JP5472356B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus.

  As an image forming apparatus such as a printer, a facsimile machine, a copying apparatus, a plotter, and a complex machine of these, for example, an ink jet recording apparatus is known as an image forming apparatus of a liquid discharge recording method using a recording head for discharging ink droplets. . This liquid discharge recording type image forming apparatus ejects ink droplets from a recording head onto a conveyed paper to form an image (recording, printing, printing, and printing are also used synonymously). Serial type image forming device that forms an image by ejecting droplets while the recording head moves in the main scanning direction, and a line type that forms images by ejecting droplets without the recording head moving There is a line type image forming apparatus using a head.

  In the present application, “image forming apparatus” means an apparatus for forming an image by landing ink on a medium such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, etc. "Image formation" is not only the application of images with meanings such as characters and figures to the medium, but also the addition of images with no meaning such as patterns to the medium (simply applying droplets to the medium) Also means landing). The term “ink” is not limited to what is referred to as ink, but is used as a general term for all liquids that can perform image formation, such as recording liquid, fixing processing liquid, liquid, and resin. . The term “paper” is not limited to paper, but includes the above-described OHP sheet, cloth, and the like, and means that ink droplets adhere to the recording medium, recording medium, recording paper, recording It is used as a general term for what includes what is called paper. In addition, the “image” is not limited to a planar one, but includes an image given to a three-dimensionally formed image, and an image formed by three-dimensionally modeling a solid itself.

  By the way, as a liquid ejection type image forming apparatus, a recording medium is conveyed in a direction along the vertical direction or in a direction inclined with respect to a direction along the vertical direction, and the horizontal direction or the horizontal direction with respect to the recording medium. In general, an image is formed on a recording medium by ejecting droplets from a recording head while reciprocating a recording head that ejects droplets in a direction inclined with respect to the image (patent) Documents 1 to 3).

  Recently, a configuration has been adopted in which an image is formed by ejecting liquid droplets from a recording head toward a lower direction along the vertical direction while conveying a recording medium in the horizontal direction.

JP 05-338175 A Japanese Patent Laid-Open No. 06-071897 JP-A-11-204288 JP 2010-023297 A

  In the image forming apparatus as described above, it is required to easily perform jam processing when a jam occurs on a recording medium to be conveyed.

  The present invention has been made in view of the above problems, and an object thereof is to facilitate jam processing.

In order to solve the above problems, an image forming apparatus according to claim 1 of the present invention provides:
A cover provided on the apparatus body so as to be openable and closable;
A transport unit that is provided inside the cover and transports the recording medium in the vertical direction;
A recording head that ejects liquid droplets from nozzles toward the recording medium transported by the transport unit;
The transport unit is disposed between a surface of the recording head on which the nozzle is formed and the cover,
The transport unit moves in a direction in which the cover is opened when the cover is opened , and widens a space between the surface of the recording head on which the nozzle is formed and the transport unit ,
The amount of movement of the transport unit when the cover is opened is smaller than the amount of movement of the cover,
When the cover is opened and the cover is viewed from the horizontal direction,
The upper end of the cover and the upper end of the transport unit are above the upper end of the surface of the recording head on which the nozzle is formed, and the transport unit covers the surface of the recording head on which the nozzle is formed. It was set as the structure arrange | positioned in the position .

  The image forming apparatus according to the present invention facilitates jam processing.

FIG. 3 is a side explanatory view of a mechanism unit of the image forming apparatus according to the present invention. It is side surface explanatory drawing of a conveyance path open state similarly. It is an elevation explanatory drawing similarly. It is block explanatory drawing which shows the outline | summary of the control part of the apparatus. FIG. 5 is a schematic side view illustrating a state in which the transport belt unit is closed during droplet discharge for explaining a relationship between opening of the transport path (opening of the transport belt unit) and droplet landing position deviation. Similarly, it is a schematic side view illustrating a state in which the transport belt unit is opened (opened) during droplet discharge. It is explanatory drawing which shows an example of the relationship between the carriage speed profile and droplet discharge area with which it uses for description of the discrimination | determination process of landing position shift occurrence in 1st Embodiment of this invention. FIG. 10 is a flowchart for explaining an example of a printing resumption process when the conveyance belt unit is opened in the embodiment. FIG. 12 is a flowchart for explaining another example of the printing interruption resuming process when the conveyance belt unit is opened. It is explanatory drawing explaining the example of a display of presence or absence of landing position deviation similarly. FIG. 10 is an explanatory diagram for explaining a display example of a selection screen for canceling / continuing printing. It is explanatory drawing which shows an example of the relationship between the carriage speed profile and droplet discharge area used for description of the discrimination | determination process of impact position shift | offset | difference generation in 2nd Embodiment of this invention. FIG. 10 is a flowchart for explaining an example of a printing resumption process when the conveyance belt unit is opened in the embodiment. FIG. 12 is a flowchart for explaining another example of the printing interruption resuming process when the conveyance belt unit is opened. FIG. 10 is a schematic side view for explaining the relationship between the paper conveyance position and the presence or absence of occurrence of landing position deviation in the third embodiment of the present invention. It is side explanatory drawing of the state which produces a landing position shift similarly. It is side explanatory drawing of the state which does not produce landing position shift similarly. It is side explanatory drawing of the state which does not produce landing position shift similarly. It is side explanatory drawing with which it uses for description of 4th Embodiment of this invention. FIG. 6 is a side view illustrating a state where the paper is reversely conveyed. It is side surface explanatory drawing which uses for description of 5th Embodiment of this invention. FIG. 6 is a side explanatory view of a state in which the paper is conveyed in the normal direction.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. First, an image forming apparatus according to the present invention will be described with reference to FIGS. 1 is an explanatory side view of the mechanism portion of the image forming apparatus, FIG. 2 is an explanatory side view of the state where the conveyance path is opened, and FIG.

