JP2001034100A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a user to safely and easily remove jammed paper by easily opening the carrying path of a unit without directly exposing a high temperature part in the unit. SOLUTION: In this image forming device, a fixing unit 110 which has a cover part 112 freely opened/closed and where a recording paper carrying path 118 is exposed when the cover part 112 is opened is provided with an attachable/ detachable inner cover 115 on the inside, and the outside of the cover 115 forms the path 118 and the inside thereof covers over a fixing roller 113 and holds an oil coating roller 117 coating the roller 113 with oil.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus having a fixing unit for fixing toner on recording paper.

[0002]

2. Description of the Related Art In a conventional image forming apparatus, a fixing unit is provided at a final exit of a conveying path for forming an image on a recording sheet. The fixing unit includes a fixing roller heated to a high temperature and a pressure roller pressed against the fixing roller. The toner is transferred to the recording paper before reaching the fixing unit, and the toner is fixed by the fixing unit. The recording paper entering the unit from the entrance of the fixing unit is drawn between the fixing roller and the pressure roller. Then, the toner is melted by the heat of the fixing roller, and the melted toner is fixed on the recording paper by the pressing force from the pressure roller. The recording paper on which the toner has been fixed is discharged from the exit of the fixing unit to the outside of the unit.

As described above, in the fixing unit, since the fixing roller and its peripheral parts become hot, the user can easily open the fixing unit so that the high-temperature portion is not inadvertently exposed to the outside. Was configured to be unable to do so.

[0004]

However, since the fixing unit forms a part of the conveyance path through which the recording paper passes, there is a possibility that paper jam may occur inside the fixing unit. Regardless, since the fixing unit could not be opened, the paper jam generated inside the fixing unit could not be removed by the user, which was inconvenient. Heretofore, when a paper jam has occurred inside the fixing unit, a serviceman must be called each time, and there is a problem that a quick response to the paper jam cannot be performed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and allows a user to easily open a transport path of a unit without directly exposing a high-temperature portion in the unit so that a user can safely and easily make paper. It is an object of the present invention to provide an image forming apparatus capable of removing a jam.

[0006]

According to the present invention, there is provided an image forming apparatus having a lid which can be opened and closed, and which is detachably mounted inside a fixing unit which exposes a recording paper conveyance path when the lid is opened. An internal cover is provided so that a recording paper conveyance path is formed outside the internal cover, and the inside covers the fixing roller and holds an oil application roller that applies oil to the fixing roller.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An image forming apparatus according to a first aspect of the present invention has a lid which can be opened and closed, and when this lid is opened, a recording paper transport path from a fixing roller to a discharge roller is exposed. The fixing unit includes a fixing unit and an internal cover that is provided inside the fixing unit and that forms the transport path on the outside and covers the fixing roller on the inside.

[0008] According to this configuration, since the fixing unit is made openable and closable, the user can easily cope with the paper jam in the fixing unit by opening the lid so that the transport path is exposed. be able to.

Further, since the fixing roller, which is hot, is covered by the internal cover even when the lid of the fixing unit is opened, when the lid of the fixing unit is opened, the high temperature of the fixing roller immediately goes outside. Avoidance can be ensured, and the user can be reliably protected.

An image forming apparatus according to a second aspect of the present invention has a fixing unit that has a cover that can be opened and closed and that exposes a recording paper conveyance path from a fixing roller to a discharge roller when the cover is opened. An internal cover that is detachably provided inside the fixing unit, forms the transport path on the outside, covers the fixing roller on the inside, and holds an oil application roller that applies oil to the fixing roller. Take.

According to this structure, the inner cover exposed by opening the cover of the fixing unit is made detachable with respect to the fixing unit, and the oil applying roller applies oil to the surface of the fixing roller inside the inner cover. , The oil application roller comes off when the internal cover is removed from the fixing unit, so that the oil application roller can be easily replaced. Also, the inner cover has a function as a conveyance path for guiding the recording paper from the fixing roller to the discharge roller, a function to cover the fixing roller, and an oil application roller in contact with the surface of the fixing roller to apply oil to the surface of the fixing roller. By providing the three functions of the application function, the size of the apparatus can be reduced.

The image forming apparatus according to a third aspect of the present invention is the image forming apparatus according to the first or second aspect, wherein a gap between the fixing roller and the pressure roller is provided between an inner surface of the lid and an outer side of the inner cover. Forming a corner portion that changes the direction of conveyance of the recording paper that has passed through in the direction substantially perpendicular to the discharge side, and separating the recording paper from the fixing roller at a location near the fixing roller outside the inner cover. It has a configuration in which a protruding portion is formed to push up.

According to this configuration, the recording paper is stretched between the contact surface between the fixing roller and the pressure roller and the vertex of the protruding portion, so that the recording paper is separated from the fixing roller by the protruding portion. Since the recording paper can be peeled off from the surface of the fixing roller by pushing up in the separating direction, it is possible to prevent the toner from adhering to the leading end of the inner cover and prevent the recording paper from being stained.

According to a fourth aspect of the present invention, in the image forming apparatus according to the third aspect, the projecting portion keeps the conveying direction of the recording paper passing between the fixing roller and the pressure roller substantially as it is. A configuration having a vertex at a position is adopted.

According to this configuration, if the height of the apex of the protruding portion is changed to change the transport direction of the recording paper discharged from the contact surface between the fixing roller and the pressure roller, the leading end of the recording paper is transported along the transport path. The paper flaps up and down, and paper jams are likely to occur. By doing so, it is possible to prevent the leading edge of the recording paper from fluttering up and down on the transport path, thereby preventing the occurrence of paper jam.

