JP2011148106A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus which can improve the determination accuracy of the occurrence of jamming. <P>SOLUTION: The image forming apparatus 1 includes a condition detecting part 9 which detects humidity or temperature and outputs humidity information HD or temperature information TD; a storage part 62 which stores both a jamming history table 65 in which the humidity Hn or temperature Tn and a jamming occurrence rate JPn are related with each other, and a jamming threshold ThJ that is a threshold of the jamming occurrence rate JPn; and a control unit 12 which acquires a jamming occurrence rate JP corresponding to the humidity information HD or temperature information TD inputted from the condition detecting part 9 out of the jamming history table 65, carries out a jamming reduction mode when the acquired jamming occurrence rate JP is not smaller than the jamming threshold ThJ, and updates the jamming history table 65 stored in the storage part 62. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a printing apparatus, a copying machine, or a multifunction machine.

  There is known an image forming apparatus that forms an image on a print medium while conveying the print medium. In such an image forming apparatus, jamming (clogging) of a print medium is a problem. In particular, in a large-sized image forming apparatus, it is difficult to eliminate a jam. Therefore, measures against jamming are required.

  Patent Document 1 discloses an image forming apparatus including a humidity detecting unit that detects humidity, a dehumidifying device that dehumidifies a paper feed tray, and a control unit. In this image forming apparatus, humidity information is input from the humidity detection means to the control unit. The control unit controls the dehumidifying device based on the humidity information to heat the temperature of the paper feed tray. Thus, the control unit sets the humidity of the paper feed tray to the target humidity. Thereafter, the control unit starts printing. Thereby, the control part is reducing the jam by humidity.

JP 2008-33259 A

  However, since the target humidity is fixed in the technique of Patent Document 1, there is a problem that the determination accuracy of whether or not a jam occurs is low.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus that can improve the accuracy of determining whether or not a jam occurs.

  In order to achieve the above object, the first feature of the image forming apparatus according to the present invention is that condition detection means for detecting humidity or temperature and outputting humidity information or temperature information, humidity or temperature and jam occurrence rate. Are stored in a jam history table, a jam threshold value that is a threshold value of a jam occurrence rate, and a jam history table that indicates a jam occurrence rate corresponding to humidity information or temperature information input from the condition detection unit. And when the acquired jam occurrence rate is equal to or greater than the jam threshold, printing is performed so as to reduce the jam, and the control unit updates the jam history table stored in the storage unit. Yes.

  A second feature of the image forming apparatus according to the present invention is that a condition detection unit that detects humidity or temperature and outputs humidity information or temperature information, and a jam in which humidity or temperature and a jam occurrence rate are associated with each other. A storage unit that stores a history table and a jam threshold that is a threshold of a jam occurrence rate, and a jam occurrence rate corresponding to humidity information or temperature information input from the condition detection unit is obtained from the jam history table and acquired. When the jam occurrence rate is equal to or greater than the jam threshold after the lapse of a threshold time from the start or stop of printing, the control unit executes printing so as to reduce the jam and updates the jam history table stored in the storage unit And.

A third feature of the image forming apparatus according to the present invention is that, when the control unit executes printing so as to reduce jamming,
Decrease the transport speed or
Reduce the amount of ink, or
Reduce the path to select a paper output destination with a short transport path, or
Force double-sided printing to single-sided printing, or
Printing is performed under at least one of reducing the image.

  A fourth feature of the image forming apparatus according to the present invention is that the control unit can execute a jam threshold value changing process for changing the jam threshold value.

  A fifth feature of the image forming apparatus according to the present invention is that the control unit can change a print setting for reducing jamming.

  According to the first feature, the control unit updates the jam history table stored in the storage unit. Further, the control unit executes printing so that the jam is reduced when the jam occurrence rate acquired from the jam history table is equal to or more than the jam threshold. Thus, since the control unit determines the occurrence of a jam based on the jam occurrence rate of the jam history table to be updated, it is possible to improve the accuracy of determining whether or not a jam occurs.

  According to the second feature, the control unit updates the jam history table stored in the storage unit. Further, the control unit executes printing so that the jam is reduced when the jam occurrence rate acquired from the jam history table is equal to or more than the jam threshold after the threshold time has elapsed. Thus, since the control unit determines the occurrence of a jam based on the jam occurrence rate of the jam history table to be updated, it is possible to improve the accuracy of determining whether or not a jam occurs. Further, since the control unit stands by for a threshold time from the start or interruption of printing even if the jam occurrence rate is equal to or greater than the jam threshold, the second feature can omit the dehumidifying device and the like. Thereby, the configuration of the second feature can be simplified.

  The third feature is that jamming can be reduced by reducing slippage of a print medium nipped by a roller or the like when the conveyance speed is reduced, the ink color is reduced, or the image is reduced. it can. The third feature is that jamming can be reduced by shortening the path when forcing one-sided printing and when shortening the path.

  The fourth feature is that the jam threshold value can be changed, so that it can cope with the desires of a user who wants to reduce jams and, conversely, a user who wants to increase printing speed.

  The fifth feature is that the setting of printing for reducing jam can be changed, so that it is possible to cope with a user who desires printing by omitting the reduction of jam.

1 is an overall schematic diagram of an image forming apparatus according to a first embodiment. 2 is a block diagram for explaining a control system of the image forming apparatus. FIG. It is a figure for demonstrating a jam log | history table. 5 is a flowchart for explaining a printing operation according to the first embodiment. It is a figure for demonstrating the jam log | history table by 2nd Embodiment. It is a figure for demonstrating the other jam log | history table by 2nd Embodiment. It is a flowchart of the jam threshold value change process by 3rd Embodiment. It is a figure for demonstrating a jam threshold value change screen. It is a flowchart of jam reduction mode selection processing by a 4th embodiment. It is a figure for demonstrating a jam reduction mode selection screen.