  This image forming apparatus is a serial type image forming apparatus, and has an image forming unit 2, a transport mechanism unit 5 and the like inside the apparatus main body, and can stack sheets 10 as recording media on the lower side of the apparatus main body. The image forming unit 2 includes a paper feed tray 4 and takes in the paper 10 fed from the paper feed tray 4 and intermittently transports the paper 10 in the vertical direction (direction along the vertical direction) by the transport mechanism 5. After a desired image is recorded by ejecting liquid droplets in the horizontal direction, the paper 10 on which the image is formed is further conveyed upward through the paper discharge unit 6 to be discharged on the upper side of the apparatus main body. The paper 10 is discharged to the tray 7.

  Further, when performing duplex printing, after completion of one-side (front) printing, the sheet 10 partially discharged to the sheet discharge tray 7 is taken into the reversing unit 8 and reversed, and the sheet 10 is reversed by the transport mechanism unit 5. While transporting, the other surface (back surface) is sent to the transport mechanism 5 again as a printable surface, and the paper 10 is discharged to the paper discharge tray 7 after the other surface (back surface) is printed.

  Here, the image forming unit 2 slidably holds a carriage 23 on which a recording head 24 is mounted with a main guide member 21 and a sub guide member 22 that are horizontally mounted between the left and right side plates 11L and 11R, and a main scanning motor. 25, the moving scanning is performed in the main scanning direction via the timing belt 28 passed between the driving pulley 26 and the driven pulley 27.

  The carriage 23 has recording heads 24a and 24b composed of liquid ejection heads for ejecting ink droplets of each color of yellow (Y), magenta (M), cyan (C), and black (K). As shown, the recording head 24 is arranged in a sub-scanning direction perpendicular to the main scanning direction, and the droplet discharge direction is mounted in the horizontal direction.

  Each of the recording heads 24 has two nozzle rows. One nozzle row of the recording head 24a has black (K) droplets, the other nozzle row has cyan (C) droplets, and the recording head 24b has one nozzle row. One nozzle row ejects magenta (M) droplets, and the other nozzle row ejects yellow (Y) droplets. As the recording head 24, a recording head having a nozzle row of each color in which a plurality of nozzles are arranged on one nozzle surface may be used.

  The liquid discharge head constituting the recording head 24 includes a piezoelectric actuator such as a piezoelectric element, a thermal actuator that utilizes a phase change due to liquid film boiling using an electrothermal conversion element such as a heating resistor, and a metal due to a temperature change. A shape memory alloy actuator using a phase change, an electrostatic actuator using an electrostatic force, or the like provided as pressure generating means for generating a pressure for discharging a droplet can be used. The carriage 23 can also be mounted with a liquid discharge head that discharges a fixing liquid that reacts with the ink to enhance the fixability of the ink.

  Although not shown, the carriage 23 is provided with a head tank (not shown) for supplying ink of each color corresponding to the nozzle row of the recording head 24. The head tank is detachably attached to the apparatus main body. Ink is supplied from each color ink cartridge (main tank).

  Further, an encoder scale 121 having a predetermined pattern is stretched between the both side plates 21L and 21R along the main scanning direction of the carriage 23, and the carriage 23 is composed of a transmission type photosensor that reads the pattern of the encoder scale 121. An encoder sensor 122 is provided, and the encoder scale 121 and the encoder sensor 122 constitute a linear encoder (main scanning encoder) 123 that detects the movement of the carriage 23.

  A maintenance / recovery mechanism 9 for maintaining and recovering the state of the nozzles of the recording head 24 is disposed in a non-printing area on one side in the scanning direction of the carriage 23. The maintenance / recovery mechanism 9 includes caps 92a and 92b for capping each nozzle surface of the recording head 24 (referred to as “cap 92” when not distinguished) and wiping by moving the nozzle surface in the direction of the arrow. A wiper member (wiper blade) 93 that performs the discharge, and an empty discharge receiver 94 that receives liquid droplets for discharging the liquid droplets that do not contribute to recording in order to discharge the thickened recording liquid.