The image forming apparatus according to a fifth aspect of the present invention is the image forming apparatus according to the fourth aspect, wherein the corner portion extends from the projection to the corner exit more than the space width near the vertex of the projection. The configuration is such that the space width of is wider.

According to this structure, when the width of the corner portion is narrowed and the conveying direction of the recording paper is suddenly rotated by 90 degrees, paper jam easily occurs at the leading end. The height of the transport path is narrow to maintain the transport direction of the recording paper discharged from the contact surface with the pressure roller almost unchanged. In the area, the conveyance direction is regulated to prevent the leading edge of the recording paper from fluttering, and in the subsequent area, the conveyance direction of the recording paper is gently changed, so that the occurrence of paper jam can be prevented. Particularly, in the case of recording paper having strong stiffness such as thick paper, if the transport direction is suddenly rotated by 90 degrees, paper jam easily occurs. Even in this case, paper jam can be prevented.

An image forming apparatus according to a sixth aspect of the present invention has a fixing unit that has a lid that can be opened and closed and that exposes a recording paper transport path from a fixing roller to a discharge roller when the lid is opened. An inner cover that is detachably provided inside the fixing unit, forms the transport path on the outside, covers the fixing roller on the inside, and holds an oil application roller that applies oil to the fixing roller; and the lid. When the sensor is closed, the sensor includes a sensor for detecting the attachment of the internal cover, and when the sensor does not detect the attachment of the internal cover, a control unit that does not perform the fixing operation.

According to this configuration, if the internal cover is made detachable, there is a possibility that the fixing of the internal cover may be forgotten and the operation may be performed with the lid of the fixing unit closed. Since the sensor detects this and prevents operation, the situation where the high temperature of the fixing unit immediately goes outside when the lid of the fixing unit is opened can be reliably avoided, and the user can be reliably protected. Also, since it does not operate without the inner cover attached, the fixing operation will not be performed without the oil application roller attached,
Since the oil is not applied to the fixing roller, it is possible to prevent the occurrence of defective fixing due to the offset.

An image forming apparatus according to a seventh aspect of the present invention has a fixing unit that has a lid that can be opened and closed and that exposes a recording paper conveyance path from a fixing roller to a discharge roller when the lid is opened. An inner cover that is detachably provided inside the fixing unit, forms the transport path on the outside, covers the fixing roller on the inside, and holds an oil application roller that applies oil to the fixing roller; A sensor that is disposed in the vicinity and detects the discharge of the recording paper and the attachment of the internal cover.

According to this structure, the internal cover is disposed near the discharge roller, and the presence or absence of the internal cover is detected by the sensor for detecting the discharge of the recording paper. Since there is no need to provide a sensor, it is possible to prevent an increase in the number of parts and reduce costs.

An image forming apparatus according to an eighth aspect of the present invention is the image forming apparatus according to the second to seventh aspects, wherein:
The configuration is such that an oil application roller disposed between the fixing roller and the discharge roller is held.

According to this configuration, the oil application roller is held inside the inner cover so as to be disposed between the discharge roller and the fixing roller, so that the arrangement positions of the discharge roller and the inner cover can be made closer. Therefore, it is possible to detect the discharge of the recording paper and the attachment of the inner cover with one sensor without increasing the size of the sensor.

An image forming apparatus according to a ninth aspect of the present invention has a fixing unit that has a lid that can be opened and closed and that exposes a recording paper conveyance path from a fixing roller to a discharge roller when the lid is opened; An inner cover that is detachably provided inside the fixing unit, forms the transport path on the outside, covers the fixing roller on the inside, and holds an oil application roller that applies oil to the fixing roller; A knob provided to extend into a space formed above the fixing roller.

According to this configuration, instead of grasping the entire inner cover by hand, the attaching / detaching operation is performed by the knob extending from the main body of the inner cover to the space inside the fixing unit. Since the various members do not hinder the operation, the attaching / detaching operation can be performed smoothly.

The heat generated by the fixing roller is transmitted to the oil application roller and the inner cover that come into contact with the fixing roller.
Since the knob is provided in a space away from the inner cover main body and not in contact with the member that transmits heat of the fixing roller, it is possible to prevent the heat from hindering the attachment / detachment work of the inner cover.

The image forming apparatus according to a tenth aspect of the present invention is the image forming apparatus according to the ninth aspect, wherein the fixing unit includes a pair of upper and lower guides for guiding the inner cover to a mounting position. The cover is guided by the upper guide to a position where the oil application roller contacts the fixing roller, and the oil application roller rotates to the lower guide position by rotating together with the fixing roller, and the lower guide To the mounting position.

According to this configuration, when the knob is provided extending from the inner cover, the knob is provided apart from the center of gravity of the inner cover. As a result, the entire inner cover is inclined, but when the tip of the inner cover passes through the upper guide of the fixing unit, the inner cover main body is in contact with the oil application roller and the fixing roller while being inclined, and the inner cover is With the rotation of both rollers, the roller moves downward and is finally guided by the lower guide, so that a guide for correcting the inclination of the inner cover is not separately provided,
Since the inner cover can be mounted by utilizing the rotation of the existing roller, the mounting operation can be smoothly performed with an inexpensive configuration.

According to an eleventh aspect of the present invention, in the image forming apparatus according to the tenth aspect, the inner cover includes a guide which is guided to a mounting position by the pair of upper and lower guides. The tip of the guide is guided by the upper guide to a position where the oil application roller and the fixing roller come into contact with each other, and the tip of the guide is rotated by the oil application roller together with the fixing roller, thereby causing the lower guide to move. , The guide is guided by the lower guide, and the inner cover is guided to the mounting position.

