JP7720802B2 - Sheet guide member, fixing device and image forming apparatus - Google Patents

Description

The present invention relates to a sheet guide member, a fixing device, and an image forming apparatus.

Conventionally, image forming devices are known that transfer a toner image to a sheet and then fix the unfixed toner image to the sheet in a nip formed between a heating rotor and a pressure rotor. A sheet guide member may also be used to guide the sheet with the transferred toner image along the sheet transport direction.

Sheet guide members that are set to a width smaller than the width of the largest printable sheet, such as that disclosed in Patent Document 1, are known. By setting the sheet guide member to this width, it is possible to prevent the sheet guide member from being soiled by toner scattered from the edges of the sheet, particularly during borderless printing (printing without margins).

Japanese Patent Application Laid-Open No. 2015-7752

By the way, as a transfer means for transferring a toner image to a sheet, a voltage of the opposite polarity (e.g., positive polarity) to the charge polarity (e.g., negative polarity) of the toner image may be applied to a transfer member such as a transfer roller. By applying this voltage, the sheet that passes through the transfer member becomes charged (e.g., positively charged).

For this reason, when a sheet with a width greater than the width of the sheet guide member passes over the sheet guide member in a charged state, there is a risk that the sheet will discharge to the edge of the sheet guide member in areas of the sheet that are close to the edge of the sheet guide member. Because the force attracting the toner image is weakened in the discharged areas of the sheet, the discharge from the sheet can cause the toner image to become distorted, ultimately resulting in image defects. Naturally, image defects caused by the above-mentioned toner image distortion become more pronounced during borderless printing (printing without margins).

The present invention was made to solve the above-mentioned problems with the conventional technology, and aims to provide a sheet guide member, fixing device, and image forming apparatus that can prevent image defects.

In order to achieve the above object, the present invention provides a sheet guide member, a fixing device, and an image forming apparatus according to the following first to sixth aspects.
(1) Sheet guide member
(1-1) Sheet guide member of the first aspect
A first aspect of the sheet guide member of the present invention is a sheet guide member that guides a sheet onto which a toner image has been transferred along a sheet transport direction, and is characterized in that, in a width direction perpendicular to the sheet transport direction, it has a width that is shorter than the width of the sheet of the maximum size onto which the toner image can be transferred, the edge portion in the direction perpendicular to the sheet transport direction extends in a direction away from the sheet, an opening is provided in the center in the direction perpendicular to the sheet transport direction, the peripheral portion of the opening is recessed in a direction away from the sheet, and the periphery of the opening is formed in an arc shape .
(1-2) Second embodiment of sheet guide member
A second aspect of the sheet guide member of the present invention is a sheet guide member that guides a sheet onto which a toner image has been transferred along the sheet transport direction, and is characterized in that in a width direction perpendicular to the sheet transport direction, it has a width that is shorter than the width of the sheet of the maximum size onto which the toner image can be transferred, the edge portion in the direction perpendicular to the sheet transport direction extends in a direction away from the sheet, an opening is provided in the center in the direction perpendicular to the sheet transport direction, the peripheral portion of the opening extends in a direction away from the sheet, and the peripheral portion of the opening is formed in an arc shape.
(1-3) Sheet guide member of the third aspect
A third aspect of the sheet guide member of the present invention is a sheet guide member that guides a sheet onto which a toner image has been transferred along the sheet transport direction, and is characterized in that an opening is provided in the center in a direction perpendicular to the sheet transport direction, the peripheral portion of the opening is recessed in a direction away from the sheet, and the periphery of the opening is formed in an arc shape.
(1-4) Sheet guide member of the fourth aspect
A fourth aspect of the sheet guide member of the present invention is a sheet guide member that guides a sheet onto which a toner image has been transferred along the sheet transport direction, and is characterized in that an opening is provided in the center in a direction perpendicular to the sheet transport direction, the peripheral portion of the opening extends in a direction away from the sheet, and the peripheral portion of the opening is formed in an arc shape.
(1-5) Sheet guide member of the fifth aspect
A fifth aspect of the sheet guide member of the present invention is a sheet guide member that guides a sheet onto which a toner image has been transferred along a sheet transport direction, and is characterized in that, in a width direction perpendicular to the sheet transport direction, it has a width that is shorter than the width of the sheet of the maximum size onto which the toner image can be transferred, the edge portion in the direction perpendicular to the sheet transport direction extends in a direction away from the sheet, an opening is provided in the center in the direction perpendicular to the sheet transport direction, the peripheral portion of the opening extends in a direction away from the sheet, and the opening is formed in the shape of a circular hole.
(1-6) Sheet guide member of the sixth aspect
A sixth aspect of the sheet guide member of the present invention is a sheet guide member that guides a sheet onto which a toner image has been transferred along the sheet transport direction, characterized in that an opening is provided in the center in a direction perpendicular to the sheet transport direction, the peripheral portion of the opening extends in a direction away from the sheet, and the opening is formed in the shape of a round hole.