  The sheets 10 in the sheet feeding tray 4 are stacked on a sheet stacking unit (pressure plate) 41, separated one by one by a sheet feeding roller (half moon roller) 43 and a separation pad (not shown), fed into the apparatus main body, and conveyed. Along the guide surfaces of the guide members 45 and 46 and the pressing member 47, the sheet is fed between the conveying belt 51 and the pressing roller 48 of the conveying mechanism unit 5 and conveyed while being pressed against the conveying belt 51 by the tip pressure roller 47. Is done.

  The conveyance mechanism unit 5 includes an endless conveyance belt 51 that is stretched between a conveyance roller 52 that is a driving roller and a driven roller 53, a charging roller 54 that charges the conveyance belt 51, and the image forming unit 2. A platen member 55 that maintains the flatness of the conveyor belt 51 at a portion facing the conveyor belt 51, a conveyor roller 56, a driven roller 53, and a spur unit 57 having a spur 58 that opposes the conveyor roller 56, and the like.

  The conveyance belt 51 rotates in the belt conveyance direction (sub-scanning direction, paper conveyance direction) when the conveyance roller 52 is rotationally driven by the sub-scanning motor 151 via the timing belt 152 and the timing pulley 153.

  Further, a high-resolution code wheel 154 is attached to the shaft 52a of the transport roller 52, and an encoder sensor 155 including a transmissive photosensor for detecting a pattern formed on the code wheel 154 is provided. These code wheel 154 and the encoder A rotary encoder (sub-scanning encoder) 156 that detects the amount and position of movement of the conveyor belt 51 by the sensor 155 is configured.

  The paper discharge unit 6 includes a conveyance guide member 61, a paper discharge roller 62A and a spur 62B, and a paper discharge roller 63A and a spur 63B. The paper 10 on which an image is formed is disposed between the paper discharge roller 63A and the spur 63B. Paper is discharged face down on the paper discharge tray 7.

  Further, the reversing unit 8 has continuous reversing paths 81a to 81c for reversing the paper 10 partially ejected to the paper discharge tray 7, and switching for switching the transport path in order to send the paper 10 to the reversing path 81a. It has a nail 83 and the like. The reverse path 81a is formed by the conveyance guide member 61 and the guide member 83a, the reverse path 81b is formed by the conveyance belt 51 and the guide member 84, and the reverse path 81c is formed by the conveyance guide members 45 and 46. The reverse path 81a is provided with a transport roller 85 and a required number of spurs 88, and the reverse path 81b is provided with transport auxiliary rollers 86 and 87 facing the driven roller 53 and the transport roller 52, respectively.

  Here, as shown in FIG. 2, a front cover 101 is provided on the front side of the apparatus main body so as to be openable and closable with a support shaft 102 at the lower end as a fulcrum. 85, conveyance auxiliary rollers 86 and 87 are attached. Further, the conveyance belt 51, the conveyance roller 52, the driven roller 53, and the conveyance roller 56 are integrated as a conveyance belt unit 50, and are provided so as to be openable and closable (swingable) with the shaft 52a of the conveyance roller 52 as a fulcrum. Further, the conveyance guide member 61 is also provided so as to be openable and closable (swingable) with the switching claw 82 side as a fulcrum.

  Thereby, by opening the front cover 101, the reversal paths 81a to 81c can be opened, and the jam processing at the time of duplex printing can be easily performed. Further, by opening the front cover 101, the conveyance belt unit 50 can be opened to separate the recording head 24 and the conveyance belt 51, and the conveyance guide member 61 can be opened to open the paper discharge path 60. Therefore, the jam processing becomes easy.

  In this image forming apparatus configured as described above, the paper 10 is separated and fed from the paper feed tray 4 one by one, and the paper 10 is electrostatically attracted to the charged transport belt 51, and the transport belt 51 is moved by the circular movement. The paper 10 is conveyed in the vertical direction. Therefore, by driving the recording head 24 according to the image signal while moving the carriage 23, ink droplets are ejected onto the stopped paper 10 to record one line, and after the paper 10 is conveyed by a predetermined amount, The next line is recorded, and the sheet 10 for which recording has been completed is discharged to the discharge tray 7.

  When performing the maintenance and recovery of the nozzles of the recording head 24, the nozzle 23 is moved to a position facing the maintenance and recovery mechanism 9 that is the home position, and is capped by the cap 92 to perform suction from the nozzles. By performing a maintenance and recovery operation such as idle ejection for ejecting droplets that do not contribute to image formation, image formation by stable droplet ejection can be performed.

