JP2010164833A - Image forming apparatus and method for controlling the image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus efficiently cooling paper in double-sided printing. <P>SOLUTION: The image forming apparatus through which the paper P is made to pass again after an image is printed on one side of the paper P includes a double-sided unit 2. The double-sided unit 2 is provided with a conveyance path of the paper P. Movable members 23a to 23c that introduce outside air by moving with passing of the paper are installed in the conveyance path. The movable members 23a to 23c have mechanisms moving about shafts A1 to A3 respectively, and come into contact with the paper passing through the conveyance path, whereby they rock about the shafts A1 to A3. An air intake port for introducing the air is formed in the lower part of each of the movable members 23a to 23c. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image forming apparatus and a method for controlling the image forming apparatus, and more particularly to an image forming apparatus capable of efficiently cooling a sheet and a method for controlling the image forming apparatus.

  An electrophotographic image forming apparatus (MFP (Multi Function Peripheral), facsimile apparatus, copier, printer, etc.) having a scanner function, a facsimile function, a copying function, a function as a printer, a data communication function, and a server function, The charged photoreceptor is exposed to form an electrostatic latent image. The electrostatic latent image is developed with toner or the like, and is thermally fixed by a fixing device.

  In an image forming apparatus, after printing an image on one side of the paper, the paper is re-passed through the image forming apparatus without discharging the paper, thereby adopting a double-sided printing method that prints an image on both sides of the paper. It has been known.

  Patent Document 1 below discloses a structure in which a sheet is cooled using a cooling fan in a duplex unit (double-sided reverse position) of an image forming apparatus. More specifically, cooling is performed by blowing air onto the paper using a cooling fan at the reverse position.

JP 2006-91705 A

  In an image forming apparatus capable of double-sided printing, a high-temperature sheet after fixing an image on one side is re-passed through the image forming apparatus. For this reason, when continuous printing is performed, the temperature in the image forming apparatus rises, causing various problems.

  On the other hand, as in Patent Document 1, a method of cooling a sheet after single-sided printing with a cooling fan is known in order to suppress a temperature rise in the image forming apparatus. However, when a cooling fan is used, a new problem arises that the apparatus itself becomes large and costs increase.

  In addition, when air is blown onto a sheet using a cooling fan, there is a problem that the temperature of the apparatus is increased by the air that has deprived the heat of the sheet.

  When adopting a configuration of an image forming apparatus that does not include a fan for cooling the paper, when the number of continuous prints increases, in order to suppress the temperature rise in the apparatus, the paper feed timing is delayed and the print speed is not reduced. must not. As a result, there is a problem that productivity is lowered.

  The present invention has been made to solve such problems, and an object thereof is to provide an image forming apparatus capable of efficiently cooling a sheet and a control method for the image forming apparatus.

  In order to achieve the above object, according to one aspect of the present invention, an image forming apparatus is an image forming apparatus capable of printing an image on one side of a sheet and then allowing the sheet to pass through the image forming apparatus again. And a movable member that is installed in the conveyance path and performs at least one of introduction of outside air or release of air in the apparatus by moving as the paper passes.

  Preferably, the movable member has a mechanism that moves around the axis, and moves around the axis by contacting the paper.

  Preferably, the movable member is suspended by a shaft, and swings about the shaft by contacting the paper.

  Preferably, the movable member is provided as a part of the cover of the duplex unit, moves by contacting the paper, and sends air into the duplex unit.

  Preferably, the movable member is formed with an air intake for introducing air into a lower portion thereof.

  Preferably, the width of the movable member is larger than the width of the paper.

  Preferably, the movable member moves by contacting a surface of the sheet on which no image is formed.

  According to another aspect of the present invention, after the image is printed on one side of the paper, the control method of the image forming apparatus that allows the paper to pass through the image forming apparatus again is as follows. An outside air introduction step for introducing outside air by moving a movable member installed in the transport path is provided.

  According to these inventions, it is possible to provide an image forming apparatus capable of efficiently cooling a sheet and a method for controlling the image forming apparatus.

