JP4385798B2 - Image forming apparatus - Google Patents

Description

  The present invention includes a first conveyance unit that conveys a sheet-like recording medium, and a print processing unit that includes a printing unit that forms an image by ejecting ink droplets onto the sheet-like recording medium conveyed by the first conveyance unit; A drying unit that receives and dries the sheet-like recording medium discharged from the print processing unit, and a drying processing unit that includes a second conveyance unit that conveys the sheet-like recording medium dried by the drying unit. The present invention relates to an image forming apparatus configured.

  A print processing unit that performs a printing process on a sheet-like recording medium, a fixing processing unit that performs a fixing process on the recording medium, and a transport mechanism that transports the recording medium from an exit of the print processing unit to an entrance of the fixing processing unit And a loop forming unit that absorbs a difference in processing speed of the recording medium between the print processing unit and the fixing processing unit by accumulating the recording medium in a loop shape. An image forming apparatus has been proposed.

According to the above-described image forming apparatus, when the recording medium printed and discharged by the print processing unit is transported to the loop forming unit, the ink ejected onto the surface of the recording medium remains wet. Because of the problem that the ink adheres to the conveyance unit of the loop forming unit and the image is disturbed, or the ink adhered to the conveyance unit may be transferred to other parts of the recording medium, it is discharged from the print processing unit. It is necessary to provide a drying unit for drying the ink ejected on the surface of the transport path of the recorded recording medium.
JP 2003-326789 A

  However, even when the above-described drying unit is provided, the recording medium is conveyed by the first conveyance unit until the printing operation in the printing unit is completed, but the printing operation in the printing unit is completed. Since the first transport unit can no longer transport the recording medium, it is necessary to transport the recording medium by providing a second transport unit on the drying unit side, and the recording medium passing through the drying unit is transported by the first transport unit. If the transport pattern such as the transport speed is different between when transported and when transported by the second transport unit, the degree of drying of the ink is different, and drying unevenness may occur. Further, depending on the conveyance speed of the recording medium by the second conveyance unit, there is a problem that the ink is not sufficiently dried and the image is disturbed, and the conveyance control by the second conveyance unit is an important problem.

  In addition, when the control system of the print processing unit and the control system of the drying processing unit are separated, the transport pattern by the first transport unit varies depending on the print size and the number of passes for the recording medium. There is also a problem that it is extremely difficult to carry out the conveyance control of the second conveyance unit corresponding to the conveyance pattern of the first conveyance unit controlled by the control system of the processing unit.

  In view of the above-described conventional drawbacks, the present invention is to provide an image forming apparatus capable of drying ink reliably without causing drying unevenness.

In order to achieve the above object, a first characteristic configuration of an image forming apparatus according to the present invention includes a first transport unit that transports a sheet-like recording medium as described in claim 1 of the document of the claims. A printing processing unit having a printing unit for forming an image by ejecting ink droplets onto the recording medium conveyed by the first conveying unit, and a drying unit for receiving and drying the recording medium discharged from the printing processing unit And a drying processing unit having a second conveying unit that conveys the recording medium dried by the drying unit, wherein the second conveying unit is disposed behind the recording medium. A first transport mode for transporting the recording medium in the same first transport pattern as the transport pattern by the first transport section until the end passes through the drying section, and the rear end of the recording medium passes through the drying section. Then, the first transfer mode The second conveyance control unit for the transport control to switch to one of the second conveying mode for conveying the recording medium in a second conveyance pattern for transporting the recording medium than the average conveyance speed of the recording medium at a high conveying speed by It is in the point which is provided.

  According to the above-described configuration, the second transport control unit includes the second transport unit after the transport of the recording medium that passes through the drying unit is dried while being transported by the first transport unit, particularly after the transport by the first transport unit is completed. The part that is dried while being transported by the part is transported in the same transport pattern as the first transport part without disturbing the transport state by the first transport part, and the recording medium after the drying process is transported efficiently by the second transport pattern Therefore, it is possible to perform uniform drying without causing uneven drying over the entire surface of the recording medium.

  In the second feature configuration, as described in claim 2, in addition to the first feature configuration described above, the second transport control unit is configured to print control data input to the print processing unit externally. The first transport pattern is determined based on the control data of any one of the print width size, resolution, number of passes, and number of paintings included, or a combination thereof.

  In the print processing unit, the first transport unit operates in synchronization with the image data and print control data externally input from a computer or the like, that is, the print unit that operates based on the print width size, resolution, number of passes, and number of paints. As a result, the recording medium is conveyed. Therefore, the second transport control unit also determines the first transport pattern based on the individual control data included in such print control data or a combination thereof, and controls the operation of the second transport unit. The recording medium can be transported in the same transport pattern as the transport section.