Next, an outline of the control unit of the image forming apparatus will be described with reference to FIG. In addition, the figure is a block explanatory drawing of the control part.
The control unit 500 temporarily stores a CPU 501 that controls the entire apparatus, various programs including a program that causes the CPU 501 to execute control (processing) according to the present invention, a ROM 502 that stores other fixed data, image data, and the like. RAM 503 for storing, rewritable nonvolatile memory 504 for holding data even while the power of the apparatus is shut off, image processing for performing various signal processing and rearrangement on image data, and other control of the entire apparatus An ASIC 505 for processing input / output signals for the purpose is provided.

  Also, a print control unit 508 including a data transfer unit for driving and controlling the recording head 24 and a driving signal generating unit, a head driver (driver IC) 509 for driving the recording head 24 provided on the carriage 23 side, A main scanning motor 25 that moves and scans the carriage 23, motor driving units 510 and 511 for driving a sub-scanning motor 151 that moves the conveyor belt 51 in a circular manner, an AC bias supply unit 512 that supplies an AC bias to the charging roller 54, and the like It has.

  The control unit 500 is connected to an operation panel 514 for inputting and displaying information necessary for the apparatus.

  The control unit 500 has an I / F 506 for transmitting and receiving data and signals to and from the host side, an information processing device such as a personal computer, an image reading device such as an image scanner, an imaging device such as a digital camera, and the like. From the host 600 side via the cable or network via the I / F 506.

  Then, the CPU 501 of the control unit 500 reads and analyzes the print data in the reception buffer included in the I / F 506, performs necessary image processing, data rearrangement processing, and the like in the ASIC 505, and prints the image data. The data is transferred from the unit 508 to the head driver 509. Note that the generation of dot pattern data for image output is performed by the printer driver 601 on the host 600 side.

  The print control unit 508 transfers the above-described image data as serial data, and outputs a transfer clock, a latch signal, a control signal, and the like necessary for transferring the image data and confirming the transfer to the head driver 509. Including a D / A converter for D / A converting D / A conversion of drive pulse pattern data stored in the ROM, a voltage signal amplifier, a current amplifier, and the like, and a drive signal or a plurality of drive pulses Is output to the head driver 509.

  The head driver 509 selectively selects a drive pulse that constitutes a drive signal provided from the print control unit 508 based on image data corresponding to one line of the print head 24 that is input serially, and drops droplets of the print head 24. The recording head 24 is driven by applying it to a driving element (for example, a piezoelectric element) that generates energy to be discharged. At this time, by selecting a drive pulse that constitutes a drive signal, for example, droplets having different droplet sizes, such as large droplets, medium droplets, and small droplets, can be ejected and dots having different sizes can be sorted.

  The I / O unit 513 includes a main scanning encoder 123, a sub-scanning encoder 156, various sensor groups 515 mounted on the apparatus, and a conveyor belt unit open / close sensor 520 that is a detection unit that detects opening / closing of the conveyor belt unit 50. Information is acquired, information necessary for printer control is extracted, and used to control the print control unit 508, motor drive units 510 and 511, and AC bias supply unit 511. The sensor group 515 monitors the voltage of an optical sensor (paper sensor 521: see FIG. 3) provided in the carriage 23 for detecting the position of the paper, the thermistor for monitoring the temperature and humidity in the machine, and the charging belt. Sensors, an interlock switch for detecting opening / closing of the cover, and the like, and the I / O unit 513 can process various sensor information.

  The conveyance belt unit open / close sensor 520 is a push-type switch installed in the casing of the apparatus main body. As shown in FIG. 2, the conveyance belt unit 50 is opened and the conveyance belt unit 50 is opened between the conveyance belt 51 and the recording head 24. When the transport path is opened, it is detected that the transport unit is opened in a slightly opened state before being completely opened.

  The CPU 501 also detects a speed detection value and a position detection value obtained by sampling a detection pulse from the encoder sensor 122 constituting the main scanning encoder 123, and a speed target value and a position target obtained from a previously stored speed / position profile. The drive output value (control value) for the main scanning motor 25 is calculated based on the value and the main scanning motor 25 is driven via the motor driving unit 210. Similarly, a speed detection value and a position detection value obtained by sampling a detection pulse from the encoder sensor 155 constituting the sub-scanning encoder 156, a speed target value and a position target value obtained from a previously stored speed / position profile, and Based on this, a drive output value (control value) for the sub-scanning motor 151 is calculated, and the sub-scanning motor 151 is driven via the motor driving unit 211.

  Next, the relationship between the opening of the conveying path (opening of the conveying belt unit) and the displacement of the droplet landing position will be described with reference to FIGS. FIG. 5 is a schematic side view illustrating a state in which the transport belt unit is closed during droplet discharge, and FIG. 6 is a schematic side view illustrating a state in which the transport belt unit is opened (opened) during droplet discharge. 5 and 6 are schematic side explanatory views of FIG. 3 viewed from the right side (the same applies to the following).

