JP5454428B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus that uses a spur to convey a recording medium.

  As an image forming apparatus such as a printer, a facsimile, a copying machine, a plotter, or a complex machine of these, for example, a liquid discharge recording type image forming using a recording head composed of a liquid discharge head (droplet discharge head) that discharges ink droplets. An apparatus (ink jet recording apparatus) is known. This liquid discharge recording type image forming apparatus means that ink droplets are transported from a recording head (not limited to paper, including OHP, and can be attached to ink droplets and other liquids). Yes, it is also ejected onto a recording medium or a recording medium, recording paper, recording paper, etc.) to form an image (recording, printing, printing, and printing are also used synonymously). And a serial type image forming apparatus that forms an image by ejecting liquid droplets while the recording head moves in the main scanning direction, and a line type head that forms images by ejecting liquid droplets without moving the recording head There are line type image forming apparatuses using

  In the present application, the “image forming apparatus” of the liquid discharge recording method is an apparatus that forms an image by discharging liquid onto a medium such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, or the like. In addition, “image formation” means not only giving an image having a meaning such as a character or a figure to a medium but also giving an image having no meaning such as a pattern to the medium (simply It also means that a droplet is landed on a medium). “Ink” is not limited to ink, but is used as a general term for all liquids capable of image formation, such as recording liquid, fixing processing liquid, and liquid. DNA samples, resists, pattern materials, resins and the like are also included. In addition, the “image” is not limited to a planar image, and includes an image given to a three-dimensionally formed image and an image formed by three-dimensionally modeling a solid itself.

  By the way, in a liquid ejection type image forming apparatus, a sheet on which an image is formed with ink is conveyed as it is toward the discharge unit in an undried state, so that the undried ink adheres to the discharge roller or the like. Thus, there is a problem in that dirt is transferred from the discharge roller portion to which the undried ink is adhered to the paper, resulting in image defects.

  Therefore, in general, the discharge means for discharging the paper on which the image is formed is guided by a spur on the side in contact with the image forming surface, and further, retransfer cannot be prevented only by the spur. A spur cleaning roller is used for cleaning. In addition, the rotating body reciprocates or swings in the axial direction with respect to a cleaner provided with dust removing means for removing dust adhering to the spur (Patent Document 1) and a cleaner for removing ink transferred to the spur. There are known ones (Patent Document 2), those equipped with means for cleaning spurs (Patent Document 3), and the like.

JP 2003-12181 A Japanese Patent No. 3126612 JP 2007-276220 A

  However, since the spur cleaning roller is provided so as to rotate in pressure contact with the spur, dust such as ink on the blade edge (dust, hereinafter referred to as “ink dust”) accumulates on the blade bottom as the number of printed sheets increases. Then, there is a problem that the accumulated ink dust is transferred to the paper and a large spur mark is generated on the paper. In addition, when the spur cleaning roller is used, cleaning is performed at the same location, so that there is a problem that the cleaning effect tends to be reduced and the life is short.

  In addition, as disclosed in Patent Document 1, it is possible to reduce spur marks by providing a dust removing member and removing it with a dust removing member when the ink dust on the blade bottom reaches a certain size. Since the ink dust on the bottom of the blade is not removed until a certain size is reached, there remains a problem that the ink dust is transferred onto the paper until a certain size is reached, resulting in an image defect.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems. The spur is cleaned without accumulating ink dust on the spur blade bottom, and the liquid adhering to the spur blade edge is also removed so as not to reattach to the recording medium. The purpose is to do.

In order to solve the above problems, an image forming apparatus according to the present invention provides:
Image forming means for discharging droplets onto a recording medium to form an image;
Conveying means for conveying the recording medium;
Discharging means having a spur for discharging the recording medium on which an image is formed;
It said cleaning means and a spur cleaning means for cleaning the spur, a cleaning member made of a material having a water absorption, the relative spur, Ri means der for cleaning by contacting the spur side,
The cleaning member is a thread-like member or a belt-like member .

According to the image forming apparatus of the present invention, it becomes possible to clean the spur without accumulating ink dust on the blade bottom, and the liquid adhering to the spur blade edge as well as the spur side surface by having water absorption. Can also be absorbed by being pulled into the cleaning member on the side surface, and reattachment of the liquid adhering to the spur blade edge to the recording medium can also be prevented.