1 is a schematic cross-sectional view showing an overall configuration of a four-cycle digital full-color printer employing an intermediate transfer method in one embodiment of the present invention. It is the figure which looked at the printer of FIG. 1 from the right. FIG. 4 is a diagram illustrating a state where a sheet P is passing through a duplex unit 2. FIG. 6 is a diagram illustrating a wind flow when there is no paper P in the duplex unit 2. FIG. 4 is a diagram showing a wind flow when there is a sheet P in the duplex unit 2.

  Hereinafter, a four-cycle image forming apparatus according to one embodiment of the present invention will be described.

  FIG. 1 is a schematic cross-sectional view showing the overall configuration of a four-cycle digital full-color printer (hereinafter simply referred to as “printer”) employing an intermediate transfer method according to one embodiment of the present invention. Hereinafter, the overall configuration of the printer will be described.

  The image forming apparatus includes a paper feed tray 21 that stores a plurality of paper, a paper feed roller 3 that feeds the paper in the paper feed tray 21, a photoconductive drum 4 that forms an image, and a toner image from the photoconductive drum 4. An intermediate transfer belt 5 for transferring toner, a transfer roller 6 for secondary transfer of a toner image held by the intermediate transfer belt 5 to a sheet, a fixing device 1 for fixing the toner image on the sheet by heat, and a toner image on one side. A double-sided unit 2 that conveys the paper after it has been fixed.

  In the image forming apparatus, transport rollers R1 to R5 for transporting paper are provided.

  The transport roller R5 is a roller for transporting either the paper fed from the paper feed roller 3 or the paper fed from the transport roller R4 in the duplex unit 2 to the position of the transfer roller 6.

  The transport roller R <b> 1 is a roller for discharging the paper after exiting the fixing device 1 to the paper discharge tray 9 or sending it into the duplex unit 2.

  The transport rollers R2, R3, and R4 are rollers for feeding paper in the duplex unit 2.

  The conveyance rollers R1 to R5 are controlled by the computer for their rotational operation and rotational direction.

  In the image forming apparatus according to the present embodiment, the sheet discharged from the fixing device 1 is passed through a predetermined position where the heat radiation effect is high, and heat is radiated from the sheet. Thereby, the temperature rise in the image forming apparatus is suppressed, and the image forming apparatus has high productivity.

  In FIG. 1, the paper is transported from the paper feed tray 21 to the inside of the apparatus, and finally transported to the paper discharge tray 9 ahead of the transport roller R1.

  When performing duplex printing, it is necessary to transport the paper after single-sided printing discharged from the fixing unit 1 into the duplex unit 2 (in the duplex transport path). FIG. 1 shows a state before the paper P enters the duplex unit 2.

  A paper transport path is provided in the duplex unit 2, and movable members 23 a to 23 c for introducing outside air by moving as the paper passes are installed in the transport path.

  The movable members 23a to 23c each have a mechanism that moves around the axes A1 to A3, and moves around the axes A1 to A3 by contacting the sheet passing through the transport path. That is, the movable members 23a to 23c are suspended by the axes A1 to A3, and swing about the axes A1 to A3 as the rotation center when they are in contact with the paper. The movable members 23a to 23c are formed with an air intake port for introducing air at the lower part thereof.

  The movable members 23 a to 23 c are provided as a part of the cover of the duplex unit 2, move when in contact with the paper, and send air into the duplex unit 2.

  In FIG. 1, each of the movable members 23a to 23c is in a normal position because it is not in contact with the sheet. That is, the movable member is in a closed state.

  As described above, a part of the transport path includes a member that can be moved by the passage (or stop) of the sheet.

  FIG. 2 is a view of the printer of FIG. 1 viewed from the right.

  The movable members 23a to 23c are exposed as part of the exterior cover of the duplex unit 2 that is the side of the printer. That is, the movable members 23a to 23c are provided on the side surfaces of the transport path.