  As described above, the paper 10 fed from the paper feed tray 4 is transported by the transport belt 51 in the upward direction (transport direction) along the vertical direction, and the carriage 23 is main-scanned and droplets are ejected from the recording head 24. By discharging in the horizontal direction, a required image is formed and discharged to the discharge tray 7. As shown in FIG. 5, the conveyance belt unit 50 is normally closed so that the carriage 23 and the conveyance belt 51 are close to each other. However, the purpose is to allow the user to remove jammed paper when a jam occurs. As shown in FIG. 6, the conveying belt unit 50 can be opened to open the conveying path (the side of the conveying belt 51 facing the recording head 24). The conveying belt unit 50 is opened when the conveying belt unit 50 is opened. It is detected by the open / close sensor 520.

  Here, as shown in FIG. 5, when the conveying belt unit 50 is closed, the gap between the recording head 24 and the paper 10 is maintained at a required interval, and the recording head 24 discharges in the horizontal direction as indicated by the arrows. The dropped liquid droplets land on the paper 10 conveyed in the conveyance direction.

  On the other hand, as shown in FIG. 6, when the conveyance belt unit 50 is opened and the conveyance path is opened, the conveyance belt unit sensor 520 detects the conveyance belt unit open.

  In this case, there is no lock mechanism for locking the opening / closing of the conveyor belt unit 50 during printing, and the conveyance belt unit 50 can be transported during printing (during droplet ejection) if the conveyor belt unit 50 can be opened and closed during printing. The belt unit 50 may be opened and closed.

  At this time, the ink droplets ejected in the horizontal direction from the recording head 24 fly in the horizontal direction as they are and land on the paper 10 sucked and held by the transport belt unit 50, and the transport belt is being ejected during droplet ejection. When the unit 50 is opened, the landing positions of the ink droplets on the paper 10 are shifted.

Accordingly, the process for determining the occurrence of a landing position deviation in the first embodiment of the present invention will be described with reference to FIG. FIG. 7 is an explanatory diagram for explaining the relationship between the carriage speed profile and the droplet discharge section.
First, as described above, the landing position shift occurs when the transport belt unit 50 is opened when the transport belt unit 50 is opened during droplet discharge.

  Incidentally, during the printing operation, droplets are ejected from the recording head 10 while scanning the carriage 23. However, the droplets are not ejected in all sections during the carriage scanning, but generally as shown in FIG. In addition, there are an ink non-ejection section in which ink droplets are not ejected in a section during acceleration until the speed of the carriage 23 (carriage speed) reaches a predetermined speed and a section during deceleration until the carriage speed stops from the predetermined speed. In addition, a section (ink ejection section) for ejecting ink droplets is provided in an equal speed section where the carriage speed is stable at a predetermined speed. The ink discharge section is a section from the ink discharge start position to the ink discharge end position, and may or may not match the constant speed section.

  Therefore, when the transport belt unit 50 is opened during the ink discharge section, the droplet landing position is shifted as shown in FIG. On the other hand, when the transport belt unit 50 is opened during the ink non-ejection section, the landing position is not shifted if the ink ejection is interrupted at that time. When the conveying belt unit 50 is closed while the paper 10 being printed is left as it is, printing can be resumed from the position where printing was interrupted.

  Further, when the transport belt unit 50 is opened during the ink discharge section, a drop landing position shift occurs. When the transport belt unit 50 is opened during the ink non-discharge section, the drop landing position shift occurs. By notifying the user that it does not occur through the host 600 or through the operation panel 514, the user can recognize the presence or absence of image quality degradation. Even when the landing position deviation occurs, printing can be resumed as it is when the user instructs to continue printing.

Accordingly, an example of the printing resumption process when the transport belt unit is opened in the present embodiment will be described with reference to the flowchart of FIG.
When it is detected that the transport belt unit 50 is opened (S101), the droplet discharge from the recording head 24 is stopped (S102). Then, it is determined whether or not the position of the carriage 23 at the time when the droplet discharge is stopped is an ink discharge section (S103), and it is determined (detected) whether or not a droplet landing position deviation occurs.

  Since the paper size of the ink discharge section varies depending on the image size and the like, the current position of the carriage 23 is detected from the detection result of the main scanning encoder 25 as described above, and the current position and the ink discharge section of the carriage 23 in the scan are detected. By comparing these, it can be determined whether or not it is within the ink discharge section.

  At this time, if the position of the carriage 23 at the time of droplet ejection stop is in the ink ejection section, it is determined that there is a drop in the landing position of the droplet landing (S104). It is determined that there is no displacement (S105).

  When it is determined that there is a landing position deviation, the paper discharge operation is performed (S107) when the transport belt unit 50 is closed (S106).

