JP2019056811A - Image forming apparatus and fixing device - Google Patents

Abstract

To provide an image forming apparatus and a fixing device that can control air from air blowing means to hit the outside of an area opposite to a recording material at both ends in the longitudinal direction of a fixing member, according to the deviation amount in the width direction of the recording material, regardless of the size of the recording material.SOLUTION: An image forming apparatus comprises: first and second fixing members that form a nip part; air blowing means that, when a recording material is a second size smaller than a first size, cools first and second ends in the longitudinal direction of at least one of the first and second fixing members; shielding members that can change the widths of openings through which air directed respectively to the first and second ends passes; detection means that detects a deviation amount in the width direction of the recording material; and a control unit that controls the widths of the openings respectively for the first and second ends to be different sizes in the longitudinal direction so that the air from the air blowing means hits the outside of an area opposite to the recording material, on the basis of an output from the detection means and the second size.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image forming apparatus and a fixing device including an air blowing unit that suppresses temperature rise of a non-sheet passing portion.

  In recent years, copying machines and printers using an electrophotographic system are used not only for large offices but also for various users in a wide range of markets such as small offices and personal use. For this reason, recording materials used in copying machines and printers are used not only in types but also in various sizes.

  Here, when a recording material (small size paper) having a width smaller than the maximum size paper having the maximum width that can be passed through the copying machine or the printer is continuously passed, so-called non-sheet passing portion temperature rise occurs. That is, the temperature rise in the portion that does not pass increases due to the difference in heat consumption between the portion through which the recording material passes and the portion that does not pass in the fixing device.

  In order to solve this phenomenon, there is provided a fixing device that cools the non-sheet passing portion by providing air blowing ports (openings) through which cooling air from the cooling fan blows in the non-sheet passing portions at both ends in the longitudinal direction of the fixing member in the fixing device. Proposed. There has also been proposed a fixing device in which the width direction (opening width) of the blower port is variable so as to be compatible with various sizes of the recording material in the width direction.

  The fixing device of Patent Document 1 detects a temperature rise at the boundary between the non-sheet passing portion and the sheet passing portion in addition to a shutter that adjusts the width (opening width) of the air blowing port according to the width of the recording material to be used. In addition, a temperature detection means is installed in the shutter, and the cooling fan is turned ON / OFF according to the detected temperature.

  Further, the image forming apparatus disclosed in Patent Document 2 detects the offset of the recording material and opens and closes the shutter. In other words, a configuration is shown in which the displacement direction of the recording material width center of the recording material is detected and the cooling air is blown to the side where the non-sheet passing portion region is enlarged.

JP 2008-032903 A JP 2012-252194 A

  However, the configuration of Patent Document 1 is a configuration in which both end portions which are non-sheet passing portions are cooled in accordance with the detection result of the size of the recording material to be printed in the width direction. Therefore, when the recording material is displaced in the width direction, the center of the recording material in the width direction is displaced from the ideal position when the recording material is not displaced in the width direction. For this reason, one of the longitudinal end portions of the fixing member (the same side as the direction in which the recording material is displaced in the width direction of the recording material) also receives cooling air in the region through which the recording material passes. The other of the both ends in the longitudinal direction of the fixing member (the side opposite to the direction in which the recording material is displaced in the width direction of the recording material) cannot apply cooling air to the entire non-sheet passing portion in the longitudinal direction.

  For this reason, the temperature of the fixing nip portion through which the recording material passes is not uniform in the longitudinal direction, and the temperature of the portion hit by the cooling air is lowered. As a result, there arises a new problem that the fixing property is lowered in the portion where the cooling air is applied. At this time, a method of enlarging the interval between the recording materials (recording material conveyance interval) in anticipation of a decrease in the fixing property, or a method of waiting for the fixing device to rise by slowing down the recording material conveyance speed itself can be considered. There is a problem that productivity per unit time is lowered.

  Further, Patent Document 2 does not disclose the detection of the shift amount even if the shift direction is detected in the width direction of the recording material. And matching the aperture width is not disclosed. That is, in the configuration of Patent Document 2, the opening width cannot be controlled in accordance with the amount of displacement in the width direction of the recording material. There remains an improvement to allow the wind from the means to hit (match the non-sheet passing width and the opening width).

  An object of the present invention is that, for various recording material sizes, depending on the amount of displacement in the width direction of the recording material, the wind from the blower means is outside the region facing the recording material at both ends in the longitudinal direction of the fixing member. An object of the present invention is to provide an image forming apparatus and a fixing device that can make contact with each other.

  In order to achieve the above object, an image forming apparatus according to the present invention includes an image forming unit that forms a toner image on a recording material, and a nip unit that fixes the toner image by nipping and conveying the recording material in the recording material conveying direction. When the width direction orthogonal to the recording material conveyance direction of the recording material is a second size smaller than the first size, the first and second fixing members Air blowing means for blowing air for cooling the first and second end portions in the longitudinal direction perpendicular to the recording material conveyance direction in at least one of the members, and wind for each of the first and second end portions In the longitudinal direction based on the shielding member capable of changing the width of the opening through which the recording medium passes, the detecting means for detecting the shift amount in the width direction of the recording material, the output of the detecting means and the second size A control unit for controlling the width of the opening with respect to each of the first and second end portions to have different sizes in the longitudinal direction so that the wind from the blower unit hits the outside of the region facing the recording material; It is characterized by having.