  The movable members 23a to 23c have a laterally long shape, and the width thereof is larger than the width of the passing paper. Thereby, the paper can be efficiently cooled.

  FIG. 3 is a diagram illustrating a state where the sheet P passes through the duplex unit 2.

  Here, the sheet P is moved into the duplex conveyance path (in the duplex unit 2) and the movable members 23a to 23c are opened.

  The paper P in FIG. 1 has an image formed on its lower surface. Therefore, in the state of FIG. 3 in which the paper P is transported into the duplex unit 2 from the state of FIG. 1 for duplex printing, the surface on which the image of the paper P is formed is the left side of the drawing.

  Therefore, the surface on which the sheet contacts the movable members 23a to 23c is a surface on which no image is formed. Thereby, there is an effect that cooling can be efficiently performed without damaging the image on the paper.

  FIG. 4 is a diagram showing the flow of wind when there is no paper P in the duplex unit 2.

  Here, the movable members 23a to 23c are in a closed state. The flow of air (wind) is indicated by an arrow, and air flows from the lower part to the upper part of the duplex unit 2. This is because the air is warmed up by the temperature of the image forming apparatus. In order to further improve the cooling efficiency, the fan 25 may be attached to the upper part of the duplex unit 2 and the air flow shown in FIG. 4 may be created by sucking air.

  FIG. 5 is a diagram showing the flow of wind when the paper P is in the duplex unit 2.

  Here, the movable members 23a to 23c are in an open state. The flow of air (wind) is indicated by an arrow, and air flows from the lower part to the upper part of the duplex unit 2. In addition, outside air is introduced from an air intake formed in the lower part of the movable members 23 a to 23 c, and flows toward the upper part of the duplex unit 2.

  In these cases, the air is warmed and raised by the temperature of the image forming apparatus. In order to further improve the cooling efficiency, the fan 25 may be attached to the upper part of the duplex unit 2 and the air flow shown in FIG. 5 may be created by sucking air.

  In the above embodiment, air is taken in from the movable members 23a to 23c. However, the apparatus may be configured to perform at least one of air intake and air release by the movable members 23a to 23c. Is possible.

  In FIG. 1, a part of the paper P has come out of the apparatus and is in a position where the cooling efficiency of the paper is good (paper cooling position). From this state, the paper roller P is fed into the duplex unit 2 by reversing the transport roller R1, so that the paper is efficiently cooled, so that the temperature rise in the apparatus can be prevented as much as possible.

  Conventionally, when continuous printing is performed, control has been performed to prevent the temperature inside the apparatus from rising. For example, the printing speed is decreased when 100 sheets are continuously printed, and the printing speed is further decreased when 200 sheets are continuously printed. For this reason, when continuous printing is performed in the prior art, there is a problem that productivity gradually decreases.

  On the other hand, in this embodiment, since the temperature rise in the apparatus can be suppressed as described above, the decrease in printing speed can be suppressed.

  In order to efficiently cool the paper in the duplex unit 2, when the paper is being transported in the normal movement direction, the paper is transported for a predetermined distance opposite to the normal movement direction, and then the paper is again loaded. You may control so that it may convey in a normal moving direction. Such a reciprocating motion of the sheet may be repeated a predetermined number of times.

  When the reciprocating motion is performed (or when the paper moves in the direction opposite to the normal moving direction), the paper may be moved slower than the normal transport speed.

  This makes it possible to efficiently cool the paper without stopping it. That is, by making the paper moving direction variable, the paper can be sufficiently cooled even with a short transport path.

  Note that the control for conveying the paper in the reverse direction (or the control for reciprocating) may be performed at another location (for example, a position on the paper discharge tray 9).

  Further, the inside of the duplex unit 2 is a position that does not affect image formation on other sheets. That is, while the sheet P is being cooled in the duplex unit 2, image formation on another sheet can be performed.

  Thus, by cooling the sheet at a position that does not affect image formation, there is an effect that the sheet can be efficiently cooled without decreasing the printing speed.

