JP5197282B2 - Transport control mechanism and transport control method for printing apparatus - Google Patents

Description

  The present invention relates to a conveyance control mechanism and a conveyance control method of a printing apparatus having an image forming unit that forms an image on a sheet surface conveyed on a conveyance path, such as an ink jet printer.

  In general, in an inkjet image forming apparatus, in order to record an image on a sheet, it is necessary to always maintain an interval between a plurality of recording nozzles of the print head and the sheet at an optimum interval for recording.

  By the way, the paper may be lifted from the paper transport unit, and if the paper float is large, the interval between the paper and the recording head is out of the set interval. I can't. Further, there is a possibility that the recording head collides with the recording head and breaks the recording head.

  In recent years, there has been a strong demand for speeding up of image forming processing in image forming apparatuses. For this reason, when image forming processing is continuously performed on a large number of sheets, a plurality of sheets are continuously arranged at short intervals. Is fed from the paper feeder.

  In such an image forming apparatus that performs image forming processing at a high speed, when paper jam occurs in a part of the transport path, a process that stops printing and transport is performed, so a large number of sheets are included in the transport path. Thus, the operation of the apparatus is stopped in the state in which there is. Removing all the paper in the transport path during the jam clearing operation makes the jam clearing operation complicated and wastes an amount of paper that should be discarded.

  On the other hand, conventionally, when a paper jam occurs in a part of the transport path, there is a technique for discharging a paper in the middle of a transport process in which recording processing is completed on the downstream side in the transport direction from the jammed paper. Yes (Patent Document 1).

Here, the floating of the paper may occur not only at the leading edge of the conveyed paper but also at the trailing edge of the paper. At this time, if floating is detected at the leading edge of the paper, printing is not performed on the paper. However, if floating is detected at the trailing edge of the paper, printing may have already started from the leading edge of the paper. is there. In this case, when the belt platen continues the paper transport operation, the recording head may be damaged.
JP 2002-137849 A

  However, in the technique of the above-mentioned document 1, since the paper floats are discharged from the discharge table through the transport path downstream in the transport direction, regardless of whether the paper floats at the leading edge or the trailing edge, the floating paper is belted. There is a possibility that the recording head may be damaged by passing through the platen. In addition, the printed matter that has been printed correctly and the printed matter that has stopped printing are discharged to the same discharge stand, and the user must later remove the printed matter that has stopped printing, which is cumbersome and burdens the user. It was.

  In view of the above, the present invention has been made in view of the above points, and by detecting the lift of the paper at the leading edge of the paper and other than the leading edge, the paper can be prevented from colliding with the recording head, and the transport path It is an object of the present invention to provide a transport control mechanism and a transport control method for a printing apparatus having a paper transport mechanism that can facilitate a jam clearing operation performed by a user when a jam occurs in a part of the print medium. To do.

In order to solve the above-described problems, the present invention provides a transport control mechanism of a printing apparatus having an image forming unit that forms an image on a surface of a sheet transported on a transport path, upstream of the image forming unit on the transport path. comprises a floating detector for detecting a floating of each of the other tip and the leading end of the sheet being conveyed on the conveying path, a conveying path control unit for controlling the drive and stop of the conveying path, the conveying path, the image An image forming path in which image formation is performed by the forming unit is included, and the image forming path includes a retraction mechanism that separates the image forming path from the conveyance path and retreats;
The transport path control unit urgently stops the paper feed mechanism that supplies the paper to the transport path when the levitation detection unit detects the lift of the leading edge of the paper, and continues for the paper that is already transported on the transport path. When the floating detection unit detects a lift other than the leading edge of the sheet, the conveyance drive of the image forming path is stopped and the image forming path is retracted by the retracting mechanism.