  The fixing device according to the present invention includes a first and second fixing members that form a nip portion for fixing a toner image by nipping and conveying a recording material in the recording material conveyance direction, and the recording material conveyance in the recording material. When the width direction perpendicular to the direction is a second size smaller than the first size, the first and second longitudinal directions perpendicular to the recording material conveyance direction in at least one of the first and second fixing members. A blowing means for blowing wind for cooling the end of the recording medium, a shielding member capable of changing the width of the opening through which the wind passes to each of the first and second ends, and the width direction of the recording material Based on the detection means for detecting the amount of deviation in the recording medium, the output of the detection means and the second size, the air from the blower means strikes the outside of the region facing the recording material in the longitudinal direction. Characterized and a control unit for controlling the different sizes in the second of said longitudinal width of said opening with respect to each of the ends, to have a.

  According to the present invention, for various recording material sizes, the wind from the blower means is generated outside the region facing the recording material at both ends in the longitudinal direction of the fixing member in accordance with the shift amount in the width direction of the recording material. You can make it hit.

1 is a longitudinal sectional view showing an overall configuration of a full-color laser beam printer as an image forming apparatus according to an embodiment of the present invention. The perspective view of the shielding unit 110 of 1st Embodiment. Shield member F111 and shield member R 112 according to the first embodiment Side view of the shielding frame 116 of the first embodiment. Operational state diagram of shielding unit 110 of the first embodiment The perspective view of the shielding unit 110 of 2nd Embodiment. External view of shielding member F111 of the second embodiment Operational state diagram of the shielding unit 110 of the second embodiment (when the recording material is not displaced in the width direction) Operational state diagram of the shielding unit 110 of the second embodiment (when the recording material is displaced to the R side in the width direction) Operational state diagram of the shielding unit 110 of the second embodiment (when the recording material is shifted to the F side in the width direction) Explanatory drawing of the detection means (paper position detection means) which detects the deviation | shift amount of the width direction of a recording material

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

<< First Embodiment >>
(Image forming device)
First, the overall configuration of the image forming apparatus 1 will be outlined with reference to FIG. FIG. 1 is a longitudinal sectional view showing an overall configuration of a full-color laser beam printer which is an aspect of the image forming apparatus according to the present embodiment.

  In the image forming apparatus 1 shown in FIG. 1, a cassette paper feeding unit 80 is disposed at the bottom and a manual paper feeding unit 70 is disposed on the right side. The cassette paper feed means 80 is provided with paper position detection means (detailed later with respect to FIG. 11) capable of detecting both end positions (both end positions) in a direction (width direction) orthogonal to the conveyance direction of the recording material P. Yes. A registration roller 51 and a registration counter roller 52 that align and convey the leading end position of the recording material P are disposed above the cassette sheet feeding unit 80.

  Similarly, a laser scanner unit 30 for forming an electrostatic latent image on a photosensitive member as an image carrier is provided above the cassette paper feeding means 80. A scanner frame 31 is disposed immediately above the laser scanner unit 30, and the laser scanner unit 30 is fixed to the scanner frame 31.

  Above the scanner frame 31, four process cartridges 10 (10Y, 10M, 10C, 10Bk) are arranged. The intermediate transfer unit 40 is disposed above the process cartridge 10 (10Y, 10M, 10C, 10Bk) so as to face the process cartridge 10 (10Y, 10M, 10C, 10Bk). The intermediate transfer unit 40 includes an intermediate transfer belt 41. A primary transfer roller 42 (42Y, 42M, 42C, 42Bk), a drive roller 43, a secondary transfer counter roller 44, and a tension roller 45 are provided inside the intermediate transfer belt 41, and a cleaning unit 46 is provided outside. Yes.

  A secondary transfer unit 90 is arranged on the right side of the intermediate transfer unit 40. The secondary transfer unit 90 includes a secondary transfer roller 91 as a part of the image forming unit so as to face the secondary transfer counter roller 44. Here, the primary transfer roller 42 (42Y, 42M, 42C, 42Bk), the intermediate transfer belt 41, and the secondary transfer roller 91 constitute an image forming unit.

  The fixing unit 20 is disposed above the intermediate transfer unit 40 and the secondary transfer unit 90. Inside the fixing unit 20, a heating roller (first fixing member) 21 that heats the recording material P and the recording material P are pressed against the heating roller 21 so as to form a nip portion that sandwiches and conveys the recording material. A pressure roller (second fixing member) 22 is provided.

  On the left side of the fixing unit 20, a cooling unit 100 including a cooling fan 101 that cools both ends of the heating roller 21 and a shielding unit 110 that can change the cooling unit of the heating roller 21 are disposed. The shielding unit 110 is a fixing unit. 20 is arranged in the vicinity.

