JP2005145600A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming device having a carrier device to carry a sheet by attracting it by electrostatic force capable of preventing static electricity from residing on the side with which a carrier belt of the sheet makes contact after separating the sheet from the carrier belt. <P>SOLUTION: This image forming device is constituted so that the sheet taken out from a paper feeding tray and carried is attracted and carried by electric charge of the carrier belt 1 charged by a charging roller 4 and an image is formed by a recording head 5. The sheet after image formation is delivered between a plurality of paper discharging rollers 7 provided with equal intervals along the overall width of a sheet passage P and a spur roller 8 and accumulated on the paper discharging tray 11 by passing through above a static eliminating sheet 10 adhered on a paper discharging guide 9. The paper discharging guide 9 is of a reversed L shape on its cross-section and provided between the adjacent paper discharging rollers 7, the static eliminating sheet 10 is adhered in a recessed part between guide ribs 9a, 9a projected to both sides and the sheet guided by the paper discharging guide 9 and the static eliminating sheet 10 never directly make contact with each other. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus that adsorbs and conveys recording paper after image formation to a conveyance belt, and more particularly, to discharge of recording paper in a paper discharge unit of an image forming apparatus that adsorbs and conveys recording paper by charge charging of the conveyance belt. .

In an image forming apparatus such as an ink jet recording apparatus, when a paper feed roller, a transport roller, and a paper discharge roller are used for transporting recording paper (recording medium), when the recording paper is transported, Friction occurs between them, static electricity is generated, and electric charges accumulate on the conveyance path and recording paper. Further, even when an adsorption belt using electrostatic force or vacuum adsorption is used for transporting the recording paper, the recording paper is likely to accumulate electric charges and needs to be removed for reliable transport of the recording paper.
2. Description of the Related Art Conventionally, various means for removing static electricity as described below are known as means for removing charges accumulated on a recording medium and a conveyance path in an image forming apparatus that records on recording paper such as paper and OHP sheets. Yes.

  In Patent Document 1, a pinch roll that is in pressure contact with a transport roll disposed on the upstream side of an ink discharge portion of a recording head and a holder that holds the pinch roll are made of a conductive material and are installed via a frame. An ink jet recording apparatus is disclosed that efficiently removes static electricity on a recording paper that is charged during conveyance before printing with a recording head.

  In Patent Document 2, a neutralizing brush as a neutralizing unit is arranged in a non-printing area on both sides of a platen with a predetermined gap so as not to contact the nozzle cover and nozzle plate of each color recording head. An ink jet recording apparatus is disclosed in which static electricity accumulated in a nozzle cover due to rubbing or the like is removed, and malfunction or damage of an actuator element or the like due to static electricity is prevented.

Patent Document 3 discloses a paper feed roller that separates and transports recording sheets one by one from a plurality of stacked recording sheets, and a recording position of a recording head in which the recording sheets transported by the paper feed rollers are mounted on a recording head cartridge. An ink jet recording apparatus having a line feed roller that feeds into the sheet, and is provided between the feed roller and the line feed roller with a neutralizing unit that neutralizes the recording sheet so that the electrostatic charge amount is a predetermined value or less. An ink jet recording apparatus is disclosed in which the recording back surface of a recording sheet is not soiled even when none recording is performed.
Japanese Patent Laid-Open No. 10-81008 Japanese Patent Laid-Open No. 10-16240 JP 2003-54069 A

  In a transport device that attracts and transports paper onto the transport belt by electrostatic force, after separating the paper from the transport belt, the paper is stacked on the paper discharge tray due to static electricity remaining on the side of the paper that is in contact with the transport belt In this case, there is a problem in that a discharge failure occurs due to sticking between sheets due to static electricity.

  In addition, even when a slow current member for removing residual static electricity is provided, if the paper is in contact with the slow current member, paper dust or ink during double-sided transport adheres to the slow current member and becomes dirty. There is a problem that the slow current efficiency is deteriorated and durability is lowered.

  The present invention has been made in order to solve the above-mentioned problems. The invention of claim 1 is directed to a conveyance belt that adsorbs and conveys a recording medium by electric charges, a charging roller that applies electric charges to the conveyance belt, and In an image forming apparatus comprising a driving roller and a driven roller for passing a conveyance belt, and a paper discharge tray for stacking the recording medium after image formation, the recording medium is disposed between the conveyance belt and the paper discharge tray. It has the slow current member which slows the conveyance belt contact surface.

  According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the grading member is disposed at a position away from the conveying surface by a predetermined distance, and the recording medium can be gradually de-energized without contact with the grading member. It is characterized by being.

  According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, the slow current member is made of a slow current cloth.

  The image forming apparatus according to the first aspect of the present invention can prevent sticking of the paper to the paper transport path or to the paper that has already been ejected stack by slowing power immediately after the paper is separated from the transport belt. It becomes.

  The image forming apparatus according to claim 2 can prevent paper dust or the like from adhering to the slow current member by preventing the paper and the slow current member from contacting each other. In addition, although the image surface comes to the side of the slow current member during double-sided printing, it is possible to prevent adhesion of ink on the slow current member and blurring of the image surface.

  In the image forming apparatus according to the third aspect, it is possible to prevent the current-carrying member that gradually powers the recording medium on the conveying belt surface side from coming into contact with the sheet with a simple and inexpensive configuration.

