JP2016212162A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an air for cooling recording materials to be ejected from adversely affecting the alignment of loaded recording materials.SOLUTION: There is provided an image forming apparatus comprising: an ejection roller 161 that ejects recording materials S; a loading tray 165 on which the recording materials S ejected by the ejection roller 161 are loaded; and an air blowing device that blows an air to the recording materials S ejected by the ejection roller 161 from an air blowing port 11c, wherein when the height of the recording materials S loaded on the loading tray 165 becomes higher than a predetermined height, the amount of air blown from the air blowing port 11c is reduced.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an image forming apparatus that forms an image on a sheet.

  As a fixing method for fixing an unfixed toner image on a recording material (recording material), a thermal fixing method is known in which an unfixed toner image on a recording material is heated and melted to be fixed on the recording material. In a thermal fixing type image forming apparatus, the recording material on the stacking tray is not completely cooled, so that the toner of the recording material stacked on the stacking tray sticks to the adjacent recording material (hereinafter referred to as “exhaust”). It is known that this is called paper adhesion.

  Japanese Patent Application Laid-Open No. 2004-228561 uses a method of cooling the recording material by blowing air toward the recording material loaded on the stacking tray from the vicinity of the paper discharge port.

Japanese Patent Laid-Open No. 7-277583

  When the number of recording materials stacked on the stacking tray increases, the position of the upper recording material among the stacked recording materials in the height direction becomes closer to the paper discharge port. As a result, the upper recording material among the stacked recording materials is lifted by the blowing air, which causes a problem that the alignment of the stacked recording materials is deteriorated.

  The image forming apparatus of the present invention includes an image forming unit that forms an image on a recording material, a discharging unit that discharges the recording material on which an image is formed by the image forming unit, and a recording material discharged by the discharging unit. According to the position in the height direction of the highest recording material among the recording materials stacked on the stacking unit, the air blowing means for blowing air to the recording material loaded on the loading unit, Adjusting means for adjusting the amount of air blown to the recording material by the air blowing means.

  According to the present invention, it is possible to reduce the deterioration of the alignment of recording materials due to air blowing.

1 is a cross-sectional view of an image forming apparatus according to the present invention. It is the flowchart and block diagram which concern on control of 1st Embodiment. It is sectional drawing which showed the loading state at the time of small mounting in 1st Embodiment which concerns on this invention. It is sectional drawing which showed the loading state at the time of the air volume adjustment in 1st Embodiment which concerns on this invention. It is sectional drawing which showed the loading state at the time of the loading limitation in 1st Embodiment which concerns on this invention. It is sectional drawing which showed the state at the time of the small mounting in 2nd Embodiment which concerns on this invention. It is sectional drawing which showed the state at the time of the air volume adjustment in 2nd Embodiment which concerns on this invention.

(First embodiment)
First, the outline of the configuration and operation of the image forming apparatus 101 will be described below. As shown in FIG. 1, the image forming apparatus 101 is a so-called intermediate transfer tandem type image forming apparatus in which four color image forming portions are arranged side by side on an intermediate transfer belt.

<Image creation process>
The image forming apparatus 101 includes an image forming unit 110Y that forms an image with yellow (Y) toner and an image forming unit 110M that forms an image with magenta (M) toner. Further, the image forming apparatus 101 includes an image forming unit 110C that forms an image with cyan (C) toner, and an image forming unit 110BK that forms an image with black (BK) toner. Since the image forming unit 110Y, the image forming unit 110M, the image forming unit 110C, and the image forming unit 110BK have the same configuration except for the color of the toner, the image forming unit 110Y will be described as a representative.

  The image forming unit 110Y includes a photoconductor 111 that is an image carrier, a charger 112 that charges the photoconductor 111, an exposure unit 113, a developing device 114, a primary transfer member 115, and a photoconductor cleaner 116. The surface of the photoconductor 111 rotating in the direction of the arrow m in the figure is uniformly charged by the charger 112. Laser light modulated in accordance with an image signal is output from a scanner unit 117 including a laser and a polygon mirror correction system lens, and this laser light is reflected by a folding mirror, and the photosensitive member 111 charged by the exposure unit 113 is exposed. As a result, an electrostatic latent image is formed. The electrostatic latent image formed on the photoconductor 111 is developed by the developing device 114, and a toner image is formed on the photoconductor. Thereafter, a yellow toner image is transferred onto the intermediate transfer belt 120 as a belt member by the primary transfer member 115 with a predetermined pressure and primary transfer bias. Thereafter, the untransferred toner remaining on the photoconductor 111 is collected by the photoconductor cleaner 116 and prepared for the next image formation again.