  A paper discharge unit 60 is disposed in the upper left part of the fixing unit 20. The paper discharge unit 60 includes a paper discharge roller pair 61, a double-sided conveyance unit 62, a reverse roller pair 63, and a double-sided flapper 64 that is a branching unit. The image forming control unit 2 collectively controls the image forming operation of the image forming apparatus 1.

(Printing operation)
As shown in FIG. 1, when print data including a print command and image information is input to the image formation control unit 2 from a host computer (not shown), the image formation control unit 2 Instruct each device to start the printing operation. In the recording material P, the width position of the recording material P is detected by a paper position detecting means (described in detail later with reference to FIG. 11), and the cassette paper feeding means is fed by a feed roller 81, a paper feed transport roller 82, and a paper feed transport corresponding roller 83. Supplied from 80 and sent to the conveyance path.

  The recording material P faces the registration roller 51 and the registration roller before the secondary transfer roller 91 in order to synchronize the forming operation of the image formed on the intermediate transfer belt 41 and the conveyance timing when the first image is formed. It stops once in a state of being held between the rollers 52. Then, it is transported after waiting until image formation is performed, but the second and subsequent sheets are transported continuously without being temporarily stopped.

  In synchronism with the operation of feeding the recording material P, each color developer image developed by the process cartridge (10Y, 10M, 10C, 10Bk) is sequentially transferred to the intermediate transfer belt 41. The developer image (color image) developed in multiple on the intermediate transfer belt 41 moves together with the intermediate transfer belt 41 to the secondary transfer counter roller 44. Then, the recording material P once stopped starts to be conveyed by the rotation of the registration roller 51 and the registration counter roller 52 and enters the nip portion between the secondary transfer roller 91 and the intermediate transfer belt 41 in accordance with the developer image. The secondary transfer is performed on the recording material P.

  The color image transferred to the recording material P is melted and fixed on the recording material P by being heated and pressed by a fixing unit 20 including a fixing roller. The recording material P after fixing is discharged to the paper discharge tray 65 by the paper discharge roller pair 61, and the normal color image forming operation is finished.

  Further, a cleaning unit 46 is provided on the intermediate transfer belt 41, and the developer remaining on the intermediate transfer belt is scraped off by a cleaning member such as a cleaning blade installed therein for the next image formation. Prepare.

(Detection of displacement in the width direction of the recording material)
Hereinafter, detection of the shift amount in the width direction of the recording material by the paper position detection unit in the present embodiment will be described. In FIG. 11A, in order to detect the positions of both ends of the recording material P (width size W) in the width direction orthogonal to the recording material conveyance direction, LED arrays Q (Q1, Q1, Q2) A one-dimensional image sensor R (R1, R2) is arranged. A lens L shown in FIG. 11B is provided below the one-dimensional imaging devices R1 and R2 in FIG.

  The light quantity distribution in the width direction of the recording material received by the one-dimensional image sensor R is a position where the light quantity when reflected from the recording material P deviates from the recording material (recording on the recording material grounding surface or recording material conveying surface). The amount of light is larger than the amount of light reflected from a position off the material. Thus, the positions of both end portions in the width direction of the recording material can be detected from the difference in light quantity.

  Here, the ideal positions of both ends in the width direction of the recording material when there is no deviation in the width direction of the recording material are stored in the apparatus together with the values of the respective sizes in advance according to the respective sizes of the recording material P. . Accordingly, when a deviation occurs in the width direction of the recording material, the deviation amount from the ideal position is detected.

  The detecting means for detecting the amount of deviation in the width direction of the recording material is provided inside the cassette paper feeding means 80 (FIG. 1) so as to face the recording material installation surface, or the fixing unit 20 (FIG. 1). ) To the recording material conveyance surface of the recording material conveyance path. It is more preferable that the area of the recording material installation surface or the recording material conveyance surface that is out of the recording material is black because the difference in the amount of light is large and the positions of both ends in the width direction of the recording material are easily detected.

  The detection of the shift amount in the width direction of the recording material may be a transmission type instead of the reflection type in which the LED array Q (Q1, Q2) and the one-dimensional imaging element R (R1, R2) are on the same side with respect to the recording material. . That is, the LED array Q (Q1, Q2) and the one-dimensional imaging element R (R1, R2) may be on the opposite side with respect to the recording material.

(Configuration of cooling unit and shielding unit)
As shown in FIG. 1, the cooling unit 100 includes a cooling fan 101. The cooling fan 101 sucks outside air into the image forming apparatus 1 and blows outside air into the duct 102. The blown outside air is sent to the shielding unit 110.

  2A is a perspective view of the shielding unit 110 viewed from above the cooling fan 101 side, and FIG. 2B is a perspective view of the shielding unit 110 viewed from above the fixing unit 20. In the following description, the F side given to the head of each member is a member provided on the front side of the apparatus, and the R side is a member provided on the rear side of the apparatus.

  2A and 2B, the shielding unit 110 includes a shielding frame 116. The shielding frame 116 includes an F-side drive motor 115 including an F-side pinion 115a and an R-side pinion 117a. An R drive motor 117 is held as the driven source. The shielding frame 116 is provided with an intake port 116 a for receiving outside air sent from the duct 102 and exhaust ports 116 b and 116 c as openings for applying the outside air to the heating roller 21.

