JP2021047339A - Image forming apparatus - Google Patents

Abstract

To provide an image forming apparatus capable of stabilizing the carrying posture of a sheet carried from a transfer part while suppressing leak to a guide member.SOLUTION: An image forming apparatus 10 for forming a toner image on a sheet comprises: a transfer part (a transfer device 133) for transferring the toner image on the sheet; a fixing part (a fixing device 134) for fixing the toner image transferred on the sheet by the transfer part on the sheet; and a guide member 20 for guiding the sheet to the fixing part from the transfer part. In the guide member 20, an end part on the side of the transfer part is formed of an insulating member.SELECTED DRAWING: Figure 1

Description

The present invention relates to an image forming apparatus.

Conventionally, an electrostatic latent image formed on a photoconductor drum is developed with toner to form a toner image, the formed toner image is transferred to paper by a transfer unit, and the transferred toner image is transferred to a fixing portion. There is known an electrophotographic image forming apparatus that forms an image on paper by heating and fixing the image.

In the above image forming apparatus, a guide member for guiding the paper from the transfer portion to the fixing portion is provided.
For example, a configuration is disclosed in which the frictional resistance before fixing is reduced by increasing the surface resistivity of the guide member before fixing (see, for example, Patent Document 1).
Further, a configuration is disclosed in which the potential of the guide member before fixing is controlled to prevent the offset of the image and the floating of the paper (see, for example, Patent Document 2).
Further, a configuration is disclosed in which a guide of a metal material electrically floating on the transfer side is arranged so as to overlap the guide on the fixing side (see, for example, Patent Document 3).
Further, a configuration is disclosed in which the inlet guide is composed of a non-conductive sheet and a conductive portion from the guide surface side, and a bias voltage is applied (see, for example, Patent Document 4).

Japanese Unexamined Patent Publication No. 6-149111 Japanese Unexamined Patent Publication No. 9-274343 Japanese Unexamined Patent Publication No. 2014-085529 Japanese Unexamined Patent Publication No. 2004-145021

However, the configuration described in Patent Document 1 is a configuration that reduces the frictional resistance before the fixing enters, and does not stabilize the transport posture of the paper transported from the transfer unit. Further, the configuration described in Patent Document 2 is a configuration for preventing image offset and paper floating, and does not stabilize the transport posture of the paper transported from the transfer unit. Further, the configuration described in Patent Document 3 prevents dusting of the toner image generated in the gap between the guides, and does not stabilize the transport posture of the paper transported from the transfer unit. Further, since the guide member is fixed to the transfer portion, there is a problem that the configuration is difficult when the transfer portion performs an operation such as pressure separation. Further, the configuration described in Patent Document 4 stabilizes the potential of the entire surface of the guide surface to prevent dusting of the toner image, and does not stabilize the transport posture of the paper transported from the transfer unit.
That is, since none of the configurations described in Patent Documents 1 to 4 stabilize the paper transport posture, it is not possible to suppress the occurrence of image defects such as paper wrinkles and bleeding.

By the way, in order to prevent leakage to the guide member due to transfer or separation in the transfer portion, it is necessary to secure a spatial distance between the transfer portion and the guide member. However, in all of the configurations described in Patent Documents 1 to 4, since the guide member is not insulated, leakage to the guide member cannot be prevented.

An object of the present invention is to provide an image forming apparatus capable of stabilizing the transport posture of paper transported from a transfer unit while suppressing leakage to a guide member.

The invention according to claim 1 has been made in order to achieve the above object.
In an image forming apparatus that forms a toner image on paper,
A transfer unit that transfers the toner image to the paper, and
A fixing portion for fixing the toner image transferred to the paper by the transfer portion to the paper, and a fixing portion.
A guide member that guides the paper from the transfer portion to the fixing portion,
With
The guide member is characterized in that the end portion on the transfer portion side is formed of an insulating member.

The invention according to claim 2 is the image forming apparatus according to claim 1.
The insulating member is a sheet-like member formed of PET.

The invention according to claim 3 is the image forming apparatus according to claim 1 or 2.
The insulating member is attached to the guide member via a support member.

The invention according to claim 4 is the image forming apparatus according to any one of claims 1 to 3.
The guide member is characterized in that a conductive fluorine coating is applied to the guide surface side of the paper.

