JP2007316466A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus having an end surface fixing device for preventing the contamination due to the excess toner (or ink etc.,) sticking to a paper sheet end surface even when an image is outputted even to the end of the paper sheet. <P>SOLUTION: The image forming apparatus in which image formation with white borders is possible by protruding a recording material from at least one end of the recording medium and transferring the recording material to the recording medium. The image forming apparatus is equipped with a fixing section to be exclusively used for the end surface which fixes only the recording material attached to the end surface of the recording medium. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as an electrophotographic copying machine, a printer, or a facsimile, and more particularly to an image forming apparatus having a fixing device that fixes an end portion of a sheet as a recording medium.

  When an image is output to the peripheral edge of a recording medium (hereinafter also referred to as paper), the recording material (toner, ink, etc.) becomes an image area up to the peripheral edge of the paper as shown in FIG. Therefore, there are inconveniences that make the user's hand dirty and problems that make other prints dirty when taking out the loaded paper and handling files.

  FIG. 5 is a diagram illustrating an example of a stain on the sheet end surface.

In order to avoid such toner smearing, a bias (same polarity as transfer) is applied to the transfer entrance guide plate that guides the paper to the transfer area so that the toner does not approach, and the timing is controlled (for example, Patent Documents) 1), a method of removing toner adhering to the back side of the paper (see, for example, Patent Document 2), a method of providing a suction fan between the transfer region and fixing, and a method of sucking the scattered and floating toner (for example, , See Patent Document 3).
JP-A-7-239617 JP 7-271256 A JP 2001-244462 A

  However, it is difficult to remove the physically attached toner only by the method of preventing the toner smearing at the end face of the paper at the timing of the bias applied to the transfer approach guide plate, which is the technique of Patent Document 1.

  Further, the technique of Patent Document 2 only removes the dirt toner on the back side of the paper, and does not describe the dirt on the end face. Patent Document 3 is effective in collecting the toner scattered from the paper, but does not have enough performance to remove the toner adhering to the paper. If the air volume is too large, the unfixed image may be disturbed.

  The present invention provides an image forming apparatus having an end surface fixing member which is an end surface fixing unit for preventing contamination due to excess toner (or ink or the like) adhering to the end surface of a sheet even when an image is output to the end of the sheet. The purpose is to provide.

  The above object is achieved by the following configuration.

  An image forming apparatus capable of forming an image without a border by protruding from at least one end of the recording medium and transferring the recording material to the recording medium, wherein only the recording material attached to the end surface of the recording medium is removed. An image forming apparatus comprising an end face fixing unit for fixing.

  The dirt on the end face of the paper can be removed, and the inconvenience of dirty hands and the worry of smearing other prints are solved, especially when the user handles the paper loaded on the tray or the like.

  The image forming apparatus of the present invention will be described below based on the embodiments.

  FIG. 1 is a schematic diagram of an ink jet printer according to a first embodiment.

  In FIG. 1, a sheet 2 fed from a sheet feeding cassette 1 is fed out by a pickup roller 5, guided to upper and lower guide plates 3 and 4, and sandwiched and transported by upper and lower rollers 6 and 7. In the process of passing through the lower guide plates 8 and 9 on the conveyance, the printing with the recording head 10 is synchronized by a resist means (not shown). The print head 10 slides along the guide rail 11 in the main scanning direction. After printing on the paper to the end in the main scanning direction by the printing unit W, the end surface fixing member 12, which is an end surface dedicated fixing unit installed on both sides in the transport process in the transport unit F, is used to transport the paper in the transport direction (secondary (Scanning direction) Excess ink at both ends is fixed. Further, the sheet is conveyed, and the leading end reaches the end surface fixing member 13 which is an end surface fixing unit including the fan 18 and the heater 19, and the ink attached to the leading end and the rear end is fixed. Thereafter, the paper is discharged onto a paper discharge tray 15.

  Next, the details of the end face fixing members 12 and 13 will be described.

  FIG. 2 is a diagram illustrating a sheet conveyance path and an end surface fixing member as viewed from the upper surface of FIG.

  In FIG. 2A, the fixing member 12 includes a heater 17 and a fan 16 that blows the heat of the heater 17 on both ends of the sheet in the sheet conveyance direction as a wind of a predetermined temperature or higher. The paper fed from the paper feed cassette 1 is printed by the printing unit W of the recording head 10, and in the process of passing through the transport unit F, excess ink at both ends of the paper is dried and fixed. . Thereafter, the leading edge of the paper reaches the fixing member 13.

  FIG. 3B shows a cross section of the fixing member 13 as viewed from the direction of the arrow X, and the configuration includes a fan 18 and a heater 19. The paper printed up to the peripheral edge of the paper is blown by the fan 18 with the heat of the heater 19, and in the process of passing through the conveyance path F, the excess ink at the leading edge and the trailing edge of the paper is dried and fixed. The paper is supported and discharged to the paper discharge tray 15. Therefore, the ink at the peripheral edge of the paper is fixed on the paper, so that the user's hand stains and other concerns about soiling other prints are eliminated.