  A shielding member 111 capable of changing the width of the opening with respect to the first end in the longitudinal direction of the fixing member is attached to the shielding frame 116. A shielding member 112 capable of changing the width of the opening with respect to the second end in the longitudinal direction of the fixing member is attached to the shielding frame 116.

  As shown in FIG. 3A, the F-side shielding member 111 is provided with a drive portion 111a for the F-side shielding member having a shape capable of transmitting drive from the F-side pinion 115a (FIG. 2B). Yes. 3A, an F-side lid 111b that shields the exhaust port 116b (FIG. 2B) is provided separately from the F-side shielding member driving unit 111a. The F-side lid 111b is provided with a convex F-side rail 111c.

  On the other hand, as shown in FIG. 3B, the R-side shielding member 112 is provided with a drive portion 112a for the R-side shielding member having a shape capable of transmitting drive from the R-side pinion 117a (FIG. 2B). It has been. In FIG. 3B, an R-side lid portion 112b that shields the exhaust port 116c (FIG. 2B) is provided separately from the drive portion 112a for the R-side shielding member. The R-side cover portion 112b is provided with a convex R-side rail 112c.

  Here, in FIG. 4 showing a side view of the shielding frame 116 (FIG. 2), as shown in FIG. 4A which is a side view of the F side, the shielding frame 116 is provided with a guide portion 116d, and the F side rail. 111c enters and can move. Similarly, as shown in FIG. 4B, which is a side view on the R side, a guide portion 116 e is provided on the shielding frame 116, and the R side rail 112 c enters and is configured to be movable.

(Shielding unit operation)
Next, the actual operation of the shielding unit 110 will be described with reference to FIG. When the user sets the recording material P in the cassette paper feeding means 80, the paper position detection means described above with reference to FIG. 11 detects the position in the width direction of the recording material P (for example, the positions of both ends (both end positions)). To do. The detection result is sent to the image formation control unit 2, and it is determined whether or not the detection result matches a predetermined value (reference).

  First, a case where the position of the end of the recording material P in the width direction matches a predetermined value (reference position) will be described. When the recording material P is arranged and set at a predetermined position (when it is detected that the recording material is not displaced in the width direction in FIG. 11), the above-described printing operation is started. As shown in FIG. 5A, an operation instruction is issued from the image forming control unit 2 to the F-side drive motor 115 and the R-side drive motor 117 according to the width of the recording material P.

  The F-side pinion 115a rotates in the direction of arrow A, transmits drive to the drive unit 111a for the F-side shielding member, and moves the F-side shielding member 111 in the direction of arrow B. At the same time, the R-side pinion 117a rotates in the direction of arrow C, transmits drive to the drive unit 112a for the R-side shielding member, and moves the R-side shielding member 112 in the direction of arrow D.

At this time, the image forming control unit 2 instructs the F drive motor 115 and the R drive motor 117 to move both the F-side shielding member 111 and the R-side shielding member 112 by a movement amount x corresponding to the width of the recording material P. Put out. As a result, the opening amounts of the exhaust ports 116b and 116c are both x (the opening width is controlled to the same size). With respect to the movement amount x corresponding to the width of the recording material P, it is assumed that the width of the recording material P is W and the length of the shielding unit 110 in the longitudinal direction is U. In FIG. 5 (a), the following equation holds:
U = W + 2x

  By performing such an operation, the opening amounts of the exhaust port 116b and the exhaust port 116c are made to coincide with each other, and the outside air sent from the cooling fan 101 is blown outside the both end positions of the width of the recording material P of the heating roller 21. It is possible to cool only the necessary parts.

  Next, the position in the width direction of the recording material P (for example, the positions of both ends (both end positions)) does not match a predetermined value (reference position) determined in advance, and shifts to the rear side (R side) of the apparatus. A case where the amount y is offset will be described. First, according to the width position of the recording material P, an operation instruction is issued from the image forming control unit 2 to the F-side drive motor 115 and the R-side drive motor 117.

  As shown in FIG. 5B, the F-side pinion 115a rotates in the direction of arrow A, transmits the drive to the drive unit 111a for the F-side shielding member, and moves the F-side shielding member 111 in the direction of arrow B. At the same time, the R-side pinion 117a rotates in the direction of arrow C, transmits drive to the drive unit 112a for the R-side shielding member, and moves the R-side shielding member 112 in the direction of arrow D.

  At this time, the image forming control unit 2 instructs the F-side drive motor 115 to move the total amount of the predetermined movement amount x and the shift amount y according to the width position of the recording material P, and sends it to the R-side drive motor 117. Gives an instruction to move by an amount obtained by subtracting a deviation amount y from a predetermined movement amount x corresponding to the width of the recording material P. Accordingly, the opening amount of the exhaust port 116b is x + y, and the opening amount of the exhaust port 116c is based on the output of the detecting means for detecting the deviation amount of the recording material from the reference position in the width direction and the size in the width direction of the recording material. xy (the opening width is controlled to a different size).