  In the third feature configuration, as described in claim 3, in addition to the second feature configuration described above, the second transport control unit is provided with an intermediate time defined by a transport speed, a transport drive time, and a transport stop time. The first conveyance pattern is determined as a conveyance pattern.

  Specifically, the second conveyance control unit stops the conveyance when the print head provided in the printing unit performs the printing operation in the main scanning direction, and at the predetermined conveyance speed in the sub-scanning direction at the end of the printing operation in the main scanning direction. This can be realized by determining, as the first conveyance pattern, the same pattern as the intermittent conveyance pattern of the recording medium by the first conveyance unit that is conveyed and driven.

In the fourth feature configuration, in addition to any one of the first to third feature configurations described above, the print processing unit cuts the rear end of the recording medium after the print processing. The second transport control unit switches from the first transport mode to the second transport mode at a timing when the rear end of the recording medium passes through the drying unit with reference to an operation timing of the cutting mechanism. In the point.

  The portion of the recording medium that is dried while being transported by the second transport unit after the transport by the first transport unit described in the first feature configuration is described above. It becomes a site | part which passes a drying part, being conveyed by the 2nd conveyance part, after an edge is cut | disconnected by the cutting mechanism. Therefore, by switching from the first transport mode to the second transport mode at a predetermined timing based on at least the operation timing of the cutting mechanism, it is possible to uniformly dry the recording medium without causing uneven drying. is there.

As described in the fifth aspect, in addition to the fourth feature configuration described above, the fifth feature configuration includes a pair of rollers in which the second transport unit sandwiches the recording medium. The control unit controls the release mechanism so that no conveying force acts on the recording medium M conveyed between the rollers by releasing the pressure bonding of the roller from the start of printing until the cutting mechanism is operated. In the point which conveys in said 1st conveyance mode, after is operated.

According to the sixth characteristic configuration, as described in claim 6, an image is formed by ejecting ink droplets onto a first transport unit that transports a sheet-like recording medium and a recording medium transported by the first transport unit. A printing processing unit having a printing unit that forms a printing unit, a drying unit that receives and dries the recording medium discharged from the printing processing unit, and a second conveyance unit that conveys the recording medium dried by the drying unit. An image forming apparatus configured to include a drying processing unit having an average transport speed by the first transport unit until the rear end of the recording medium passes through the drying unit. A first transport mode for transporting the recording medium at the same transport speed, and a transport speed higher than the average transport speed of the recording medium in the first transport mode when the trailing end of the recording medium passes through the drying unit. in the conveying said recording medium Lies in is provided with a second conveyance control unit that conveys control is switched to one of the transport modes.

  In this case, the second transport control unit uses the second transport unit after the transport of the recording medium passing through the drying unit to be dried while being transported by the first transport unit, particularly after the transport by the first transport unit is completed. In a part that is dried while being transported, the recording medium transported in the first transport mode without disturbing the transport state by the first transport unit may be switched so that the recording medium after the drying process is transported efficiently in the second transport pattern. Therefore, it is possible to uniformly dry the recording medium without causing uneven drying over the entire surface of the recording medium. Here, the average transport speed by the first transport unit is based on the operation timing of the cutting mechanism described in the fourth feature configuration after the leading edge of the recording medium discharged from the print processing unit is received by the drying processing unit, for example. The average transport speed can be determined based on the time until the predetermined timing and the size of the recording medium, and based on the individual control data included in the print control data described in the second characteristic configuration or a combination thereof. Is also possible.

  As described above, according to the present invention, it is possible to provide an image forming apparatus capable of reliably drying ink without causing drying unevenness.

  Embodiments of an image forming apparatus according to the present invention will be described below. As shown in FIG. 1, the image forming apparatus 1 receives a print processing unit 1A that forms an image by ejecting ink droplets onto a sheet-like recording medium M, and a recording medium M that is discharged from the print processing unit 1A. A drying processing unit 1B for drying, a loop forming unit 1C for accumulating the recording medium M dried by the drying processing unit 1B in a loop shape, and a fixing processing unit for heating and fixing the recording medium M accumulated by the loop forming unit 1C 1D is comprised.

  As shown in FIG. 2, the recording medium M used in the image forming apparatus is integrated with a sheet-like base material M1 having a predetermined rigidity made of a synthetic resin material such as polyethylene terephthalate (PET) and the upper surface thereof. And a protective layer M2 made of a highly weatherable material such as a fluororesin, and an ink receiving layer M3 adhered to the upper surface of the protective layer M2 in a peelable manner with an adhesive.