  In the case of FIG. 1, the image forming unit 110 described above has four sets of yellow (Y), magenta (M), cyan (C), and black (Bk). Therefore, the magenta toner image formed by the image forming unit M is transferred to the intermediate transfer belt 120 with respect to the yellow toner image formed on the intermediate transfer belt 120. Further, the cyan toner image formed in the image forming portion C is transferred to the intermediate transfer belt 120 with respect to the formed magenta toner image. Further, the black toner image formed by the image forming unit BK is transferred to the intermediate transfer belt 120 with respect to the cyan toner image. In this way, the toner images of different colors are formed on the intermediate transfer belt 120 so as to overlap each other, so that a full color image is formed on the intermediate transfer belt 120. Although the number of colors in this embodiment is four, the number of colors is not limited to four, and the color arrangement order is not limited to this.

  The image forming process of each color processed in parallel by each of the image forming units 110Y, 110M, 110C, and 110BK described above is performed at the timing of superimposing on the upstream color toner image that is primarily transferred onto the intermediate transfer belt 120. As a result, a full-color toner image is finally formed on the intermediate transfer belt 120 and conveyed to the secondary transfer unit. Here, the secondary transfer portion is a transfer nip between the intermediate transfer belt 120 and the secondary transfer outer roller (transfer means) 156.

<Recording material transport process>
The recording material S is stored so as to be stacked on the lift-up device 152 in the recording material storage unit 151. The recording material is fed by the paper feed roller 153 at the timing of image formation. The recording material S sent out by the paper feed roller 153 passes through the paper feed conveyance path 154 and is conveyed to the registration roller 155. The recording material S is subjected to skew correction and timing correction in the registration roller 155 and then sent to the secondary transfer unit. In the secondary transfer portion, the toner image on the intermediate transfer belt 120 is transferred onto the recording material S by the secondary transfer outer roller 156.

<Process after secondary transfer>
The operation after the full-color toner image formed on the intermediate transfer belt 120 in the secondary transfer unit is transferred onto the recording material S will be described below. The recording material S is conveyed to the fixing device 158 by the pre-fixing conveyance unit 157. The fixing roller 159 includes a heater serving as a heat source. The pressure roller 160 is urged toward the fixing roller 159. The fixing device 158 that fixes the toner image on the recording material using heat applies a predetermined pressure and heat to the recording material in a fixing nip formed by the fixing roller 159 and the pressure roller 160 to form the toner image on the recording material. To melt and fix.

  The recording material S that has passed through the fixing device 158 is conveyed to a discharge roller 161 serving as a discharge unit, and discharged onto a stacking tray 165 serving as a stacking unit.

  Each image forming unit, the intermediate transfer belt 120, and the fixing device 158 constitute an image forming unit that forms an image on a recording material.

  When images are formed on both sides of the recording material S, the recording material S that has passed through the fixing device 158 is guided to the reverse roller 162 by the branching device 163. When the reverse roller 162 performs a switchback operation, the recording material is conveyed to the double-sided conveying device 164 with the leading and trailing ends thereof being replaced. Thereafter, the recording material is sent to the secondary transfer unit through a refeeding path 166 that joins the feeding conveyance path 154. The image forming process on the back surface (second surface) is the same as that of the above-described front surface (first surface), and thus description thereof is omitted.

<Configuration for recording material cooling>
As shown in FIG. 1, an air blower 10 is disposed in the image forming apparatus 101. The blower 10 is disposed in the cooling duct 11. The cooling duct 11 includes an introduction path 11a for taking outside air and guiding the air to the blower 10 and a blower path 11b for guiding the wind from the blower 10 to an exhaust port (blower port) 11c. The blowing device 10 and the duct 11 constitute a blowing means. The exhaust port (air blowing port) 11c is disposed at a position facing the space above the stacking tray 165 (the recording material stacking space). In the present embodiment, the exhaust port 11c is disposed below the discharge roller 161, that is, below the recording material discharge port for discharging the recording material to the outside of the apparatus.