  By performing such an operation, the opening amounts of the exhaust port 116b and the exhaust port 116c can be changed in accordance with the position where the position of the recording material P is shifted from the apparatus. As a result, the outside air sent from the cooling fan 101 can be blown to the outside of both end positions (both end positions) of the width of the recording material P of the heating roller 21, and only necessary portions (non-sheet passing areas) can be blown. Can be cooled.

  Here, when the position of the end portion in the width direction of the recording material P is shifted to the opposite side (the front side of the apparatus) by the shift amount y, the opening amount of the exhaust port 116b is xy, and the opening amount of the exhaust port 116c. Becomes x + y.

  As described above, in this embodiment, the end position in the longitudinal direction (width direction) of the opening with respect to each of the first and second ends in the longitudinal direction of the fixing member is changed to the end position (side) in the width direction of the recording material. End position). Accordingly, the non-sheet passing width and the opening width can be matched with each of the first and second end portions.

  Thereby, in this embodiment, even when the recording material width center of the recording material when passing through the fixing device does not match the reference regardless of the size of the recording material, the temperature rise of the non-sheet passing portion is appropriately cooled. be able to. Further, it is possible to suppress deterioration of the fixing property on the side where the recording material width center is shifted, and more reliably suppress the temperature rise in the region where the recording material does not pass through the fixing member. Furthermore, it is possible to prevent the fixing property from being lowered and maintain the productivity.

<< Second Embodiment >>
In the first embodiment, the drive motor and the pinion corresponding to the F side and the R side are separately provided, but in the present embodiment, the drive motor and the pinion corresponding to the F side and the R side are provided in common. In addition, about the same structure and operation | movement as 1st Embodiment, a same sign is attached | subjected and description is abbreviate | omitted.

(Shielding unit configuration)
FIG. 6A is a perspective view of the shielding unit 210 of the present embodiment as viewed from the upper part on the cooling fan 101 (FIG. 1) side. FIG. 6B is a perspective view of the shielding unit 210 of this embodiment viewed from the upper part of the fixing unit 20 (FIG. 1). The shielding unit 210 is provided with a shielding frame 116, and the shielding frame 116 holds a drive motor 220 provided with a pinion 220a.

  As shown in FIGS. 6B and 7A, the F-side shielding member 211 of the present embodiment includes an F-side drive member 213 that receives drive from the pinion 220a (FIG. 6B), and an exhaust. It is comprised with the F side cover member 214 as a shielding member which shields the opening | mouth 116b. The F-side cover member 214 includes a convex F-side rail 214c, and the F-side rail 214c enters the guide portion 116d (FIG. 4A) of the shielding frame 116 so as to be movable. .

  FIG. 7B shows an enlarged view of a part of the F-side shielding member 211 (FIG. 7A). As shown in FIG. 7B, the F-side drive member 213 is provided with an elongated round hole (long hole) 213 a that is long in the moving direction of the F-side shielding member 211 and has a common diameter. The F-side cover member 214 is provided with a shaft 214a. The shaft 214a enters the oblong hole 213a of the F-side drive member 213, and the F-side drive member 213 and the F-side cover member 214 are fitted and connected in the apparatus height direction. ing. The long diameter of the oblong hole 213a of the F-side drive member 213 is set to a length in which a gap t is provided on the left and right of the shaft diameter of the shaft 214a.

  That is, in this embodiment, the drive motor 220 is provided as a common drive source that changes the width of the opening with respect to each of the first and second end portions in the longitudinal direction of the fixing member. In addition, when the width of the opening with respect to one of the first and second end portions is to be changed to the first direction in the longitudinal direction, the second direction is not changed by the first predetermined amount and is the reverse direction. A moving mechanism having a movement dead zone that is not changed by a second predetermined amount when changing to Here, the first predetermined amount and the second predetermined amount can be set to the same value t.

  The F-side cover member 214 is connected to the F-side drive member 213 as a drive transmission unit that transmits the drive from the drive source, and the F-side drive member 213 includes an elongated hole 213a in the longitudinal direction. The F-side cover member 214 includes a shaft 214a that forms play on both sides of the oblong hole 213a in the longitudinal direction.

(Shielding unit operation)
Next, the operation of the shielding unit 210 in the actual embodiment will be described.

1) When the position of the recording material P in the width direction (for example, the positions of both ends (both end positions)) coincides with a predetermined value (reference position) determined in advance by the paper position detection means of FIG. When it is detected that P is placed and set at a predetermined position, the above-described printing operation is started. As shown in FIG. 8A, an operation instruction is issued from the image formation control unit 2 (FIG. 1) to the drive motor 220 (FIG. 6A) according to the width of the recording material P. The pinion 220a rotates in the direction of arrow A, transmits drive to the drive unit 112a for the R-side shielding member, and moves the R-side shielding member 112 in the direction of arrow B. Similarly, the pinion 220a transmits drive to the F-side drive member 213, and moves the F-side drive member 213 in the direction of arrow C.