  Next, a second embodiment will be described.

  FIG. 3 is a schematic diagram of a full-color electrophotographic apparatus according to the second embodiment.

  FIG. 4 shows a sheet conveyance path diagram in FIG.

  An image forming unit 1A includes a photosensitive drum 21, a charger 24, a developing unit 22, a cleaning unit 23, and the like. Reference numeral 25 denotes a writing device which is a digital exposure writing means. Reference numeral 20 denotes an intermediate transfer belt which is an intermediate transfer member. The arrangement of the image forming unit 1A for each color is in the order of Y, M, C, K with respect to the traveling direction of the intermediate transfer belt 20. At the time of transfer, the primary transfer roller 26 presses the intermediate transfer belt 20 to the photoreceptor 21. In the pressure-bonding region, the photosensitive drum 21 rotates in the same direction as the traveling direction of the intermediate transfer belt 20 and at the same linear speed.

  Since the mechanical configuration of the image forming unit 1A for each color is the same, only the Y color configuration is given a reference symbol in FIG. 1, and the reference symbols are omitted for the other three sets of components.

  The intermediate transfer belt 20 is stretched around a driving roller 27, an earth roller 28, a tension roller, a driven roller, and the like. The intermediate transfer belt unit 2A is constituted by these rollers, the intermediate transfer belt 20, the primary transfer roller 26, the cleaning device 29, and the like. Constitute. An electrostatic charge is charged on the photosensitive drum 21 by the charger 24, an electric signal corresponding to the image data is converted into an optical signal by the image forming laser, and the latent image is projected onto the photosensitive drum 21 by the writing device 25. Is formed. The latent image is visualized (toner image) by the developing device 22.

  The intermediate transfer belt 20 travels by rotation of the drive roller 27 by a drive motor (not shown).

  The primary transfer roller 26 is applied with a DC voltage having a polarity opposite to that of the toner, and presses the intermediate transfer belt 20 against the photosensitive drum 21 from the inside of the belt by a pressure-bonding and pressure-release mechanism (not shown), and the toner image is transferred to the intermediate transfer belt. First transfer onto 20.

  First, starting from the Y image forming process, the toner image is transferred onto the intermediate transfer belt 20. In synchronization with this, a superimposed toner image is formed on the intermediate transfer belt 20 in the order of M, C, and K in the same image forming process. The intermediate transfer belt 20 carrying the superimposed toner image is fed clockwise as indicated by an arrow. The paper P is delivered from the paper cassette 72 by the paper delivery roller 70, passed through the transport roller 73, transported to the timing roller 71, temporarily stopped, synchronized with the superimposed toner image on the intermediate transfer belt 20, and thereafter The timing roller 71 is driven to be fed to the nip portion S (secondary transfer portion) of the secondary transfer roller 30 (which is in a pressure-bonded state to the intermediate transfer belt 20) to which a DC voltage having a polarity opposite to that of the toner is applied. The superimposed toner images on the intermediate transfer belt 20 are secondarily transferred onto the paper P at once.

  A fixing device 40 is an image surface fixing unit, and includes a heating roller 41 and a pressure roller 42. The heating roller 41 has a cylindrical shape made of thin aluminum and has a halogen heater 43 and the like for heating from the inside to a predetermined temperature, and the temperature is a contact (not shown) installed on the heating roller 41. It is detected and controlled by a temperature sensor.

  70 is a paper feed roller, 71 is a timing roller, 72 is a paper cassette, and 73 is a transport roller. A paper discharge roller 81 discharges the fixed transfer material to a paper discharge tray 82 having a predetermined inclination angle.

  The control unit B1 performs image forming process control, fixing temperature control, transfer material conveyance control, toner density control, and the like.

  The components related to the image forming process have been described above. Next, the sheet conveyance path will be described.

  FIG. 6 is a diagram illustrating a sheet conveyance path corresponding to the type (mode) of image formation.

  In the case of normal printing (with a border), the paper P on which the toner image has been transferred at the nip S passes through the fixing device 40 and is then discharged to the paper discharge tray 82 through the conveyance path 51 (FIG. 6A). reference). In the case of double-sided printing, after fixing, the sheet passes through the conveyance path 52 side, is not stacked on the stacker 53, is reversed by the reverse feeding roller 54, passes through the conveyance path 55, and is transferred onto the intermediate transfer belt 20 by the same image forming process described above. After the superimposed toner image formed on the toner image is transferred to the back side of the paper P at the nip portion S, it is fixed by the fixing device 40 and discharged to the paper discharge tray 82 through the conveyance path 51 (FIG. 6B). reference).

  Next, a description will be given of the conveyance path and the sheet end surface fixing when printing on the entire surface of the sheet (without border).