According to this configuration, when the tip of the guide of the inner cover passes through the upper guide, the inner cover can be rotated according to the rotation of both rollers about the contact portion between the guide and the upper guide. , The inclination of the inner cover can be corrected without applying load to the guide,
The guide can be prevented from being damaged when the inner cover is attached or detached.

An image forming apparatus according to a twelfth aspect of the present invention is the image forming apparatus according to the tenth and eleventh aspects, wherein the fixing roller and the oil application roller are made of an elastic material.

According to this configuration, when the leading end of the inner cover passes through the upper guide of the fixing unit, the oil application roller and the fixing roller come into contact with each other. In addition, both rollers act as a cushion, and the inner cover can be stably mounted without damaging the members.

According to a thirteenth aspect of the present invention, in the image forming apparatus according to the tenth to twelfth aspects, the oil application roller has an elastic flange having a diameter larger than the diameter of the oil application roller at both ends thereof. Take.

According to this configuration, when the leading end of the inner cover passes through the upper guide of the fixing unit, the oil application roller and the fixing roller come into contact with each other. By providing an elastic circular body having a diameter, the two rollers come into contact with each other in a stepwise manner from both ends, so that even when the fixing roller is used as a guide, the impact on the surface of the fixing roller can be suppressed.

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

FIG. 1 is a schematic side view showing the structure of an image forming apparatus having a fixing unit according to an embodiment of the present invention. As shown in FIG. 1, the present image forming apparatus 100
A paper feed cassette 101 is provided at the bottom. The topmost recording paper is picked up by a pickup roller 103 from the recording paper bundle 102.
Is taken out of the sheet cassette 101. The recording paper taken out of the paper feed cassette 101 is transferred to a registration roller 104. A transfer unit 105 is provided in front of the registration roller 104.

The transfer unit 105 has a transfer film 106 on which images of four colors are superimposed. A process unit 108 is provided adjacent to the transfer unit 105. The process unit 108 includes four color process cartridges. An image of a color corresponding to the photoconductor 109 provided for each cartridge is formed. The four color images produced by the four color process cartridges are superimposed on the transfer film 106 at the same position. Transfer unit 1
In the step 05, the image formed on the transfer film 106 is transferred to the recording paper by the transfer roller 107. At this time, the position adjustment between the transfer film 106 and the leading end of the recording paper is controlled by the registration roller 104. The recording paper on which the image has been transferred is transferred from the transfer unit 105 to the fixing unit 110.
Passed to

The fixing unit 110 includes a main body 111 for performing a fixing process and a lid 112 that can be freely opened and closed. The fixing roller 113 and the pressure roller 1
14 are installed. The fixing roller 113 applies heat to the recording surface of the recording sheet, and the pressing roller 114 presses the recording sheet between the recording sheet and the fixing roller 113, whereby the image is fixed on the recording sheet.

The main body 111 includes a fixing roller 113.
Is detachably attached to the inner cover 115 that covers the cover from above. The inner cover 115 holds a cleaning roller 116 for removing the toner remaining on the fixing roller 113 and an oil application roller 117 for applying oil for improving the releasability of the toner remaining on the fixing roller 113. When the inner cover 115 is mounted on the main body 111, the peripheral surfaces of the cleaning roller 116 and the oil application roller 117 are in contact with the peripheral surface of the fixing roller 113. The inner cover 115 is attached to the main body 111
When the lid 112 is closed with the lid 112
Transport path 1 between the lower surface of the recording paper and the surface of the inner cover 115.
18 are formed. Discharge rollers 119 and 120 are provided at the end of the transport path 118.

FIG. 2 is a perspective view of the fixing unit 110 described above. FIG. 2 shows the inner cover 1 with the lid 112 opened.
15 shows a state in which 15 is taken out. In the fixing unit 110 shown in FIG. 2, the surface on which the lid 112 is attached is defined as a rear surface, and the opposite surface is defined as a front surface.

As shown in FIG. 2, on the surface of the inner cover 115, a first slope 2 which forms a part of the lower surface of the transport path 118 when the inner cover 115 is mounted on the main body 111.
01a and a second slope 201b are formed. A plurality of ribs 202 are provided over the first slope 201a and the second slope 201b. Rib 202
Is provided to reduce the friction between the surface of the inner cover 115 and the recording paper. The rib 202 is provided on the first slope 20.
The first rib 202a and the second slope 201 provided on the side 1a
and a second rib 202b provided on the b side. The first rib 202a has a triangular shape having a height for transporting the recording paper at a position slightly away from the surface of the inner cover 115. In addition, the second rib 202b is
In comparison with 2a, the recording paper has an arc shape having a height for conveying the recording paper near the surface of the inner cover 115.

The first slope 201a and the second slope 201b
Is fixed to the side surface 203 of the inner cover 115. A knob 204 is provided on the front side of the side surface 203. The knob portion 204 is a portion held by the user when the internal cover 115 is mounted on the main body portion 111. When the inner cover 115 is attached to the main body 111, the knob 204 is disposed in a space just above the fixing roller 113.

A predetermined space 205 is provided at a predetermined position on the rear surface side of the inner cover 115. This space 205 is provided to prevent contact between the blades of the shaft with blades, which are the detection targets of the detection sensors described later, and the inner cover 115.

A guide guide 206 is provided on the rear side of the side portion 203.
Is provided. The guide guide 206 is provided on the side surface 203.
Are provided substantially perpendicularly to. Information guide 206
Is composed of a pair of upper and lower shafts 206a and 206b.
The guide guide 206 attaches the inner cover 115 to the main body 111.
When installed in the main body 111, the entrance guide 207a and the end guide 207b provided at predetermined positions inside the main body 111.
Is used to position the inner cover 115 by contacting the inner cover 115. The structure for attaching and detaching the inner cover 115 will be described later.