  At this time, the image forming control unit 2 instructs the drive motor 220 to move the R-side shielding member 112 by a total amount corresponding to the movement amount x and the gap t corresponding to the width of the recording material P. Therefore, as shown in FIG. 8A, the opening amount of the R-side exhaust port 116c is x + t.

  On the other hand, the F-side drive member 213 moves in the direction of the arrow C, but as described with reference to FIG. 7B, there is a gap t between the oblong hole 213a of the F-side drive member 213 and the shaft 214a of the F-side cover member 214. Is provided. For this reason, the F portion lid member 214 does not move until the end of the oblong hole 213a of the F side drive member 213 hits the shaft 214a of the F side lid member 214 (that is, the gap t). Then, after the end of the oblong hole 213a of the F-side drive member 213 contacts the shaft 214a of the F-side cover member 214, the F-side cover member 214 moves. Therefore, as shown in FIG. 8A, the opening amount of the exhaust port 116b on the F side is x.

  Here, a spring (biasing means) (not shown) provided in the shielding frame 116 is always pressed against the F-side lid member 214 provided with the shaft 214a so that the F-side lid member 214 does not move. That is, a brake (braking force) is applied to the F-side cover member 214, and the F-side cover member 214 does not move with the F-part drive member 213 due to friction generated at the contact portion between the end of the elongated round hole 213a and the shaft 214a. .

  Next, from the state of FIG. 8A described above, the image formation control unit 2 issues an instruction to operate the pinion 220a in the direction of arrow D shown in FIG. 8B (the direction opposite to the direction of arrow A). Then, as shown in FIG. 8B, the pinion 220a rotates in the arrow D direction, and the R-side shielding member 112 is moved in the arrow C direction. Similarly, the F-side drive member 213 is moved in the arrow B direction. At this time, the image forming control unit 2 instructs the drive motor 220 to move the R-side shielding member 112 by the gap t. Therefore, the opening amount of the exhaust port 116c on the R side is x (FIG. 8B).

  On the other hand, the F-side drive member 213 provided with the oblong hole 213a (FIG. 7B) moves by the gap t in the direction of arrow B shown in FIG. 8B. However, only one end of the elongated hole 213a is separated from the shaft 214a, the other end of the elongated hole 213a does not contact the shaft 214a, and the F-side cover member 214 does not move. Therefore, the opening amount of the exhaust port 116b on the F side remains x.

  By performing such an operation, the opening amounts of the exhaust port 116b and the exhaust port 116c are matched (FIG. 8B), and the outside air sent from the cooling fan 101 is changed to the width of the recording material P of the heating roller 21. Can be sprayed to the outside of both end positions, and only necessary portions can be cooled.

2) When the position in the width direction of the recording material P (for example, the positions of both ends (both end positions)) does not coincide with a predetermined value (reference position) determined in advance. The case where it is detected that the recording material P has moved to the apparatus rear side (R side) in the width direction will be described in the order of the case where it is detected that the recording material P has moved to the apparatus front side (F side).

2-a) When the recording material has moved to the rear side (R side) of the apparatus First, the position of the recording material P in the width direction (for example, the positions of both ends (both end positions)) is predetermined. A case will be described in which the position (reference position) is not coincident and the recording material P has moved to the rear side (R side) of the recording material P by the displacement amount y. As shown in FIG. 9A, an operation instruction is issued from the image formation control unit 2 (FIG. 1) to the drive motor 220 (FIG. 6A) according to the width of the recording material P. The pinion 220a rotates in the direction of arrow A, transmits drive to the drive unit 112a for the R-side shielding member, and moves the R-side shielding member 112 in the direction of arrow B. Similarly, the pinion 220a transmits drive to the F-unit drive member 213, and moves the F-side drive member 213 in the direction of arrow C.

  At this time, the image forming control unit 2 instructs the drive motor 220 to move the R-side shielding member 112 to the movement amount x corresponding to the width of the recording material P by the total amount corresponding to the gap t and the displacement amount y. . Therefore, the opening amount of the R-side exhaust port 116c is (x + t) + y.

  On the other hand, the F-side drive member 213 moves in the direction of the arrow C, but as described with reference to FIG. 7B, there is a gap t between the oblong hole 213a of the F-side drive member 213 and the shaft 214a of the F-side cover member 214. Is provided. For this reason, the F portion lid member 214 does not move until the end of the oblong hole 213a of the F side drive member 213 hits the shaft 214a of the F side lid member 214 (that is, the gap t).

  Then, after the end of the oblong hole 213a of the F-side drive member 213 contacts the shaft 214a of the F-side cover member 214, the F-side cover member 214 moves. Therefore, as shown in FIG. 9A, the opening amount of the exhaust port 116b on the F side is x + y.

  Next, from the state of FIG. 9A described above, the image formation control unit 2 issues an instruction to operate the pinion 220a in the direction of arrow D shown in FIG. 9B (the direction opposite to the direction of arrow A). Then, as shown in FIG. 9B, the pinion 220a rotates in the arrow D direction, and the R-side shielding member 112 is moved in the arrow C direction. Similarly, the F-side drive member 213 is moved in the arrow B direction. At this time, the image formation control unit 2 instructs the drive motor 220 to move the R-side shielding member 112 by the total amount of the gap t and twice the displacement amount y. Therefore, the opening amount of the exhaust port 116c on the R side is (x + t) + y− (t + 2y) = xy (FIG. 9B).