  In the present invention, the driving portion of the transport path depends on whether the floating of the paper detected by the floating detection unit is the leading edge or other than the leading edge (for example, the trailing edge or the side edge, the slack of the inside of the paper, etc.) Since the stop portion is changed, the contact between the image forming unit and the sheet floating can be prevented, and the recording head and the like can be protected. As a result, according to the present invention, for example, the printed paper can be discharged to the normal paper discharge tray by the downstream conveyance path, and the waste of printed matter can be eliminated. It is possible to take action according to the situation, such as urgently stopping the printing process or giving priority to the protection of the recording head by evacuating the paper to another path.

In the above invention, the conveyance path control unit, when the floating detection unit detects the lift of the leading edge of the sheet, causes the paper feeding mechanism that supplies the sheet to the conveyance path to be stopped urgently and is already being conveyed on the conveyance path. Since the paper is transported continuously , when the floating detector detects a lift at the leading edge of the paper, the paper feed mechanism stops the emergency to prevent the recording head of the image forming unit from being damaged. On the other hand, the printed matter in the image forming path and the printed sheet in the downstream transport path can be discharged via the transport path, thereby eliminating the waste of the paper. be able to.

In the above invention, the transport path includes an image forming path on which image formation is performed by the image forming unit, and the image forming path includes a retreat mechanism that separates the image forming path from the transport path and retreats the transport path. routing unit, when the floating detecting section detects floating of the non-leading edge of the sheet, stops the conveying operation of the image forming path, so to retract the image forming path by retracting mechanism, floating detecting unit of the paper tip In the case where a float is detected, the printing process is in progress for the paper on the image formation path where the float is detected. It is possible to prevent the paper from coming into contact with the recording head in the image forming unit and being damaged by being separated from the forming unit.

Another invention relates to a conveyance control method for a printing apparatus having an image forming unit that forms an image on the surface of a sheet conveyed on a conveyance path, wherein image formation is performed on the conveyance path by the image forming unit. The image forming path includes a retraction mechanism that separates and retracts the image forming path from the transport path, and the leading edge of the paper transported on the transport path upstream of the image forming unit on the transport path. And a floating detection step for detecting the floating of each other than the leading edge, and when the floating of the leading edge of the paper is detected in the floating detection step, the paper feeding mechanism that supplies the paper to the conveyance path is stopped urgently and is already conveyed. The paper that is being transported on the path is continuously transported, and if a lift other than the leading edge of the paper is detected in the lift detection step, the image formation process is It stops the conveying drive of, and a conveying path control step of retracting said imaging path by retracting mechanism.

  According to such another invention, the drive part and stop part of the transport path are changed in the transport path control step due to the difference that the detected paper float is at the leading edge or other than the leading edge in the floating detection step. To do. This prevents contact between the recording head and the floating sheet and protects the recording head. For example, when printing is completed, the sheet can be discharged to the normal sheet discharge tray by the downstream conveyance path. , Waste of printed matter can be eliminated, and for unfinished paper, the printing process is urgently stopped or the paper head is evacuated to another path, giving priority to the protection of the recording head, etc. You can take action.

In the above invention, in the transport path control step, when the floating detection step detects the lift of the leading edge of the paper, the paper feed mechanism that supplies the paper to the transport path is stopped urgently and is already transported on the transport path. Convey paper continuously .

  In this case, when floating is detected at the leading edge of the sheet in the floating detection step, priority is given to prevention of damage to the recording head of the image forming unit for the unprinted sheet due to an emergency stop of the sheet feeding mechanism. On the other hand, the printed matter being printed in the image forming path and the paper having been printed in the downstream transport path can be discharged via the transport path, and the waste of the paper can be saved.

In the above invention, the transport path includes an image forming path on which image formation is performed by the image forming unit, and the image forming path includes a retreat mechanism that separates the image forming path from the transport path and retreats the transport path. the route control step, when the floating detecting section detects floating of the non-leading edge of the sheet, stops the conveying operation of the image forming path, Ru retracts the image forming path by retracting mechanism.

  In this case, if the float detection step detects a float other than the leading edge of the sheet, the printing process is in progress for the sheet on the image forming path where the float is detected. The sheet can be separated from the image forming unit for each image forming path by the retraction mechanism, and the sheet can be prevented from coming into contact with the recording head in the image forming unit and being damaged.