  The print processing unit 1A prints an image such as a photographic image, an illustration, or a character on the surface of the ink receiving layer M3 with water-based ink containing a sublimation dye, and after drying in the drying processing unit 1B, heat treatment is performed in the fixing processing unit 1D. As a result, the sublimable dye I is sublimated and penetrates into the protective layer M2 to be fixed. Thereafter, the ink receiving layer M3 is peeled off to obtain a sheet on which a very glossy and vivid image is recorded. The recording medium M can be used for signboards, trains, buses, etc. installed outdoors. It is suitably used for an advertising image recording medium or the like attached to a vehicle body.

  As shown in FIGS. 1, 3, and 4, the print processing unit 1 </ b> A applies ink droplets to the print conveyance unit 10 that conveys the sheet-like recording medium M and the recording medium M that is conveyed by the print conveyance unit 10. The printing unit 20 is configured to be ejected to form an image, and is printed out on the recording medium M based on print data input via the communication control line L1 connected to the image processing system 100.

  The print transport unit 10 pulls out the recording medium M from a recording medium storage unit 10a in which a long recording medium M wound in a roll shape is rotatably supported by a pair of rollers 11 in the sub-scanning direction. The feeding unit includes a driving roller 12 driven by a transporting stepping motor and a pressing roller 13, and a suction unit 15 that prevents the recording medium M transported by the feeding unit from floating on the platen. . That is, the recording medium M is nipped and conveyed by the drive roller 12 and the pressing roller 13.

  The printing unit 20 ejects six sublimation inks of “black”, “cyan”, “magenta”, “yellow”, “light cyan”, and “light magenta” to form a color image. Drive including a head 21, a guide rod 22, 22 that supports the print head 21 so as to be reciprocally movable in the width direction of the recording medium M, and a stepping motor and a timing belt that reciprocally drive the print head 21 along the guide rod 22. An image is formed while reciprocating in the main scanning direction orthogonal to the sub-scanning direction with respect to the recording medium M that is configured to include a mechanism (not shown) and the like and is conveyed in the sub-scanning direction by the print conveying unit 10. .

  The print head 21 is attached with an ink cartridge 23 for supplying ink to an ejection mechanism (not shown) made of a piezo element and the like, and is lowered as necessary to cut the recording medium M along the main scanning direction. A cutter 24 is provided.

  The drying processing unit 1B includes a drying unit 30 that receives and dries the recording medium M discharged from the printing processing unit 1A, and a receiving conveyance unit 40 that conveys the recording medium M dried by the drying unit 30. ing.

  As shown in FIGS. 3 and 5, the drying unit 30 sucks hot air from the heater 31 disposed at the lower back of the apparatus and the guide passage 32 toward the ink application surface of the recording medium M. The receiving and conveying unit 40 includes an accepting roller 41 that receives and conveys the recording medium M delivered by the driving roller 12 of the print processing unit 1A on the downstream side of the drying unit 30. Yes.

  The loop forming unit 1C includes a first accumulation unit 50 that accommodates the recording medium M from the drying processing unit 1B in a loop shape without applying unnecessary tension, and the recording medium M accumulated in the first accumulation unit 50. The second storage unit 70 that similarly stores in a loop shape is provided, and the print processing unit 1A, the drying processing unit 1B, and the fixing processing unit 1D are provided. It is configured to absorb the difference between the respective processing speeds, that is, the conveyance speed of the recording medium M.

  As shown in FIGS. 3 and 5, the first accumulating unit 50 includes a receiving roller 41 that receives and conveys the recording medium M discharged from the print processing unit 1 </ b> A, and a recording medium M that is conveyed by the receiving roller 41. An intermediate roller 51 conveyed downstream, and a pair of receiving guide plates 56 and 57 disposed between the receiving roller 41 and the intermediate roller 51 are provided, and loop formation control is performed by a first loop control unit described later. Accordingly, the receiving roller 41 is also used as the receiving and conveying unit 40.

  The first loop control unit is conveyed by the receiving roller 41 and guided by the receiving guide plates 56 and 57, and the intermediate roller 51 and the intermediate roller 51 after a predetermined time after the leading end of the recording medium M is detected by the sensor S2. If the intermediate roller 51 is determined to be sandwiched between the first roller 52 and the first roller 52 disposed in pressure contact with each other, the lower end of the right guide plate 57 of the receiving guide plates 56 and 57 is swung to the right. By moving and opening, the recording medium M carried into the lower space is controlled to be accumulated in a loop between the receiving roller 41 and the intermediate roller 51.

  The second accumulator 70 is provided with an intermediate roller 51, a discharge roller 71, and a pair of discharge guide plates 72 and 73 for guiding the recording medium M between the intermediate roller 51 and the discharge roller 71. The loop formation control is performed by the second loop control unit.