On the other hand, the conveyance path 11
There are provided a plurality of ribs 208 forming the upper surface of 8. When the lid 112 is closed with the inner cover 115 attached to the main body 111, the plurality of ribs 208 are arranged at positions facing the first slope 201 a of the inner cover 115.

A guide plate 209 that forms a part of the lower surface of the conveyance path 118 at a position separated from the rear surface of the lid 112 by a predetermined distance.
Is provided. The guide plate 209 is attached to a fixed portion of the lid 112 and moves together with the lid 112. The guide plate 209 has a plurality of notches 20 at predetermined positions.
9a are formed. The inner cover 115 is attached to the main body 11
Each of the notches 209a is arranged so that the upper end of the second rib 202b enters the notch 209a when the lid 112 is closed in a state where the cover 112 is mounted on the first member.

The guide plate 209 has an opening 210 at a predetermined position. A bladed shaft 211 is arranged near the opening 210. The bladed shaft 211 has three blades 211a, 211b, 211
c is attached. The blade 211a is in the opening 2
The bladed shaft 211 is disposed so as to be inserted into the shaft 10. The bladed shaft 211 is
9 is rotatably attached to the fixed portion. A spring 212 is wound around the bladed shaft 211. The spring 212 applies a force to lightly bias the bladed shaft 211 in a predetermined direction when the lid 112 is closed.

A detection sensor 213 is provided at a predetermined position inside the main body 111. The detection sensor 213 includes a light emitting element and a light receiving element. When the lid 112 is closed with the inner cover 115 attached to the main body 111, the detection sensor 213 is provided at a position where the blade 211b of the shaft 211 with the blade is located at the detection position.

Next, the positional relationship of each part in the fixing unit 110 will be described with reference to a schematic sectional view of the fixing unit 110 when the inner cover 115 shown in FIG. In the fixing unit 110 shown in FIG.
The surface on which the discharge rollers 119 and 120 are arranged is defined as the rear surface of the fixing unit 110, and the surface on the opposite side is defined as the front surface. The same applies to the following drawings.

As shown in FIG. 3, in the lower surface of the fixing unit 110, an entrance 301 into which the recording paper on which the image has been transferred enters in the transfer unit 105 is provided.
The fixing roller 113 and the pressure roller 114 are arranged ahead of the entrance 301. The fixing roller 113 and the pressure roller 114 are in contact on the peripheral surface. The contact surface is located just above the entrance 301. The fixing roller 113 and the pressure roller 114 rotate in directions indicated by arrows A and B in FIG. 3, respectively.

The inner cover 115 is attached to the main body 111 such that the cleaning roller 116 and the oil application roller 117 come into contact with the cleaning roller 116 and the oil application roller 117 in the rotational direction from the contact surface with the pressure roller 114 along the peripheral surface of the fixing roller 113. Is done. The lower end of the first slope 201a of the inner cover 115 is
Slightly above the fixing roller 113, the fixing roller 1
13 is located slightly behind the contact surface between the pressure roller 114 and the pressure roller 13. A first rib 202a is formed from the lower end of the first slope 201a along the recording paper conveyance direction.

As shown, the first rib 202a has a triangular cross section, and has the highest apex 302 near the center of the first slope 201a. Vertex 3
Numeral 02 is provided at a position where the conveyance direction of the recording paper conveyed from the contact surface between the fixing roller 113 and the pressure roller 114 is maintained almost as it is. The second rib 202b is formed continuously at the rear end of the first rib 202a along the recording paper conveyance direction. The second rib 202b is a first rib 202
a at the position closest to the first slope 201a.
02a. The second rib 202b is formed so as to draw a gentle arc in the vicinity of the second slope 201b from the portion connected to the first rib 202a. Second
The upper end of the rib 202b enters a notch 209a provided in the guide plate 209, and is located slightly above the tip of the guide plate 209. The first inclined surface 201a, the second inclined surface 201b, and the guide plate 209 form the lower surface of the recording paper conveyance path 118.

The first slope 201a and the second slope 201b
The rib 208 is arranged at a position opposed to. This rib 2
08 forms the upper surface of the recording paper transport path 118. As shown, the transport path 118 is
Above b, it is largely bent in the direction of the discharge rollers 119 and 120. Hereinafter, a portion that is largely bent above the second rib 202b is referred to as a corner portion 118a. The transport path 118 regulates the transport of the recording paper by the first rib 202a and the second rib 202b. Therefore, the width of the transport path 118 becomes narrow near the apex portion 302 and becomes wide near the corner portion 118a.

Below the guide plate 209 and behind the inner cover 115, a bladed shaft 211 is disposed. The bladed shaft 211 is arranged such that the blades 211 a enter the opening 210 of the guide plate 209. The portion of the blade 211a that has entered the opening 210 protrudes from the lower surface of the transport path 118.

The blade 211b is provided on the opposite side of the blade 211a with respect to the axis of the shaft 211 having the blade.
The blade 211b is provided on the same plane as the blade 211a. Further, the blade 211b is provided at a position corresponding to the space 205 provided on the rear surface side of the inner cover 115. Therefore, the blade 211b is
Never touch.

The blade 211c is provided perpendicular to the blade 211a and the blade 211b with respect to the axis of the bladed shaft 211. The blade 211c is a blade 211a
And the blades 211 b are provided on the side surface of the fixing unit 110, and are not provided at positions corresponding to the spaces 205. The bladed shaft 211 is lightly urged by a spring 212 in the direction of arrow C in the figure. Therefore, when the inner cover 115 is attached, the blade 211c contacts the surface of the inner cover 115. That is, the blade 21
1c regulates rotation of the bladed shaft 211 when the inner cover 115 is attached. FIG. 3 illustrates a case where the blade 211c contacts the surface of the inner cover 115.