  As described above, according to the present invention, it is possible to prevent the paper from colliding with the recording head of the image forming unit by detecting the floating of the paper at the leading edge and other than the leading edge of the paper, and conveying the paper. When the print medium is jammed in a part of the path, it is possible to facilitate the jam clearing operation performed by the user.

(Overall configuration of printing device)
Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram illustrating an outline of a printing paper conveyance path of the printing apparatus 100 according to the present embodiment. In the present embodiment, the printing apparatus 100 includes a plurality of ink heads having a large number of nozzles, prints black or color ink from each ink head, performs printing in units of lines, and prints on a recording sheet on a conveyance belt. An ink-jet line color printer that forms a plurality of images so as to overlap each other will be described as an example.

  As shown in FIG. 1, the printing apparatus 100 is an apparatus that forms an image on the surface of a sheet transported on an annular transport path. The transport path includes a paper feed system transport path FR that supplies the paper, and this paper feed. A general path CR from the system transport path FR through the head unit 110 to the paper discharge path DR and a reverse path SR branched and connected to the normal path CR are roughly configured.

  In the paper feed system conveyance path FR, as a paper feed mechanism for supplying printing paper, a side paper feed stand 120 disposed outside the side surface of the housing and a plurality of paper feed trays (inside the housing) 130a, 130b, 130c, 130d). A paper discharge port 140 is provided as a paper discharge mechanism for discharging printed printing paper.

  Printing paper fed from one of the side paper feed tray 120 and the paper feeding tray 130 is conveyed along a paper feeding system conveyance path FR in the housing by a driving mechanism such as a roller, and the printing paper It is guided to the resist portion R which is the reference position of the head portion. A head unit 110 having a plurality of print heads is provided further on the registration direction R in the transport direction side. While the printing paper is conveyed at a speed determined by printing conditions by a platen belt 160 provided on the opposite surface of the head unit 110, an image is formed line by line with ink ejected from each printing head.

  The printed printing paper is further conveyed on the normal route CR by a driving mechanism such as a roller. In the case of single-sided printing, in which printing is performed only on one side of the printing paper, the paper is directly discharged to the paper discharge port 140 through the paper discharge route DR, and is discharged as a tray for the paper discharge port 140. It is loaded on the table 150 with the printing surface facing down. The paper discharge table 150 has a tray shape protruding from the housing, and has a certain thickness. The paper discharge table 150 is inclined, and the printing paper discharged from the paper discharge port 140 is naturally arranged and overlapped by a wall formed at a position below the inclination.

  On the other hand, in the case of double-sided printing in which printing is performed on both sides of the printing paper, the front side (the first printed side is “front side” and the next printed side is “back side”). Without being guided to, the inside of the casing is further transported and sent out to the reverse path SR. For this reason, the printing apparatus 100 is provided with a switching mechanism 170 for switching the transport path for backside printing, and the printing paper that has not been sent to the discharge path by the switching mechanism 170 is drawn into the reversing path SR.

  In the reversing path SR, a sheet is transferred from the normal path CR, and a so-called switchback is performed in which the sheet is reversed by reciprocating the sheet. Then, it is returned to the normal route CR via the switching mechanism 172 by a driving mechanism such as a roller, and is fed again through the registration portion R, and the back side is printed by the same procedure as the front side. After that, the printing paper on which the back side is printed and the image is formed on both sides is guided to the paper discharge port 140 through the paper discharge route DR and discharged, and the paper discharged as a receiving base of the paper discharge port 140 is discharged. It is loaded on the table 150.