  The wind sent out from the blower 10 and out of the blower port 11c flows in substantially the same direction as the discharge roller 161 discharges the recording material. The wind sent from the blower 10 flows along the lower surface of the recording material being discharged from the discharge roller 161 toward the stacking tray 165. Therefore, the recording material discharged to the discharge roller 161 is cooled by the wind sent from the blower 10. The wind sent from the blower 10 flows along the upper surface of the uppermost recording material of the recording materials already loaded on the stacking tray 165. Therefore, the wind sent from the blower 10 also cools the loaded recording material. In this way, the wind sent from the blower 10 cools the recording material heated by the fixing device 158, so that the paper discharge adhesion on the stacking tray 165 is prevented.

  2 to 5 are used, the configuration in the vicinity of the stacking tray 165 and the operation of the blower 10 will be described in detail below.

  As shown in FIG. 3, a rotatable detection flag 20 is disposed above the stacking tray 165. Moreover, the 1st detection sensor 21 and the 2nd detection sensor 22 are provided so that the signal according to the position of the detection flag 20 may be generated. When the leading edge of the detection flag 20 is in contact with the recording material S loaded on the stacking tray 165, the detection flag is positioned at a position corresponding to the height position of the uppermost recording material of the recording material S loaded on the stacking tray 165. 20 rotates. Accordingly, the first detection sensor 21 and the second detection sensor 22 output signals corresponding to the recording material stacking amount (stacking height).

  The signal output from the first detection sensor 21 is changed depending on whether or not the first sensor detection unit 20a of the detection flag 20 enters between the light emitting unit and the light receiving unit of the first detection sensor 21. The signal output from the second detection sensor 22 is changed depending on whether or not the second sensor detection unit 20b of the detection flag 20 enters between the light emitting unit and the light receiving unit of the second detection sensor 22.

  Specifically, when there is no recording material on the stacking tray 165 or when a small number of recording materials are stacked, the first detection sensor 21 is in an OFF (no shielding) state and the second detection is performed. The sensor 22 is in an ON (shielded) state (see FIG. 3). When the detection flag 20 is rotated to a predetermined position by the loaded recording material, the second detection sensor 22 is switched to an OFF (no shielding) state (see FIG. 4). Note that the second detection sensor 22 is switched to the OFF (no shielding) state when the position of the uppermost recording material of the stacked recording materials reaches or exceeds a predetermined height. When the detection flag 20 is further rotated from the state shown in FIG. 4 by being pushed by the loaded recording material, the first detection sensor 21 is switched to ON (shielding) (see FIG. 5).

  As shown in FIG. 2B, the first detection sensor 21 and the second detection sensor 22 are connected to the control unit 119 serving as an adjustment unit. And the control part 119 controls the air blower 10 according to the signal from the 1st detection sensor 21 and the 2nd detection sensor 22. FIG. Specifically, the air blower 10 includes a fan, and the control unit 119 controls the rotation speed of the fan. FIG. 2A shows a control flow by the control unit 119 that adjusts the air flow rate of the blower 10 based on the detection results of the first detection sensor 21 and the second detection sensor 22. Hereinafter, the control related to the blower 10 will be described with reference to the flowchart of FIG. 2 and FIGS. 3 to 5 showing the state of the apparatus in accordance with the loading amount.

  Until the second detection sensor 22 is switched off from the small number of sheets shown in FIG. 3, the control unit 119 sets the air volume of the blower 10 to the normal air volume (S10 in FIG. 2A). As a result, the fixed recording material S is cooled by a normal air flow.

  As shown in FIG. 4, when the stacking height is equal to or higher than the predetermined value and the second detection sensor 22 is turned OFF (YES in S11 of FIG. 2A), the state of a small number of sheets (see FIG. 3) is started. The control part 119 controls the air blower 10 so that it may become a small air volume (S12 of Fig.2 (a)). As a result, the recording material S is cooled with a small amount of air. That is, when the position of the uppermost recording material of the loaded recording material exceeds a predetermined height, the position of the uppermost recording material of the loaded recording material is less than the predetermined height. The recording material is cooled with a small air flow. Note that as the small air volume here, an air volume of 50% of the normal air volume is adopted.

