording sheets stored in the cassettes 240, 241 or set in the manual feed section 253 are fed one by one through a feeding path 266, and are placed on a registration roller (hereinafter referred to as , abbreviated as registration roller) 255. When the passage of the sheet is detected by the registration sensor 256 disposed immediately before the registration roller 255, the conveyance of the sheet by the conveyance roller upstream of the registration roller 255 is interrupted after an appropriate period of time has elapsed. As a result, the sheet hits the stopped registration roller 255, and the leading edge position of the sheet in the conveying direction follows the nip of the registration roller 255 and is fixed perpendicular to the conveying direction, thereby preventing skewed feeding of the sheet. Corrected. After this skew correction processing (also called registration processing), the registration rollers 255 are activated to supply the sheet to the secondary transfer device 231.

In the secondary transfer device 231, the toner image carried on the transfer belt 226 is secondarily transferred to the sheet fed as described above. The sheet to which the unfixed toner image has been transferred is conveyed to a fixing device 234 via a fixing conveyor belt 230 . The fixing device 234 includes a pair of rotating bodies that sandwich the sheet and a heat source such as a halogen lamp that heats the toner image on the sheet, and performs the fixing process by applying heat and pressure to the toner image to melt it. . When the sheet that has passed through the fixing device 234 is to be ejected as is, it is guided by the ejection flap 257 to the ejection path 258 and ejected to the sheet cutting device B0.

Note that the image forming unit A1 is capable of continuously feeding sheets from the cassettes 240 and 241 and the manual feeding section 253. In this case, the sheet length of the preceding sheet is taken into account, and the feeding timing and conveyance speed of the sheets from the cassettes 240, 241 or the manual feeding section 253 are controlled at the shortest interval so that the sheets do not overlap. After the registration roller 255 sends out the preceding sheet to the secondary transfer device 231, the drive transmission from the clutch is stopped, so that the registration roller 255 temporarily stops and prepares for registration of the subsequent sheet.

The operation when forming images on both sides of a sheet will be explained. After the image is formed on the first side of the sheet as described above, the sheet is guided to the back path 259 by the discharge flap 257 when an image is to be formed on the second side of the sheet. The reversing roller 260 disposed on the back path 259 once conveys the sheet to the reversing path 261 and then reverses to switch back the sheet and send it to the double-sided path 263.

The sheet is then conveyed via a double-sided path 263 toward a refeed roller 264 . When the passage of the sheet is detected by the refeeding sensor 265 immediately before the refeeding roller 264, the conveyance of the sheet in the double-sided path 263 is interrupted, and the sheet temporarily hits the stopped refeeding roller 264. Stop. This corrects the skew of the sheet that occurs from the time the toner image is transferred to the first surface until it reaches the refeed roller 264 (refeed registration). Thereafter, by activating the refeed roller 264, the sheet reaches the registration roller 255 again with the first and second surfaces reversed, and passes through the secondary transfer device 231 and the fixing device 234. An image is formed on the second side. Then, the sheet with images formed on both sides is guided to a discharge path 258 by a discharge flap 257 and discharged to the sheet cutting device B0.

The image forming section A11 provided in the image forming unit A1 is an example of an image forming means, and is, for example, an electrophotographic unit of a direct transfer type in which a toner image formed on a photoreceptor is transferred to a sheet without going through an intermediate transfer member. May be used. Furthermore, the image forming means is not limited to the electrophotographic method, and an inkjet printing mechanism or an offset printing mechanism may be employed as the image forming means.

The scanner unit A2 installed above the image forming unit A1 includes a platen 17 on which a document is placed, and a carriage 18 that reciprocates along the platen 17. The scanner unit A2 further includes a photoelectric conversion means 19 such as a charge-coupled device, and a reduction optical system 20 that guides light reflected by the carriage 18 from the document on the platen 17 to the photoelectric conversion means 19. The photoelectric conversion means 19 photoelectrically converts the optical output from the reduction optical system 20 into image data and outputs it as an electrical signal to the image forming unit A1.

Further, the scanner unit A2 includes a traveling platen 21 in order to read sheets sent from the feeder unit A3. The feeder unit A3 includes a feeding tray 22, a feeding path 23 that guides the sheet fed from the feeding tray 22 to the traveling platen 21, and a discharge tray 24 that stores the original that has passed through the traveling platen 21. The originals fed one by one from the feeding tray 22 are optically scanned by the carriage 18 and the reduction optical system 20 as they pass through the traveling platen 21, and the image data is photoelectrically converted by the photoelectric conversion means 19. is sent to image forming unit A1.