<First Embodiment>
Hereinafter, a first embodiment in which the present invention is applied to an ink jet printing apparatus capable of duplex printing will be described with reference to the drawings. FIG. 1 is an overall schematic diagram of an image forming apparatus according to a first embodiment. FIG. 2 is a block diagram for explaining a control system of the image forming apparatus. FIG. 3 is a diagram for explaining the jam history table. In the following description, the paper surface direction of FIG. Further, as indicated by arrows in FIG. 1, when viewed from the user, the vertical and horizontal directions are the vertical and horizontal directions.

  Note that a path indicated by a thick line in FIG. 1 is a transport path through which the printing paper is transported. A route indicated by a solid line among the transport routes is a normal route RC. The route indicated by the alternate long and short dash line in the transport route is the reverse route RR. Out of the transport routes, the routes indicated by dotted lines are the paper discharge routes RD1 and RD2. A path indicated by a two-dot chain line in the transport path is a paper feed path RS. In the following description, upstream and downstream mean upstream and downstream in the transport path.

  Here, in the case of single-sided printing, the printing paper (corresponding to the print medium in the claims) PA is conveyed in the order of the paper feed path RS, the normal path RC, the first paper discharge path RD1, or the second paper discharge path RD2. The In duplex printing, the printing paper PA is conveyed in the order of the paper feed path RS, the normal path RC, the reverse path RR, the normal path RC, the first paper discharge path RD1, or the second paper discharge path RD2.

  As shown in FIGS. 1 and 2, the image forming apparatus 1 according to the first embodiment includes a paper feeding unit 2, a transport printing unit 3, a first paper discharge unit 4, a transport unit 5, and a second paper discharge. Unit 6, reversing unit 7, jam detecting unit 8, condition detecting unit 9, operation panel 10, timer 11, control unit 12, and housing 13 for storing or holding each unit 2 to 12. ing.

  The paper feed unit 2 transports and feeds the printing paper PA to the normal route RC. The paper feed unit 2 is arranged on the most upstream side of the transport path. The sheet feeding unit 2 includes a sheet feeding table 15, a plurality of sheet feeding rollers 16, and a sheet feeding driving unit 17.

  The paper feed tray 15 is for loading printing paper PA for paper feed. The paper feed roller 16 is for transporting the printing paper PA stacked on the paper feed tray 15 to the transport printing unit 3. The paper feed roller 16 is disposed along the paper feed path RS. The paper feed drive unit 17 drives the paper feed roller 16 to rotate. The paper feed driving unit 17 has a plurality of motors.

  The transport printing unit 3 prints an image on the print paper PA while transporting the print paper PA. The transport printing unit 3 is disposed on the downstream side of the paper feeding unit 2. The conveyance printing unit 3 includes a registration roller 21, a belt conveyance unit 22, an inkjet head unit 23, and a first conveyance driving unit 24.

  The registration roller 21 conveys the printing paper PA conveyed from the paper feeding unit 2 or the reversing unit 7 to the belt conveyance unit 22. The registration roller 21 is disposed on the normal route RC, upstream of the transport printing unit 3. In other words, the registration roller 21 is disposed in the vicinity of the junction point between the sheet feeding path RS and the reversing path RR.

  The belt conveyance unit 22 conveys the lower surface of the printing paper PA conveyed from the registration roller 21 to the first paper discharge unit 4 or the conveyance unit 5 while sucking the lower surface of the printing paper PA by the endless belt. The belt conveyance unit 22 is disposed on the downstream side of the normal path RC from the registration rollers 21. The belt conveyance unit 22 is disposed below the normal route RC.

  The ink jet head unit 23 prints an image on the printing paper PA. The inkjet head unit 23 includes a plurality of line-type inkjet heads (not shown). The inkjet head unit 23 is disposed on the opposite side of the belt conveyance unit 22 with the normal route RC interposed therebetween. That is, the inkjet head unit 23 is disposed so as to face the belt conveyance unit 22. The plurality of ink jet heads ejects four different colors of ink.

  The first conveyance drive unit 24 drives the belt conveyance unit 22 while rotating the registration rollers 21. The first transport driving unit 24 has a plurality of motors.

  The first paper discharge unit 4 discharges and holds the printed printing paper PA. The first paper discharge unit 4 is arranged along a first paper discharge path RD1 extending from the boundary between the transport printing unit 3 and the transport unit 5. The first paper discharge unit 4 includes a first switching unit 26, a pair of first paper discharge rollers 27, a first paper discharge table 28, and a first paper discharge drive unit 29.

  The first switching unit 26 switches the transport route between the normal route RC and the first paper discharge route RD1. The first switching unit 26 is disposed at a branch point between the normal route RC and the first paper discharge route RD1.

  The first paper discharge roller 27 discharges the printing paper PA conveyed from the belt conveyance unit 22 to the first paper discharge tray 28. The first paper discharge roller 27 is disposed between the first switching unit 26 and the first paper discharge stand 28 along the first paper discharge path RD1.

  The first paper discharge tray 28 is used for stacking printed printing paper PA. The printing paper PA stacked on the first paper discharge tray 28 is discharged such that the side on which the image is printed (or the side on which the image is printed later) faces upward.

  The first paper discharge drive unit 29 drives the first paper discharge roller 27 to rotate. The first paper discharge drive unit 29 has a motor.

  The transport unit 5 transports the printing paper PA transported by the transport printing unit 3 so as to make a U-turn. The transport unit 5 includes a plurality of transport rollers 31 and a transport drive unit 32.

  The plurality of pairs of conveyance rollers 31 convey the printing paper PA while nipping it. The plurality of pairs of transport rollers 31 are arranged along the normal route RC between the transport printing unit 3 and the second switching unit 35. The transport driving unit 32 rotationally drives a plurality of pairs of transport rollers 31. The second transport drive unit 32 has a plurality of motors.