  In the present embodiment, switchback at the time of duplex printing is performed using a space provided in the paper discharge tray 150. The space provided in the paper discharge tray 150 is configured to be covered so that the printing paper cannot be taken out from the outside at the time of switchback. As a result, it is possible to prevent the user from accidentally pulling out the printing paper being reversed. Further, the paper discharge tray 150 is originally provided in the printing apparatus 100, and by performing switchback using the space in the paper discharge tray 150, a separate switchback is provided in the printing apparatus 100. There is no need to provide space. Therefore, an increase in the size of the housing can be prevented. Furthermore, since the paper discharge path and the reverse path are not shared, the switchback process and the paper discharge of other sheets can be performed in parallel.

  In the printing apparatus 100, one-side printed printing paper is also re-fed to the registration portion R, which is the reference position of the leading portion of the fed printing paper, during duplex printing. For this reason, a junction point where a transport path for newly fed printing paper and a refeed path for circulating and feeding back-side printing paper is formed immediately before the registration portion R. The Then, the registration unit R sends out the paper in the vicinity of the merging point between the paper feeding system conveyance path FR and the normal path CR.

  In the present embodiment, the path on the sheet feeding mechanism side is defined as the sheet feeding system conveyance path FR, and the other paths are defined as the conveyance paths based on the merging point. This transport path is annular, and includes the normal path CR and the reverse path SR as described above. FIG. 2 is an explanatory diagram schematically showing the sheet feeding system conveyance path FR, the normal path CR, and the reverse path SR. In the figure, the number of rollers constituting the drive unit is omitted as appropriate.

  In the paper feed system conveyance path FR, the side paper feed driving unit 220 for feeding paper from the side paper feed tray 120 and the paper feed from the paper feed trays 130 (130a, 130b, 130c, 130d) are provided. A tray 1 driving unit 230a, a tray 2 driving unit 230b,. These constitute a paper feeding means for feeding paper to the registration unit R.

  Further, any of the driving units (tray 1 driving unit 230a, tray 2 driving unit 230b...) In the above-described paper feeding system conveyance path FR includes a driving mechanism constituted by a plurality of rollers and the like. Are taken one by one and conveyed in the direction of the registration portion R. Each drive unit can be driven independently, and necessary drive unit operations are performed in accordance with a paper feed mechanism that feeds paper.

  In addition, a plurality of conveyance sensors are arranged in the paper feeding system conveyance path FR so that a conveyance jam in the paper feeding system conveyance path FR can be detected. That is, each conveyance sensor is a sensor that detects the presence or absence of printing paper or the leading edge of printing paper. For example, a plurality of conveyance sensors are arranged at appropriate intervals on a conveyance path, and a conveyance sensor provided on the paper feeding side is provided. If the conveyance sensor on the conveyance direction side does not detect the printing paper within a predetermined time after detecting the printing paper, it can be determined that the conveyance jam has occurred.

  Among these conveyance sensors, the registration sensor in front of the registration unit R that sends out the paper measures the size of the paper that is being conveyed, and measures the size of the paper that is passing, for example, based on the passage speed and the passage time of the paper. If the conveyance sensor does not detect the printing paper within a predetermined time after driving the side paper feed driving unit 220, the tray 1 driving unit 230a, etc., it is determined that a conveyance jam (paper feeding error) has occurred. Can do.

  The normal path CR forms a part of the circulation transport path, and is a path from the paper feed system transport path FR for supplying paper to the paper discharge path DR through the head unit 110. An image is formed. In this normal path CR, a registration driving unit 240 that guides printing paper to the registration unit R, a belt driving unit 250 that drives the platen belt 160 provided on the opposite surface of the head unit 110 to move endlessly, and in the conveyance direction side. The first upper surface transport driving unit 260 and the second upper surface transport driving unit 265 arranged in order, the upper surface discharge driving unit 270 that guides the printed paper to the paper discharge port 140, and the drive for drawing the printing paper into the reverse path SR for back side printing. Means are provided. Each drive unit includes a drive mechanism composed of one or a plurality of rollers and the like, and conveys printing sheets one by one along the conveyance path. Each drive unit can be driven independently, and necessary drive unit operations are performed in accordance with the conveyance status of the printing paper.