  In contrast, when it is determined that there is no landing position deviation, when the transport belt unit 50 is closed (S108), it is determined by detecting whether or not the paper 10 is on the transport belt 51 by the paper sensor 521 ( If there is the paper 10 (S109), printing is resumed from the position where the droplet ejection is interrupted (S110).

Next, another example of the printing interruption resumption process when the conveyance belt unit is opened will be described with reference to the flowchart of FIG.
When it is detected that the transport belt unit 50 is opened (S101), the droplet discharge from the recording head 24 is stopped (S102). Then, it is determined whether or not the position of the carriage 23 at the time when the droplet discharge is stopped is an ink discharge section (S103), and it is determined (detected) whether or not a droplet landing position deviation occurs.

  At this time, if the position of the carriage 23 at the time of droplet ejection stop is in the ink ejection section, it is determined that there is a drop in the landing position of the droplet landing (S104). It is determined that there is no displacement (S105).

  Then, according to the determination result, for example, a display with landing position deviation shown in FIG. 10 (a) and a display without landing position deviation shown in FIG. 10 (b) are made and notified to the user (S111). As shown in FIG. 11, a selection screen for canceling printing or continuing printing is displayed, and a print continuation instruction is accepted (S112).

  Here, it is determined whether or not continuation of printing has been instructed (S113). When continuation of printing is instructed, printing is resumed from the position where the droplet ejection is interrupted when the conveyor belt unit 50 is closed (S114). (S115).

  As described above, when it is detected that the transport unit is opened, it is determined whether or not the landing position deviation of the droplet occurs. When it is determined that the landing position shift does not occur, the transport unit By adopting a configuration in which the image forming operation is restarted when closed, it is possible to reduce wasteful consumption of consumables such as a recording medium and liquid accompanying the opening of the conveyance path in the horizontal driving method.

  Further, when it is detected that the transport means is opened, it is determined whether or not the landing position deviation of the droplet occurs, the determination result is notified, and an instruction to continue the printing operation for the notification result is accepted. In such a case, it is possible to reduce wasteful consumption of consumables such as recording media and liquid when the conveyance path is opened in the horizontal driving method by controlling the image forming operation to resume when the conveying unit is closed. can do.

Next, a determination process for occurrence of landing position deviation in the second embodiment of the present invention will be described with reference to FIG. FIG. 12 is an explanatory diagram for explaining the relationship between the carriage speed profile and the landing position deviation occurrence section.
In the present embodiment, when the transport belt unit 50 is opened during carriage scanning (scanning of the recording head 24), droplet ejection is performed as it is for one scan, and printing is stopped after the scan is completed. Yes.

  In this case, when the conveyance belt unit 50 is opened between the ink non-ejection section at acceleration and the end of the ink ejection section at constant speed (landing position deviation occurrence section) shown in FIG. However, when the transport belt unit 50 is opened during the ink non-ejecting section at the time of deceleration (the landing position deviation non-occurrence section), the ink ejection during the scanning is completed, and thus the landing position deviation does not occur.

  Therefore, when the conveyance belt unit 50 is opened in a section where no landing position deviation has occurred, when the conveyance belt unit 50 is closed while the paper 10 being printed is left as it is, printing is performed from the position next to the scan where printing is finished. Can be resumed.

  Further, when the conveying belt unit 50 is opened in the landing position deviation occurrence section, the droplet landing position deviation occurs, and when the conveyance belt unit 50 is opened in the landing position deviation non-occurrence section, the droplet landing position is generated. By notifying the user through the host 600 side or through the operation panel 514 that the deviation does not occur, the user can recognize the presence or absence of image quality deterioration. Even when the landing position deviation occurs, printing can be resumed as it is when the user instructs to continue printing.

Therefore, an example of the printing resumption process when the transport belt unit is opened in this embodiment will be described with reference to the flowchart of FIG.
When it is detected that the conveyor belt unit 50 is opened (S201), the carriage position when the conveyor belt unit 50 is opened is stored (S202), and droplet discharge is continued from the recording head 24 as it is. 23 is completed (S203).

  Then, after the scanning is completed, it is determined whether or not the stored carriage position is the landing position deviation occurrence section (S204), and it is determined (detected) whether or not the landing position deviation occurs. At this time, when the stored carriage position is within the landing position deviation occurrence section, it is determined that there is a droplet landing position deviation (S205), and when the stored carriage position is within the landing position deviation non-occurrence section, It is determined that there is no deviation in the landing position (S206).

  When it is determined that there is a landing position deviation, a paper discharge operation is performed (S208) when the transport belt unit 50 is closed (S207).

  On the other hand, when it is determined that there is no landing position deviation, when the transport belt unit 50 is closed (S209), it is determined by detecting whether or not the paper 10 is on the transport belt 51 by the paper sensor 521 ( If there is the paper 10 (S210), the printing is resumed from the position where the droplet ejection is interrupted (S211).