  The second paper discharge unit 6 discharges and holds the printed printing paper PA. The second paper discharge unit 6 is disposed along the second paper discharge path RD2 extending from the downstream end of the normal path RC. The second paper discharge unit 6 includes a second switching unit 35, a plurality of pairs of second paper discharge rollers 36, a second paper discharge table 37, and a second paper discharge drive unit 38.

  The second switching unit 35 switches the transport path between the second paper discharge path RD2 and the reverse path RR. The second switching unit 35 is disposed at a branch point between the second paper discharge route RD2 and the reversal route RR.

  The second paper discharge roller 36 discharges the printing paper PA conveyed by the conveyance unit 5 to the second paper discharge tray 37. The second paper discharge roller 36 is disposed between the second switching unit 35 and the second paper discharge table 37 along the second paper discharge path RD2.

  The second paper discharge tray 37 is for stacking printed printing paper PA. The printing paper PA loaded on the second paper discharge tray 37 is discharged such that the surface on which the image is printed (or the surface on which the image is printed later) faces downward.

  The second paper discharge drive unit 38 rotates the second paper discharge roller 36. The second paper discharge driving unit 38 has a motor.

  The reversing unit 7 reverses the single-side printed printing paper PA and feeds it again to the transport printing unit 3 during double-sided printing. The reversing unit 7 includes a forward roller 41, a reversing roller 42, a returning roller 43, a switchback unit 44, a flipper 45, and a reversing drive unit 46.

  The forward roller 41 and the reverse roller 42 carry the printing paper PA conveyed from the conveyance unit 5 into the switchback unit 44. The forward roller 41 and the reverse roller 42 are disposed between the second switching unit 35 and the switchback unit 44 along the reverse route RR. The reversing roller 42 and the return roller 43 carry out the printing paper PA carried into the switchback unit 44. The return path roller 43 is disposed between the reverse roller 42 and the registration roller 21.

  The switchback portion 44 is a space formed inside the second paper discharge tray 37. The switchback portion 44 is opened on the reverse roller 42 side.

  The flipper 45 guides the printing paper PA conveyed by the forward roller 41 to the reverse roller 42. Further, the flipper 45 guides the printing paper PA carried out of the switchback unit 44 by the reverse roller 42 to the return roller 43. The flipper 45 is arranged at a location where the forward path and the return path branch in the reversal path RR.

  The reverse drive unit 46 rotationally drives the forward roller 41, the reverse roller 42, and the backward roller 43. Here, the reversing drive unit 46 drives the reversing roller 42 to rotate in both the forward direction (when carrying in) and the reverse direction (when carrying out). The inversion drive unit 46 has a plurality of motors.

  The jam detection unit 8 is for detecting the printing paper PA so that the control unit 12 determines the occurrence of a jam. The jam detection unit 8 includes a plurality of paper sensors 50 to 54. The sheet sensors 50 to 54 are optical sensors each having a light emitting element and a light receiving element. The plurality of paper sensors 50 to 54 are arranged on the transport routes RC, RD2, and RR. Specifically, the paper sensor 50 is disposed on the normal route RC in the vicinity of the upstream end portion of the belt conveyance unit 22. The sheet sensor 51 is disposed on the normal route RC in the vicinity of the downstream end of the belt conveyance unit 22. The sheet sensor 52 is disposed on the normal route RC in the vicinity of the second switching unit 35. The paper sensor 53 is disposed on the second paper discharge path RD2 in the vicinity of the second paper discharge tray 37. The paper sensor 54 is disposed on the reverse path RR in the vicinity of the reverse roller 42.

  The condition detection unit 9 detects and outputs a condition inside the housing 13. The condition detection unit 9 includes a humidity sensor 56 and a temperature sensor 57. The humidity sensor 56 is attached to the inner peripheral surface of the housing 13. The humidity sensor 56 detects the humidity inside the housing 13 and outputs the humidity to the control unit 12 as humidity information HD. The temperature sensor 57 is attached to the inner peripheral surface of the housing 13. The temperature sensor 57 detects the temperature inside the housing 13 and outputs the temperature to the control unit 12 as temperature information TD. The location where the humidity sensor 56 and the temperature sensor 57 can be attached can be changed as appropriate. However, the vicinity of a device (inkjet head unit) that becomes highly humid or a device (such as a motor) that becomes hot is not preferable.

  The operation panel 10 displays various images and information, and is used by the user to input information and instructions. The operation panel 10 includes a liquid crystal panel, a touch panel, operation keys, and the like.

  The timer 11 outputs the current time TR to the control unit 12.

  Next, the control system of the image forming apparatus 1 will be described with reference to FIG.

  The control unit 12 governs overall control of the image forming apparatus 1. That is, the control unit 12 includes the paper feeding unit 2, the transport printing unit 3, the first paper discharge unit 4, the transport unit 5, the second paper discharge unit 6, the reversing unit 7, and the jam detection unit 8. The condition detection unit 9, the operation panel 10, and the timer 11 are controlled. The control unit 12 includes a calculation unit 61, a storage unit 62, a bus 63, and an input / output (I / O) interface 64.

  The calculation unit 61 executes various programs such as a printing program. The calculation unit 61 has a CPU (Central Processing Unit).

  The storage unit 62 stores various information and programs. The storage unit 62 stores a RAM (Random Access Memory) in which information is temporarily stored, a ROM (Read Only Memory) in which basic programs are stored, and a program for normal printing and jam reduction mode printing. HDD (Hard Disk Drive).