  Among the recording materials S loaded by the above control, the upper recording material S1 (see FIG. 5) is discharged in a state in which the cooling air flow rate is reduced.

  The problem of adhesion of paper discharge becomes conspicuous in the lower recording material among the stacked recording materials. This is because the lower recording material has a higher pressure at which the sheets contact each other due to the weight of the upper recording material. Another reason is that when the load is large, the lower recording material is covered with a larger number of upper recording materials, so that heat radiation from the lower recording material is reduced. In the present embodiment, the lower recording material of the recording materials is cooled with a normal air flow, so that the paper discharge adhesion is prevented.

  After the second detection sensor 22 is switched OFF, the upper recording material among the stacked recording materials approaches the exhaust port 11c in the height direction. In the present embodiment, after the second detection sensor 22 is switched to OFF, the wind blown from the exhaust port 11c is changed to a small flow rate. Although the upper recording material among the loaded recording materials is close to the exhaust port 11c, the amount of air blown from the exhaust port 11c is small, so the upper recording material is lifted by the wind from the exhaust port 11c and the recording materials are aligned. Sex is rarely disturbed.

  As shown in FIG. 5, when the first detection sensor 21 is turned ON, the stacking upper limit state (full load) of the stacking tray 165 is reached and the control unit 119 interrupts the image forming process. The control unit 119 controls the blower 10 so that the blower 10 blows with an air volume smaller than the normal air volume even when the image forming process is stopped due to the stacking upper limit state. Then, when the first detection sensor 21 is in the ON state for a certain period of time, the control unit 119 controls the air blower 10 so as to stop the air blow by the air blower 10. Note that the control unit 119 may be configured to control the air blower 10 so as to stop the air blow by the air blower 10 in response to the first detection sensor 21 being switched ON.

  As described above, it is possible to prevent the recording material S from being adhered to the paper discharged and maintain a good state with respect to the alignment of the stacked recording paper.

  In addition, an example in which a detection flag and a photo interrupter type detection sensor are used as detection means for detecting the loading height (position of the highest recording material) of the loaded recording material is exemplified. However, the detection means is not limited to this, and any configuration capable of detecting the stacking height, such as directly detecting the stacking height using an optical sensor or the like, may be used. Further, the air flow during adjustment (the air flow after the second detection sensor 22 is switched off) is set to 50% of the normal air flow, but the present invention is not limited to this. It is sufficient to set the air volume so as not to cause a problem. Furthermore, in this embodiment, after the 2nd detection sensor 22 switched to OFF, the form which performs ventilation with the flow volume smaller than usual was illustrated, However, after the 2nd detection sensor 22 switches to OFF The control unit 119 may stop the air blowing by the blower 10.

(Second Embodiment)
6 to 8 show a configuration in the vicinity of the stacking tray 165 in the second embodiment. The configuration of the image forming apparatus is the same as that of the above-described embodiment, and the description is omitted.

  FIG. 6 shows a state in which a small number of recording materials S are stacked on the stacking tray 165. In a state where only a small number of recording materials S are stacked on the stacking tray 165, the recording device S is blown from the blowing device 10 to the recording material through the exhaust port 11c with a normal air volume. FIG. 6B is an enlarged view of FIG.

  A wall portion 30 is provided on the upstream side of the stacking tray 165 and below the discharge roller 161, and the upstream end of the recording material on the stacking tray 165 in the conveying direction slides down due to gravity. A movable adjustment member 31 that adjusts the amount of air blown from the blower 10 is disposed on the upper portion of the wall 30. The adjusting member 31 as the adjusting means is urged in the downstream direction of the recording material S by an elastic member (not shown). The adjustment member 31 is movably attached so that the air volume adjustment part 31a of the adjustment member 31 moves in the air blowing path 11b.