Furthermore, in the sheet guide member, the edge portion may extend in a direction away from the sheet over the entire area along the sheet conveying direction.

Furthermore, the sheet guide member may have an opening in its central portion in a direction perpendicular to the sheet conveying direction, and the periphery of the opening may be recessed in a direction away from the sheet.

Furthermore, the sheet guide member may have an opening in its central portion in a direction perpendicular to the sheet conveying direction, and the peripheral edge of the opening may extend in a direction away from the sheet.

Another sheet guide member described in this application is a sheet guide member that guides a sheet onto which a toner image has been transferred along the sheet transport direction, and is characterized in that an opening is provided in the center in a direction perpendicular to the sheet transport direction, and the periphery of the opening is recessed in a direction away from the sheet.

Another sheet guide member described in this application is a sheet guide member that guides a sheet onto which a toner image has been transferred along the sheet transport direction, and is characterized in that an opening is provided in the center in a direction perpendicular to the sheet transport direction, and the peripheral edge of the opening extends in a direction away from the sheet.

Furthermore, in the sheet guide member, the peripheral edge of the opening may be formed in an arc shape.

Furthermore, in the sheet guide member, the opening may be formed in the shape of a round hole.

The fixing device described in this application comprises the sheet guide member, a heating rotor that is heated by a heat source, and a pressure rotor that contacts the heating rotor, and is characterized in that the sheet guide member guides the sheet to the nip formed between the heating rotor and the pressure rotor.

The image forming apparatus described in this application is characterized by being equipped with both or either the sheet guide member and the fixing device.

This invention makes it possible to prevent image defects.

1 is a schematic cross-sectional view illustrating a configuration of an image forming apparatus according to a first embodiment. 1 is a schematic cross-sectional view showing a fixing device according to a first embodiment. FIG. 3 is a schematic perspective view of the fixing device of FIG. 2 as viewed from below. FIG. 2 is a perspective view showing a sheet guide member according to the first embodiment. 5 is a plan view of the sheet guide member of FIG. 4 as viewed from the sheet side. FIG. 6 is a cross-sectional view of the sheet guide member of FIG. 5 taken along line AA. FIG. 10 is a perspective view showing a sheet guide member according to a second embodiment. 8 is a plan view of the sheet guide member of FIG. 7 as viewed from the sheet side. FIG. 9 is a cross-sectional view of the sheet guide member of FIG. 8 taken along line BB.

Embodiments of the present invention will be described below with reference to the accompanying drawings. Note that identical components in the embodiments described below will be assigned the same reference numerals, and redundant descriptions of those components will be omitted.

(Embodiment 1)
--Overall configuration of image forming apparatus--
First, the overall configuration of the image forming apparatus A in the first embodiment will be described.

Figure 1 is a schematic cross-sectional view showing the configuration of image forming apparatus A in embodiment 1. In the figure, the symbol X indicates the width direction (depth direction), with the -X direction (negative X direction) being the front direction and the +X direction (positive X direction) being the rear direction. The symbol Y indicates the left-right direction perpendicular to the width direction X, with the -Y direction (negative Y direction) being the left direction and the +Y direction (positive Y direction) being the right direction. The symbol Z indicates the up-down direction, with the -Z direction (negative Z direction) being the down direction and the +Z direction (positive Z direction) being the up direction. These settings are the same in subsequent embodiments.

Image forming apparatus A is an electrophotographic image forming apparatus and an intermediate transfer color multifunction machine capable of printing full-color images. Image forming apparatus A has an image reading unit 1, an image forming unit 2, a transfer body 3, a secondary transfer unit 4, a fixing device 5, a sheet storage unit 8, a sheet roller group 9, and a sheet discharge unit 90 (see Figure 1). Image forming apparatus A is provided with a sheet transport path S along which sheets are transported. In this embodiment, image forming apparatus A uses toners of the colors yellow (Y), magenta (M), cyan (C), and black (K) for printing.