The storage unit 62 stores a jam history table 65 shown in FIG. As shown in FIG. 3, the jam history table 65 associates the jam occurrence rate JPn with the humidity Hn and the temperature Tn. “N” is “n = 1, 2, 3,...”. For example, the jam occurrence rate in the case of humidity H1 and temperature T3 is “JP11”. Here, the jam occurrence rate JPn is calculated by the following equation (1), where “NP” is the cumulative number of printed sheets and “NJ” is the cumulative number of jams.
JPn = NJ / NP (1)
That is, the jam occurrence rate JPn is the number of jam occurrences per sheet of printing paper. Here, the jam occurrence rate JPn increases as the humidity Hn increases because the printing paper PA changes. Further, the jam occurrence rate JPn increases as the temperature Tn increases because the friction of the rollers 16, 21, 27, 31, 36, 41 to 43 decreases.

  Further, the storage unit 62 stores a jam threshold ThJ that is a threshold of the jam occurrence rate JP, and a threshold time ThT that is a threshold of the elapsed printing time. When the jam occurrence rate JP acquired from the jam history table 65 is equal to or greater than the jam threshold ThJ, the control unit 12 determines that the probability of jam occurrence is high, and executes printing in the jam reduction mode described later. Further, the control unit 12 updates the jam history table 65 after printing is completed. The control unit 12 compares the threshold time ThT with the elapsed time from the printing start time TS, and executes a jam reduction mode described later.

  The bus 63 connects the calculation unit 61, the storage unit 62, and the input / output interface 64 so that signals can be input and output with each other.

  The input / output interface 64 is for connecting the units 2 to 10 and the control unit 12. Hereinafter, the connection relationship between the control unit 12 and the units 2 to 10 will be described in detail.

  The input / output interface 64 is connected to the paper feed drive unit 17 of the paper feed unit 2 so that signals can be transmitted. Thus, the control unit 12 controls the paper supply roller 16 via the paper supply driving unit 17 to convey the printing paper PA on the paper supply table 15 to the conveyance printing unit 3.

  The input / output interface 64 is connected to the inkjet head unit 23 and the first transport driving unit 24 of the transport printing unit 3 so as to transmit signals. Thus, the control unit 12 conveys the printing paper PA by controlling the registration roller 21 and the belt conveyance unit 22 via the first conveyance driving unit 24. Further, the control unit 12 controls the ink jet head unit 23 to eject ink and print an image on the printing paper PA.

  The input / output interface 64 is connected to the first switching unit 26 and the first paper discharge driving unit 29 of the first paper discharge unit 4 so that signals can be transmitted. Accordingly, the control unit 12 controls the first switching unit 26 to switch the transport path between the normal path RC and the first paper discharge path RD1. Further, the control unit 12 controls the first paper discharge roller 27 via the first paper discharge driving unit 29 to discharge the printing paper PA to the first paper discharge table 28.

  The input / output interface 64 is connected to the second transport driving unit 32 of the transport unit 5 so that signals can be transmitted. Accordingly, the control unit 12 controls the transport roller 31 via the second transport driving unit 32 to transport the printing paper PA.

  The input / output interface 64 is connected to the second switching unit 35 and the second paper discharge driving unit 38 of the second paper discharge unit 6 so that signals can be transmitted. Accordingly, the control unit 12 controls the second switching unit 35 to switch the transport path between the second paper discharge path RD2 and the reverse path RR. Further, the control unit 12 controls the second paper discharge roller 36 via the second paper discharge driving unit 38 to discharge the printing paper PA to the second paper discharge tray 37.

  The input / output interface 64 is connected to the inversion drive unit 46 of the inversion unit 7 so as to transmit signals. Accordingly, the control unit 12 controls the forward roller 41, the reverse roller 42, and the backward roller 43 via the reverse driving unit 46, thereby reversing the printing paper PA and refeeding it to the transport printing unit 3. To do.

  The input / output interface 64 is connected to the paper sensors 50 to 54 of the jam detection unit 8 so as to be able to receive signals. Thereby, the control unit 12 determines the occurrence of a jam based on the detection signals input from the paper sensors 50 to 54.

  The input / output interface 64 is connected to the humidity sensor 56 and the temperature sensor 57 of the condition detection unit 9 so as to be able to receive humidity information HD and temperature information TD. Thereby, the control unit 12 acquires the jam occurrence rate JPn corresponding to the humidity information HD input from the humidity sensor 56 and the temperature information TD input from the temperature sensor 57 from the jam history table 65.

  The input / output interface 64 is connected to the operation panel 10 so that signals can be transmitted and received. As a result, the control unit 12 displays various screens on the operation panel 10. Further, the control unit 12 receives information input by the user from the operation panel 10.

  The input / output interface 64 is connected to the timer 11 so as to receive the current time TR. Accordingly, the control unit 12 stores the printing start time TS in the storage unit 62 based on the current time TR input from the timer 11.

  The input / output interface 64 is connected to an external terminal 90 such as a personal computer. Thus, the control unit 12 can receive image data for printing from the external end 90.

(Printing operation)
Next, the printing operation by the image forming apparatus 1 described above will be described. FIG. 4 is a flowchart for explaining the printing operation according to the first embodiment. The printing operation is executed when image data is input from the outside end 90.

  As shown in FIG. 4, first, the control unit 12 records the current time TR input from the timer 11 as the start time TS in the storage unit 62 (S1).

  Next, the control unit 12 shows the jamming rate JP corresponding to the humidity information HD input from the humidity sensor 56 and the temperature information TD input from the temperature sensor 57 as shown in FIG. Obtained from the jam history table 65 (S2).

  Next, the control unit 12 compares the acquired jam occurrence rate JP with the jam threshold ThJ stored in the storage unit 62 (S3).

  When determining that the jam occurrence rate JP is not equal to or greater than the jam threshold ThJ (S3: No), the control unit 12 starts normal printing (S4). Hereinafter, the normal printing in step S4 will be described separately for single-sided printing and double-sided printing.