  The second loop control unit is transported by the intermediate roller 51 and the third roller 54 and is discharged after a predetermined time after the leading edge of the recording medium M guided by the discharge guide plates 72 and 73 is detected by the sensor S3. If it is determined that the sheet is held between the two, the discharge roller 71 is stopped and the lower end of the left guide plate 73 of the discharge guide plates 72 and 73 is left swinging open to the left. Control is performed so that the recording medium M is accumulated in a loop between the discharge roller 71 and the intermediate roller 51.

  Although not described in detail, the receiving guide plate 57 and the discharge guide plate 73 act as guide plates for the recording medium M by rotating the sector gear mechanisms 58 and 74 connected to the swing shaft forward and backward by stepping motors, respectively. The position can be switched between an initial position to be opened and an open position in which the rocker is opened to form a loop.

  The recording medium M accumulated in the second accumulation unit 70 is then conveyed to the fixing processing unit 1D by a discharge roller 71 driven at a predetermined timing. As described above, the recording medium M discharged from the print processing unit 1 </ b> A is conveyed so as to be accommodated in the second accumulation unit 70 after being accommodated in the first accumulation unit 50, and further fixed from the second accumulation unit 70. It is conveyed to part 1D. Then, after the recording medium is conveyed from the first accumulation unit 50 to the second accumulation unit 70, a new recording medium M from the print processing unit 1 </ b> A is conveyed to the first accumulation unit 50, thereby printing the recording medium M, Each of the drying and fixing processes is continuously performed.

  As shown in FIG. 3, the fixing processing unit 1D includes a metal outer casing 80 and a heating casing 81 disposed in the outer casing 80. The heating casing 81 includes a heat insulating material (FIG. The inside of the heating casing 81 is configured as a heating area 82 of the recording medium M that is conveyed in the horizontal direction.

  The heating area 82 is provided with a heating and conveying mechanism 83 that conveys the recording medium M supplied from the loop forming unit 1C. The heating and conveying mechanism 83 sequentially receives and conveys the recording medium M from the upstream side in the conveying direction of the recording medium M. , A first transport roller group 85, a second transport roller group 86 disposed near the center of the fixing processing unit 1D, and a third transport roller group 87 disposed on the most downstream side, and a stepping motor and a transmission mechanism (not shown). Thus, any roller is driven to rotate at a peripheral speed synchronized with each other. Further, the peripheral surface of each roller is made of a material such as silicon rubber having a high friction coefficient and high heat resistance.

  The heating area 82 includes a plurality of rod-shaped heating elements 88 disposed upstream of the center of the heating area 82 above the conveyance surface of the recording medium M, and the heating area 82 above the conveyance surface of the recording medium M. A first heating mechanism 91 that heats the internal air to a predetermined temperature (for example, around 180 degrees), a first transport roller group 85, and a second The back surface of the recording medium M includes a first heating panel 92 disposed between the transport roller group 86 and a second heating panel 93 disposed between the second transport roller group 86 and the third transport roller group 87. The recording medium M heated by contact is heated with the second heating mechanism 94, and the recording medium M heated by this is a slope-like discharge chute 95 formed of a polyethylene film provided outside the apparatus after the fixing process is completed. Discharged to the top.

As shown in FIG. 1, the image processing system 100 includes a general-purpose computer 101, a monitor device 102, a keyboard 103 and a mouse 104, a film scanner 105 that photoelectrically converts image information of a developed photographic film F, and the like. The computer 102 includes a media drive unit 101a for reading image data recorded on various electronic data recording media such as a CD-R, MO, CompactFlash (registered trademark) card, floppy (registered trademark) disk, etc. Is built-in.

  Photo image data read by the film scanner 105, image data read from an electronic data recording medium, and the like are edited by the image processing system 100, and are sent as print data to the above-described image forming apparatus via the communication control line L1. A predetermined image forming operation is activated by the input.

Control block configuration of the above-described image forming apparatus, as shown in FIG. 8, the print processing control unit 200 for controlling the printing processing by the above-described Printout processing section 1A, drying of the recording medium by drying section 1B above A drying processing control unit 300 for performing the above, a loop control unit 400 for controlling the conveyance and accumulation of the recording medium M by the loop forming unit 1C, and a fixing processing control unit 500 for controlling the fixing processing by the fixing processing unit 1D. It is configured.

  The print processing control unit 200 includes a microcomputer 201, memories of ROM 202 and RAM 203, a communication interface circuit 204 with the computer 101 of the image processing system 100, and a driving roller 12 that conveys the recording medium M in the sub-scanning direction. , A suction fan provided in the suction unit 15, a drive mechanism for reciprocally driving the print head 21 in the main scanning direction, a driver circuit 205 for a print head for discharging ink droplets, the remaining amount of the recording medium M, a transport position, ink A signal input buffer circuit 206 such as the remaining amount of the cartridge 23 is provided, and each load is driven and controlled based on a predetermined sequence program and an input signal stored in the ROM 202.