1 is an overall configuration diagram of an example of an image forming apparatus according to the present invention. It is side surface explanatory drawing of the spur cleaning mechanism of the same apparatus. It is a plane explanatory drawing similarly. It is explanatory drawing similarly seen from the bottom. It is block explanatory drawing which shows the outline | summary of a control part. It is a flowchart with which it uses for description of spur cleaning operation | movement. It is side explanatory drawing similarly used for description of spur cleaning operation | movement. FIG. 6 is a schematic explanatory view for explaining the spur cleaning operation.

Embodiments of the present invention will be described below with reference to the accompanying drawings. An example of an image forming apparatus according to the present invention will be described with reference to FIG. FIG. 1 is an overall configuration diagram of the image forming apparatus.
This image forming apparatus is a line type image forming apparatus, has an image forming unit 402 and the like inside the apparatus main body 401, and can supply a large number of recording media (sheets) 403 on the lower side of the apparatus main body 401. A paper tray 404 is provided. The paper 403 fed from the paper feed tray 404 is taken in, and a required image is recorded by the image forming unit 402 while the paper 403 is transported by the transport mechanism 405. The paper 403 is discharged to a paper discharge tray 406 attached to the side of the apparatus main body 401.

  Also, a duplex unit 407 that can be attached to and detached from the apparatus main body 401 is provided, and when performing duplex printing, the sheet 403 is conveyed into the duplex unit 407 while being transported in the reverse direction by the transport mechanism 405 after one-side (front) printing is completed. Then, the other side (back side) is sent back to the transport mechanism 405 as the printable side, and the paper 403 is discharged to the paper discharge tray 406 after the other side (back side) printing is completed.

  Here, the image forming unit 402 includes, for example, four full-line liquid ejection heads that eject droplets of each color of yellow (Y), magenta (M), cyan (C), and black (K). The recording heads 411y, 411m, 411c, and 411k (referred to as “recording head 411” when not distinguished from each other; the same applies to other members), and each recording head 411 formed a nozzle for ejecting droplets. The head holder 413 is mounted with the nozzle surface facing downward.

  In addition, a maintenance / recovery mechanism 412y, 412m, 412c, and 412k for maintaining and recovering the head performance corresponding to each recording head 411 is provided. During the head performance maintenance operation such as purge processing and wiping processing, the recording head 411 and The maintenance / recovery mechanism 412 is relatively moved so that the capping member constituting the maintenance / recovery mechanism 412 faces the nozzle surface of the recording head 411.

  Here, the recording head 411 is arranged to eject droplets of each color in the order of yellow, magenta, cyan, and black from the upstream side in the paper conveyance direction, but the arrangement and the number of colors are not limited to this. Further, as the line type head, one or a plurality of heads provided with a plurality of nozzle rows for discharging droplets of each color at a predetermined interval can be used, or a head and a liquid cartridge for supplying ink to the head are integrated. Or a separate body.

  The paper 403 in the paper feed tray 404 is separated one by one by a paper feed roller (half-moon roller) 421 and a separation pad (not shown) and fed into the apparatus main body 401, and is registered along the guide surface 423 a of the transport guide member 423. It is sent between 425 and the conveyor belt 433, and is sent to the conveyor belt 433 of the conveyor mechanism 405 via the guide member 426 at a predetermined timing.

  At this time, the paper type of the paper 403 in the paper feed tray 404 is detected by the paper detection sensor 443. Immediately after the sheet 403 is sent to the conveyance belt 433, a pretreatment mechanism 442 disposed on the upstream side of the image forming unit 2 applies a treatment liquid on the sheet 403 to improve the ink fixing property. Note that the user can select whether to apply the pretreatment liquid.

  In addition, the conveyance guide member 423 is also formed with a guide surface 423 b for guiding the paper 403 sent out from the duplex unit 407. Further, a guide member 427 for guiding the sheet 403 returned from the transport mechanism 405 to the duplex unit 407 during duplex printing is also provided.

  The conveyance mechanism 405 includes an endless conveyance belt 433 that is stretched between a conveyance roller 431 that is a driving roller and a driven roller 432, a charging roller 434 that charges the conveyance belt 433, and an image forming unit 402. A platen member 435 that maintains the flatness of the conveying belt 433 at the opposite portion, a pressing roller 436 that presses the paper 403 fed from the conveying belt 433 against the conveying roller 431 side, and other ink (not shown) that adheres to the conveying belt 433. It has a cleaning roller made of a porous body or the like as a cleaning means for removing.