(2. Sheet cutting device)
FIG. 2 shows the configuration of a sheet cutting device B0 that cuts a sheet on which an image has been formed by the image forming device A0. The sheet cutting device B0 includes a leading edge/trailing edge cutter section 305, a top and bottom cutter section 307, a conveyance path 310, and a waste box 319. The leading edge/trailing edge cutter section 305 and the top and bottom cutter sections 307 constitute a cutting section B1 that performs sheet cutting processing in the sheet cutting device B0.

The leading edge/trailing edge cutter unit 305 cuts the sheet in the width direction of the sheet (main scanning direction during image formation) perpendicular to the conveying direction of the sheet in the conveying path 310 (left direction in the figure). The leading edge/trailing edge cutter section 305 not only trims the leading edge or trailing edge of the sheet in the conveyance direction, but also can divide the sheet into predetermined lengths.

The top and bottom cutter unit 307 cuts the sheet in the sheet conveyance direction on the conveyance path 310 (sub-scanning direction during image formation). The top and bottom cutter section 307 not only trims the top and bottom portions when the sheet processing device C0 performs the center folding process, but also can divide the sheet into predetermined widths by replacing the cutter blade.

The conveyance path 310 is a sheet conveyance path extending linearly over a horizontal range from a position X1 where the sheet is cut by the leading edge/trailing edge cutter section 305 to a position X2 where the sheet is cut by the top and bottom cutter sections 307. It is a road. In other words, the arrangement is such that the members constituting the upper or lower guide surface of the conveyance path 310 do not intersect with the virtual line connecting these positions X1 and X2. Therefore, the leading edge/trailing edge cutter section 305 and the top/bottom cutter section 307 can cut a sheet stretched in a plane on the conveyance path 310. This has the advantage that it is possible to improve the cutting accuracy and reduce the transport load for paper having high rigidity. The conveyance path 310 is actually formed by a guide member supported by the frame of the sheet cutting device B0, and guide members provided in the leading edge/trailing edge cutter section 305 and the top and bottom cutter sections 307.

The sheet cutting device B0 is installed between the image forming device A0 and the sheet processing device C0 in the horizontal direction (FIG. 1), and the conveyance path 310 runs from one side to the other in the horizontal direction (from the right side to the left side in the figure). extending towards. The conveyance path 310 includes a receiving port 312 facing the discharge port through which the image-formed sheet is discharged from the image forming unit A1, and a discharge port 313 facing the receiving port through which the sheet processing apparatus C0 receives the sheet. . The receiving port 312 is provided on one side surface of the sheet cutting device B0 in the horizontal direction, and the discharge port 313 is provided on the other side surface of the sheet cutting device B0 in the horizontal direction. Since the two cutter sections are disposed on the conveyance path 310 extending in a substantially horizontal direction, the front/rear end cutter sections are arranged on a straight line connecting the opening position Zin of the intake port 312 and the opening position Zout of the discharge port 313. 305 and a top and bottom cutter section 307 are located there. However, the opening positions Zin and Zout of the intake port 312 and the discharge port 313 are the passage positions when the sheet passes through each opening in a normal posture.

In addition to the leading edge/trailing edge cutter section 305 and the top and bottom cutter sections 307, the conveyance path 310 includes an entrance roller 302, a registration roller 303, an intermediate roller 306, and a discharge roller 308 as conveyance means for conveying the sheet. It is provided. Further, in the conveyance path 310, a lateral registration detection sensor 304 is arranged between the registration roller 303 and the cutting section B1. Further, an inlet sensor 301 that detects sheet inlet 312 of the conveyance path 310 is arranged to detect the sheet being carried in, and an outlet sensor 309 that detects the sheet outlet is arranged near the discharge outlet 313.

The sheets discharged one by one by the discharge rollers provided in the discharge path 258 (FIG. 1) of the image forming unit A1 are received by the entrance roller 302 of the sheet cutting device B0 via the reception opening 312 of the conveyance path 310, It is conveyed toward registration rollers 303. At this time, the entrance sensor 301 detects the passage of each sheet.