Next, another example of the printing interruption resumption process when the transport belt unit is opened will be described with reference to the flowchart of FIG.
When it is detected that the conveyor belt unit 50 is opened (S201), the carriage position when the conveyor belt unit 50 is opened is stored (S202), and droplet discharge is continued from the recording head 24 as it is. 23 is completed (S203).

  Then, after the scanning is completed, it is determined whether or not the stored carriage position is the landing position deviation occurrence section (S204), and it is determined (detected) whether or not the landing position deviation occurs. At this time, when the stored carriage position is within the landing position deviation occurrence section, it is determined that there is a droplet landing position deviation (S205), and when the stored carriage position is within the landing position deviation non-occurrence section, It is determined that there is no deviation in the landing position (S206).

  Then, according to the determination result, a display with landing position deviation or a display without landing position deviation is made in the same manner as in the first actual form to notify the user (S212), and then printing is stopped or printing is continued. A screen for selecting whether to perform printing is displayed and a print continuation instruction is accepted (S213).

  Here, it is determined whether or not the continuation of printing has been instructed (S214). When the continuation of printing is instructed, the printing is resumed from the position where the droplet ejection is interrupted when the conveying belt unit 50 is closed (S215). (S216).

Next, the relationship between the paper conveyance position and the presence or absence of occurrence of landing position deviation in the third embodiment of the present invention will be described with reference to FIGS.
Here, a conveyance guide 201 is provided on the downstream side of the conveyance belt unit 50, and the conveyance guide (paper guide) 201 is provided with a conveyance roller 203 that conveys the paper 10 while nipping (the portion sandwiched between the conveyance rollers 203 is “ The sheet sensor 202 for detecting the sheet 10 is provided in the vicinity of the upstream of the conveyance roller 203.

First, a description will be given of a case where a landing position shift occurs due to the opening of the conveyance belt unit 50.
As shown in FIG. 15, when the conveyance belt unit 50 is opened when the leading edge of the paper 10 being printed is at a position sandwiched by the nip portion 203 of the paper guide 201, as shown in FIG. It peels from the conveyor belt 21. When the paper 10 is peeled from the transport belt 51, the paper 10 is not attracted to the transport belt 51 and floats from the transport bell 51 even when the transport belt unit 50 is closed. Therefore, when the conveyance belt unit 50 is closed and printing is resumed, the image is deteriorated or a jam occurs.

  Therefore, when the paper detection sensor 202 detects the paper 10 as described above, it is determined that the landing position deviation occurs when the transport belt unit 50 is opened.

  On the other hand, as shown in FIG. 17, when the rear end of the paper 10 is out of the detection position of the paper sensor 202, the paper 10 is not displaced even if the transport belt unit 50 is opened. Therefore, in this case, it is determined that there is no deviation in the landing position.

  Further, as shown in FIG. 18, even when the leading edge of the paper 10 being printed has not reached the detection position of the paper detection sensor 202, the positional deviation of the paper 10 does not occur. Accordingly, in this case, it can be determined that there is no landing position deviation unless the droplet is being discharged. If droplet ejection is in progress, it is determined that there is a landing position deviation as in the first embodiment.

Next, a fourth embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 19, when the leading edge of the paper 10 is detected by the paper sensor 202, the landing position deviation is present in the third embodiment. Therefore, when it is detected that the leading end of the sheet 10 is sandwiched between the nip portions 203, when it is detected that the conveying belt unit 50 is opened, the conveying belt 51 is rotated reversely, as shown in FIG. 10 is moved in the direction opposite to the conveyance direction, and returned to a position where the leading edge of the paper 10 is not detected by the paper sensor 202. Thereby, it can be determined that there is no landing position deviation.

  As described above, when the “landing position deviation present” condition and “no landing position deviation” condition are met, when the opening of the conveyor belt unit is detected, the paper is immediately reverse-conveyed to deteriorate the image. Can be prevented.

  Here, whether or not the sheet 10 is in the state shown in FIG. 19 is determined based on the conveyance amount obtained by the sub-scanning encoder 156 after the leading edge of the sheet 10 is detected by the sheet sensor 202. To do. And when carrying out reverse conveyance, it is preferable to carry out reverse conveyance before the conveyance belt unit 50 is completely open | released (for about 0.5 second). Therefore, when the transport amount after the leading edge of the paper 10 is detected by the paper sensor 202 is X mm and the reverse transport speed is V mm / s, the reverse transport is performed when the transport amount is obtained by X = 0.5 × V. Is preferably executed.

Next, a fifth embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 21, when the trailing edge of the sheet 10 is detected by the sheet sensor 202, the landing position deviation is present in the third embodiment. Therefore, when it is detected that the rear end of the paper 10 is sandwiched between the nip portions 203, when it is detected that the conveyor belt unit 50 is opened, the conveyor belt 51 is rotated forward, as shown in FIG. The paper 10 is moved in the transport direction and sent to a position where the rear end of the paper 10 is not detected by the paper sensor 202. Thereby, it can be determined that there is no landing position deviation.