  As the transport mechanism, for example, a mechanism that sucks the recording medium onto the transport belt by air suction can be used. Further, the transport roller 431 can delay the transport speed according to the discharge conditions, and can provide ink drying time.

  Disposed on the downstream side of the transport mechanism 405 is a sheet discharge unit 408 for sending out a sheet 403 on which an image is recorded to a sheet discharge tray 406. The sheet discharge unit 408 includes a sheet discharge roller 438 and a spur as a driven member. 439. In the case of an image with a large amount of adhesion and undried ink adhering to the spur 439 in the case of high-speed conveyance, a spur cleaning mechanism 440 that is a spur cleaning means for wiping off the adhered dirt is provided. Further, a heating mechanism 441 is also provided between the recording head 411 and the driven roller 439 in order to improve the drying property of the ink.

  In the image forming apparatus configured as described above, the conveyance belt 433 moves in the direction indicated by the arrow, and is charged by contact with the charging roller 434 to which a high potential application voltage is applied. The conveyance belt is charged to this high potential. When the sheet 403 is fed onto the sheet 433, the sheet 403 is electrostatically attracted to the conveyance belt 433. In this way, the sheet 403 that is strongly adsorbed to the transport belt 433 is calibrated for warpage and unevenness, and forms a highly flat surface.

  Then, the paper 403 is moved around the conveyor belt 433 and droplets are ejected from the recording head 411, whereby a required image is formed on the paper 403, and the paper 403 on which the image has been recorded is the paper discharge roller 438. As a result, the paper is discharged to the paper discharge tray 406.

  Next, details of the spur cleaning mechanism will be described with reference to FIGS. 2 is an explanatory side view of the spur cleaning mechanism, FIG. 3 is an explanatory plan view, and FIG. 4 is an explanatory view seen from below.

  As described above, a plurality of spurs 439 arranged on the support shaft 439a in a direction orthogonal to the paper transport direction are disposed downstream of the image forming unit 2 in the paper transport direction (hereinafter simply referred to as “transport direction”). The sheet discharge roller 438 is disposed so as to oppose it. The rotation direction of the spur 439 and the paper discharge roller 438 is the direction of the white arrow.

  Here, the spur cleaning mechanism 440 for cleaning the spur 439 includes a cleaning member 201 disposed between the spurs 439 along the conveyance direction. The cleaning member 201 is a thread-like member made of a material that absorbs water. The cleaning member 201 is wound around a supply roller 203 disposed on the downstream side of the spur 439, passes between the spurs 439, and is guided by the guide member 205 disposed on the upstream side of the spur 439, and then the cleaning member 201 It is taken up by the collecting take-up roller 202. The winding roller 202 is rotationally driven by the rotation of the cleaning member collecting motor 204.

  Then, as a cleaning member contact / separation mechanism for bringing the cleaning member 201 into contact with the side surface of the spur 439 and separating the cleaning member 201, the cleaning member moving members 206a and 206b are orthogonal to the transport direction on the upper side of the spur 439 (opposite to the transport surface) It is arrange | positioned so that a movement is possible. Engagement members (pin members) 210a and 210b that can be engaged with the cleaning member 201 are provided on the lower surface side (cleaning member 201 side) of the cleaning member moving members 206a and 206b. Further, a spring 208 as an urging means is disposed on one end side of the cleaning members 206a and 206b, and solenoids 207a and 207b as actuator means are disposed on the other end side.

  Further, as a mechanism for moving the cleaning member 201 when the cleaning member 201 is wound (collected) on the winding roller 202, the cleaning member moving member 206c is placed on the upper side of the spur 439 (on the opposite side to the conveying surface) in the conveying direction. It is arranged to be movable in a direction orthogonal to the direction. An engaging member (pin member) 210c that can be engaged with the cleaning member 201 is provided on the lower surface side (the cleaning member 201 side) of the cleaning member moving member 206c. Further, a spring 208 as an urging means is disposed on one end side of the cleaning member 206c, and is in contact with an eccentric cam 209 that is rotationally driven by the motor 204 on the other end side.