  The loop control unit 400 includes a microcomputer 401, ROM 402 and RAM 403 memories, a communication interface circuit 404 with the computer 101 of the image processing system 100, a receiving roller 41, an intermediate roller 51, a discharging roller 71, and a receiving guide. The driver circuit 405 for the plate 57, the discharge guide plate 73, and the like, and a plurality of signal input buffer circuits 406 for detecting the transport position of the recording medium M, are configured based on a predetermined sequence program and input signals stored in the ROM 402. The first loop control unit that controls the storage of the recording medium M by the first storage unit 50 and the second loop control unit that controls the storage of the recording medium M by the second storage unit 70 by driving and controlling each load. Function as.

  The drying processing control unit 300 and the fixing processing control unit 500 are configured to include driver circuits 301 and 501 for heaters, fans, conveyance rollers, and the like, and signal input buffer circuits 302 and 502 such as temperature sensors, and the loop control unit. The microcomputer 401 is driven and controlled.

  The schematic basic operation of the above-described image forming apparatus will be described below with reference to the flowcharts shown in FIGS. As shown in FIG. 9, when print data is input from the computer 101 to the print processing control unit 200 via the signal cable L1, the suction unit 15 is operated and the driving roller 12 is driven to drive the leading end of the recording medium M. Is transported so as to be positioned at a predetermined position with respect to the print head 21 (S1). Next, while moving the print head 21 in the main scanning direction, that is, along the guide rod 22, the ink droplets of each color are ejected and controlled according to the image data included in the print data, and an image for one line is formed on the recording medium M. Form (S2). Thereafter, the print head 21 is moved back to the home position set on the base end side of the guide rod 22 and the recording medium M is conveyed by one line in the sub-scanning direction. By repeating such an operation, a color image by ink droplets is formed on the recording medium M.

  The transport pattern of the recording medium M by the print transport unit 10 at the time of the above-described print control is the print control data included in the print data, that is, the print width size that defines the scanning distance of the print head 21, and one line in the sub-scanning direction. The resolution that defines the transport amount, the number of passes that defines the number of times the head reciprocates to print one line (set to either 8 or 16 passes in this print processor), and the same line is overcoated It is expressed as an intermittent driving pattern of a predetermined interval determined based on any one of the number of coatings that defines the number of times (set to one or two in the print processing unit) or a combination thereof.

  When printing of one screen is completed in this way, the cutter 24 provided in the print head 21 is lowered while the drive roller 12 of the print transport unit 10 is stopped, and the home position is moved to the other end. The recording medium M is cut by moving the print head 21 forward.

  The recording medium M discharged while being intermittently conveyed by the conveying force of the driving roller 12 of the print processing unit 1A is subjected to ink drying processing by blowing hot air from the surface in the downstream drying processing unit 1B. Guided to the loop forming unit 1C.

  At the same time when print data is input to the print processing control unit 200, the above-described print control data is input to the loop control unit 400 from the computer 101 via the signal cable L2. Here, the print control data or the data corresponding thereto may be directly input from the print processing control unit 200. The ROM 402 of the loop control unit 400 stores in advance the process data of the print processing unit 1A such as the scanning speed data of the print head 21 and the conveyance speed data of the driving roller 12, and the loop control unit 400 controls the process data and the print control. Based on the data, a driving pattern in which the driving roller 12 of the print processing unit 1A intermittently conveys the recording medium M, that is, an intermittent conveying pattern defined by the conveying speed, the conveying driving time, and the conveying stop time, is generated and dried. Drive control of the receiving roller 41 of the section 1B (also used as the receiving roller of the loop forming unit) so as to transport the recording medium M in the same first transport pattern as the transport pattern of the recording medium M by the driving roller 12 The recording medium M is transported in a first transport mode to be performed and a second transport pattern different from the first transport pattern. It is configured to switch control between the second conveying mode.

  More specifically, as shown in FIG. 6A, the loop control unit 400 (first loop control unit) drives and controls the receiving roller 41 and the intermediate roller 51 in the first transport mode when the printing process is started. (S3), if it is determined that the front end of the recording medium M has been sandwiched between the intermediate roller 51 and the first roller 52 after a predetermined time after the front end of the recording medium M is detected by the sensor S2 (S4), FIG. As shown, the intermediate roller 51 is stopped and the receiving guide plate 57 is rocked and released, and the recording medium M is accumulated in a loop between the receiving roller 41 and the intermediate roller 51 (S5). In this state, in the first accumulation unit 50, the loop amount gradually increases as the recording medium M is conveyed by the receiving roller 41.