The detection sensor 213 is arranged so as to sandwich the position where the blade 211b is disposed when the blade 211c contacts the surface of the inner cover 115. The detection sensor 213 detects that the inner cover 115 is attached to the fixing unit 110 when the blade 211b is located at the detection position.

After the inner cover 115 is mounted on the fixing unit 110, if the blade 211b is shifted from the detection position, the detection sensor 213 detects that the recording paper has been discharged. That is, when the recording paper comes into contact with the blade 211 a protruding into the transport path 118, the blade 211 a
a rotates in the direction of arrow D in FIG. In response, the blade 211b moves from the detection position of the detection sensor 213.
When the recording paper is discharged, the blade 211b
Returns to the detection position, the detection sensor 213 detects that the recording paper has been discharged.

That is, the detection sensor 213 detects both the presence or absence of the inner cover 115 and the discharge of the recording paper. Therefore, there is no need to separately provide a sensor for detecting whether or not the inner cover 115 is attached and a sensor for detecting whether or not recording paper is discharged. Thereby, an increase in the number of parts can be prevented. As a result, cost can be reduced.

As described above, according to the fixing unit 110, the inner cover 115 is attached to the position that covers the fixing roller 113 inside the lid 112 that can be freely opened and closed. Then, the first slope 20 formed on the inner cover 115 is formed.
A recording paper transport path 118 is formed by the upper surfaces of the first and second slopes 201b and the lower surface of the lid 112. Therefore,
If a paper jam occurs in the transport path 118, it is possible to easily cope with the jam by opening the lid 112.

Further, since the fixing roller 113 having a high temperature is covered by the internal cover 115, even when the lid 112 of the fixing unit 110 is opened, the fixing roller 113 is not immediately exposed. Thereby, the user can be reliably protected.

Further, a function as a conveyance path for guiding the recording paper from the fixing roller 113 to the discharge rollers 119 and 120 on the surface of the inner cover 115, a function to cover the fixing roller 113, and an oil application roller 117 to the fixing roller 113. By providing three functions of applying oil to the surface of the fixing roller 113 by contacting the surface, the fixing unit 110 can be made more compact.

The inner cover 115 is configured to be detachable from the fixing unit 110. Therefore, by removing the inner cover 115, the oil application roller 117 and the like held by the inner cover 115 can be easily replaced. Further, the main fixing unit 110
In the case where the inner cover 115 is not attached to the fixing unit 110, the blade 211c
Do not touch the surface of For this reason, the blade 211b is
As shown in (2), it moves to a position shifted from the detection position of the detection sensor 213. At this time, the detection sensor 213 detects that the inner cover 115 is not attached to the fixing unit 110, and notifies the control unit of the image forming apparatus of that fact. Upon receiving this notification, the control unit controls the image forming apparatus so that the fixing operation cannot be performed. Thus, it is possible to prevent the fixing process from being performed when the inner cover 115 is not attached.

Further, by holding the oil application roller 117 inside the inner cover 115 so that the oil application roller 117 is disposed between the discharge rollers 119 and 120 and the fixing roller 113, the discharge rollers 119 and 120
And the inner cover 115 can be arranged closer to each other, so that the discharge of the recording paper and the attachment of the inner cover 115 can be detected by one sensor without increasing the size of the bladed shaft 211.

Next, the action of the apex portion 302 and the corner portion 118a provided on the inner cover 115 on the recording paper will be described in detail with reference to FIG.

As shown in FIG. 5, the recording paper fed from the contact surface between the fixing roller 113 and the pressure roller 114 passes above the vertex 302 of the first rib 202a. At this time, the apex portion 302 is provided at a position where the conveying direction of the recording paper fed from between the fixing roller 113 and the pressure roller 114 is maintained substantially as it is. Therefore,
The recording paper is transported almost straight from the contact surface between the fixing roller 113 and the pressure roller 114.

In the fixing unit 110, the oil applying roller 117 is brought into contact with the fixing roller 113 to apply oil, thereby enhancing the releasability of the toner attached to the fixing roller 113. This oil application roller 1
When the replacement time of 17 is approaching, the amount of oil applied to the fixing roller 113 decreases. For this reason, the fixing roller 113
Toner tends to remain on the surface. When the toner remains on the fixing roller 113, the fixing roller 113 and the pressure roller 11
4, a phenomenon occurs in which the recording paper that has passed between the fixing rollers 4 and 4 adheres to the fixing roller 113.

When the phenomenon that the recording paper sticks to the fixing roller 113 occurs, if the apex 302 is not provided on the inner cover 115 as in the fixing unit 110, FIG.
As shown in (2), the leading end of the inner cover comes into contact with the recording surface of the recording paper at an acute angle, and acts to peel off the recording paper from the fixing roller 113. In this case, the tip of the inner cover 115 functions as a blade for scraping off the toner adhering to the recording paper, so that the toner accumulates at the tip of the inner cover 115. FIG. 7 is an enlarged view of a case where toner is accumulated at the tip of the inner cover 115. It is not preferable that the recording paper is conveyed in a state where the toner is accumulated at the leading end of the inner cover 115 because the toner stains the recording paper.

In the present embodiment, the vertex 302 is provided at a position where the conveying direction of the recording paper conveyed from the contact surface between the fixing roller 113 and the pressure roller 114 is maintained substantially as it is, so that the vertex 302 is Fixing roller 113 for recording paper
It works to push up in the direction away from This can prevent the tip of the inner cover 115 from contacting the recording surface of the recording paper at an acute angle, and prevent the recording paper from being stained with toner.