Next, an outline of the control unit of the image forming apparatus will be described with reference to a block diagram of FIG.
The main control unit 501 includes a microcomputer including a CPU, ROM, RAM, I / O, and the like that controls the entire image forming apparatus. The main control unit 501 processes the received image data and transfers it to the print control unit 502. The print control unit 502 controls driving of the head 411 via the head driver 503 according to the image data, and according to the image data. A droplet is discharged. Further, the main control unit 501 drives and controls the conveyance motor 505 that rotates the conveyance belt 433 through the motor driving unit 504 to convey the sheet 403.

  In addition, the main control unit 501 controls the winding of the cleaning member 201 by driving the motor 204 via the motor driving unit 511 and rotating the winding roller 202 in order to control the spur cleaning mechanism 400, and solenoid driving. The solenoids 207a and 207b are driven via the part 512 to move the cleaning member moving members 206a and 206b, and the cleaning member 201 is brought into contact with and separated from the spur 439.

Next, the spur cleaning operation by the spur cleaning mechanism configured as described above will be described with reference to the flowchart of FIG.
First, the necessity of the spur 439 is determined from the discharge amount data discharged from the head 411 in order to print the print image, and it is determined whether or not the spur 439 needs to be cleaned. If the spur 439 needs to be cleaned, the solenoids 207a and 207b are driven to move the cleaning member 210 to contact the side surface of the spur 439.

  By performing printing in this state, the paper discharge roller 438 rotates, and the spur 439 rotates as the paper discharge roller 438 follows. By the rotation of the spur 439, the cleaning member 201 in contact with the spur 439 is cleaned.

  Then, the motor 204 is driven to rotate the winding roller 202, the cleaning member 201 is wound up by a predetermined amount, and a new portion of the cleaning member 210 is moved to a position facing the spur 439.

  Thereafter, the necessity of the spur 439 is determined from the next discharge amount data, it is determined whether or not the spur 439 needs to be cleaned, and if cleaning is necessary, the cleaning of the spur 439 accompanying the printing operation is continued as it is. To do.

  When the spur 439 does not need to be cleaned, the solenoids 207a and 207b are returned to the original state, and the cleaning member 201 is separated from the spur 439 and returned to the original position.

  Further, even when there is no need for the spur 439 from the discharge amount data, the spur 439 is cleaned as described above when the cleaning is not performed for a certain period (when not performed).

  Here, as described above, the cleaning member is brought into contact with and separated from the side surface of the cleaning member according to the ejection amount data, that is, according to the amount of liquid attached to the paper (recording medium) in the printing operation. This eliminates the waste of the cleaning operation and extends the life of the cleaning member.

  In addition, by adopting a winding method for the cleaning member, the portion in contact with the spur always becomes a new portion where undried ink is not adhered to the cleaning, so that the cleaning effect can be further improved and the life of the cleaning member can be increased. Can be long.

  Furthermore, by assuming that the cleaning member is a thread-like member, the portion that contacts the spur blade becomes a point, the wasteful portion of the cleaning member is reduced, and the cleaning member is also reduced, so that the space can be reduced. . Moreover, since many cleaning members can be put in the apparatus, the life of the cleaning member is greatly increased, and the replacement of the cleaning member becomes unnecessary or the replacement frequency can be reduced. Furthermore, by being thread-like, it is possible to clean one by one even in a so-called multiple-type (similar to this embodiment) spur group with a narrow spur interval.

Such a cleaning operation will be specifically described with reference to FIGS.
First, when the spur 439 does not need to be cleaned, the cleaning member moving members 206a and 206b are moved in the direction indicated by the arrow a as shown in FIG. In addition, the cleaning member moving member 206b is in the position moved in the direction of the arrow b. In this state, as shown in FIG. 4A, the cleaning member 201 is guided by the pin members 210a and 210b of the cleaning member moving members 206a and 206b and is not in contact with the side surface of the spur 439 (a separated position). I'm in.

  When the spur 439 needs to be cleaned, such as when an image with a large discharge amount is printed, the cleaning member moving member 206b is moved to the right (in the direction of arrow b) and 206c is moved to the left by the solenoids 207a and 207b. 4 (b), the cleaning member 201 is moved to the side surface of the right spur 439 by the pin member 210a and to the side surface of the left spur 439 by the pin member 210b, respectively. Touch.

  Then, as the spur 439 rotates, as shown in FIG. 7, the undried ink 301 transferred to the spur 439 from the image 300 formed on the sheet 403 is absorbed by the cleaning member 201, and the spur 439 is cleaned. The sheet 403 is discharged. After cleaning, the cleaning member 201 is separated from the spur 439 by the solenoid 207 and returned to the original position shown in FIG.