The invention according to claim 5 is the image forming apparatus according to any one of claims 1 to 4.
The guide member is characterized in that a rib shape is provided on the guide surface side of the paper.

The invention according to claim 6 is the image forming apparatus according to claim 5.
A wear-resistant, low-friction, and antistatic guide member is arranged between the insulating member and the rib shape.

The invention according to claim 7 is the image forming apparatus according to claim 6.
The guide member is characterized in that it is formed of an ultra-high molecular weight PE film.

The invention according to claim 8 is the image forming apparatus according to claim 6 or 7.
The guide member is characterized in that it is formed in a planar shape.

The invention according to claim 9 is the image forming apparatus according to any one of claims 1 to 8.
The transfer unit is provided with a static elimination mechanism.

The invention according to claim 10 is the image forming apparatus according to any one of claims 1 to 9.
The transfer unit is provided with a pressure contact separation mechanism.

The invention according to claim 11 is the image forming apparatus according to any one of claims 1 to 10.
The guide member is fixed to the fixing portion.

According to the present invention, it is possible to stabilize the transport posture of the paper transported from the transfer unit while suppressing leakage to the guide member.

It is a front view which shows the schematic structure of the image forming apparatus which concerns on this embodiment. It is a functional block diagram which shows the control structure of the image forming apparatus which concerns on this embodiment. It is a front view which shows the structure of the transfer apparatus. It is a perspective view which shows the structure of the fixing device. It is a perspective view which shows an example of the structure of the guide member. It is a side view which shows an example of the structure of a guide member. It is a perspective view which shows the modification 1 of the structure of the guide member. It is a side view which shows the modification 1 of the structure of the guide member. It is a perspective view which shows the structure of the part which arranges the guide member of the guide member which concerns on modification 1. FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

As shown in FIGS. 1 and 2, the image forming apparatus 10 according to the present embodiment includes a control unit 11, an image reading unit 12, an image forming unit 13, a storage unit 14, and an operation panel 15 (display unit 151). , Operation unit 152) and communication unit 16.

The control unit 11 includes a CPU, RAM, ROM, and the like. In response to the operation signal input from the operation unit 152 or the instruction signal received by the communication unit 16, the CPU reads various processing programs stored in the ROM, develops them in the RAM, and develops the various programs in the RAM. The operation of the image forming apparatus 10 is comprehensively controlled by the cooperation of.

The image scanning unit 12 scans and exposes an image of a document placed on a platen or an automatic document feeder (ADF: Auto Document Feeder) (not shown) by the optical system of a scanning exposure device, and scans and exposes the reflected light by a line image sensor. Read, thereby obtaining an image signal. This image signal is input to the control unit 11 as image data after being subjected to processing such as A / D conversion, shading correction, and compression. The image data input to the control unit 11 is not limited to the data read by the image reading unit 12, and may be, for example, received from an external device (not shown) via the communication unit 16.

The image forming unit 13 forms an image composed of four colors of C, M, Y, and K on the paper according to the pixel values of the four colors of each pixel of the image-processed original image.
As shown in FIG. 1, the image forming unit 13 includes four writing units 131, an intermediate transfer belt 132, a transfer device (transfer unit) 133, a fixing device (fixing unit) 134, and the like.

The four writing units 131 are arranged in series (tandem) along the belt surface of the intermediate transfer belt 132 to form images of each color C, M, Y and K. Each writing unit 131 has the same configuration except that the color of the image to be formed is different, and as shown in FIG. 2, the optical scanning device 131a, the photoconductor 131b, the developing unit 131c, the charging unit 131d, the cleaning unit 131e, and the primary unit 131 are used. It is configured to include a transfer roller 131f.

At the time of image formation, each writing unit 131 charges the photoconductor 131b by the charging unit 131d, and then scans the photoconductor 131b with the luminous flux emitted by the optical scanning device 131a based on the original image to obtain an electrostatic latent image. Form. When a coloring material such as toner is supplied by the developing unit 131c for development, an image is formed on the photoconductor 131b.
The images formed on the photoconductors 131b of the four writing units 131 are sequentially superimposed and transferred (primary transfer) on the intermediate transfer belt 132 by the respective primary transfer rollers 131f. As a result, an image composed of each color is formed on the intermediate transfer belt 132. The intermediate transfer belt 132 is an image carrier that is wound around a plurality of rollers and rotates. After the primary transfer, the cleaning unit 131e removes the coloring material remaining on the photoconductor 131b.