Further, the apex 302 is fixed to the fixing roller 113.
If the recording paper transported from the contact surface of the recording paper and the pressure roller 114 is provided at a position where the transport direction of the recording paper is substantially maintained as it is, the leading end of the recording paper can be prevented from fluttering up and down on the transport path. There is also an advantage that the flow of the paper becomes smooth and the occurrence of paper jam can be suppressed.

On the other hand, the recording paper conveyed by the apex portion 302 so as to maintain the conveyance direction of the recording paper substantially as it is, the conveyance direction thereof is substantially 9 by the corner portion 118a.
It is bent toward the discharge side at an angle close to 0 degrees.

It is extremely important to bend the recording paper conveyance path at an angle close to 90 degrees in the fixing unit 110 in order to reduce the size of the entire apparatus. However, on the other hand, the probability of occurrence of paper jam increases at the corner portion 118a where the transport path is bent by nearly 90 degrees. As shown in FIG. 8, if the width of the corner portion 118a is reduced before the recording paper conveyance path is completely bent, paper jam is likely to occur at that portion.

In the present embodiment, the width of the corner portion 118a is made sufficiently wide until the recording paper conveyance path is completely bent, so that the recording paper passing through the corner portion 118a changes the conveyance direction gently. can do. For this reason, it is possible to prevent the recording paper from being caught on the upper surface of the transport path 118, and to prevent paper jam.

Next, the inner cover 1 is fixed to the fixing unit 110.
The operation when the camera 15 is mounted will be described. FIGS. 9 and 10 show the main cover 1 and the inner cover 1 respectively.
15A and 15B are a top view and a side view before mounting 15;

The above-mentioned guide 206 is used for the inner cover 11.
5 and is provided along the rear surface. The oil application roller 117 is attached to a lower portion of the inner cover 115 and slightly to the rear from the center. The oil application roller 117 is urged to the front side by a spring (not shown). Further, the cleaning roller 116 is attached to an intermediate portion of the inner cover 115 and slightly closer to the front surface than the oil application roller 117. Further, the knob 204 is provided above the cleaning roller 116 and at a position closer to the front than the cleaning roller 116 so as to protrude toward the front.

On the other hand, the side portion 20 of the inner cover 115
A pair of upper and lower entrance guides 207a and end guides 207b are provided on the inner surface of the side wall of the fixing unit 110 facing the third unit 3. Inlet guide 207a and end guide 2
07b is vertically separated at a predetermined interval. Inlet guide 207a and end guide 207b
Is just the width of the shafts 206a, 20
The width is set to accommodate 6b. Entrance guide 2
07a has a shape whose upper end is opened outward so that the guide 206 can be easily inserted. End guide 207b
Is tapered at the upper end so that the guide 206 can be easily inserted. The lower end of the end guide 207b is
The guide 206 has an arc shape that receives the shaft 206b.

When the inner cover 115 is mounted on the fixing unit 110, the lid 112 is set upright on the rear side of the fixing unit 110 as shown in FIG. Lid 112
Is opened, the interior of the fixing unit 110 is exposed, and an entrance guide 207a appears on the inner surface of the side wall of the unit. Therefore, the user can attach the inner cover 115 to the fixing unit 110 without being obstructed by the lid 112.
Can be attached to

The user operates the knob 2 of the inner cover 115.
When the inner cover 115 is lifted while holding the inner cover 115, the guide guide 20 is moved by the weight of the oil application roller 117 attached to the rear side of the center of the inner cover 115.
The entire inner cover is tilted so that 6 is substantially the same as the opening angle of the upper end of the entrance guide 207a and tilts in the same direction.

FIG. 11 shows a state immediately before the inner cover 115 is mounted on the fixing unit 110. When attaching the inner cover 115 to the fixing unit 110, first, the user operates the inner cover 1 so that the shaft 206b of the guide guide 206 enters the entrance guide 207a.
15 is moved inside the fixing unit 110.

FIG. 12 shows a state where the shaft 206b of the guide 206 has entered the entrance guide 207a. As shown in FIG. 12, the inner cover 115 enters the entrance guide 207a in an inclined state. Thereafter, the user further moves the inner cover 115 into the fixing unit 110. Also in this case, the inner cover 115 moves inside the fixing unit 110 in an inclined state. At this time, the entrance guide 207a and the end guide 207b are provided at positions separated by a predetermined distance. For this reason, the guide 206 can smoothly enter even when the inner cover 115 is inclined. And the inner cover 1
When 15 moves to a predetermined position, oil application roller 117 held by internal cover 115 contacts fixing roller 113.

FIG. 13 shows a state where the oil application roller 117 is in contact with the fixing roller 113. FIG.
As shown in FIG. 3, the oil application roller 117 is in contact with the fixing roller 113 in a state where the inner cover 115 is inclined. At this time, the shaft 206b of the guide guide 206 is disposed slightly above the end guide 207b and on the front side of the fixing unit 110.

The oil application roller 117 is
3, the oil application roller 117 is pushed into the inner cover 115, rotates in the direction of arrow A in the figure, and the fixing roller 113 rotates in the direction of arrow B in the figure. The oil application roller 117 and the fixing roller 11
By the rotation of 3, the shaft 206b of the guide 206 moves to the rear side of the fixing unit 110. Then, the shaft 206b of the guide part guide 206 enters into the end part guide 207b. At the same time, the inner cover 115 moves downward. As the inner cover 115 moves downward, the shaft 206a of the guide
07a.

That is, the oil application roller 117 contacts the fixing roller 113 with the inner cover 115 inclined. Then, the rotation of the oil application roller 117 and the fixing roller 113 guides the inner cover 115 to the end guide 207b. Therefore, the inner cover 1
The internal cover 115 can be attached to the fixing unit 110 by utilizing the rotation of the existing roller without separately providing a member or the like for correcting the inclination of the fixing unit 15. Thus, the internal cover 115 can be mounted inside the fixing unit 110 with an inexpensive configuration.