  Further, a plurality of conveyance sensors are also arranged on the normal route CR so that a conveyance jam in the normal route CR can be detected. Further, it is possible to confirm that the printing paper is properly conveyed also in the registration portion R. In the normal route CR, a conveyance sensor is provided corresponding to the drive unit, and it is possible to specify in which drive unit of the normal route CR the conveyance jam has occurred.

  The reversing path SR is branched and connected to the normal path CR, the paper is delivered from the normal path CR, and the paper is reciprocated (switched back) to return to the normal path CR, thereby reversing the front and back of the paper and the transport mechanism. The reversing path SR is provided with a reversing drive unit 281 that reverses the sheet and guides it to the joining point. The reverse route SR can be transported at a speed different from that of the normal route CR. When the paper is taken over from the normal route CR, acceleration / deceleration is performed, and a stop time at the time of switchback is extended or shortened. can do.

  In this embodiment, after a certain printing paper is fed, the next printing paper is not fed after waiting for printing to be performed on the printing paper and discharged. Before the printing paper is discharged, subsequent printing paper can be fed and printed continuously at a predetermined interval. Therefore, in normal scheduling at the time of duplex printing, a space is secured in advance so as to secure a position where the sheet returned from the reversing path SR is inserted when feeding the front sheet. Thereby, in this apparatus, printing on the front surface and printing on the back surface can be performed in parallel, and half the productivity can be ensured with respect to single-sided printing.

  The platen belt 160 is stretched around a driving roller 161 and a driven roller 162 other than the front end and the front end of the surface facing the head unit 110, and rotates in a clockwise direction in FIG. In addition, on the upper surface of the platen belt 160, four ink heads of yellow (Y), magenta (M), cyan (C), and black (K) are arranged side by side along the belt moving direction, and a plurality of images are arranged. The head units 110 that form color images are arranged so as to face each other.

  Further, as illustrated in FIG. 1, the printing apparatus 100 includes an arithmetic processing unit 330. The arithmetic processing unit 330 is configured by a processor such as a CPU or DSP (Digital Signal Processor), memory, hardware such as other electronic circuits, software such as a program having the function, or a combination thereof. Various functional modules are virtually constructed by appropriately reading and executing a program, and various functional modules for processing related to image data, operation control of each unit, and user operations are constructed by each constructed functional module. Process. In addition, an operation panel 340 is connected to the arithmetic processing unit 330, and an instruction and a setting operation by a user can be received through the operation panel 340.

(Transport control mechanism)
In the present embodiment, control related to the paper transport mechanism is performed in the arithmetic processing unit 330. FIG. 3A is a block diagram showing a module according to the paper transport mechanism of the present embodiment, and FIGS. 3B and 3C are explanatory diagrams showing the configuration and operation of the floating sensor. As shown in FIG. 3A, a module relating to the paper transport mechanism includes a jam detection unit 331, an emergency stop mechanism 332, a transport path control unit 333, and a paper discharge control unit 334.

  The jam detection unit 331 is a module that detects the occurrence of a failure in the transport path based on detection results from the floating sensor 301 and other transport path sensors installed upstream of the head unit 110. In the present embodiment, the jam detection unit 331 further includes a double feed detection unit 331a that detects double feed of paper, and a tip / non-tip discrimination unit 331b that discriminates lifting of the paper edge.

  The multi-feed detection unit 331a and the tip / non-tip determination unit 331b, among the jams in the transport path, are especially transported when a sheet floats in the path from the registration unit R to the head unit 110 and a plurality of sheets overlap. This is a module that detects so-called double feed.

  The float sensor 301 is a contact sensor that detects the lift of the sheet upstream of the head unit 110 on the transport path. In this embodiment, as shown in FIGS. 3B and 3C, the floating sensor 301 has a configuration in which a contact portion 301c having an L-shaped cross section is pivotally supported by a shaft portion 301b. When the floating portion (for example, the leading end) 10a of the paper 10 collides with the contact portion 301c, the contact portion 301c is pushed up by the floating portion 10a, and the light shielding portion 301d rotates together with the contact portion 301c. By this rotation, the light shielding by the light shielding unit 301d is released, and the optical sensor 301a reacts to detect the floating of the paper. In the present embodiment, a contact sensor is used as the floating sensor. However, a reflection sensor, a transmission sensor, and other various sensors may be used as long as the sensor detects changes in the shape and thickness of the paper. it can.