The image reading unit 1 reads images from documents and is located on top of the image forming device A. The image reading unit 1 has a document reading device 10, a document placing table 11, and an automatic document processing device 12 (see Figure 1).

The document reading device 10 illuminates a document and reads an image from the document based on the reflected light. The document reading device 10 incorporates, for example, a light source that illuminates the document, a lens, an image sensor, and a mirror that guides the reflected light from the document to the lens. The reflected light from the document is incident on the image sensor via the lens and is photoelectrically converted by the image sensor to generate image data.

The document tray 11 is where the user places the document and is located above the document reading device 10 (see Figure 1). The document tray 11 is made of transparent glass. The automatic document processing device 12 is located above the document tray 11 and automatically and continuously transports documents inserted by the user to the document reading device 10 (see Figure 1). The image of the document is read by the document reading device 10 while it is placed on the document tray 11 or while it is transported to the document reading device 10 by the automatic document processing device 12.

The image forming unit 2 forms a toner image based on image data and includes an exposure device 20, a developing device 21, an image carrier 22, a charging device 23, and a cleaning unit 24 (see Figure 1). Note that the image data may be generated by the image reading unit 1 or may be supplied from an external device.

The exposure device 20 exposes the surface of the image carrier 22, which has been charged by the charging device 23, to light of each color, thereby forming an electrostatic latent image corresponding to each color on the image carrier 22. The exposure device 20 contains a light source (not shown), a polygon mirror 200 that scans the laser beam emitted from the light source, and optical elements (such as a lens 201 and a mirror 202) that guide the laser light reflected by the polygon mirror 200 to the image carrier 22.

The developing device 21 forms a toner image by visualizing the electrostatic latent image formed on the surface of each image carrier 22 using toner of each color (Y, M, C, K) supplied from the toner cartridge T. The developing device 21 has a developer carrier 25 that causes toner to fly onto the surface of the image carrier 22. When a high-voltage development bias is applied to the developer carrier 25, toner is caused to fly to the image carrier 22, and the toner is supplied to the electrostatic latent image formed on the surface of the image carrier 22, forming a toner image on the surface of the image carrier 22.

The image carrier 22, on whose surface an electrostatic latent image is formed, is rotated in a predetermined direction by the drive of a main motor (not shown). As the image carrier 22 is rotated, the toner image visualized on the image carrier 22 is transported to the transfer body 3.

The charging device 23 applies a high-voltage charging bias to uniformly charge the surface of the image carrier 22 to a predetermined potential. The charging device 23 may be, for example, a contact-type charger (e.g., a roller-type or brush-type charger) or a charger-type charger.

The cleaning unit 24 removes and collects any toner remaining on the surface of the image carrier 22 after development and image transfer.

The transfer body 3 is positioned above the image carrier 22, and the toner images of each color formed on the surface of the image carrier 22 are transferred to it. The transfer body 3 has an intermediate transfer belt 30, a drive roller 31, a driven roller 32, and a primary transfer unit 33.

The intermediate transfer belt 30 is an endless belt that rotates in a predetermined direction and is suspended between a drive roller 31 and a driven roller 32. The outer surface of the intermediate transfer belt 30 is in contact with the image carrier 22. The toner images of each color visualized on the image carrier 22 are transferred onto the intermediate transfer belt 30 in succession, superimposed on top of each other. The toner images transferred onto the intermediate transfer belt 30 are transported to the secondary transfer unit 4 by the rotation of the intermediate transfer belt 30. The intermediate transfer belt 30 is formed, for example, from a film with a thickness of approximately 100 μm to 150 μm.

The drive roller 31 is a roller that is driven to rotate in a predetermined direction by the drive of a belt motor (not shown), and is provided on the right end side of the transfer body 3 (see Figure 1). The rotation of the drive roller 31 rotates the intermediate transfer belt 30.

The driven roller 32 is a roller that is rotatably mounted along the intermediate transfer belt 30 (see Figure 1). The driven roller 32 rotates in accordance with the rotation of the intermediate transfer belt 30.

The primary transfer unit 33, which is a transfer roller, for example, transfers the toner image onto the transfer body 3 and is provided to correspond to the image carrier 22 via the intermediate transfer belt 30 (see Figure 1). A high-voltage transfer bias is applied to the primary transfer unit 33, causing the toner image on the image carrier 22 to be transferred onto the intermediate transfer belt 30.