When a predetermined time has elapsed since the entrance sensor 301 detected the passage of the sheet, the entrance roller 302 temporarily stops conveying the sheet. As a result, the sheet hits the stopped registration roller 303, and the leading edge of the sheet follows the nip portion of the registration roller 303 and is fixed perpendicular to the conveying direction, thereby correcting the skew of the subsequent sheet ( cashier). Thereafter, by activating the registration rollers 303, the sheet is conveyed to the leading edge/trailing edge cutter section 305.

FIG. 3 is a perspective view of the tip/back end cutter section 305. The leading edge/trailing edge cutter section 305 has a guillotine blade 305a extending in the width direction perpendicular to the sheet conveyance direction, and by moving the guillotine blade 305a up and down with respect to the opposing blade 305b using a driving means, the conveyance path can be changed. Cut the sheet along the width direction. That is, the moving direction of the guillotine blade 305a, which is the first cutting blade in this embodiment, is up and down. The cutting position of the sheet is determined based on the cutting amount instruction information notified to the sheet cutting device B0 from the control section of the image forming apparatus A0, which will be described later. In this embodiment, after the registration roller 303 and intermediate roller 306 shown in FIG. 2 convey the sheet at a feed amount corresponding to the cutting amount, the sheet is temporarily stopped and the sheet is cut at that position. By cutting the sheet in the width direction by the leading edge/trailing edge cutter unit 305, the length of the sheet is determined when measured in the conveying direction on the conveying path (the vertical direction of the sheet folded in the middle by the sheet processing device C0). .

When cutting one sheet multiple times, the guillotine blade 305a is moved up and down multiple times while repeatedly driving and temporarily stopping the registration roller 303 and the intermediate roller 306 to perform the cutting. If the length of the sheet after cutting in the transport direction is short, if necessary, after cutting the top and bottom of the sheet by the top and bottom cutter section 307, the sheet is reversely fed by the intermediate roller 306, and the sheet is cut by the guillotine blade 305a. Trim the rear end. The sheet cut by the leading edge/trailing edge cutter section 305 is conveyed to the top/bottom cutter section 307 by an intermediate roller 306 .

FIG. 4 is a diagram of the top and bottom cutter section 307 viewed from the downstream side in the conveyance direction (from the viewpoint of arrow X in FIG. 2). The top and bottom cutter portion 307 has a disc-shaped cutter blade 307a and an abutment piece 307b. The cutter blade 307a, which is the second cutting blade of this embodiment, is a cutting blade that cuts the sheet while rotating. The cutter blade 307a and the abutment piece 307b are rotatably supported by rotating shafts 307c and 307d, respectively, and are in contact with each other within the conveyance path. When cutting a sheet, the cutter blade 307a is urged against the abutting piece 307b by the urging spring 307e, receives the sheet into the meshing portion of the cutter blade 307a and the abutting piece 307b, and cuts the sheet continuously while conveying the sheet. to cut. By cutting the sheet in the cutting direction by the top and bottom cutter unit 307, the length of the sheet is determined when measured in the width direction (the top and bottom direction of the sheet bundle folded in the middle by the sheet processing device C0) in the conveyance path.

In the top and bottom cutter portion 307, a set of a cutter blade 307a and an abutment piece 307b is arranged at at least one location in the width direction. In the illustrated configuration example, two sets of cutter blades 307a and abutting pieces 307b are arranged on one side and the other side with respect to the center position of the conveyance path in the width direction. Further, each set of cutter blade 307a and abutment piece 307b is configured to be movable in the width direction by a driving means. However, as a modification, one or more cutter blades may be arranged, and a structure in which the cutter blade does not move in the width direction may be adopted. In addition, the top and bottom cutter sections 307 are made removable from the sheet cutting device B0, and multiple types of top and bottom cutter sections with different cutter blade arrangements are prepared so that users or service personnel can replace them according to the purpose of use. You can also do this.

In FIG. 2, a lateral registration detection sensor 304 disposed upstream of the leading edge/trailing edge cutter section 305 detects the edge position in the width direction of the sheet conveyed through the conveying path 310. In the cutting process by the top and bottom cutter section 307, the cutting position is determined based on the edge position of the sheet detected by the lateral registration detection sensor 304. In other words, the cutter blade 307a and the abutment piece 307b operate based on the cutting amount instruction information notified from the control unit of the image forming apparatus A0, which will be described later, and the edge position of the sheet detected by the lateral registration detection sensor 304. Move to the cutting position and cut the top and bottom of the sheet. The sheet cut by the top and bottom cutter section 307 is discharged by a discharge roller 308 to the sheet processing apparatus C0.