  When the floating sensor 301 detects the floating of the sheet, the double feed detection unit 331a and the other than the leading edge / leading edge determination unit 331b receive detection signals from other conveyance path sensors positioned before and after the floating sensor 301. Analysis is performed to detect whether the float is generated at the leading edge of the paper or other than the leading edge.

  The conveyance path control unit 333 is a module that controls driving and stopping of each drive mechanism that drives each conveyance path including the retraction mechanism, the platen belt 160, the reverse path SR, and the normal path CR. The paper discharge control unit 334 is a module that controls a drive mechanism for paper discharge. Further, the transport path control unit 333 and the paper discharge control unit 334 also control a so-called recovery operation in which the paper stagnated in the transport path after an emergency stop is discharged.

  The emergency stop mechanism 332 controls the timing, operation speed, and operation direction for stopping conveyance and printing processing in the case of an emergency stop, and continues the operation for the conveyance route that should continue to operate without performing an emergency stop. To control.

  In the present embodiment, when an emergency stop mechanism 332, a conveyance path control unit 333, and a paper discharge control unit 334 detect a failure (jam) such as lifting or double feeding in the conveyance path, the platen belt 160 is retreated by a retraction mechanism, and for the paper located on the forward path in the normal path CR or the reversing path SR, control is performed such as temporarily stopping the conveyance roller or discharging the paper.

  In particular, when the floating sensor detects a floating portion 10a at the leading edge of the paper as shown in FIG. 5A, and when the floating sensor is not at the leading edge of the paper as shown in FIG. When the floating portion 10b is detected, the driving and stopping of the transport path are changed. Specifically, when the floating sensor 301 detects the lift of the leading edge of the sheet, the conveyance path control unit 333 urgently stops the paper feed mechanism that supplies the sheet to the conveyance path, and is already conveying on the conveyance path. Convey paper continuously. On the other hand, when the lift sensor 301 detects a lift other than the leading edge of the paper, the transport path control unit 333 stops the transport drive of the platen belt 160 and uses a retraction mechanism as shown in FIG. The platen belt 160 is retracted.

  As the above-described retraction mechanism, the platen belt 160 is a device that lowers the rollers 161 and 162 that circulate the platen belt 160 and their drive units as one unit. A mechanism for moving the actuator downward by an elastic force by an urging means such as an actuator, a motor, or a spring can be considered. In this embodiment, the platen belt 160 is lowered. However, the sheet can be retracted in any direction as long as the sheet on the platen belt 160 can be prevented from colliding with the head unit 110. It's okay.

(Transport control method)
The transport control method according to the present embodiment can be implemented by the transport control mechanism described above. FIG. 4A is a flowchart illustrating the operation of the paper transport mechanism according to the present embodiment, and FIG. 5 is an explanatory diagram schematically illustrating the operation of the paper transport mechanism.

  As shown in FIG. 4A, while the paper is being transported and printed on the transport path by a normal operation (S101), the paper lift is monitored upstream of the head unit 110 (S102). . When the sheet lift is not detected (“N” in S102), the normal operation is continued (S101).

  In step S102, when the sheet lift is detected upstream of the head unit 110 (“Y” in S102), the emergency stop mechanism 332 controls to immediately stop the registration roller in the registration unit R (S103). After the emergency stop of the registration roller, it is determined whether the detected float is at the leading edge of the paper or other than the leading edge (S104).

  In step S104, when a lift other than the leading edge of the sheet is detected (“other than the leading edge” in S104), the image forming path portion (the platen belt 160, the driving roller 161, the driven roller 162, etc.) is urgently stopped by the retraction mechanism. Then, the image forming path is lowered by the retracting mechanism (S105), and the image forming path is retracted so as to be separated from the normal transport path as shown in FIG. Thereafter, the paper downstream of the platen belt 160 is transported through the normal transport path and discharged from the paper discharge path DR.