  When printing is finished and a signal to the effect that cutting of the recording medium M is finished by the cutter 24 is input from the print processing unit 1A (S6), as shown in FIG. By transporting the recording medium M while maintaining the first transport mode for the distance until the trailing edge of the medium M passes through the drying unit 30, the recording medium M is uniformly dried over the entire surface in the drying unit 30. (S7).

When the trailing edge of the recording medium M passes through the drying unit 30, the receiving roller 41 is driven and controlled by switching from the first conveyance mode to the second conveyance mode (S8). The second transport mode is set at a constant and higher transport speed than the average transport speed of the recording medium M in the first transport mode. As shown in FIG. 7 (a), when the trailing end of the recording medium M by the sensor S1 is judged to have reached the receiving roller 41 is detected (S9), after the recording medium M by the acceptance Re roller 41 is stopped The end is held (S10).

  Next, loop formation control in the first accumulation unit 50 will be described. A loop forming space of the first storage unit 50 is provided with a first loop detection sensor LS1 that detects the loop amount of the recording medium M to be stored, and the first loop control unit detects that the detected loop amount is the minimum allowable storage amount. And the intermediate roller 51 is driven at a constant conveyance speed higher than the average conveyance speed of the recording medium M in the first conveyance mode so as not to exceed the maximum allowable accumulation amount and conveyed to the second accumulation unit 70. To do.

  That is, as shown in FIG. 10, when the detected accumulated amount (S11) is larger than the minimum allowable accumulated amount (S12), the intermediate roller 51 is driven at a constant speed (S13), and the accumulated amount is smaller than the minimum allowable accumulated amount. Is smaller (S12), and when the receiving roller 41 is driven in the first transport mode to accumulate the recording medium M (S14), the intermediate roller 51 is stopped to promote the formation of a loop (S14). S15). When it is smaller than the minimum allowable accumulation amount (S12) and when the receiving roller 41 is stopped so as to sandwich the rear end portion of the recording medium M (S14), the intermediate roller 51 is driven at a constant speed (S16). ), The receiving roller 41 is driven, and the receiving guide plate is returned to the initial position (S17, S18). When the rear end of the recording medium M reaches the intermediate roller 51 (S19), the intermediate roller 51 is stopped and the rear end is clamped (S20). In step S12, when an accumulation amount larger than the minimum allowable accumulation amount and slightly smaller than the maximum allowable accumulation amount is detected, the intermediate roller 51 is driven to secure a sufficient accumulation amount within the allowable range. Can do.

  As shown in FIG. 7B, the loop amount of the recording medium in the first accumulation unit 50 is gradually reduced by driving the intermediate roller 51. Therefore, when the loop amount of the recording medium M in the first storage unit 50 reaches a predetermined allowable minimum loop amount, the first loop control unit drives the receiving roller 41 to move the rear end portion of the recording medium M. The first storage unit 50 is dropped and the receiving guide plate 57 is returned to the initial position to prepare for receiving the next recording medium M.

  The minimum allowable accumulation amount is a predetermined margin added to the linear distance between the receiving roller 41 and the intermediate roller 51 so as not to forcibly pull and convey the recording medium M conveyed or pinched by the receiving roller 41. Both conveying rollers that are not in contact with the print surface of the recording medium M that is stored when the trailing edge of the recording medium M falls through the receiving roller 41 in that state. The minimum amount of deflection required for the recording medium M is the maximum allowable accumulation amount. The maximum allowable accumulation amount is the maximum amount of deflection in which contact between the print surfaces is avoided by the formed loop. Both the minimum allowable accumulation amount and the maximum allowable accumulation amount are values that can be set based on the type of recording medium and / or the amount of ink attached to the printing area on the recording medium M by repeating thought and error such as experiments. The loop amount is detected by the first loop detection sensor LS1. The first loop detection sensor LS1 can be realized by arranging a single or a plurality of reflection type or transmission type optical sensors in the loop forming space, and the driving time of the receiving roller 41 after the intermediate roller 51 is stopped and its time It can also be configured by a program module that calculates and derives from the conveyance speed.

  Next, loop formation control in the second storage unit 70 will be described. A second loop detection sensor LS2 for detecting the loop amount of the recording medium M to be stored is provided in the loop formation space of the second storage unit 70, and the second loop control unit determines that the detected loop amount is the minimum required storage amount. The discharge roller 71 is driven at the same conveyance speed as the receiving conveyance roller 84 of the fixing processing unit 1D and conveyed to the fixing processing unit 1D so as not to exceed the maximum allowable accumulation amount.

  That is, as shown in FIG. 11, when it is determined that the leading end portion of the recording medium M conveyed from the intermediate roller 51 has reached the discharge roller 71 after a predetermined time after being detected by the sensor S3 (S21), the discharge roller 71 (S22), the discharge guide plate 73 is swung open (S23), and the recording medium M is controlled to accumulate in a loop between the discharge roller 71 and the intermediate roller 51. In this state, in the second accumulation unit 70, the loop amount gradually increases as the recording medium M is conveyed by the intermediate roller 51.