  In the single-sided printing, when the control unit 12 starts single-sided printing, the printing paper PA is transported from any one of the paper feed bases 15 to the transport printing unit 3 by the paper feed roller 16. Note that the printing paper PA is sequentially fed from the paper feeding unit 2 to the transport printing unit 3 at a predetermined interval. That is, a plurality of printing papers PA are simultaneously transported on the transport path. In the transport printing unit 3, the printing paper PA is transported to the belt transport unit 22 by the registration rollers 21. Thereafter, the image is printed on the printing paper PA by the inkjet head unit 23 while the printing paper PA is conveyed by the belt conveyance unit 22. Next, the printing paper PA is conveyed to the conveyance unit 5 by the belt conveyance unit 22 while being guided by the first switching unit 26. In the transport unit 5, the printing paper PA is guided to the second paper discharge unit 6 by the second switching unit 35 while being transported by the transport roller 31. In the second paper discharge unit 6, the printing paper PA is discharged to the second paper discharge tray 37 by the second paper discharge roller 36 with the printed surface facing down.

  On the other hand, in the case of single-sided printing, when the printed printing paper PA is discharged to the first paper discharge unit 4, the printed printing paper PA is guided by the first switching unit 26 while being guided by the belt transport unit 22. 1 is conveyed to the paper discharge unit 4. Thereafter, the printing paper PA is discharged to the first paper discharge tray 28 by the first paper discharge roller 27 with the printed surface facing up.

  In double-sided printing, when the control unit 12 starts double-sided printing, the printing paper PA is fed from the paper feeding unit 2 and then conveyed by the conveyance printing unit 3. Note that the printing paper PA is sequentially fed from the paper feeding unit 2 to the transport printing unit 3 at a predetermined interval. That is, a plurality of printing papers PA are simultaneously transported on the transport path. Thereafter, after the image is printed on one surface of the printing paper PA, the printing paper PA is conveyed to the second switching unit 35 by the conveyance unit 5. Next, the printing paper PA is conveyed to the reversing unit 7 by the conveying unit 5 while being guided to the reversing unit 7 by the second switching unit 35. In the reversing unit 7, the printing paper PA is guided by the flipper 45 to the reversing roller 42 while being conveyed by the forward roller 41. Next, the printing paper PA is carried into the switchback unit 44 by the reverse roller 42. Thereafter, the printing paper PA is unloaded from the switchback unit 44 by the reverse roller 42 and guided to the return roller 43 by the flipper 45. Next, the printing paper PA is fed again to the transport printing unit 3 by the return roller 43. In the transport printing unit 3, the printing paper PA is transported from the registration roller 21 to the belt transport unit 22. Here, since the printing paper PA is reversed by the reversing unit 7, the unprinted surface (the other surface) of the printing paper PA is directed to the inkjet head unit 23. Next, after the image is printed on the other surface of the printing paper PA by the inkjet head unit 23 of the transport printing unit 3, the printing paper PA is first printed by the transport unit 5 and the second paper discharge unit 6. The paper is discharged to the second paper discharge tray 37 with the surface facing up.

  On the other hand, when the printed print paper PA is discharged to the first paper discharge unit 4, after the image is printed on the other side of the print paper PA (that is, after double-sided printing), the print paper PA is The first switching unit 26 guides the first paper discharge roller 27. Thereafter, the printing paper PA is discharged to the first paper discharge tray 28 by the first paper discharge roller 27 with the printed surface facing upward.

  When the control unit 12 determines in step S3 that the jam occurrence rate JP is equal to or greater than the jam threshold ThJ (S3: Yes), the control unit 12 determines whether or not the threshold time ThT has elapsed from the start time TS stored in the storage unit 62. (S5).

  When the control unit 12 determines that the threshold time ThT has not elapsed (S5: No), the control unit 12 returns to step S2 and re-acquires the jam occurrence rate JP from the jam history table 65 (S2), and then the jam occurrence rate JP. Is again determined whether or not is greater than the jam threshold ThJ (S3).

  Thus, the control unit 12 repeats steps S2, S3, and S5. When the jam occurrence rate JP becomes less than the jam threshold ThJ before the threshold time ThT elapses (S3: No), the control unit 12 performs the normal printing in step S4 described above.

  On the other hand, when the jam occurrence rate JP remains equal to or greater than the jam threshold ThJ (S4: Yes) and the threshold time ThT has elapsed (S5: Yes), the control unit 12 starts printing in the jam reduction mode (S6). In other words, when the jam occurrence rate JP is equal to or greater than the jam threshold ThJ, the control unit 12 stands by without executing printing for the threshold time ThT from the start of printing.

  Hereinafter, printing in the jam reduction mode will be described. In the jam reduction mode, printing is executed under at least one of the following low speed mode, light color mode, path shortening mode, forced single-sided printing mode, and reduction mode.

[Low speed mode]
In the low speed mode, the control unit 12 sets the conveyance speed of the printing paper PA to be lower than that of the normal printing described above. Specifically, the control unit 12 includes a paper feed drive unit 17 of the paper feed unit 2, a first transport drive unit 24 of the transport printing unit 3, a first paper discharge drive unit 29 of the first paper discharge unit 4, and a transport unit. 5, the second conveyance driving unit 32, the second paper ejection driving unit 38 of the second paper ejection unit 6, and the reversal driving unit 46 of the reversing unit 7 to control each of the rollers 16, 21, 27, 31, 36, The conveyance speed of the printing paper PA conveyed to 41 to 43 is lowered. As a result, the torque of each of the rollers 16, 21, 27, 31, 36, 41 to 43 increases, so that the printing paper PA nipped between the rollers 16, 21, 27, 31, 36, 41 to 43 slips. Reduced. As a result, jamming is reduced.