When the inner cover 115 is mounted inside the fixing unit 110 by the rotation of the oil application roller 117 and the fixing roller 113, the inner cover 11
Reference numeral 5 rotates with the rotation of the oil application roller 117 and the fixing roller 113 around a portion where the guide guide 206 and the entrance guide 207a are in contact with each other. Accordingly, it is possible to prevent a load when the inner cover 115 is attached from being applied to the guide. Therefore, it is possible to prevent the guide from being damaged or the like in the work of attaching the inner cover 115.

FIGS. 14 and 15 show the inner cover 1 respectively.
15 is a side view when 15 is mounted on the fixing unit 110;
It is a top view. As shown in FIGS. 14 and 15, when the inner cover 115 is mounted on the fixing unit 110, the knob 204 is disposed in a space formed above the fixing roller 113. The user holds the knob 204 and performs the work of mounting the inner cover 115.

On the other hand, when the knob 204 is provided and the inner cover 115 is not attached to the fixing unit 110 while holding the knob 204 as in the main fixing unit 110, the following problem occurs.

That is, when such an inner cover 115 is mounted on the fixing unit 110, the inner cover 115
The fixing unit 110 is held by hand.
It is necessary to attach to. Around the fixing roller 113,
Various members such as the discharge rollers 119 and 120 and the detection sensor 213 are arranged. Therefore, the inner cover 115
When the entire structure of the fixing roller 11 is held by hand,
The finger comes into contact with a member around 3. This causes a problem that the mounting work of the inner cover 115 is hindered.

The fixing roller 113 is heated to about 180 ° C. when the fixing process is performed. Therefore, the oil application roller 11 arranged in contact with the fixing roller 113
The heat is also transmitted to 7 and the inner cover 115. Therefore, the temperature of the oil application roller 117 and the inner cover 115 also becomes high. For this reason, in a case where the entire inner cover 115 is held by hand, it is necessary to wait for a while until the heat cools down when attaching and detaching the inner cover 115. This causes a problem that the attachment / detachment work of the inner cover 115 cannot be performed immediately.

Further, when the inner cover 115 is mounted, it cannot be mounted unless it is aligned with a predetermined position of a guide provided on the fixing unit 110 side. Therefore,
The user needs to hold the entire inner cover 115 by hand and align it with a predetermined position of the guide. For this reason,
There is a problem that the mounting work of the inner cover 115 becomes complicated.

For this reason, in this embodiment, the knob 204 is provided in a space formed above the fixing roller 113,
By holding the knob 204, the work of mounting the inner cover 115 is performed.

The knob 204 is provided in a space formed above the fixing roller 113. In other words, the knob portion 204 is provided in a space separated from the main body of the inner cover 115 and not in contact with a member that transmits heat of the fixing roller 113. Therefore, the fixing unit 110
It is possible to prevent the other members inside from hindering the mounting work of the inner cover 115. Thereby, the mounting work of the inner cover 115 can be performed smoothly. The heat generated by the fixing roller 113 is transmitted to the knob 20.
4, it is possible to prevent the heat of the fixing roller 113 from hindering the attachment / detachment work of the inner cover 115.

Further, the fixing unit 110 of the present embodiment
Now, the oil application roller 117 and the fixing roller 113
The material is not particularly limited. However, when the oil application roller 117 and the fixing roller 113 are made of an elastic material, when the oil application roller 117 and the fixing roller 113 come into contact with each other, both rollers act as cushions. Therefore, it is possible to prevent the members in the fixing unit 110 from being damaged by the contact between the oil application roller 117 and the fixing roller 113. Thus, the user can stably perform the work of attaching the inner cover 115.

As shown in FIG. 16, an elastic flange 1601 having a diameter larger than the diameter of the oil application roller 117 may be provided at both ends of the oil application roller 117. When such a change is made, the inner cover 115
Is mounted on the fixing unit 110, the fixing roller 113
First, the elastic flange 1601 comes into contact. Then, the oil application roller 117 is fixed to the fixing roller 11.
Touch 3. Therefore, even when the fixing roller 113 is used as a guide for the inner cover 115, the impact on the surface of the fixing roller 113 can be minimized.

[0094]

As described above, according to the present invention,
The fixing unit is configured to be freely opened and closed. Even when the fixing unit is opened, the fixing roller is covered, and an internal cover that forms a part of the recording paper conveyance path is provided on the surface, so that the high-temperature portion in the fixing unit can be easily exposed without being directly exposed. It is possible to provide an image forming apparatus that allows a user to safely and easily remove a paper jam by opening a transport path of a unit.

[Brief description of the drawings]

FIG. 1 is a schematic side view illustrating a configuration of an image forming apparatus including a fixing unit according to an embodiment of the present disclosure.

FIG. 2 is a perspective view of a fixing unit according to the embodiment.

FIG. 3 illustrates a fixing unit according to the embodiment.
Schematic sectional view when the inner cover is attached

FIG. 4 illustrates a fixing unit according to the embodiment.
Schematic sectional view when the inner cover is not attached

FIG. 5 is a schematic cross-sectional view when a recording sheet conveys the fixing unit according to the embodiment.

FIG. 6 is a schematic cross-sectional view of the fixing unit when an internal cover provided with a rib having no apex is mounted.

FIG. 7 is an enlarged view of a tip portion of an inner cover provided with a rib having no apex.

FIG. 8 is a schematic cross-sectional view of the fixing unit when an internal cover provided with a rib having no apex is mounted.