  When a predetermined amount of loop is formed and the accumulation amount (S24) detected by the second loop detection sensor LS2 is larger than the minimum allowable accumulation amount (S25), the discharge roller 71 is driven (S26), and the minimum allowable accumulation amount is obtained. If smaller than (S25), the intermediate roller 51 is driven (S27), and the discharge guide plate 73 is returned to the initial position to prepare for the next recording medium M (S28). As shown in FIG. 7C, the loop amount of the recording medium M in the second accumulation unit 70 is gradually reduced by driving the discharge roller 71. Therefore, when the loop amount of the recording medium in the second accumulation unit 70 reaches a predetermined allowable minimum loop amount, the intermediate roller 51 is driven to drop the rear end portion of the recording medium M onto the second accumulation unit. is there. In step S24, when the accumulation amount larger than the minimum allowable accumulation amount and slightly smaller than the maximum allowable accumulation amount is detected, the discharge roller 71 is driven to ensure a sufficient accumulation amount within the allowable range. Can do.

  Here, the minimum allowable accumulation amount is a predetermined margin in the linear distance between the intermediate roller 51 and the discharge roller 71 so that the recording medium M conveyed or sandwiched by the intermediate roller 51 is not forcibly pulled and conveyed. In addition, both conveyances in which the trailing edge does not come into contact with the print surface of the recording medium M accumulated when the trailing edge of the recording medium falls through the receiving roller in this state. The minimum amount of deflection required for the recording medium M between the rollers is referred to, and the maximum allowable accumulation amount is the maximum amount of deflection in which contact between the print surfaces is avoided by the formed loop. Both the minimum allowable accumulation amount and the maximum allowable accumulation amount are values that can be set for each type of recording medium and / or the amount of ink adhering to the printing area on the recording medium M through repeated thoughts and errors such as experiments. The amount is detected by the second loop detection sensor LS2. The second loop detection sensor LS2 can be realized by arranging a single or a plurality of reflective or transmissive optical sensors in the loop forming space, and the driving time of the intermediate roller 51 after the discharge roller 71 is stopped and its conveyance. It can also be composed of program modules that derive operations from speed.

  That is, the image forming apparatus according to the present invention ejects ink droplets onto the print transport unit 10 as a first transport unit that transports the sheet-like recording medium M and the recording medium M transported by the first transport unit. A printing processing unit 1A having a printing unit 20 for forming an image, a drying unit 30 for receiving and drying the recording medium M discharged from the printing processing unit 1A, and the recording medium M dried by the drying unit 30 And a drying processing unit 1B having a receiving roller 41 as a second conveying unit that conveys the recording medium, and the second conveying unit is configured to record the first conveying pattern in the same first conveying pattern as the conveying pattern formed by the first conveying unit. A second transport control unit that controls transport by switching between a first transport mode for transporting the medium M and a second transport mode for transporting the recording medium M in a second transport pattern different from the first transport pattern; Loop control unit 400 is provided, and the second transport control unit performs transport control with the first transport pattern until the rear end of the recording medium passes through the drying unit, The print processing unit 1A is provided with a cutter 24 as a cutting mechanism for cutting the rear end of the recording medium M after the printing process, and the second transport control unit is configured to perform the above operation at a predetermined timing based on the operation timing of the cutting mechanism. The first transport mode is switched to the second transport mode.

  In the above-described embodiment, the drive roller 41 is driven and controlled in the first transport mode from the beginning until the trailing edge of the recording medium M passes through the drying unit 30. The drive control in the mode may be performed at least from the cutting of the recording medium M by the cutting mechanism until the trailing edge of the recording medium M passes through the drying unit 30. That is, while the transport driving force by the print transport unit 10 is acting on the recording medium M, the second transport mode different from the first transport mode, that is, the recording medium on which the receiving roller 41 is transported by the print transport unit 10. The receiving roller 41 may be configured by conveying with a conveyance pattern that does not exert a compulsory conveyance force on M (for example, a conveyance pattern (including intermittent conveyance) having a conveyance speed lower than the conveyance speed by the print conveyance unit 10). Control may be performed so that the conveyance force does not act on the recording medium M conveyed between the rollers by releasing the pressure bonding of the pair of rollers. In the latter case, after the rear end of the recording medium M passes through the drying unit 30, the roller is pressed and conveyed.

  Further, the first transport mode in which the second transport unit transports the recording medium at the same transport speed as the average transport speed by the first transport unit, and the recording medium is transported at a transport speed different from the average transport speed. A second conveyance control unit that controls conveyance by switching to one of the second conveyance modes is provided, and at least a period from when the recording medium is cut by the cutting mechanism until the trailing edge of the recording medium passes through the drying unit is provided. The conveyance control may be performed in the conveyance mode.