[Light color mode]
In the light color mode, the control unit 12 reduces the amount of ink applied to the printing paper PA, reduces the amount of ink, and lightens the color. Specifically, the control unit 12 reduces the voltage applied to the inkjet head unit 23 to reduce the amount of ink ejected at one time, or reduces the number of applied voltages to reduce the number of ink ejections. To reduce. As a result, the amount of ink applied to the printing paper PA is reduced, so that the sliding of the printing paper PA nipped between the rollers 16, 21, 27, 31, 36, 41 to 43 is reduced. As a result, jamming is reduced.

[Route shortening mode]
In the path shortening mode, the control unit 12 prints with the transport path shortened by discharging the printing paper PA to the first paper discharge unit 4. Specifically, the control unit 12 sets the first switching unit 26 of the first paper discharge unit 4 so that the printing paper PA is discharged to the first paper discharge tray 28. As a result, the printed printing paper PA is conveyed to the first paper discharge unit 4 by the belt conveyance unit 22 while being guided by the first switching unit 26. Then, the printing paper PA is discharged to the first paper discharge tray 28 by the first paper discharge roller 27. As a result, the transport path after printing is shortened, and jamming is reduced.

[Forced single-sided printing mode]
In the forced single-sided printing mode, the control unit 12 switches double-sided printing to single-sided printing. Specifically, the control unit 12 prints images to be printed on the front and back surfaces of double-sided printing on the front surfaces of two printing sheets. As a result, the printing paper PA is transported without going through the reversing unit 7, so that jamming is reduced.

[Reduction mode]
In the reduction mode, the control unit 12 reduces the image and prints it. Then, the control unit 12 reselects a small printing paper PA in accordance with the reduction of the image. Thereby, since the printing paper PA is reduced from being nipped by the two rollers 16, 21, 27, 31, 36, 41 to 43, the sliding of the printing paper PA is reduced. As a result, jamming is reduced.

  Thereafter, the control unit 12 determines whether or not a jam has occurred during normal printing or during printing in the jam reduction mode (S7). Here, the control unit 12 determines a jam based on the detection signal of the printing paper PA input from the paper sensors 50 to 54 of the jam detection unit 8. More specifically, if the difference between the detection timing by the paper sensors 50 to 54 and the detection timing predicted based on the length of the printing paper PA in the conveyance direction and the conveyance speed is equal to or greater than a threshold value, the control unit 12 determines that a jam has occurred. If the control unit 12 determines that a jam has not occurred (S7: No), the control unit 12 determines whether or not printing is finished based on the number of printed sheets (S8).

  If the control unit 12 determines that the printing has not ended (S8: No), the control unit 12 returns to step S7. Thereafter, the control unit 12 repeats steps S7 and S8 until a jam occurs or printing is completed.

  If the control unit 12 determines that a jam has occurred (S7: Yes), it stops printing (S9) and then executes step S10. Further, when the control unit 12 determines that the printing is finished (S8: Yes), the control unit 12 executes Step S10.

  In step S10, the control unit 12 updates the jam history table 65 by associating the current humidity Hn and temperature Tn with the jam occurrence rate JPn. Specifically, the control unit 12 calculates the jam occurrence rate JPn of the current humidity Hn and temperature Tn by the above-described equation (1). Here, the total number of printed sheets NP in the denominator is added to the number of sheets printed this time. Further, when a jam occurs and printing is stopped, the cumulative number NJ of numerator jams is incremented by “1”. Thereby, the control unit 12 calculates the jam occurrence rate JPn of the current humidity Hn and temperature Tn, and updates the jam history table 65.

  Thereby, the control part 12 complete | finishes printing operation.

(Effect of 1st Embodiment)
As described above, in the image forming apparatus 1 according to the first embodiment, the control unit 12 updates the jam history table 65 in which the humidity Hn, the temperature Tn, and the jam occurrence rate JPn are associated with each print (for each job). , Stored in the storage unit 62. The control unit 12 acquires the jam occurrence rate JP corresponding to the humidity information HD and the temperature information TD input from the humidity sensor 56 and the temperature sensor 57 from the jam history table 65. Then, the control unit 12 compares the updated jam occurrence rate JP with the jam threshold ThJ and determines whether or not a jam occurs. Thus, since the control unit 12 determines whether or not a jam occurs based on the updated jam occurrence rate JP, the image forming apparatus 1 can improve the determination accuracy of the jam occurrence.

  In the image forming apparatus 1, the control unit 12 stands by for the threshold time ThT when the jam occurrence rate JP is equal to or greater than the jam threshold ThJ. Then, the control unit 12 executes normal printing when the jam occurrence rate JP is less than the jam threshold ThJ during the threshold time ThT. As described above, the image forming apparatus 1 waits for the reduction of the jam occurrence rate JP during the threshold time ThT, so that jam can be reduced without providing a dehumidifying device or the like. Furthermore, the image forming apparatus 1 can reduce the printing cost by setting the threshold time ThT so that the time for executing printing is an inexpensive time of power such as midnight.

  In the image forming apparatus 1, when the jam occurrence rate JP is equal to or greater than the jam threshold ThJ, the control unit 12 determines that the probability of jam occurrence is high and executes printing in the jam reduction mode after the threshold time ThT has elapsed. . Thereby, the image forming apparatus 1 can reduce the jam even under the humidity and temperature where the jam occurrence rate JP is high.

  Specifically, the control unit 12 can improve the torque of each of the rollers 16, 21, 27, 31, 36, 41 to 43 by executing the low speed mode as the jam reduction mode. As a result, the image forming apparatus 1 can reduce the slippage of the printing paper PA nipped by the rollers 16, 21, 27, 31, 36, 41 to 43, so printing with the printing paper PA being conveyed is possible. An appropriate distance from the paper PA can be maintained. As a result, the image forming apparatus 1 can reduce jamming.