  In a state where an external force other than the elastic member is not applied to the adjustment member 31, the contact portion 31b of the adjustment member 31 protrudes downstream of the wall portion 30 in the transport direction as shown in FIG. As shown in FIG. 6, in a state where a small number of recording materials are stacked, the contact portion 31b of the adjustment member 31 is not in contact with the stacked recording materials S.

  FIG. 7 shows a state in which the recording material S is stacked up to the vicinity of the stacking limit. FIG. 7B is an enlarged view of FIG.

  As shown in FIG. 7, the adjustment member 31 moves when the contact portion 31 is pushed by the recording material stacked until the uppermost recording material becomes higher than a predetermined position. When the adjustment member 31 is pushed by the loaded recording material, the air volume adjustment unit 31a of the adjustment member 31 is in a state of blocking a part of the air passage 11b. A part of the air passage 11b is blocked by the air volume adjusting unit 31a of the adjusting member 31, and thus the flow of the wind toward the exhaust port 11c is limited, so that the air volume of the wind W blown from the exhaust port 11c is small. Become. That is, when the recording material increases beyond a predetermined amount, the air volume blown from the exhaust port 11c is adjusted to a small air volume by the adjusting member 31 so that the wind W does not affect the stackability.

  The second embodiment also has the same effect as the first embodiment.

DESCRIPTION OF SYMBOLS 10 Blower 11 Cooling duct 20 Detection flag 21 1st detection sensor 22 2nd detection sensor 30 Wall part 31 Adjustment member 165 Loading tray

Claims (8)

Image forming means for forming an image on a recording material;
Discharging means for discharging the recording material on which an image is formed by the image forming means;
A stacking unit on which the recording material discharged by the discharging unit is stacked;
A blowing means for blowing the recording material loaded on the loading section;
Adjusting means for adjusting the amount of air blown to the recording material by the air blowing means according to the position in the height direction of the uppermost recording material among the recording materials loaded on the stacking section, Image forming apparatus. A sensor for generating a signal corresponding to the position in the height direction of the topmost recording material among the recording materials stacked on the stacking unit;
The image forming apparatus according to claim 1, wherein the adjusting unit is a control unit that controls an operation of the blowing unit in accordance with a signal from the sensor.   When the signal from the sensor indicates that the position of the uppermost recording material is greater than or equal to a predetermined height, the blower means is more than the case where the position of the uppermost recording material is less than the predetermined height. The image forming apparatus according to claim 2, wherein the control unit controls the blower so that the blown amount is reduced. The air blowing means includes a fan,
The image forming apparatus according to claim 2, wherein the control unit controls the number of rotations of the fan in order to adjust the amount of air blown to the recording material by the fan. The blower means includes a blower and a blower passage through which air blown from the blower and directed to the discharge means passes,
The adjustment means includes a movable adjustment member, a part of which is disposed on the stacking unit,
The adjusting member is pushed by the recording material stacked on the stacking unit when the height of the uppermost recording material of the recording material stacked on the stacking unit is higher than a predetermined position. The image forming apparatus according to claim 1, wherein the image forming apparatus is moved to a position where at least a part thereof is blocked.   The image according to any one of claims 1 to 5, wherein the blower unit includes an exhaust port disposed below a discharge port through which the discharge unit discharges the recording material to the outside of the apparatus. Forming equipment. Image forming means for forming an image on a recording material;
Discharging means for discharging the recording material on which an image is formed by the image forming means;
A stacking unit on which the recording material discharged by the discharging unit is stacked;
A fan that blows air to the recording material loaded on the loading section;
Detecting means for detecting the position in the height direction of the topmost recording material among the recording materials stacked on the stacking unit;
When the detection unit detects that the position of the uppermost recording material is equal to or higher than a predetermined height, the fan is more than in the case where the position of the uppermost recording material is less than the predetermined height. An image forming apparatus comprising: a control unit that controls the rotation speed of the image forming apparatus to be reduced. Image forming means for forming an image on a recording material;
Discharging means for discharging the recording material on which an image is formed by the image forming means;
A stacking unit on which the recording material discharged by the discharging unit is stacked;
A blower and a blower passage through which the wind from the blower to the discharge means passes;
An image forming apparatus comprising: an adjustment member that is pushed by a recording material stacked on the stacking unit and moves in the air passage.

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