  On the other hand, the F-side drive member 213 moves in the direction of the arrow B by the gap t and twice the displacement amount y. However, just by separating one end of the elongated round hole 213a from the shaft 214a, the other end of the elongated round hole 213a is connected to the shaft 214a for the sum of the left and right gaps t of the shaft 214a (twice the gap t). Since it does not contact, the F side cover member 214 does not move. Therefore, if twice the gap t is larger than twice the gap t and the deviation y, that is, if the gap t is larger than twice the deviation y, the opening of the exhaust port 116b on the F side is opened. The amount remains the same as x + y and does not change.

  With the above-described operation, even if the side end position of the recording material P is shifted in the width direction from the reference position that should be originally located with respect to the apparatus, the opening area of the exhaust port 116b and the exhaust port 116c is removed from the recording material. The exhaust port 116b and the exhaust port 116c can be changed so as to coincide with the end region. That is, the outside air sent from the cooling fan 101 can be blown to both end regions of the heating roller 21 that are out of the region in the width direction of the recording material P, and only a necessary region can be cooled.

2-b) When the recording material has moved to the front side of the apparatus (F side) Next, the position in the width direction of the recording material P (for example, the positions of both ends (both end positions)) is predetermined. A case where the position (reference position) does not coincide and the recording material P has moved to the front side (F side) of the recording material P by the displacement amount z will be described with reference to FIG. FIG. 10 and FIG. 9 match in the relationship of z = −y, and will be described in detail below.

  As shown in FIG. 10A, an operation instruction is issued from the image forming control unit 2 to the drive motor 220 in accordance with the width of the recording material P. The pinion 220a rotates in the direction of arrow A, transmits drive to the drive unit 112a for the R-side shielding member, and moves the R-side shielding member 112 in the direction of arrow B. Similarly, the pinion 220a transmits drive to the F-side drive member 213, and moves the F-side drive member 213 in the direction of arrow C.

  At this time, the R side shielding member 112 is moved from the total value corresponding to the width x of the recording material P to the drive motor 220 by the shift amount z by the shift amount z from the image forming control unit 2 to the drive motor 220. Therefore, the opening amount of the R-side exhaust port 116c is (x + t) -z.

  On the other hand, the F-side drive member 213 moves in the direction of the arrow C, but as described with reference to FIG. 7B, there is a gap t between the oblong hole 213a of the F-side drive member 213 and the shaft 214a of the F-side cover member 214. Is provided. For this reason, the F portion lid member 214 does not move until the end of the oblong hole 213a of the F side drive member 213 hits the shaft 214a of the F side lid member 214 (that is, the gap t). Then, after the end of the oblong hole 213a of the F-side drive member 213 contacts the shaft 214a of the F-side cover member 214, the F-side cover member 214 moves. Therefore, as shown in FIG. 10A, the opening amount of the exhaust port 116b on the F side is xz.

  Next, from the state of FIG. 10A described above, the image formation control unit 2 issues an instruction to operate the pinion 220a in the direction of arrow D shown in FIG. 10B (the direction opposite to the direction of arrow A). Then, as shown in FIG. 10B, the pinion 220a rotates in the arrow D direction, and the R-side shielding member 112 is moved in the arrow C direction. Similarly, the F-side drive member 213 is moved in the arrow B direction. At this time, the image forming control unit 2 instructs the drive motor 220 to move the R-part shielding member 112 by an amount obtained by reducing the gap t by twice the amount of deviation z. Therefore, the opening amount of the exhaust port 116c is (x + t) −z− (t−2z) = x + z (FIG. 10B).

  On the other hand, the F-side drive member 213 moves in the direction of the arrow B by an amount that is reduced by twice the deviation amount z from the gap t. However, the amount of the sum of the left and right clearances t of the shaft 214a (twice the clearance t) is reduced by twice the shift amount z from the clearance t only by separating one end of the oblong hole 213a from the shaft 214a. The larger end of the elongated hole 213a does not contact the shaft 214a. For this reason, the opening amount of the exhaust port 116b on the F side remains the same as xz and does not change.

  With the above-described operation, even if the side end position of the recording material P is shifted in the width direction from the reference position that should be originally located with respect to the apparatus, the opening area of the exhaust port 116b and the exhaust port 116c is removed from the recording material. The exhaust port 116b and the exhaust port 116c can be changed so as to coincide with the end region. That is, the outside air sent from the cooling fan 101 can be blown to both end regions of the heating roller 21 that are out of the region in the width direction of the recording material P, and only a necessary region can be cooled.

  As described above, in the above-described embodiment, even when the recording material width center of the recording material when passing through the fixing device does not match regardless of the size of the recording material, the temperature rise of the non-sheet passing portion is appropriately set. Can be cooled. Further, it is possible to suppress deterioration of the fixing property on the side where the recording material width center is shifted, and more reliably suppress the temperature rise in the region where the recording material does not pass through the fixing member. Furthermore, it is possible to prevent the fixing property from being lowered and maintain the productivity.