  Further, the control unit 12 can reduce the amount of ink applied to the printing paper PA by executing the light color mode as the jam reduction mode. Thereby, the image forming apparatus 1 can reduce the slip of the printing paper PA nipped by the rollers 16, 21, 27, 31, 36, 41 to 43, and thus can reduce jamming.

  Moreover, the control part 12 can shorten the conveyance path | route after the printing by the conveyance printing part 3 by performing path | route shortening mode as jam reduction mode. Thereby, the image forming apparatus 1 can reduce a jam.

  Moreover, the control part 12 can abbreviate | omit conveyance by the inversion part 7 by performing forced single-sided printing mode as jam reduction mode. Thereby, the image forming apparatus 1 can reduce a jam.

  In addition, the control unit 12 can reduce the time during which the printing paper PA is nipped by the two rollers 16, 21, 27, 31, 36, 41 to 43 by executing the reduction mode as the jam reduction mode. As a result, the image forming apparatus 1 can reduce slippage of the printing paper PA nipped between the two rollers 16, 21, 27, 31, 36, 41 to 43, and thus can reduce jamming.

Second Embodiment
Next, a second embodiment in which the jam history table of the above-described embodiment is changed will be described. FIG. 5 is a diagram for explaining a jam history table according to the second embodiment. FIG. 6 is a diagram for explaining another jam history table according to the second embodiment. In addition, the same code | symbol is attached | subjected to the structure similar to embodiment mentioned above, and description is abbreviate | omitted.

  In the second embodiment, a jam history table 65A shown in FIG. The jam history table 65A is a table in which the humidity Hn and the jam occurrence rate JPn are associated with each other. In the second embodiment, the control unit 12 acquires the jam occurrence rate JP from the jam history table 65A based on the humidity information HD input from the condition detection unit 9. At the end of printing, the control unit 12 associates the current humidity information HD with the jam occurrence rate JPn and updates the jam history table 65A.

  As shown in FIG. 6, the control unit 12 may store the jam history table 65 </ b> B in which the temperature Tn and the jam occurrence rate JPn are associated with each other in the storage unit 62. In this case, the control unit 12 acquires the jam occurrence rate JP from the jam history table 65B based on the temperature information TD input from the condition detection unit 9. At the end of printing, the control unit 12 updates the jam history table 65B by associating the current temperature information TD with the jam occurrence rate JPn.

(Effect of 2nd Embodiment)
In the second embodiment, since either one of the humidity Hn or the temperature Tn is associated with the jam occurrence rate JPn, the jam history tables 65A and 65B can be simplified.

<Third Embodiment>
Next, a third embodiment in which a part of the above-described embodiment is changed will be described. FIG. 7 is a flowchart of jam threshold value change processing according to the third embodiment. FIG. 8 is a diagram for explaining a jam threshold value change screen. In addition, the same code | symbol is attached | subjected to the structure similar to embodiment mentioned above, and description is abbreviate | omitted.

  In 3rd Embodiment, the control part 12 is comprised so that execution of the jam threshold value change process for changing the jam threshold value shown in FIG. 7 is possible. Note that the jam threshold value changing program is stored in the storage unit 62.

  In the jam threshold value changing process, the control unit 12 displays the jam threshold value changing screen shown in FIG. 8 on the operation panel 10 or the display unit with no external end 90 (S21). Thereafter, when the user desires to change the jam threshold ThJ, the user operates the “up” button or the “down” button to change the displayed jam threshold ThJ.

  Next, the control unit 12 determines whether or not the user has operated the “OK” button on the jam threshold value change screen (S22). If the user does not operate the “OK” button (S22: No), that is, if it is determined that the “cancel” button is operated, the control unit 12 ends the jam threshold value changing process.

  On the other hand, when determining that the user has operated the “OK” button (S22: Yes), the control unit 12 determines whether or not the user has changed the jam threshold ThJ by the above-described operation (S23).

  When it is determined that the user has not changed the jam threshold ThJ (S23: No), the control unit 12 ends the jam threshold changing process. On the other hand, when determining that the user has changed the jam threshold ThJ (S23: Yes), the control unit 12 updates the jam threshold ThJ stored in the storage unit 62 to the changed jam threshold ThJ. Thereby, the control part 12 complete | finishes a jam threshold value change process.

(Effect of the third embodiment)
The third embodiment is configured to be able to change the jam threshold ThJ. Accordingly, the third embodiment can cope with a case where the user gives priority to the printing speed over the reduction of jam. Conversely, the third embodiment can also cope with a user who wants to further reduce the occurrence of jam.

  Note that the jam threshold value changing process may be executed at an initial stage after the start of the printing operation, or may be executed separately from the printing operation. Further, the jam threshold ThJ and the user may be associated with each other and stored in the storage unit 62.

<Fourth embodiment>
Next, a fourth embodiment in which a part of the above-described embodiment is changed will be described. FIG. 9 is a flowchart of jam reduction mode change processing according to the fourth embodiment. FIG. 10 is a diagram for explaining a jam reduction mode change screen. In addition, the same code | symbol is attached | subjected to the structure similar to embodiment mentioned above, and description is abbreviate | omitted.

  In the fourth embodiment, as illustrated in FIG. 9, the control unit 12 executes jam reduction mode change processing for changing print settings for reducing jamming, that is, for changing jam reduction mode settings. It is configured to be possible. Note that a program for changing the jam reduction mode is stored in the storage unit 62.

  In the jam reduction mode change process, the control unit 12 displays the jam reduction mode change screen shown in FIG. 10 on the operation panel 10 or the display unit without the external end 90 (S31).