  As described above, when the “landing position deviation present” condition and “no landing position deviation” condition are met, when the opening of the conveyance belt unit is detected, the paper is immediately conveyed normally and the image deteriorates. Can be prevented.

  Here, whether or not the sheet 10 is in the state shown in FIG. 21 is determined based on the conveyance amount obtained by the sub-scan encoder 156 after the conveyance amount after the leading edge of the sheet 10 is detected by the sheet sensor 202. To do. And when carrying forward rotation, it is preferable to complete conveyance before the conveyance belt unit 50 is completely opened (for about 0.5 sec). Therefore, when the transport amount after the leading edge of the paper 10 is detected by the paper sensor 202 is X mm, the transport speed is V mm / s, and the paper length is L mm, X = (L−0.5 × V). It is preferable to perform forward rotation conveyance in the case of the required conveyance amount.

  It should be noted that the above-described determination of landing position deviation, processing relating to resuming printing, processing relating to paper conveyance, and reverse feed control can be performed by a computer using a program stored in a ROM or the like. This program is stored in a storage medium. It can be stored and provided, or provided by downloading through a network such as the Internet. The image forming system can also be configured by combining the image forming apparatus described in the above embodiment and the host side (information processing apparatus).

  In the above embodiment, the paper is conveyed in the direction along the vertical direction (vertical direction) and the liquid droplets are ejected in the horizontal direction. However, the paper is moved in the direction along the vertical direction (vertical direction). Even if the liquid droplets are transported in an inclined direction and the liquid droplets are discharged in a horizontal direction or a direction inclined with respect to the horizontal direction, the bleeding of the landed liquid droplets is different in the vertical direction of the gravity direction. Can be applied as well.

2 Paper feed tray 10 Paper (recording medium)
23 Carriage 24 Recording Head 50 Conveying Belt Unit 51 Conveying Belt 500 Control Unit

Claims (7)

A cover provided on the apparatus body so as to be openable and closable;
A transport unit that is provided inside the cover and transports the recording medium in the vertical direction;
A recording head that ejects liquid droplets from nozzles toward the recording medium transported by the transport unit;
The transport unit is disposed between a surface of the recording head on which the nozzle is formed and the cover,
The transport unit moves in a direction in which the cover is opened when the cover is opened , and widens a space between the surface of the recording head on which the nozzle is formed and the transport unit ,
The amount of movement of the transport unit when the cover is opened is smaller than the amount of movement of the cover,
When the cover is opened and the cover is viewed from the horizontal direction,
The upper end of the cover and the upper end of the transport unit are above the upper end of the surface of the recording head on which the nozzle is formed, and the transport unit covers the surface of the recording head on which the nozzle is formed. An image forming apparatus, wherein the image forming apparatus is disposed at a position . The cover and the transport unit are respectively supported by the apparatus main body so that the upper part swings around the lower part and can be opened.
Swing angle of the transfer portion is not smaller than the swing angle of the cover
The image forming apparatus according to claim 1, wherein the this. The transport unit has a transport belt capable of sucking and transporting the recording medium,
The conveying unit in a state where the conveyor belt has adsorbed the recording medium, the image forming apparatus according to claim 1, wherein the cover is thus being moved to the front Symbol cover side when it is opened. The recording head ejects droplets forward in a horizontal direction or a direction inclined with respect to the horizontal direction,
The image according to claim 1, wherein the transport unit transports the recording medium in a direction along the vertical direction or in a direction inclined with respect to a direction along the vertical direction so as to face the recording head. Forming equipment. The conveyor belt is wound around an upper roller and a lower roller,
The image forming apparatus according to claim 3, wherein the conveyor belt is swingable about the lower roller. A spur unit disposed at a position facing the transport unit in the apparatus main body,
The image forming apparatus according to claim 1, wherein the spur unit remains on the apparatus main body side when the cover and the transport unit are opened. A cover that can be opened forward,
A transport unit that is provided inside the cover and transports the recording medium in the vertical direction;
A recording head that is provided inside the transport unit and ejects liquid droplets forward from nozzles toward the recording medium transported by the transport unit;
The transport unit is disposed between a surface of the recording head on which the nozzle is formed and the cover,
When the front cover is opened forward, the transport unit moves forward to widen a space between the surface of the recording head on which the nozzle is formed and the transport unit ,
The amount of movement of the transport unit when the cover is opened is smaller than the amount of movement of the cover,
When the cover is opened and the cover is viewed from the horizontal direction,
The upper end of the cover and the upper end of the transport unit are above the upper end of the surface of the recording head on which the nozzle is formed, and the transport unit covers the surface of the recording head on which the nozzle is formed. An image forming apparatus, wherein the image forming apparatus is disposed at a position .

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