The operation when cutting a sheet by the leading edge/trailing edge cutter section 305 and the top and bottom cutter sections 307 has been described above.

By the way, as the leading edge/trailing edge cutter section 305 and the top/bottom cutter section 307 perform the cutting process, the sheets received by the sheet cutting device B0 from the image forming unit A1 are divided into sheet pieces that make up the product and sheet pieces that make up the product. Unnecessary fragments (chips) are generated. This sheet waste falls into a waste box 319, which serves as a collection container, and is collected below the cutting section B1. In this embodiment, the leading/rear end cutter section 305 and the top and bottom cutter sections 307 are arranged adjacent to each other in the substantially horizontal direction, so the waste box 319 can be shared by the two cutter sections.

(3. Sheet processing device)
The sheet discharged from the sheet cutting device B0 is delivered to the sheet processing device C0. The sheet processing device C0 includes a post-processing section that performs post-processing on the sheet, and performs post-processing on the sheet conveyed from the sheet cutting device B0. The post-processing includes, for example, a folding process in which a sheet is folded in two, a binding process in which a staple is driven into a sheet bundle consisting of a plurality of sheets, and the sheet bundle is bound. The sheets that have been subjected to post-processing by the post-processing section are discharged to a stacking tray 36 or a saddle tray 44 provided outside the device housing 27.

When post-processing is not performed, the sheet processing device C0 discharges the sheet discharged from the sheet cutting device B0 onto a stacking tray 46 provided outside the device housing 27.

In the image forming system 100 of this embodiment shown in FIG. 1, all sheets discharged from the sheet cutting device B0 are delivered to the sheet processing device C0 regardless of whether post-processing is performed or not. However, it is also possible to provide a configuration in which a discharge tray is installed in the sheet cutting device B0 and the sheets discharged from the discharge port 313 are stacked on the discharge tray as a product of the image forming system.

(4. Control of image forming system)
Next, the control configuration and operation flow of the image forming system 100 will be explained. FIG. 5 is a control block diagram of the image forming apparatus A0 and the sheet cutting apparatus B0. Here, the sheet post-treatment device C0 is omitted. The image forming apparatus A0 and the sheet cutting apparatus B0 each have an image forming control section A01 and a cutting control section B01.

The image forming control section A01 and the cutting control section B01 are configured to be electrically connected so as to be able to communicate with each other, and control the operation of the image forming system 100 in cooperation with each other. In other words, the image forming control unit A01 and the cutting control unit B01 that cooperate with each other function as a control unit that controls the operation of the image forming system 100 including the sheet cutting device B0.

The image forming control unit A01 includes an arithmetic unit as an execution means for executing a program, and a memory as a storage means for storing information. The arithmetic device reads and executes a program stored in the memory, and controls the operation of each part of the image forming unit A1. Memory includes nonvolatile storage media such as read-only memory or magnetic disks, and volatile storage media such as random access memory, and serves as a storage location for programs and data, and also serves as a place for processing when a computing device executes a program. It becomes a space. Such a memory is an example of a non-transitory storage medium that stores a program for controlling the image forming apparatus.

The cutting control unit B01 also includes an arithmetic unit as an execution means for executing a program, and a memory as a storage means for storing information.

The cutting control section B01 sends command signals to the power source B02, the conveyance drive section B03, the leading/trailing cutter drive section B04, and the top and bottom cutter drive sections B05 to control the operations of each section. A power source B02 supplies power to operate the conveyance drive unit B3, the leading/back end cutter drive unit B04, and the top and bottom cutter drive unit B05. The conveyance drive unit B3 includes a drive motor and its drive circuit that drive conveyance rollers (for example, the entrance roller 302 and the registration roller 303) arranged in the sheet cutting device B0. The front/back end cutter drive unit B04 includes a drive motor and its drive circuit that move the guillotine blade 305a of the front/back end cutter unit 305 up and down. The top and bottom cutter drive unit B05 includes a drive motor and its drive circuit that rotate and move the cutter blade of the top and bottom cutter unit 307 in the width direction.