As shown in FIGS. 1 to 3, the transfer device 133 includes a secondary transfer roller 133a that transfers a toner image onto paper, a static electricity elimination mechanism 133b such as a static electricity elimination needle that removes static electricity charged on the paper, and a pair of secondary units. It is configured to include a pressure contact separation mechanism 133c such as a cam that presses / separates one of the transfer rollers 133a from the other.

The image forming unit 13 feeds paper from the manual feed tray T1 or the paper feed tray T2 at the timing when the image on the rotating intermediate transfer belt 132 reaches the position of the secondary transfer roller 133a. The secondary transfer roller 133a constitutes one of a plurality of rollers in which one pair of rollers presses against the intermediate transfer belt 132 and the other winds the intermediate transfer belt 132. When the image is transferred (secondary transfer) from the intermediate transfer belt 132 to the paper by pressure welding of the secondary transfer roller 133, the paper is conveyed to the fixing device 134 via the guide member 20 to perform the fixing process, and the paper ejection tray is performed. Discharge to T3. The fixing process is a process of heating and pressurizing the paper with the fixing roller 134a to fix the image on the paper. When forming an image on both sides of the paper, the paper is conveyed to the reversing path 135 to invert the paper surface, and then the paper is fed again to the position of the secondary transfer roller 133.

The storage unit 14 is a non-volatile storage means composed of an HDD (Hard Disk Drive), an SSD (Solid State Drive), etc., and stores various programs, various setting data, and the like readable and writable from the control unit 11.

The operation panel 15 includes a display unit 151 that displays various information to the user, and an operation unit 152 that receives operation input by the user.
The display unit 151 is composed of a color liquid crystal display or the like, and displays an operation screen or the like (various setting screens, various buttons, operating status of each function, etc.) according to a display control signal input from the control unit 11.
The operation unit 152 includes a touch panel provided on the screen of the display unit 151 and various hard keys arranged around the screen of the display unit 151. When the button displayed on the screen is pressed with a finger, a stylus, or the like, the operation unit 152 detects the XY coordinates of the pressed force point with a voltage value, and controls the operation signal associated with the detected position. Output to unit 11. The touch panel is not limited to the pressure-sensitive type, and may be, for example, an electrostatic type or an optical type. Further, when the hard key is pressed, the operation unit 152 outputs an operation signal associated with the pressed key to the control unit 11. The user can operate the operation unit 152 to perform image formation-related settings such as image quality setting, magnification setting, application setting, output setting, and paper setting, paper transport instruction, and stop operation of the device.

The communication unit 16 is an interface for connecting the image forming apparatus 10 to the communication network N. The communication unit 16 has a communication IC, a communication connector, and the like, and under the control of the control unit 11, transmits and receives various information to and from an external device connected to the communication network N using a predetermined communication protocol. Further, the communication unit 16 can also input / output various information via USB.

FIG. 4 shows a perspective view of the fixing device 134. Further, FIGS. 5 and 6 show an example of the configuration of the guide member 20 that guides the paper from the transfer device 133 to the fixing device 134.
The guide member 20 is fixed to the fixing device 134 as shown in FIGS. 3 and 4. As shown in FIGS. 5 and 6, the guide member 20 is formed of an insulating member 21 which is a sheet-like member formed of PET (polyethylene terephthalate) at an end portion on the transfer device 133 side. By extending the tip of the guide member 20 on the transfer device 133 side with the insulating member 21, the gap between the guide member 20 and the transfer device 133 can be reduced, so that the guide member 20 is conveyed from the transfer device 133. It is possible to stabilize the paper transport posture and suppress the occurrence of image defects such as paper wrinkles and bleeding, and it is possible to prevent leakage to the guide member 20 due to transfer or separation in the transfer device 133.

The insulating member 21 is attached to the guide member 20 via the support member 22. Specifically, as shown in FIG. 6, the support member 22 is attached to the non-guide surface (back surface) side of the guide member 20, and the insulating member 21 is attached to the support member 22. In this way, when it is difficult to attach the component to the guide member 20, such as when the surface of the guide member 20 is coated by attaching the insulating member 21 to the guide member 20 via the support member 22. Even so, it can be attached.