A conductive elastic material (made of a material such as EPDM or urethane foam) is provided on the outer peripheral surface of the primary transfer unit 33. The provision of this conductive elastic material makes it possible to apply a uniform high voltage to the intermediate transfer belt 30. Hereinafter, the transfer of the toner images of each color formed on the image carrier 22 onto the intermediate transfer belt 30 will be referred to as "primary transfer."

The secondary transfer unit 4 transfers the toner images of each color that have been primarily transferred onto the intermediate transfer belt 30 onto a sheet. The secondary transfer unit 4 has a secondary transfer roller 40 located at the transfer position where the sheet and intermediate transfer belt 30 face each other. A voltage is applied to the secondary transfer roller 40 to transfer the toner images of each color on the intermediate transfer belt 30 onto the sheet, i.e., a voltage of the opposite polarity (e.g., positive polarity) to the charge polarity (e.g., negative polarity) of the toner. Hereinafter, the transfer of the toner images of each color that have been transferred onto the intermediate transfer belt 30 onto the sheet will be referred to as "secondary transfer."

The fixing device 5 heats and melts the toner image that has been secondarily transferred onto the sheet, thereby fixing the toner image to the sheet. It is located downstream of the secondary transfer unit 4 on the sheet transport path S.

The sheet storage unit 8 is located at the bottom of the image forming apparatus A and has a cassette 80 that stores sheets used in image formation. The sheet storage unit 8 may have multiple cassettes 80. Furthermore, each of the multiple cassettes 80 may store sheets of any material or size.

The sheet roller group 9 includes a pickup roller 9a, conveyor rollers 9b to 9d, and a registration roller 9e.

Pickup roller 9a pulls out the topmost recording paper (sheet) from the stack of paper in sheet storage unit 8 and transports it to sheet transport path S. Transport rollers 9b to 9d transport the sheet along sheet transport path S. Registration roller 9e temporarily stops the sheet being transported from sheet storage unit 8 and aligns the leading edge of the sheet. Each of these sheet rollers 9 is rotated by a motor (not shown).

The sheet discharge unit 90 is located at the top of the image forming device A and is used to load printed sheets face down.

In addition to the above configuration, image forming device A is provided with a control unit (not shown) that controls each of the above-described components in response to input operations by the user, etc.

The image forming apparatus A described above prints on a sheet as follows. First, the image forming unit 2 forms a toner image based on image data generated by the image reading unit 1 or supplied from an external device. This toner image is primarily transferred onto the intermediate transfer belt 30 of the transfer body 3. During this time, the sheet is pulled out of the sheet storage unit 8 by the pickup roller 9a, transported by the transport roller 9b to the registration roller 9e, and then transported by the registration roller 9e to the secondary transfer unit 4. Next, the secondary transfer unit 4 performs a second transfer of the toner image primarily transferred onto the intermediate transfer belt 30 onto the sheet. The fixing device 5 fixes the secondarily transferred toner image onto the sheet. The sheet is then transported by the transport roller 9d and discharged onto the sheet discharge unit 90, completing the printing on the sheet.

- Fixing device -
Fig. 2 is a schematic cross-sectional view showing the fixing device 5 in embodiment 1. Fig. 3 is a schematic perspective view of the fixing device 5 as seen from below. In Fig. 3, the fastening member B at the center of the sheet guide member 6 is not shown.

The fixing device 5 includes a heating rotor 50, a pressure rotor 51, a frame 52, a sheet guide member 6, and a sheet sensor 7. Each component of the fixing device 5 is described in detail below.

In this embodiment, the heating rotor 50 has a fixing roller 500, a heating roller 501, a heat source 502, and a fixing belt 503 (see Figure 2).

The fixing roller 500 is supported by a frame 52 so as to be rotatable in the direction of its rotation axis along the X direction. The heating roller 501 has a built-in heat source 502. The heat source 502 is composed of a lamp heater such as a halogen lamp. The fixing belt 503 is an endless belt that is suspended between the fixing roller 500 and the heating roller 501 and is rotatable in the direction of its rotation axis along the X direction, and has a predetermined width along the X direction. The fixing belt 503 is heated to a predetermined temperature (fixing temperature) by the heat source 502 via the heating roller 501. In this embodiment, the fixing belt 503 rotates in response to the rotation of the pressure rotor 51.