  When printing on the entire surface of the sheet, the toner image is transferred to the entire surface of the sheet at the nip portion S, and after passing through the fixing device 40, is sent to the conveyance path 52 side. It is stacked on the stacker 53 through the conveyance path 52 and temporarily stops. In the stacker 53, the toner adhered to the four paper end faces is fixed by the end face fixing member 56 which is an end face fixing unit. After the fixing is completed, the sheet is fed again from the stacker 53, returns to the conveyance path 52 side, and is discharged to the discharge tray 82 by the discharge roller 81 through the transfer path 51 (FIG. 6C, ( d)). During double-sided printing, the paper carrying the single-sided image is fed again from the stacker 53, reversed by the reverse feeding roller 54, passes through the conveyance path 55, and is formed on the intermediate transfer belt 20 by the same image forming process as described above. After the transferred toner image is transferred to the back side of the paper P at the nip S, it is fixed by the fixing device 40, stacked again on the stacker 53 through the transport path 52, and the paper edge is fixed and re-supplied. The paper travels in the direction of the arrow indicated by the dotted line, and is discharged to the paper discharge tray 82 through the conveyance path 51 (see FIGS. 6D and 6E).

  Hereinafter, the configuration of the end face fixing member will be described.

  FIG. 7 shows an end face fixing member for fixing toner on the end face of the paper.

  FIG. 8 shows a plan view of the stacker as viewed from the direction of arrow Y in FIG.

  In FIG. 7, the end surface fixing member 56 is formed by sandwiching a sheet heating element 562 as a heater between a silicone rubber plate 563 and a polyimide resin plate 561.

  In FIG. 8, the stacker 53 includes a side portion restricting plate 531, an end portion restricting plate 532, an abutting restricting plate 533, and the like. The side portion restricting plate 531 and the end portion restricting plate 532 have a sheet size. It can be moved accordingly. The side regulating plates 531 are on both sides of the sheet and slide independently along a guide (not shown) in the direction of arrow H. The end regulating plate 532 also slides in the direction of arrow V along the guide rail g.

  The end surface fixing member 56 is attached to the side portion restricting plate 531, the end portion restricting plate 532, and the abutting restricting plate 533 with the polyimide resin plate 561 on the sheet end surface side. Therefore, the sheets stacked in the stacker 53 are aligned by the end portion restricting plate 532 and the abutting restricting plate 533, and at the same time, the end surfaces are fixed. At this time, the side restricting plate 531 is retracted to the retracted position so as not to interfere with the end restricting plate 532 (see FIG. 8A). Next, the end portion restricting plate 532 moves backward and moves to the retracted position, and the side portion restricting plate 531 comes into contact with the end surface of the sheet to perform alignment and fixing (see FIG. 8B). When the end face fixing is completed, the paper is fed again from the stacker 53 (see FIG. 8C).

  As described above, the excessive toner on the end surface of the paper is fixed, so that the inconvenience of dirty hands and the worry of smearing other prints when handling by the user are solved.

The schematic diagram of the inkjet printer which is 1st Embodiment is shown. FIG. 2 is a diagram illustrating a sheet conveyance path and an end surface fixing member as viewed from the upper surface of FIG. The schematic diagram of the full-color electrophotographic apparatus which is 2nd Embodiment is shown. FIG. 4 is a sheet conveyance path diagram in FIG. 3. FIG. 10 is a diagram illustrating an example of a stain on a sheet end surface. FIG. 6 is a diagram illustrating a sheet conveyance path corresponding to a type of image formation. An end surface fixing member that fixes toner on the end surface of a sheet is shown. The top view of the stacker seen from the arrow Y direction in FIG. 4 is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Recording head 12, 13 End surface fixing member 14 Spur 15, 82 Discharge tray 16, 18 Fan 17, 19 Heater 52 Transport path 53 Stacker 531 Side part restricting plate 532 End part restricting plate 533 Abutting restricting plate 56 End face fixing member

Claims (6)

An image forming apparatus capable of forming an image without a border by protruding from at least one end of the recording medium and transferring the recording material to the recording medium, wherein only the recording material attached to the end surface of the recording medium is removed. An image forming apparatus comprising an end face fixing unit for fixing. The image forming apparatus according to claim 1, wherein the end surface fixing unit is provided separately from an image surface fixing unit that fixes a recording material on an image surface of the recording medium. 3. The image forming apparatus according to claim 1, wherein the recording material is toner, and the image surface fixing unit fixes the recording material on the image surface by a nip formed by a heating member and a pressure member. apparatus. 4. The image forming apparatus according to claim 1, wherein the end face fixing unit is provided at a place where the recording medium is temporarily stopped, and performs fixing when the conveyance movement of the recording medium is stopped. 5. . 5. The image forming apparatus according to claim 1, wherein the end face fixing unit fixes the recording material onto the recording medium by blowing air at a predetermined temperature or higher. The image forming apparatus according to claim 1, wherein the end face dedicated fixing unit fixes the recording medium by a planar heating element.

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