(Modification)
In the above-described embodiment, the preferred embodiment of the present invention has been described. However, the present invention is not limited to this, and various modifications can be made within the scope of the present invention.

(Modification 1)
In the above-described embodiment, as shown in FIG. 11, the one-dimensional imaging elements R1 and R2 of the paper position detecting unit are separately provided with a short length in the width direction. However, as one long one-dimensional imaging element. Also good. In this case, not only the amount of displacement of the recording material in the width direction but also the size of the recording material in the width direction can be easily detected.

(Modification 2)
In the above-described embodiment, the fixing device using the heating roller and the pressure roller as the first and second fixing members for forming the nip portion that sandwiches and conveys the recording material carrying the toner image has been described. Is not limited to this. A film heating type fixing device using an endless belt that rotates one or both of the first and second fixing members may be used.

(Modification 3)
In the embodiment described above, the recording paper has been described as the recording material. However, the recording material in the present invention is not limited to paper. Generally, a recording material is a sheet-like member on which a toner image is formed by an image forming apparatus. For example, regular or irregular plain paper, cardboard, thin paper, envelope, postcard, seal, resin sheet, OHP sheet, Includes glossy paper. In the embodiment described above, for the sake of convenience, the recording material (sheet) P has been described using terms such as passing paper, but the recording material in the present invention is not limited to paper.

(Modification 4)
In the above-described embodiment, the fixing device that fixes an unfixed toner image to a sheet has been described as an example. However, the present invention is not limited to this, and the toner image that is supposedly attached to the sheet is used to improve the gloss of the image. The present invention can be similarly applied to a device for heating and pressing (also called a fixing device in this case).

2 .. Image formation control unit 21.. Heating roller 22.. Pressure roller 41 41 Intermediate transfer belt 42 Primary transfer roller 91 Secondary transfer roller 101 Cooling fan 110 ..Shielding unit 111 ..Shield member F, 112 ..Shield member R, 116b, 116c ..Exhaust port (opening), P..Recording material, Q1, Q2 ..LED array, R1, R2 .. 1D image sensor

Claims (8)

An image forming unit for forming a toner image on a recording material;
First and second fixing members that form a nip portion for fixing the toner image by nipping and conveying the recording material in the recording material conveyance direction;
When the width direction perpendicular to the recording material conveyance direction of the recording material is a second size smaller than the first size, the recording material is orthogonal to the recording material conveyance direction in at least one of the first and second fixing members. A blowing means for blowing wind for cooling the first and second ends in the longitudinal direction;
A shielding member capable of changing a width of an opening through which wind passes to each of the first and second ends;
Detecting means for detecting a shift amount in the width direction of the recording material;
Based on the output of the detection means and the second size, each of the first and second ends is adapted to allow the wind from the blower means to strike the outside of the region facing the recording material in the longitudinal direction. A control unit for controlling the width of the opening to a different size in the longitudinal direction;
An image forming apparatus comprising: A common drive source that changes the width of the opening for each of the first and second ends;
When the width of the opening with respect to one of the first and second ends is to be changed to the first direction in the longitudinal direction, the first predetermined amount is not changed and the direction opposite to the first direction A moving mechanism unit having a movement dead zone that does not change by a second predetermined amount when changing to the second direction,
The image forming apparatus according to claim 1, further comprising:   The image forming apparatus according to claim 2, wherein the second predetermined amount is the same as the first predetermined amount. The shielding member corresponding to one of the first and second ends is connected to a drive transmission unit that is driven and transmitted from the drive source,
4. The image according to claim 2, wherein the drive transmission unit includes a long hole in the longitudinal direction, and the shielding member includes a shaft that forms play on both sides of the long hole in the longitudinal direction. 5. Forming equipment.   The image forming apparatus according to claim 1, further comprising first and second driving sources that change a width of the opening with respect to each of the first and second ends. The detection means detects the amount of deviation from the reference position of the end position in the width direction of the recording material,
2. The control unit according to claim 1, wherein an end position in the longitudinal direction of the opening with respect to each of the first and second ends is matched with each end position in the width direction of the recording material. 6. The image forming apparatus according to any one of items 1 to 5.   The image forming apparatus according to claim 1, further comprising an urging unit that applies a braking force to the moving direction of the shielding member. A first fixing member and a second fixing member that form a nip portion that fixes the toner image by nipping and conveying the recording material in the recording material conveying direction;
When the width direction perpendicular to the recording material conveyance direction of the recording material is a second size smaller than the first size, the recording material is orthogonal to the recording material conveyance direction in at least one of the first and second fixing members. A blowing means for blowing wind for cooling the first and second ends in the longitudinal direction;
A shielding member capable of changing a width of an opening through which wind passes to each of the first and second ends;
Detecting means for detecting a shift amount in the width direction of the recording material;
Based on the output of the detection means and the second size, each of the first and second ends is adapted to allow the wind from the blower means to strike the outside of the region facing the recording material in the longitudinal direction. A control unit for controlling the width of the opening to a different size in the longitudinal direction;
A fixing device.