  According to the present invention, in an image forming apparatus having a conveyance device that adsorbs and conveys a sheet onto a conveyance belt by electrostatic force, after separating the sheet from the conveyance belt, static electricity remains on the side of the sheet on which the conveyance belt is in contact. A conveying belt that adsorbs and conveys a recording medium with electric charges, a charging roller that applies electric charges to the conveying belt, a driving roller and a driven roller that span the conveying belt, and image formation A discharge tray on which the recording medium is stacked; and a slow current-carrying member that gradually powers a conveyance belt contact surface of the recording medium between the transport belt and the discharge tray. With this configuration, paper discharge does not occur due to sticking of paper due to static electricity, and paper dust or ink adheres to the gradual charging member that removes residual static electricity. Dirt Xu electric efficiency is deteriorated, in which durability is so does not decrease.

The image forming apparatus of the present invention will be described below based on the embodiments shown in FIGS.
FIG. 1 is a schematic sectional view showing an image forming apparatus according to an embodiment of the present invention.
The image forming apparatus shown in FIG. 1 includes a conveying belt 1 that adsorbs and conveys paper by electric charge, a driving roller 2 that drives the conveying belt 1, a driven roller 3 that cooperates with the driving roller 2 and passes the conveying belt 1, and conveying. A charging roller 4 for applying charge to the belt 1, a recording head 5, a discharge roller 7 for discharging a sheet after image formation, a spur roller 8 facing the discharge roller 7, and a sheet discharged from the discharge roller 7 A paper discharge guide 9 for guiding, a slow current sheet 10 for gradually removing the charge remaining on the paper, and a paper discharge tray 11 for stacking the paper after image formation discharged by the paper discharge roller 7 are provided.
As the recording method of the image forming apparatus, all kinds of methods such as an ink jet method, a wire dot method, a thermal method, and a laser beam method can be adopted.

  In the image forming apparatus shown in FIG. 1, when a sheet taken out from a sheet feeding tray (not shown) and conveyed through a conveyance path comes into contact with a conveyance belt 1 that is stretched between a driving roller 2 and a driven roller 3, the conveyance belt. 1 is adsorbed by the electric charge charged by the charging roller 4, conveyed below the recording head 5, and a predetermined image is formed by the recording head 5 driven at that position based on image information. The sheet after image formation is fed between the sheet discharge roller 7 and the spur roller 8, passes over the sheet discharge guide 9 and the slow current sheet 10, and is stacked on the sheet discharge tray 11.

2 is a cross-sectional view taken along line XX in FIG. 1, and FIG. 3 is a cross-sectional view taken along line YY in FIG.
A plurality of paper discharge rollers 7 are supported at predetermined intervals over the entire width of the paper path P on a paper discharge roller shaft 6 driven by a driving device (not shown). Further, a spur roller 8 is provided so as to face the plurality of paper discharge rollers 7, and the paper after image formation is sandwiched between the paper discharge roller 7 and the spur roller 8 by driving the paper discharge roller shaft 6. Is discharged.

  A paper discharge guide 9 is provided between the paper discharge rollers 7 adjacent to the paper discharge roller shaft 6 to guide the paper discharged from the paper discharge roller 7. The discharge guide 9 has an inverted L-shaped cross section as shown in FIG. 3, and guide ribs 9a and 9a are formed so as to protrude from both sides including the bent portion. A slow current sheet 10 is attached to the recess between the guide ribs 9a, 9a so that the paper guided by the paper discharge guide 9 and the slow current sheet 10 are separated from each other by a predetermined distance so that they do not come into direct contact with each other. It has become.

  Any material can be used for the slow current sheet 10 as long as it is a sheet material having electrical conductivity. However, if a slow current cloth is used, a sufficient neutralizing effect can be obtained, and handling when sticking to the paper discharge guide 9 is also possible. Easy.

  The positional relationship among the paper discharge roller 7, the paper discharge guide 9, and the slow current sheet 10 is such that the guide rib 9a on the upper side of the paper discharge guide 9 protrudes from the uppermost portion of the paper discharge roller 7 as shown in FIG. The guide rib 9 a at the bottom of the paper discharge guide 9 is set to a sufficient length in relation to the paper discharge tray 11.

  According to the present invention, the slow current sheet 10 is affixed to the concave surface between the ribs 9a and 9a of the paper discharge guide 9 so as not to contact the paper after image formation. A slow charging effect that does not become dirty with ink at the time and is not permanently changed is obtained, sticking to a paper transport path or already stacked paper can be prevented, and good transportability can be obtained.

1 is a schematic cross-sectional view illustrating an image forming apparatus according to an embodiment of the present invention. It is XX sectional drawing of FIG. It is YY sectional drawing of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Conveyance belt, 2 ... Drive roller, 3 ... Driven roller, 4 ... Charging roller, 5 ... Recording head, 6 ... Discharge roller shaft, 7 ... Discharge roller, 8 ... Spur roller, 9 ... Discharge guide, 9a ... Guide rib, 10... Slow current sheet, 11.

Claims (3)

  A conveying belt that adsorbs and conveys a recording medium with electric charge, a charging roller that applies electric charge to the conveying belt, a driving roller and a driven roller that span the conveying belt, and the recording medium after image formation are stacked. An image forming apparatus comprising a paper discharge tray, wherein the image forming apparatus includes a slow current member that gradually powers a transport belt contact surface of the recording medium between the transport belt and the paper discharge tray.   The image forming apparatus according to claim 1, wherein the grading member is disposed at a position away from a conveying surface by a predetermined distance, and the recording medium is capable of grading without contact with the grading member. Image forming apparatus.   3. The image forming apparatus according to claim 1, wherein the grading member is made of a grading cloth.

Images