  On the other hand, if the lifting of the leading edge of the sheet is detected in step S104, the sheet downstream of the platen belt 160 is discharged from the sheet discharge path DR while the registration roller is stopped without performing step S105. .

  Thereafter, until the end of paper discharge (S107) ("N" in S107), the paper transport operation on the downstream side is continued for the paper that is already being transported on the transport path (S106), and after all the paper has been discharged (S106) ("Y" in S107), the downstream paper transport operation is stopped (S108), and the paper transport is terminated.

  In the present embodiment, the paper discharge control unit 334 performs control to use the lowered platen belt 160 as a paper discharge table in the paper transport operation in step S106 described above. FIG. 4B is a flowchart illustrating the operation of the paper transport mechanism according to the present embodiment, and FIG. 6 is an explanatory diagram schematically illustrating the operation of the paper transport mechanism.

  As shown in FIG. 6, the normal paper path CR includes an image forming path CR1 configured by the platen belt 160 and the like, and a downstream transport path CR2 that transports the paper to the paper discharge path DR after image formation. The retreat mechanism separates the image forming path CR1 from the transport path and retreats. When the platen belt 160 is retracted by the retraction mechanism, the transport path control unit 333 and the paper discharge control unit 334 discharge the paper in the reversing path SR into the retracted platen belt 160.

  In this embodiment, the sheet is discharged to the image forming path CR1 when the platen belt portion is urgently stopped and lowered (S105), as shown in FIG. 6, the image forming path CR1 is retracted. On top, the paper being transported in the transport path is discharged.

  Specifically, in step S106 of FIG. 4A, as shown in FIG. 4B, when the sheet transport operation is continued on the downstream side, depending on whether or not the platen is lowered (S201). Then, it is determined whether or not there is paper on the reverse path (S203). If the platen belt is lowered and there is paper on the reverse path ("Y" in S201 and "Y" in S203), the reverse path SR After the paper remaining inside is discharged onto the lowered platen belt 160, the paper downstream of the platen belt 160 is discharged (S202). In other cases, recovery in the reversing path SR is not performed, and only downstream paper discharge is executed (S202).

(Action / Effect)
According to this embodiment, when the sheet floating is detected, the operation after the emergency stop of the registration roller is changed according to whether the floating is the leading edge of the sheet or other than the leading edge. As a result, the head unit 110 can be protected from contact with the floating portion of the paper by protecting the head unit 110, and the printed paper can be discharged to the normal paper discharge path DR by the downstream side conveyance path CR2. , Waste of printed matter can be eliminated, and for unfinished paper, the printing process is urgently stopped or the paper head is evacuated to another path, giving priority to the protection of the recording head, etc. You can take action.

  More specifically, in this embodiment, when floating is detected at the leading edge of a sheet, priority can be given to preventing damage to the recording head of the image forming unit for an unprinted sheet due to an emergency stop of the sheet feeding mechanism. On the other hand, the printed matter on the image forming path CR1 and the paper on which the printing on the downstream transport path CR2 has been completed can be discharged via the normal path CR as usual, thereby eliminating the waste of the sheet. be able to.

  On the other hand, when the float is detected at a position other than the leading edge of the sheet, the printing process has been progressed halfway for the sheet on the image forming path CR1 where the float has been detected. The mechanism can separate the image forming path CR1 from the head unit 110 and prevent the paper from coming into contact with the head unit 110 and being damaged.

  Further, in the present embodiment, when the floating detection unit detects the floating of the sheet, when the image forming path CR1 is retracted by the retracting mechanism, the sheet in the reversing path SR is placed on the retracted image forming path CR1. Therefore, if a paper failure occurs in the reversing path SR, the paper staying in the reversing path SR can be discharged onto the platen belt 160 that has been lowered. The sheet remaining on the reversing path SR having a complicated mechanism can be easily removed.