The pressure rotor 51 abuts against the outside of the fixing belt 503, facing the fixing roller 500 of the heating rotor 50, and is supported by a frame 52 so that it can rotate about its axis of rotation along the X direction. The pressure rotor 51 is driven to rotate by a drive unit (not shown). The pressure rotor 51 is also biased toward the fixing belt 503 by a biasing member (not shown). A nip FN, through which a sheet can pass, is formed between the pressure rotor 51 and the heating rotor 50 along the X direction. Sheets of the maximum size that can be passed through the image forming apparatus A (e.g., A3 size in the vertical feed direction or A4 size in the horizontal feed direction) can pass through the nip FN. The pressure rotor 51 and the heating rotor 50 melt unfixed toner on the sheet with heat at the nip FN, and sandwich and transport the sheet.

The frame 52 is formed from a metal material such as galvanized steel plate. An inlet 53 is formed in the frame 52 on the upstream side of the nip FN in the sheet conveying direction F, and an outlet 54 is formed on the downstream side of the nip FN in the sheet conveying direction F (see Figure 2).

Figure 4 is a perspective view showing the sheet guide member 6 in embodiment 1. Figure 5 is a plan view of the sheet guide member 6 in Figure 4 as seen from the sheet side. Figure 6 is a cross-sectional view of the sheet guide member 6 in Figure 5 taken along line A-A.

The sheet guide member 6 guides the sheet onto which the toner image has been transferred along the sheet transport direction F, and is fixed to the frame 52 at the inlet 53 with fastening members B, such as screws (see Figure 3). In this embodiment, the sheet guide member 6 guides the sheet to the nip portion FN. The sheet guide member 6 is formed from a metal material, such as a stainless steel plate. In the width direction (X direction in this embodiment) perpendicular to the sheet transport direction F, the sheet guide member 6 has a width that is shorter than the width of the largest sheet size onto which a toner image can be transferred (for example, A3 size in the vertical feed direction or A4 size in the horizontal feed direction).

In this embodiment, the edge portions 60, 61 of the sheet guide member 6 in the direction (X direction) perpendicular to the sheet conveying direction F (the edge portion 60 on the -X direction side and the edge portion 61 on the +X direction side) are extended in a direction away from the sheet (see Figures 4 and 6). The extension amount of the edge portions 60, 61 is, for example, approximately 2 to 3 mm.

By extending the edge portions 60 and 61 away from the sheet, image defects can be prevented. Specifically, this is as follows:

The sheet passes through the secondary transfer unit 4 and then through the sheet guide member 6. That is, the sheet passing through the sheet guide member 6 becomes charged (positively charged in this embodiment) due to the voltage applied during secondary transfer. Here, if the sheet has a width greater than the width of the sheet guide member 6 in the direction (X direction) perpendicular to the sheet conveyance direction F, the charged sheet approaches the edge portions 60, 61 of the sheet guide member 6.

If the edge portions 60, 61 were not extended away from the sheet, the distance between the sheet and the edge portions 60, 61 could become small enough for the sheet to discharge to the edge portions 60, 61. High-resistivity sheets, such as cardboard and coated paper, can become excessively charged during secondary transfer, making the sheet more susceptible to discharge to the edge portions 60, 61. If the sheet discharges to the edge portions 60, 61 as it passes through the sheet guide member 6, the charge disturbance can disrupt the unfixed toner image on the sheet. In particular, in the case of borderless printing (printing without margins), the toner image at the side edge portions of the sheet can become disrupted. This disruption of the toner image can result in poor image quality.

As described above, by extending the edge portions 60, 61 away from the sheet, a sufficient distance is ensured between the sheet and the edge portions 60, 61 to prevent discharge of the sheet to the edge portions 60, 61. Therefore, even if a high-resistance sheet passes through the sheet guide member 6, discharge of the sheet is prevented, and disturbance of the toner image due to discharge of the sheet is prevented. This prevents image defects.

In this embodiment, the edge portions 60, 61 extend away from the sheet over the entire area along the sheet conveying direction F (see Figure 4). This ensures a sufficient distance between the sheet and the edge portions 60, 61 over the entire area along the sheet conveying direction F to prevent discharge of the sheet to the edge portions 60, 61, thereby reliably preventing discharge of the sheet.