The cutting control unit B01 changes the content of the process and the timing of executing the process on the sheet delivered from the image forming apparatus A0, based on information notified from the image forming control unit A01. Information notified from the image forming control unit A01 includes sheet size information, basis weight information, paper type information, number of sheets information, cutting amount for each sheet, margin amount information (x), etc. of the sheet used in the job being executed. is included. Note that the margin amount information is information set in advance by the user. The amount of margin can also be set individually for the left side, right side, top side, and bottom side of the image. The image forming control unit A01 also sends information such as the start time of job execution, the expected time when each sheet will be ejected from the image forming apparatus A0, and a signal indicating job interruption to the sheet cutting device B0 and the sheet processing device C0 when the sheet cutting device B0 and the sheet processing device C0 operate. It will also notify you of the information necessary to determine the timing.

For example, when the sheet cutting device B performs marginless cutting, the cutting control unit B01 receives size information, basis weight information, paper type information, number of sheets information, margin amount information (x), etc. notified from the image forming control unit A01. Receive information. Then, the cutting control unit B01 controls each unit to cut the sheet at appropriate timing and position. The above information received from the image forming control unit A01 is information set by the user, or information selected by the image forming control unit A01 based on the information.

By the way, as mentioned above, sheet lengths vary, and in the case of a product whose image length has been adjusted with priority given to the margin setting amount, determining the cutting position based on the nominal length will result in a product with no margins. Even if you try to create a file, there may be blank spaces left after cutting.

Therefore, in this embodiment, information obtained by a paper edge detection sensor provided in the sheet conveyance path in the image forming apparatus A0 is used as length information in the conveyance direction of the sheet. Since information after the expansion and contraction of the sheet due to the image forming process is desirable, in this embodiment, after the toner image on the second side is thermally fixed by the fixing device 234, the sheet ejection sensor located on the sheet ejection path 258, which is the sheet conveyance path, is used. 270 information shall be used. The paper discharge sensor 270 is an example of a detection unit that detects the leading edge and trailing edge of the sheet.

FIG. 6 is a flowchart showing the flow of operations from image formation to cutting in the image forming system 100. Further, FIG. 7 is a diagram schematically showing the relationship between a sheet and an image formed on the sheet. 6 and 7, the following describes operations when images are continuously formed on a sheet, all four sides of the sheet are cut, and the sheets are folded into a bundle.

First, the secondary transfer device 231 of the image forming apparatus A0 forms an image on a sheet (F1). The sheet on which the image has been formed is conveyed to a paper discharge path 258, which is a sheet conveyance path in A0 within the image forming apparatus. Here, the sheet discharge sensor 270 detects the leading edge and trailing edge of the sheet (F2), and the timing information is sent to the image forming control unit A01. From the sheet leading edge detection timing t1 (sec.), the sheet trailing edge timing t2 (sec.), and the sheet conveyance speed v (mm/sec.) known in advance, the image forming control unit A01 calculates The length L (mm) of the sheet in the conveying direction is calculated.
L=(t2-t1)×v

In the case of marginless cutting, the cutting margin Δx (mm) is usually taken, so the distance L1 from the leading edge of the sheet to the leading edge cutting position and the distance L2 from the leading edge cutting position to the trailing edge cutting position are calculated from the following formula. .
L1=x+Δx
L2=L−L1−(x+Δx)

On the other hand, the sheet that has passed through the paper ejection path 258 of image forming apparatus A is ejected from image forming apparatus A0 (F4). The sheet discharged from the image forming apparatus A0 is conveyed to the sheet cutting device B (F5), hits the registration roller 303, and is stopped and registered (F6). Thereafter, the sheet cutting device B0 transports the sheet by a predetermined distance y1 instructed by the image forming control unit A01 from the leading edge of the sheet (F7), and after once stopping the sheet transport, performs main scanning direction cutting processing on the leading edge side of the sheet. (F8). The predetermined distance y1 is calculated by the following formula using the distance z from the roller nip position of the registration roller 303 to the front/back end cutter section 305.
y1=z+L1

After cutting the leading edge side in the main scanning direction, the sheet cutting unit B0 restarts conveying the sheet (F9), and starts cutting the sheet in the sub-scanning direction while the sheet is being conveyed (F10). Then, when the sheet has been conveyed by a distance L2 from the cutting on the leading edge side (F11), the sheet conveyance is temporarily stopped, and then the cutting process on the trailing edge side of the sheet in the main scanning direction is executed (F12). Thereafter, the sheet conveyance is restarted, and the sheet is conveyed to the sheet post-processing device C0 (F13).