In the embodiment described above, the second transport mode in which the recording medium is transported in a second transport pattern different from the first transport pattern does not mean a specific single transport pattern, and is different from the first transport pattern. If it is a conveyance pattern, it means that a plurality of conveyance patterns are included. For example, during printing on the recording medium while being transported by the first transport unit, and at least during printing even if both transport patterns after the recording medium is cut and its trailing edge passes through the drying unit are not the same all transport pattern different from the first conveyance pattern corresponding to the transport pattern is intended to mean a second conveying pattern.

  The above-described embodiment is merely one embodiment of the present invention. According to the description, the specific configuration of the first transport unit, the second transport unit, and another transport unit, or the print processing unit, the drying processing unit, and the loop are described. The specific configurations of the forming unit, the fixing processing unit, and the like are not limited, and can be appropriately changed and configured within the range where the effects of the present invention can be achieved.

1 is an external perspective view showing a schematic configuration of an image forming apparatus according to the present invention. Illustration of recording medium Side sectional view showing schematic configuration of image forming apparatus Side sectional view showing the schematic configuration of the print processing unit Side sectional view showing schematic configuration of loop forming unit Explanatory drawing showing the general operation of the loop forming unit Explanatory drawing showing the general operation of the loop forming unit Control block diagram of image forming apparatus Flowchart explaining operation of image forming apparatus Flowchart explaining operation of image forming apparatus Flowchart explaining operation of image forming apparatus

1: Image forming apparatus 1A: Print processing unit 1B: Drying processing unit 1C: Loop forming unit 1D: Fixing processing unit 10: First transport unit (print transport unit)
20: Printing unit 24: Cutting mechanism (cutter)
30: Drying unit 41: Second transport unit (receiving roller)
400: Loop control unit M: Recording medium

Claims (6)

A first transport unit that transports a sheet-like recording medium, a print processing unit that includes a printing unit that forms an image by ejecting ink droplets onto the recording medium transported by the first transport unit, and the print processing unit. An image forming apparatus comprising: a drying unit that receives and dries the discharged recording medium; and a drying processing unit that includes a second conveyance unit that conveys the recording medium dried by the drying unit. ,
A first conveyance mode for conveying the recording medium in the same first conveyance pattern as the conveyance pattern by the first conveyance unit until the rear end of the recording medium passes through the drying unit through the second conveyance unit; When the trailing edge of the recording medium passes through the drying unit, the recording medium is transported in a second transport pattern that transports the recording medium at a transport speed higher than the average transport speed of the recording medium in the first transport mode. An image forming apparatus provided with a second conveyance control unit that performs conveyance control by switching to one of the second conveyance modes.   The second transport control unit is based on control data of print width size, resolution, number of passes, number of paints included in print control data externally input to the print processing unit, or a combination thereof. The image forming apparatus according to claim 1, wherein the first transport pattern is determined.   The image forming apparatus according to claim 2, wherein the second transport control unit determines the first transport pattern as an intermittent transport pattern defined by a transport speed, a transport drive time, and a transport stop time. The print processing unit includes a cutting mechanism that cuts the trailing end of the recording medium after the printing process, and the second transport control unit passes the drying unit through the drying unit based on the operation timing of the cutting mechanism. 4. The image forming apparatus according to claim 1 , wherein the image forming apparatus is switched from the first conveyance mode to the second conveyance mode at a timing of performing. The second transport unit includes a pair of rollers that sandwich the recording medium, and the second transport control unit releases the press-bonding of the roller from the start of printing until the cutting mechanism is operated. The image forming apparatus according to claim 4, wherein a control is performed so that a transport force does not act on the recording medium M transported between rollers, and the recording medium is transported in the first transport mode after the cutting mechanism is operated. A first transport unit that transports a sheet-like recording medium, a print processing unit that includes a printing unit that forms an image by ejecting ink droplets onto the recording medium transported by the first transport unit, and the print processing unit. An image forming apparatus comprising: a drying unit that receives and dries the discharged recording medium; and a drying processing unit that includes a second conveyance unit that conveys the recording medium dried by the drying unit. ,
Said second transport section, until said trailing end of the recording medium passes through the drying unit, a first conveying mode for conveying the recording medium at an average transport speed and same conveying speed of the first conveyance portion, the When the trailing edge of the recording medium passes through the drying unit, the recording medium is switched to one of the second conveyance modes for conveying the recording medium at a conveyance speed higher than the average conveyance speed of the recording medium in the first conveyance mode. An image forming apparatus provided with a second conveyance control unit to be controlled.

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