In this embodiment, a roughly home plate-shaped opening 62 is provided in the center of the sheet guide member 6 in the direction (X direction) perpendicular to the sheet conveying direction F (see Figures 3 to 6). A sheet sensor 7 is attached to the opening 62 (see Figure 2).

The sheet sensor 7 is a sensor that faces the opening 62 of the sheet guide member 6 and detects the passage of a sheet without contact, and is composed of, for example, a reflective photosensor.

In this embodiment, the peripheral portion 63 of the opening 62 in the sheet guide member 6 is recessed in a direction away from the sheet (see Figures 5 and 6). The recession of the peripheral portion 63 is, for example, approximately 2 to 3 mm.

The peripheral portion 63 of the opening 62 in the sheet guide member 6 is recessed in the direction away from the sheet, which has the effect of preventing image defects. Specifically, this is as follows:

Depending on the distance between the sheet and the peripheral edge 62a of the opening 62, there is a risk of discharge of the sheet against the peripheral edge 62a of the opening 62. Discharge of the sheet against the peripheral edge 62a of the opening 62 is similar to discharge of the sheet against the edge portions 60 and 61 described above, but differs in that discharge of the sheet can occur regardless of the width of the sheet relative to the width of the sheet guide member 6.

As described above, because the peripheral portion 63 of the opening 62 in the sheet guide member 6 is recessed away from the sheet, a sufficient distance is secured between the sheet and the peripheral edge 62a of the opening 62 to prevent discharge of the sheet to the peripheral edge 62a of the opening 62. This prevents discharge of the sheet and prevents disturbance of the toner image due to discharge of the sheet. This prevents image defects.

Note that the configuration of the fixing device 5 described above is a so-called belt fixing type, but this is not limited to this, and the fixing roller 500 may also be directly pressed by the pressure rotor 51.

Furthermore, the shape and extension amount of the edge portions 60, 61 described above are merely examples; what is important is that a sufficient distance is maintained between the sheet and the edge portions 60, 61 to prevent discharge of the sheet to the edge portions 60, 61.

Furthermore, the amount of recession of the peripheral portion 63 of the opening 62 described above is an example; the key point is that it is sufficient to ensure a distance between the sheet and the peripheral portion 62a of the opening 62 that is sufficient to prevent discharge of the sheet to the peripheral portion 62a of the opening 62.

Furthermore, the shape of the opening 62 is an example, and for example, the periphery of the opening 62 may be formed in an arc shape. When the periphery of the opening 62 is formed in an arc shape, local concentration of electric charge at the periphery 62a of the opening 62 is avoided, thereby efficiently suppressing discharge of the sheet to the periphery 62a of the opening 62.

(Embodiment 2)
Hereinafter, only the differences between the second embodiment and the first embodiment will be described.

Figure 7 is a perspective view showing the sheet guide member 6 in embodiment 2. Figure 8 is a plan view of the sheet guide member 6 in Figure 7 as seen from the sheet side. Figure 9 is a cross-sectional view of the sheet guide member 6 in Figure 8 taken along line B-B.

In embodiment 2, a circular opening 64 is provided in the center of the sheet guide member 6 in the direction (X direction) perpendicular to the sheet conveying direction F (see Figures 7 to 9). The peripheral edge 64a of the opening 64 extends in a direction away from the sheet (see Figures 7 and 9). The extension amount of the peripheral edge 64a is, for example, approximately 2 to 3 mm.

By extending the peripheral edge 64a of the opening 64 in a direction away from the sheet, a sufficient distance is secured between the sheet and the peripheral edge 64a of the opening 64 to prevent discharge of the sheet to the peripheral edge 64a of the opening 64. This prevents discharge of the sheet and prevents disturbance of the toner image due to discharge of the sheet. This prevents image defects.

In addition, in embodiment 2, the periphery of the opening 64 is formed in an arc shape, which prevents localized concentration of electric charge at the periphery 64a of the opening 64, thereby efficiently preventing discharge of the sheet to the periphery 64a of the opening 64.

Furthermore, by making the opening 64 a round hole, the peripheral edge 64a of the opening 64 can be made to extend in a direction away from the sheet, for example, using burring. In other words, it is easy to ensure a distance between the sheet and the peripheral edge 64a of the opening 64 that is sufficient to prevent discharge of the sheet to the peripheral edge 64a of the opening 64.