  Thereafter, the cleaning member 201 is wound around the winding roller 202 and collected. At this time, due to the rotation of the eccentric cam 209 driven by the motor 204, the cleaning member 201 moves to the left and right by the cleaning member moving member 206c and is collected by the cleaning member winding roller 202 without being biased.

  That is, as shown in FIG. 8A, the undried ink 301 is attached to the spur 439, and as shown in FIG. 8B, the cleaning member 201 comes into contact with the spur 439 by the pin members 201a and 210b. The dry ink 301 is absorbed by the cleaning member 201, and as shown in FIG. 5C, all of the undried ink 301 is absorbed by the cleaning member 201 by the rotation of the spur 439. Thereafter, as shown in FIG. 4D, after the cleaning member 201 is separated from the spur 439, the cleaning member 201 is wound around the winding roller 202, and a new portion of the cleaning member 201 faces the side surface of the spur 439.

  Thus, by bringing the cleaning member 201 into contact with the side surface of the spur 439, the spur can be cleaned without accumulating ink dust on the blade bottom of the spur 439. At this time, since the cleaning member 439 is formed of a water-absorbing member, not only the side surface of the spur 439 but also the liquid adhering to the blade edge of the spur 439 is drawn to the side cleaning member 201 and absorbed. Therefore, reattachment of the liquid (ink) attached to the cutting edge of the spur 439 to the recording medium can also be prevented.

  Here, as the water content of the ink increases, the ink on the blade edge side also easily moves to the cleaning member 201 side, so that a greater cleaning effect can be obtained during high-speed printing. In the conventional cleaning roller or the like, dry ink dust is accumulated on the blade bottom of the spur 439. However, in the present invention, since the undried ink is absorbed on the side surface of the spur 439, the ink dust is difficult to accumulate on the blade bottom.

  In this way, by providing a spur cleaning means for cleaning the spur, the cleaning means is a means for cleaning the cleaning member made of a material having water absorption from the spur side surface with respect to the spur. It becomes possible to clean the spur without accumulating ink dust on the blade bottom, and by having water absorption, not only the spur side but also the liquid adhering to the spur blade tip can be drawn into the side cleaning member and absorbed, It is also possible to prevent reattachment of the liquid adhering to the spur edge to the recording medium.

  In addition, a cleaning effect can be improved more by setting it as the structure which makes a cleaning member contact the both sides | surfaces of a spur.

  In addition, a belt-shaped member is used as the cleaning member, and after cleaning on one side, cleaning is performed on the other side. For example, the cleaning member is movable to each side surface of two spurs sandwiching the cleaning member in FIG. Can extend the service life.

  In the above embodiment, the present invention has been described with reference to an example in which the present invention is applied to an image forming apparatus having a printer configuration. However, the present invention is not limited to this. For example, the present invention may be applied to an image forming apparatus such as a printer / fax / copier multifunction machine. it can. Further, the present invention can be applied to an image forming apparatus using a liquid other than the narrowly defined ink, a fixing processing liquid, or the like.

DESCRIPTION OF SYMBOLS 201 Cleaning member 202 Winding roller 203 Supply roller 206a, 206b Cleaning member moving member 402 Image formation part 403 Paper (recording medium)
405 Transport mechanism 408 Paper discharge means

Claims (5)

Image forming means for discharging droplets onto a recording medium to form an image;
Conveying means for conveying the recording medium;
Discharging means having a spur for discharging the recording medium on which an image is formed;
It said cleaning means and a spur cleaning means for cleaning the spur, a cleaning member made of a material having a water absorption, the relative spur, Ri means der for cleaning by contacting the spur side,
The image forming apparatus , wherein the cleaning member is a thread-like member or a belt-like member .   The image forming apparatus according to claim 1, wherein the cleaning unit winds up the cleaning member wound around a supply roller with a winding roller.   The image forming apparatus according to claim 1, wherein the cleaning unit contacts the cleaning member with both side surfaces of the spur. The image forming apparatus according to claim 1, wherein the cleaning is performed on one surface of the cleaning member, which is the belt-shaped member, and then the cleaning is performed on the other surface. The image forming apparatus according to any one of claims 1 to 4, characterized in that it comprises a means for contacting and spacing said cleaning member relative to the spur.

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