The guide member 20 is provided with a rib shape (see A1 in FIG. 5) on the guide surface (front surface) side of the paper. Specifically, as shown in FIG. 5, the guide member 20 is provided with a plurality of protrusions oblique to the paper passing direction on the guide surface side of the paper. This makes it possible to prevent streaks from being formed on the back image of the paper.

Further, the guide member 20 has a conductive fluorine coating (see A2 in FIG. 6) on the guide surface side of the paper. This makes it possible to prevent dirt and the like from adhering to the guide member 20.

As described above, the image forming apparatus 10 according to the present embodiment has a transfer unit (transfer device 133) that transfers the toner image to the paper and a fixing unit (transfer device 133) that fixes the toner image transferred to the paper by the transfer unit to the paper. A fixing device 134) and a guide member 20 for guiding the paper from the transfer portion to the fixing portion are provided. Further, the guide member 20 has an end portion on the transfer portion side formed by an insulating member 21.
Therefore, according to the image forming apparatus 10 according to the present embodiment, the gap between the guide member 20 and the transfer portion can be reduced, so that the transport posture of the paper conveyed from the transfer portion is stabilized and the paper wrinkles are formed. It is possible to suppress the occurrence of image defects such as occurrence and bleeding, and it is possible to prevent leakage to the guide member 20 due to transfer or separation at the transfer portion.

Further, according to the image forming apparatus 10 according to the present embodiment, the insulating member 21 is a sheet-like member formed by PET.
Therefore, according to the image forming apparatus 10 according to the present embodiment, since the insulating member 21 is made of a member having a low hardness, even the paper conveyed from the transfer apparatus 133 provided with the pressure contact separation mechanism 133c is conveyed. The posture can be stabilized.

Further, according to the image forming apparatus 10 according to the present embodiment, the insulating member 21 is attached to the guide member 20 via the support member 22.
Therefore, according to the image forming apparatus 10 according to the present embodiment, even when it is difficult to attach the component to the guide member 20, such as when the surface of the guide member 20 is coated, the image forming apparatus 10 is attached. be able to.

Further, according to the image forming apparatus 10 according to the present embodiment, the guide member 20 is provided with a conductive fluorine coating on the guide surface side of the paper.
Therefore, according to the image forming apparatus 10 according to the present embodiment, it is possible to prevent adhesion of dirt and the like to the guide member 20 and charging.

Further, according to the image forming apparatus 10 according to the present embodiment, the guide member 20 is provided with a rib shape on the guide surface side of the paper.
Therefore, according to the image forming apparatus 10 according to the present embodiment, it is possible to prevent the sticking of the paper, and thus it is possible to prevent the formation of streaks on the back image of the paper.

Further, according to the image forming apparatus 10 according to the present embodiment, the transfer unit is provided with a static elimination mechanism 133b.
Therefore, according to the image forming apparatus 10 according to the present embodiment, it is possible to stabilize the paper transport posture while preventing leakage to the guide member 20 due to transfer or separation in the transfer apparatus 133 provided with the static elimination mechanism 133b.

Further, according to the image forming apparatus 10 according to the present embodiment, the transfer portion is provided with a pressure contact separation mechanism 133c.
Therefore, according to the image forming apparatus 10 according to the present embodiment, the conveying posture can be stabilized even if the paper is conveyed from the transfer apparatus 133 provided with the pressure contact separation mechanism 133c.

Further, according to the image forming apparatus 10 according to the present embodiment, the guide member 20 is fixed to the fixing portion.
Therefore, according to the image forming apparatus 10 according to the present embodiment, the guide member 20 is fixed to the side other than the transfer apparatus 133 side provided with the pressure contact separation mechanism 133c, so that the paper transport posture can be stabilized and the guide can be stabilized. Leakage to the member 20 can be prevented.

Although the specific description has been given above based on the embodiment of the present invention, the present invention is not limited to the above embodiment and can be changed without departing from the gist thereof.

(Modification example 1)
For example, in the example shown in FIG. 7, a wear-resistant, low-friction, and antistatic guide member 23 is provided between the insulating member 21 and the rib shape of the guide member 20A (see A1 in the drawing) as compared with the configuration of the embodiment. It differs in that it is arranged.
Specifically, as shown in FIGS. 7 and 8, there is wear resistance, low friction, and antistatic between the rib shape of the guide member 20A (see A1 in the drawing) and the insulating member 21 according to the first modification. Guide member 23 is arranged.