  The movable members 23a to 23c are members that swing around the axis, but may be members that rotate around the axis. For example, a member in which blades or protrusions are formed radially from the rotation shaft may be used as a movable member and rotated by contact with a sheet.

  [Effects of the embodiment]

  As described above, in the present exemplary embodiment, after the image is printed on one side of the paper, the image forming apparatus can pass the paper again without discharging the paper. More specifically, the image forming apparatus applies a high-temperature sheet after fixing the one-sided image discharged from the fixing unit to a predetermined position where the heat radiation effect is high (the heat radiation effect is higher than the other parts in the paper passing path). For example, at least a part of the sheet goes out of the machine (touches outside air) or continues to move without stopping when the outside air is introduced. Thereby, the temperature rise in an apparatus can be suppressed.

  More specifically, a movable portion that makes it easier to take in outside air by moving as the paper passes or stops is provided in the conveyance path through which the high-temperature paper passes after fixing the image on one side. As a result, the heat of the paper can be moved above the apparatus, the paper and the inside of the apparatus can be cooled, and the temperature of the apparatus can be prevented from rising.

  In other words, the image forming apparatus is provided with a conveyance path for radiating the paper discharged from the fixing unit. A member that moves only when there is a sheet and easily takes in outside air is installed in at least a part of the conveyance path.

  Only when it is desired to cool the sheet, the image forming apparatus moves the heat in the vicinity of the sheet passing path upward by the air taken in by the movable member. Thereby, the inside of the paper and the conveyance path can be efficiently cooled. Further, it is possible to prevent a decrease in the speed of double-sided printing (a decrease in productivity).

  Further, in the image forming apparatus according to the present embodiment, the sheet can be cooled without using a cooling fan. Therefore, if the fan is not provided, the entire apparatus can be made compact and cost increase can be prevented. it can.

  Furthermore, when the paper discharged from the fixing unit is radiated at a predetermined position where the heat radiation effect is high, if the movement of the paper being radiated is not stopped, the traces of the conveyance rollers and the conveyance guide ribs are printed on the printed image. It is prevented from sticking. That is, the sheet can be cooled while maintaining a good print image without damaging the image after single-sided printing, and the printing speed can be prevented from being reduced as much as possible.

  In addition, it should be thought that the said embodiment is an illustration and restrictive at no points. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 1 Fixing device 2 Duplex unit 3 Paper feed roller 4 Photosensitive drum 5 Intermediate transfer belt 6 Transfer roller 9 Paper discharge tray 21 Paper feed tray 23a-23c Movable member 25 Fan A1-A3 Axis P Paper after R1-R5 conveyance roller

Claims (8)

An image forming apparatus capable of causing an image forming apparatus to pass the paper again after printing an image on one side of the paper,
An image forming apparatus provided with a movable member that is installed in the paper conveyance path and performs at least one of introduction of outside air or release of air in the apparatus by moving as the paper passes.   The image forming apparatus according to claim 1, wherein the movable member has a mechanism that moves around an axis, and moves around the axis by contacting the sheet.   The image forming apparatus according to claim 1, wherein the movable member is suspended by a shaft, and swings about the shaft by contacting the sheet.   4. The image forming apparatus according to claim 1, wherein the movable member is provided as a part of a cover of the duplex unit, moves when contacting the sheet, and sends air to the duplex unit. 5.   The image forming apparatus according to claim 1, wherein the movable member is formed with an air intake port for introducing air into a lower portion thereof.   The image forming apparatus according to claim 1, wherein a width of the movable member is larger than a width of the sheet.   The image forming apparatus according to claim 1, wherein the movable member moves by contacting a surface of the sheet on which an image is not formed. A method of controlling an image forming apparatus, wherein an image is printed on one side of a sheet, and then the sheet can be passed through the image forming apparatus again.
A control method for an image forming apparatus, comprising: an outside air introduction step for introducing outside air by moving a movable member installed in the sheet conveyance path according to passage of the sheet in the conveyance path.

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