In the embodiment described above, the sheet guide member 6 guides the sheet to the nip portion FN in the fixing device 5, but the sheet guide member 6 may be any member that guides the sheet onto which the toner image has been transferred along the sheet transport direction F, and may be applied to the sheet transport path S after the toner transfer process onto the sheet and up to the fixing process. For example, the sheet guide member 6 may be applied as a guide member that guides the sheet into the nip portion of the transfer roller (in this example, the secondary transfer unit 4).

The above-described embodiments and examples are illustrative in all respects and are not intended to be limiting. Therefore, the technical scope of the present invention should not be interpreted solely by the above-described embodiments and examples, but should be defined based on the claims. Furthermore, all modifications within the scope and meaning equivalent to the claims are also included.

A Image forming apparatus 5 Fixing device 50 Heating rotor 500 Fixing roller 501 Heating roller 502 Heat source 503 Fixing belt 51 Pressurizing rotor 52 Frame 6 Sheet guide members 60, 61 Edge portion 62 Opening 62a Peripheral edge portion 63 Peripheral portion 64 Opening 64a Peripheral edge portion 7 Sheet sensor F Conveying direction FN Nip portion

Claims (10)

A sheet guide member that guides a sheet on which a toner image has been transferred along a sheet conveying direction,
the width of the sheet is set to be shorter than the width of the sheet having a maximum size onto which the toner image can be transferred in a width direction perpendicular to the sheet conveying direction,
an edge portion in a direction perpendicular to the sheet conveying direction extends in a direction away from the sheet ,
an opening is provided at a center portion in a direction perpendicular to the sheet conveying direction,
The peripheral portion of the opening is recessed in a direction away from the sheet,
A sheet guide member , wherein the periphery of the opening is formed in an arc shape . A sheet guide member that guides a sheet on which a toner image has been transferred along a sheet conveying direction,
the width of the sheet is set to be shorter than the width of the sheet having a maximum size onto which the toner image can be transferred in a width direction perpendicular to the sheet conveying direction,
an edge portion in a direction perpendicular to the sheet conveying direction extends in a direction away from the sheet,
an opening is provided at a center portion in a direction perpendicular to the sheet conveying direction,
The peripheral edge of the opening extends in a direction away from the sheet,
A sheet guide member, wherein the periphery of the opening is formed in an arc shape. A sheet guide member that guides a sheet on which a toner image has been transferred along a sheet conveying direction,
an opening is provided at a center portion in a direction perpendicular to the sheet conveying direction,
The peripheral portion of the opening is recessed in a direction away from the sheet ,
A sheet guide member , wherein the periphery of the opening is formed in an arc shape . A sheet guide member that guides a sheet on which a toner image has been transferred along a sheet conveying direction,
an opening is provided at a center portion in a direction perpendicular to the sheet conveying direction,
The peripheral edge of the opening extends in a direction away from the sheet ,
A sheet guide member , wherein the periphery of the opening is formed in an arc shape . A sheet guide member that guides a sheet on which a toner image has been transferred along a sheet conveying direction,
the width of the sheet is set to be shorter than the width of the sheet having a maximum size onto which the toner image can be transferred in a width direction perpendicular to the sheet conveying direction,
an edge portion in a direction perpendicular to the sheet conveying direction extends in a direction away from the sheet,
an opening is provided at a center portion in a direction perpendicular to the sheet conveying direction,
The peripheral edge of the opening extends in a direction away from the sheet,
The sheet guide member is characterized in that the opening is formed in a round hole shape. A sheet guide member that guides a sheet on which a toner image has been transferred along a sheet conveying direction,
an opening is provided at a center portion in a direction perpendicular to the sheet conveying direction,
The peripheral edge of the opening extends in a direction away from the sheet,
The sheet guide member is characterized in that the opening is formed in a round hole shape. The sheet guide member according to claim 1 , claim 2 or claim 5 ,
The sheet guide member is characterized in that the edge portion extends in a direction away from the sheet over the entire area along the sheet conveying direction. 5. The sheet guide member according to claim 2 or 4 ,
The sheet guide member is characterized in that the opening is formed in a round hole shape. a sheet guide member according to any one of claims 1 to 8;
a heating rotor that is heated by a heat source;
a pressure rotating body that contacts the heating rotating body,
a sheet guide member for guiding the sheet to a nip portion formed between the heating rotary member and the pressure rotary member; An image forming apparatus equipped with both or either the sheet guide member described in any one of claims 1 to 8 and the fixing device described in claim 9.