The guide member 23 is formed of an ultra-high molecular weight PE (polyethylene) film, and the fluorine coating applied to the guide surface side of the guide member 20A is masked and attached. As shown in FIG. 9, the portion (end side of the transfer device 133 side) A3 on which the guide member 23 of the guide member 20A is arranged is formed in a flat shape without providing a rib shape, and is formed in a flat shape. The guide member 23 is attached.

In the first modification, the support member 22 is screwed and fixed to the guide member 20A. Further, the insulating member 21 is attached so as to cover the support member 22.

As described above, according to the image forming apparatus 10 according to the first modification, the wear-resistant, low-friction, and antistatic guide member 23 is arranged between the insulating member 21 and the rib shape.
Therefore, according to the image forming apparatus 10 according to the first modification, the paper transportability of the portion where a large amount of paper lands can be ensured, so that the transport posture is stabilized even when the thin paper is transported at high speed, which is defective. Occurrence can be suppressed.

Further, according to the image forming apparatus 10 according to the first modification, the guide member 23 is formed of an ultra-high molecular weight PE film.
Therefore, according to the image forming apparatus 10 according to the first modification, the paper transportability of the portion where a large amount of paper lands can be ensured, so that the transport posture is stabilized even when the thin paper is transported at high speed, which is defective. Occurrence can be suppressed.

Further, according to the image forming apparatus 10 according to the first modification, the guide member 23 is formed in a flat shape.
Therefore, according to the image forming apparatus 10 according to the first modification, the paper transportability of the portion where a large amount of paper lands can be ensured, so that the transport posture is stabilized even when the thin paper is transported at high speed, which is defective. Occurrence can be suppressed.

(Other variants)
Further, in the above embodiment, when the insulating member 21 is attached to the guide member 20, the insulating member 21 is attached via the support member 22, but the present invention is not limited to this. For example, the insulating member 21 may be attached without the support member 22.

In addition, the detailed configuration of each device constituting the image forming apparatus and the detailed operation of each device can be appropriately changed without departing from the spirit of the present invention.

10 Image forming device 11 Control unit 12 Image reading unit 13 Image forming unit 131 Writing unit 132 Intermediate transfer belt 133 Transfer device (transfer unit)
133a Secondary transfer roller 133b Static elimination mechanism 133c Pressure welding separation mechanism 134 Fixing device (fixing part)
14 Storage unit 15 Operation panel 151 Display unit 152 Operation unit 16 Communication unit 20, 20A Guide member 21 Insulation member 22 Support member 23 Guide member

Claims (11)

In an image forming apparatus that forms a toner image on paper,
A transfer unit that transfers the toner image to the paper, and
A fixing portion for fixing the toner image transferred to the paper by the transfer portion to the paper, and a fixing portion.
A guide member that guides the paper from the transfer portion to the fixing portion,
With
The guide member is an image forming apparatus characterized in that an end portion on the transfer portion side is formed of an insulating member. The image forming apparatus according to claim 1, wherein the insulating member is a sheet-like member formed of PET. The image forming apparatus according to claim 1 or 2, wherein the insulating member is attached to the guide member via a support member. The image forming apparatus according to any one of claims 1 to 3, wherein the guide member is provided with a conductive fluorine coating on the guide surface side of the paper. The image forming apparatus according to any one of claims 1 to 4, wherein the guide member is provided with a rib shape on the guide surface side of the paper. The image forming apparatus according to claim 5, wherein a wear-resistant, low-friction, and antistatic guide member is arranged between the insulating member and the rib shape. The image forming apparatus according to claim 6, wherein the guide member is formed of an ultra-high molecular weight PE film. The image forming apparatus according to claim 6 or 7, wherein the guide member is formed in a plane shape. The image forming apparatus according to any one of claims 1 to 8, wherein the transfer unit is provided with a static elimination mechanism. The image forming apparatus according to any one of claims 1 to 9, wherein the transfer unit is provided with a pressure contact separation mechanism. The image forming apparatus according to any one of claims 1 to 10, wherein the guide member is fixed to the fixing portion.

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