FIG. 9 illustrates a fixing unit according to the embodiment.
Top view before mounting the inner cover

FIG. 10 is a side view of the fixing unit according to the embodiment before an inner cover is attached.

FIG. 11 is a side view showing a state of the mounting operation of the inner cover in the fixing unit according to the embodiment.

FIG. 12 is a side view showing a state of mounting work of the inner cover in the fixing unit according to the embodiment.

FIG. 13 is a side view showing a state of the mounting operation of the inner cover in the fixing unit according to the embodiment.

FIG. 14 is a side view of the fixing unit according to the embodiment when an internal cover is attached.

FIG. 15 is a top view of the fixing unit according to the embodiment when an internal cover is attached.

FIG. 16 is a top view of the fixing unit according to the embodiment, in which an oil application roller held by an internal cover is provided with an elastic flange.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 Image forming apparatus 105 Transfer unit 108 Process unit 110 Fixing unit 111 Main unit 112 Cover 113 Fixing roller 114 Pressure roller 115 Inner cover 116 Cleaning roller 117 Oil application roller 118 Conveyance path 119, 120 Discharge roller 201a First slope 201b First 2 slope 202a first rib 202b second rib 203 side surface 204 knob 205 space 206 guide 207a entrance guide 207b end guide 208 rib 209 guide plate 210 opening 211 bladed shaft 212 spring 213 detection sensor

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Hiroyoshi Miyoshi 2-3-8 Shimomeguro, Meguro-ku, Tokyo Matsushita Electric Transmission System Co., Ltd. F-term (reference) 2H033 AA37 BA03 BA06 BA10 BA43 BA44 CA01 CA22 CA38 2H071 AA02 AA17 BA13 BA17 BA43 DA12 DA24 DA32 2H072 BA03 BA17 BA20 CA01 CB02 CB08 EA16 3F049 AA04 DA12 DA19 LA01 LB03

Claims (13)

[Claims] A fixing unit that has a cover that can be opened and closed and that exposes a conveyance path of a recording sheet from a fixing roller to a discharge roller when the cover is opened; and a fixing unit that is provided inside the fixing unit. An image forming apparatus, comprising: an inner cover that forms a conveyance path and covers the fixing roller on the inside. 2. A fixing unit having an openable and closable lid and exposing a conveyance path of a recording sheet from a fixing roller to a discharge roller when the lid is opened, and a fixing unit detachably provided inside the fixing unit. An image forming apparatus, comprising: an inner cover that forms the transport path on the outside, covers the fixing roller on the inside, and holds an oil application roller that applies oil to the fixing roller. 3. The conveyance direction of the recording paper passing between the fixing roller and the pressure roller is changed in a direction substantially perpendicular to the discharge side between the inner surface of the lid and the outer side of the inner cover. The corner portion is formed, and a protruding portion that pushes up the recording paper in a direction away from the fixing roller is formed outside the internal cover and near the fixing roller. Image forming apparatus. 4. The image according to claim 3, wherein the projecting portion has a vertex at a position where the conveying direction of the recording paper passing between the fixing roller and the pressure roller is maintained substantially as it is. Forming equipment. 5. A space width of a region of the corner portion extending from a protrusion to a corner exit is larger than a space width near a vertex of the protrusion. The image forming apparatus as described in the above. 6. A fixing unit having an openable and closable lid and exposing a recording paper conveyance path from a fixing roller to a discharge roller when the lid is opened, and a fixing unit detachably provided inside the fixing unit. An inner cover that forms the transport path on the outside, covers the fixing roller on the inside, and holds an oil application roller that applies oil to the fixing roller, and detects attachment of the internal cover when the lid is closed. An image forming apparatus comprising: a sensor; and a control unit that does not perform a fixing operation when the sensor does not detect the attachment of the internal cover. 7. A fixing unit having an openable and closable lid and exposing a recording paper conveyance path from a fixing roller to a discharge roller when the lid is opened, and a fixing unit detachably provided inside the fixing unit. An inner cover that forms the transport path on the outside, covers the fixing roller on the inside, and holds an oil application roller that applies oil to the fixing roller; and is disposed near the discharge roller to detect discharge of the recording paper. And a sensor for detecting attachment of the inner cover. 8. The image forming apparatus according to claim 2, wherein the internal cover holds an oil application roller disposed between a fixing roller and a discharge roller. 9. A fixing unit having a lid that can be opened and closed, and a fixing unit that exposes a conveyance path of a recording sheet from a fixing roller to a discharge roller when the lid is opened, and is detachably provided inside the fixing unit. An inner cover that forms the transport path on the outside, covers the fixing roller on the inside, and holds an oil application roller that applies oil to the fixing roller; and a space provided in the internal cover and formed above the fixing roller. An image forming apparatus comprising: 10. The fixing unit includes a pair of upper and lower guides for guiding the inner cover to a mounting position, wherein the inner cover is configured so that the oil application roller contacts the fixing roller. 10. The image according to claim 9, wherein the oil application roller is guided by a guide, rotates along with the fixing roller to the lower guide position, and is guided to the mounting position by the lower guide. Forming equipment. 11. The internal cover includes a pair of upper sides,
A guide that is guided to a mounting position by a lower guide; a tip of the guide is guided by the upper guide to a position where the oil application roller and the fixing roller come into contact with each other; The tip of the guide guide moves to the position of the lower guide by rotating with the roller, the guide guide is guided by the lower guide, and the internal cover is guided to the mounting position. The image forming apparatus according to claim 10. 12. The apparatus according to claim 10, wherein the fixing roller and the oil application roller are made of an elastic material.
An image forming apparatus according to claim 11. 13. The image forming apparatus according to claim 10, wherein the oil application roller has an elastic flange having a diameter larger than a diameter of the oil application roller at both ends.