  When enabling the jam reduction mode, the user selects a “jam reduction mode” button displayed on the screen. As a result, a check mark (re) is displayed in the frame on the left side of the “jam reduction mode” button. When the jam reduction mode is selected in this way, the control unit 12 performs printing under the jam reduction mode when the jam occurrence rate JPn is equal to or greater than the jam threshold ThJ.

  Further, when the user selects the jam reduction mode, any one of the jam reduction modes can be selected. As a result, as shown in FIG. 10, when the user selects the low speed mode, the control unit 12 displays a check mark (L) in the left frame of the “low speed mode” button. In this case, in printing in the jam reduction mode, printing is executed in the low speed mode in which the conveyance speed is reduced.

  Thereafter, the control unit 12 determines whether or not the user has operated the “OK” button (S32). If the user determines that the user has not operated the “OK” button (S32: No), that is, has operated the “cancel” button, the jam reduction mode changing process is terminated.

  On the other hand, when determining that the user has operated the “OK” button (S32: Yes), the control unit 12 determines whether or not the user has changed the setting of the jam reduction mode (S33). When it is determined that the user has not changed the setting of the jam reduction mode (S33: No), the control unit 12 ends the jam reduction mode selection process.

  On the other hand, if it determines with the user having changed the setting of jam reduction mode (S33: Yes), the control part 12 will update the setting of jam reduction mode memorize | stored in the memory | storage part 62 (S34), and jam reduction mode will be described. The selection process ends.

(Effect of 4th Embodiment)
As described above, in the fourth embodiment, whether or not to execute the jam reduction mode can be selected. Therefore, even when the jam occurrence rate JPn is high, the user can execute printing by normal printing. Furthermore, in the fourth embodiment, when executing the jam reduction mode, it is possible to set which mode to execute, so that it is possible to flexibly cope with the user's desire.

  The jam reduction mode change process may be executed separately from the printing operation.

  As mentioned above, although this invention was demonstrated in detail using embodiment, this invention is not limited to embodiment described in this specification. The scope of the present invention is determined by the description of the claims and the scope equivalent to the description of the claims. Hereinafter, modified embodiments in which the above-described embodiment is partially modified will be described.

  The arrangement, shape, numerical value, and the like of the configuration of each embodiment described above can be changed as appropriate.

  The contents of the processing of each embodiment described above can be changed as appropriate.

  In the above-described embodiment, in the jam reduction mode, control is performed so that printing is performed under at least one of the low speed mode, the light color mode, the path shortening mode, the forced single-sided printing mode, and the reduction mode. Although the control unit is configured, the control unit may be configured to select and execute any one of these modes by self-learning. For example, when a specific user selects the low-speed mode a predetermined number of times, and further prints the user's print in the jam reduction mode, the control unit selects the low-speed mode and performs the jam reduction mode under the low-speed mode. May be executed. As described above, when the self-learning image forming apparatus is configured, the control unit may select the mode automatically when the user selects a specific mode more than the specified number of times.

  In the above-described embodiment, when the jam occurrence rate is equal to or greater than the jam threshold, the control unit is configured to wait without executing printing for a threshold time from the start of printing. However, if the jam occurrence rate is equal to or higher than the jam threshold (that is, the surrounding humidity or temperature is equal to or higher than the predetermined humidity or temperature during printing), and the printing is interrupted, the control unit waits for the threshold time from the printing interruption. You may comprise so that it may wait, without performing printing.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Paper feed part 3 Conveyance printing part 4 1st paper discharge part 5 Carry part 6 2nd paper discharge part 7 Inversion part 8 Jam detection part 9 Condition detection part 10 Operation panel 11 Timer 12 Control part 50-54 Paper Sensor 56 Humidity sensor 57 Temperature sensor 62 Storage unit 63 Bus 64 Input / output interface 65, 65A, 65B Jam history table HD Humidity information Hn Humidity TD Temperature information Tn Temperature JP, JPn Jam occurrence rate PA Printing paper RS Paper feed path RC Normal path RD1 Paper discharge path RD2 Paper discharge path RR Reverse path ThJ Jam threshold ThT Threshold time

Claims (5)

Condition detection means for detecting humidity or temperature and outputting humidity information or temperature information;
Storage means for storing a jam history table in which humidity or temperature and a jam occurrence rate are associated, and a jam threshold that is a threshold of the jam occurrence rate;
The jam occurrence rate corresponding to the humidity information or temperature information input from the condition detection unit is acquired from the jam history table, and when the acquired jam occurrence rate is equal to or more than the jam threshold, printing is performed so that the jam is reduced. And an image forming apparatus comprising: a control unit that updates the jam history table stored in the storage unit. Condition detection means for detecting humidity or temperature and outputting humidity information or temperature information;
Storage means for storing a jam history table in which humidity or temperature and a jam occurrence rate are associated, and a jam threshold that is a threshold of the jam occurrence rate;
When the jam occurrence rate corresponding to the humidity information or temperature information input from the condition detection unit is acquired from the jam history table, and the acquired jam occurrence rate is equal to or greater than the jam threshold after a threshold time has elapsed from the start or interruption of printing. An image forming apparatus comprising: a control unit that executes printing so as to reduce jamming and updates the jam history table stored in the storage unit. In the case where the control unit executes printing so as to reduce jamming,
Decrease the transport speed or
Reduce the amount of ink, or
Reduce the path to select a paper output destination with a short transport path, or
Force double-sided printing to single-sided printing, or
The image forming apparatus according to claim 1, wherein printing is performed under at least one of reducing an image.   The image forming apparatus according to claim 1, wherein the control unit is capable of executing a jam threshold value changing process for changing the jam threshold value.   The image forming apparatus according to claim 1, wherein the control unit is capable of changing a print setting that reduces jamming.