With the above configuration and operation, margin-less cutting can be performed with high precision even when the length of the sheet varies and, as a result, the distance from the leading edge of the sheet to the trailing edge of the image changes from sheet to sheet. . Furthermore, by using a sensor in the image forming apparatus as a detection means, it is possible to prevent the sheet cutting apparatus from increasing in cost and size. Furthermore, by detecting it within the image forming apparatus, it is possible to ensure sufficient processing time until the sheet cutting process, and it is possible to prevent productivity from decreasing in the sheet cutting apparatus.

In the above embodiment, the sheet cutting device B0 was described as a so-called floor-standing optional device installed between the image forming device A0 and the sheet processing device C0 in the horizontal direction. However, for example, when the image forming apparatus A0 has a so-called internal discharge type configuration, the sheet cutting device B0 may be installed in the internal discharge space of the image forming apparatus A0. The in-body discharge type configuration is one in which a discharge space is formed between the image forming unit A1 and the image reading device in the vertical direction, and the sheet on which the image has been formed by the image forming unit A1 is discharged into the discharge space. It is.

(Other embodiments)
The present invention provides a system or device with a program that implements one or more of the functions of the embodiments described above via a network or a storage medium, and one or more processors in the computer of the system or device reads and executes the program. This can also be achieved by processing. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

46 Loading tray 100 Image forming system 305 Lead/back end cutter section 305a Guillotine blade 307 Top and bottom cutter section 307a Cutter blade 310 Conveyance path 312 Receiving port 313 Discharge port 319 Waste box A0 Image forming device A1 Image forming control section B1 Cutting control section B0 Sheet cutting device C0 Sheet processing device

Claims (9)

an image forming means for forming an image on the sheet;
a detection means provided in a sheet conveyance path to detect a leading edge and a trailing edge of the sheet being conveyed;
a cutting unit that performs cutting processing on the sheet on which an image has been formed by the image forming unit;
The cutting means cuts the sheet from the leading edge position of the sheet based on the length of the sheet in the transport direction calculated based on information detected by the detection means and preset margin amount information of the sheet. a control means for calculating the distance to the cutting position;
An image forming apparatus comprising: The image forming means has a fixing means for fixing the image on the sheet,
The image forming apparatus according to claim 1, wherein the detection means is provided downstream from the fixing means in the transport direction and upstream from the cutting means in the transport direction. 3. The image forming apparatus according to claim 1, wherein the cutting unit cuts the sheet in a width direction that intersects with a conveying direction of the sheet. 4. The image forming apparatus according to claim 3, wherein the cutting means has a cutting blade that moves in a moving direction intersecting the conveying direction and the width direction. The image forming apparatus according to any one of claims 1 to 4, further comprising a sheet processing unit that performs folding processing or binding processing on the sheet cut by the cutting unit. 6. The image forming apparatus according to claim 1, further comprising a stacking tray for discharging and stacking the sheets cut by the cutting unit one by one. The control means determines the length of the sheet in the conveying direction based on a time when the leading edge of the sheet is detected by the detecting means, a time when the trailing edge of the sheet is detected by the detecting means, and a length of the sheet conveyed on the sheet conveying path. The image forming apparatus according to any one of claims 1 to 6, wherein the image forming apparatus calculates the amount based on the conveyance speed. The control means is based on the calculated length of the sheet in the transport direction and the margin amount information that is set in advance and includes a margin amount on the leading edge side of the sheet and a margin amount on the trailing edge side of the sheet. 8. The image forming apparatus according to claim 7, further comprising calculating a distance from a leading end position of the sheet to a cutting position by the cutting means with respect to a rear end of the sheet. an image forming device that forms an image on a sheet;
a sheet cutting device that performs cutting processing on the sheet conveyed from the image forming device;
a detection means provided in a sheet conveyance path of the image forming apparatus to detect a leading edge and a trailing edge of the conveyed sheet;
The cutting device cuts the sheet from the leading edge position of the sheet based on the length of the sheet in the transport direction calculated based on information detected by the detection means and preset margin amount information of the sheet. a control means for calculating the distance to the cutting position;
An image forming system comprising:

Images