  As described above, according to the present embodiment, it is possible to prevent the sheet from colliding with the recording head of the image forming unit by detecting the lifting of the sheet at the leading edge and other than the leading edge of the sheet, and When the print medium is jammed in a part of the conveyance path, it is possible to facilitate the jam clearing operation performed by the user.

FIG. 2 is a configuration diagram illustrating an outline of a printing paper conveyance path of the printing apparatus according to the embodiment. FIG. 6 is an explanatory diagram schematically showing a paper feed system conveyance path FR, a normal path CR, and a reverse path SR according to the embodiment. (A) is a block diagram showing a module relating to the paper transport mechanism of the embodiment, and (b) and (c) are explanatory diagrams showing the configuration and operation of the floating sensor. FIG. 10 is a flowchart illustrating the operation of the paper transport mechanism according to the embodiment. FIG. 6 is an explanatory diagram schematically illustrating the detection of sheet floating and the operation of the transport mechanism according to the embodiment. FIG. 10 is an explanatory diagram schematically showing the operation of the paper transport mechanism according to the embodiment.

Explanation of symbols

CR ... Normal route DR ... Discharge route FR ... Paper feed route R ... Registration SR SR ... Reverse route 100 ... Printer 110 ... Head unit 120 ... Side paper feed stand 130 ... Feed tray 140 ... Discharge port 150 ... Discharge stand 160 ... Platen belt 161 ... Drive roller 162 ... Driven roller 170, 172 ... Switching mechanism 220 ... Side paper feed drive unit 230a, 230b ... Tray drive unit 240 ... Registration drive unit 250 ... Belt drive unit 260 ... First upper surface Conveyance drive unit 265 ... second upper surface conveyance drive unit 270 ... upper surface discharge drive unit 281 ... reverse drive unit 301 ... sensor 330 ... calculation processing unit 331 ... jam detection unit 331a ... multiple feed detection unit 331b ... non-tip / tip discriminating unit 331b ... Floating detector 332 ... Emergency stop mechanism 333 ... Conveyance path controller 334 ... Discharge controller 340 ... Operation Nel

Claims (2)

A conveyance control mechanism of a printing apparatus having an image forming unit that forms an image on a sheet surface conveyed on a conveyance path,
A levitation detection unit that detects a lift of each of the paper conveyed on the conveyance path at a position upstream of the image forming unit on the conveyance path;
A transport path control unit that controls driving and stopping of the transport path,
The transport path includes an image forming path on which image formation by the image forming unit is performed,
The image forming path is provided with a retreat mechanism that separates the image forming path from the transport path and retreats.
The transport path control unit urgently stops the paper feed mechanism that supplies the paper to the transport path when the floating detection unit detects the lift of the leading edge of the paper, and the paper that is already transported on the transport path. Is continuously conveyed, and when the floating detection unit detects a lift other than the leading edge of the sheet, the conveyance driving of the image forming path is stopped and the image forming path is retracted by the retracting mechanism. > A transport control mechanism for a printing apparatus. A conveyance control method for a printing apparatus having an image forming unit that forms an image on a surface of a sheet conveyed on a conveyance path,
The transport path includes an image forming path on which image formation by the image forming unit is performed,
The image forming path is provided with a retreat mechanism that separates the image forming path from the transport path and retreats.
A levitation detecting step for detecting respective lifts at the leading edge and other than the leading edge of the paper being conveyed on the conveying path upstream of the image forming unit on the conveying path;
In the floating detection step, when lifting of the leading edge of the paper is detected, the paper feeding mechanism that supplies the paper to the transport path is stopped urgently, and the paper that is already transported on the transport path is continuously transported And a conveyance path control step of stopping conveyance driving of the image forming path and retreating the image forming path by the retraction mechanism when a lift other than the leading edge of the sheet is detected in the floating detection step. A conveyance control method for a printing apparatus, comprising: