JP2010078674A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus that can solve problems that vapor is produced from a form and forms discharged from an apparatus body and stocked stick on each other and so on by cooling the forms discharged from a form discharge portion with simple constitution using an existent fan. <P>SOLUTION: The image forming apparatus discharges a form where a toner image is fixed by heating, pressing and fixing a toner image, transferred onto the form at an image formation unit, at a fixing unit from the form discharge unit 26 to outside the apparatus body, and includes a fan 29 for discharging heat in the apparatus body to the outside nearby the form discharge unit 26. The image forming apparatus includes a guide member for guiding air from the fan 29 to the form discharge unit 26. Here, an existent lever 27 is used as the guide member. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image forming apparatus provided with a fan in the vicinity of a paper discharge unit for discharging a paper on which an image has been formed through an electrophotographic process to the outside of the apparatus main body.

  In an image forming apparatus such as a copying machine or a printer that forms an image on a sheet by electrophotography, the toner image transferred onto the sheet in the image forming unit is heated and pressed by the fixing unit to be fixed. The fixed sheet is discharged from the sheet discharge unit to the outside of the apparatus main body.

  In such an image forming apparatus, when the paper discharge portion is close to the fixing portion, the paper heated in the fixing portion is discharged while it is not sufficiently cooled. This causes a problem that a plurality of sheets stocked on the screen stick.

Therefore, in Patent Document 1, a cooling unit including a sheet cooling fan and a duct member is provided in the sheet discharge unit, and the sheet is cooled by blowing air toward the sheets discharged from the plurality of discharge ports. An image forming apparatus is proposed.
JP 2002-072729 A

  However, in the configuration described in Patent Document 1, since it is necessary to newly provide a sheet cooling fan and a duct member that constitute the cooling means, the number of parts increases and the cost increases, and the installation space for the cooling means is reduced. There is a problem that it is necessary to newly secure and the apparatus becomes large.

  The present invention has been made in view of the above problems, and the object of the present invention is to cool the paper discharged from the paper discharge unit with a simple configuration using an existing fan, thereby preventing steam from the paper from being discharged. An object of the present invention is to provide an image forming apparatus capable of solving problems such as occurrence and sticking of sheets stocked after being discharged out of the apparatus main body.

  In order to achieve the above object, according to the first aspect of the present invention, the toner image transferred onto the paper in the image forming unit is fixed by heating and pressing in the fixing unit, and then the paper on which the toner image is fixed is discharged to the paper. In the image forming apparatus, wherein a fan for discharging heat inside the apparatus main body to the outside is provided in the vicinity of the paper discharge section. A guide member that leads to the discharge portion is provided.

  According to a second aspect of the present invention, in the first aspect of the invention, an openable / closable front cover having the paper discharge portion is provided, and a lever for opening and closing the front cover is disposed beside the paper discharge portion. The lever is configured as the guide member, and an air passage for guiding the wind from the fan to the paper discharge unit is formed therein.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the paper discharge portion is provided with two upper and lower discharge openings, and a branching portion is formed inside the guide member so that the air from the fan is blown. It is configured to be divided up and down and led to the respective outlets.

  According to a fourth aspect of the present invention, in the third aspect of the present invention, at least one of the upper and lower two-stage discharge ports is a reverse discharge port.

  According to the first aspect of the present invention, since the existing fan is used and the wind from the fan is guided to the paper discharge unit by the guide member, the paper discharge unit is not used even when the paper discharge unit is close to the fixing unit. The paper discharged from the discharge unit can be effectively cooled by the wind from the fan, and steam is generated from the discharged paper, or a plurality of sheets discharged and stocked out of the main body of the device stick together. These problems can be solved without increasing the number of parts, increasing the cost, and increasing the size of the apparatus.

  According to the invention described in claim 2, since the existing lever for opening and closing the front cover is used as a guide member, there is no need to separately provide components, and an increase in the number of components and the associated cost increase can be avoided. it can.

  According to the third and fourth aspects of the present invention, since the winds divided up and down by the guide member are respectively guided to the discharge ports provided in the upper and lower stages of the paper discharge unit, the paper discharged from each discharge port Is effectively cooled by the wind, and problems such as generation of steam from the paper are solved.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  1 and 2 are perspective views of an image forming apparatus according to the present invention, FIG. 3 is a perspective view of a sheet discharge portion of the image forming apparatus, and FIG. 4 is a partial side view of the image forming apparatus showing a state in which a front cover is opened. It is.

  The illustrated image forming apparatus is a color laser printer, and includes an apparatus body 100 having a rectangular box shape. A front cover 101 that rotates up and down around a rotation fulcrum (not shown) provided at the lower portion of the apparatus main body 100 is opened and closed on the front surface of the apparatus main body 100 (the oblique right side in FIG. 1 is the front). The front cover 101 is opened as shown in FIG. 4 when maintenance or the like is required.

  By the way, on the upper surface of the apparatus main body 100 of the color laser printer, there is provided a paper discharge tray 21 on which the paper on which the image is formed is discharged and stocked, and is opposed to the paper discharge tray 21 above the front cover 101. As shown in FIGS. 2 and 3, a sheet discharge portion 26 is formed on the surface. The paper discharge unit 26 is for discharging the paper on which the image is formed to the paper discharge tray 21, and has two upper and lower discharge ports 26a and 26b that are long in the width direction. . As will be described later, the upper discharge port 26a is a reverse discharge port for double-sided printing, and the lower discharge port 26b is for single-sided printing.

  As shown in FIGS. 2 and 3, levers 27 for releasing the fixing lock of the front cover 101 to the apparatus main body 100 are provided on the left and right sides of the paper discharge portion 26 of the front cover 101, respectively. If both levers 27 are pressed when opening the front cover 101, the fixing lock of the front cover 101 to the apparatus main body 100 is released, and the front cover 101 is rotated around a rotation fulcrum (not shown) at the lower end. It can be opened as shown in FIG.

  Next, the internal structure of the color laser printer will be described with reference to FIG.

  FIG. 5 is a cross-sectional view of a color laser printer. The illustrated color laser printer is a tandem type, and a magenta image forming unit 1M, a cyan image forming unit 1C, and a yellow image forming unit are disposed in the center of the apparatus main body 100. The unit 1Y and the black image forming unit 1K are arranged in tandem at regular intervals.

  Each of the image forming units 1M, 1C, 1Y, and 1K is provided with photosensitive drums 2a, 2b, 2c, and 2d, which are image carriers, and a charger 3a is disposed around each of the photosensitive drums 2a to 2d. , 3b, 3c, 3d, developing devices 4a, 4b, 4c, 4d, transfer rollers 5a, 5b, 5c, 5d as primary transfer means, and drum cleaning devices 6a, 6b, 6c, 6d, respectively.

  Here, each of the photosensitive drums 2a to 2d is a drum-shaped photosensitive body, and these are predetermined processes in a direction indicated by an arrow (clockwise) by a driving force transmitted from a motor (not shown) via a power transmission mechanism. Driven by speed.

  The chargers 3a to 3d uniformly charge the surfaces of the photosensitive drums 2a to 2d to a predetermined potential by a charging bias applied from a charging bias power source (not shown).

  Further, the developing devices 4a to 4d contain magenta (M) toner, cyan (C) toner, yellow (Y) toner, and black (K) toner, respectively, and are formed on the photosensitive drums 2a to 2d. In addition, the toner of each color is attached to each electrostatic latent image to visualize each electrostatic latent image as a toner image of each color.

  The transfer rollers 5a to 5d are arranged so as to be in contact with the photosensitive drums 2a to 2d via an endless intermediate transfer belt 7 which is an intermediate transfer body at each primary transfer portion. Here, the intermediate transfer belt 7 is an endless belt configured as a multilayer structure including a rubber layer, and the outermost rubber layer is in contact with the photosensitive drums 2a to 2d. The intermediate transfer belt 7 is stretched between the rollers 8 and 9 and is disposed on the upper surface side of each of the photosensitive drums 2a to 2d.

  Incidentally, toner containers 12a, 12b, 12c, and 12d for supplying toner to the developing devices 4a to 4d are arranged in a line above the image forming units 1M, 1C, 1Y, and 1K in the apparatus main body 100. It is installed.

  In addition, a laser scanner unit (LSU) 13 is disposed below the image forming units 1M, 1C, 1Y, and 1K in the apparatus main body 100, and a paper feed cassette 14 is detachably attached to the bottom of the main body 100 below the image forming units. is set up. A plurality of sheets (not shown) are stacked and accommodated in the paper feed cassette 14, and a pickup roller 15 for taking out the paper one by one from the paper feed cassette 14 is taken out in the vicinity of the paper feed cassette 14. A feed roller 16 and a retard roller 17 are provided for feeding the fed paper to the transport path L.

  Further, the conveyance path L extending in the vertical direction on the side of the apparatus main body 100 includes a conveyance roller pair 18 that conveys the sheet, and the intermediate transfer belt 7 that rotatably supports the intermediate transfer belt 7 at a predetermined timing after the sheet is temporarily held. There is provided a registration roller pair 19 that supplies a secondary transfer portion that is a contact portion between the driving roller 8 and the secondary transfer roller 10. Next to the transport path L, another transport path L ′ used for forming an image on both sides of the sheet is formed, and a plurality of transport roller pairs 20 are appropriately used in the transport path L ′. Are provided at regular intervals.

  By the way, the conveyance path L arranged in the vertical direction on one side in the apparatus main body 100 extends to the paper discharge tray 21 provided on the upper surface of the apparatus main body 100, and the fixing device 22 and the discharge path are in the middle. A paper roller pair 23 is provided.

  Next, an image forming operation by the color laser printer having the above configuration will be described.

  When an image formation start signal is issued, the photosensitive drums 2a to 2d in the image forming units 1M, 1C, 1Y, and 1K are respectively rotated at a predetermined process speed in a direction indicated by an arrow (clockwise) in FIG. When driven, the photosensitive drums 2a to 2d are uniformly charged by the charging rollers 3a to 3d. The laser scanner unit 13 emits a laser beam modulated by a color image signal for each color, irradiates the surface of each photosensitive drum 2a to 2d with the laser beam, and each color is applied to each photosensitive drum 2a to 2d. An electrostatic latent image corresponding to the color image signal is formed.

  First, magenta toner is attached to the electrostatic latent image formed on the photosensitive drum 2a of the magenta image forming unit 1M by the developing device 4a to which a developing bias having the same polarity as the charged polarity of the photosensitive drum 2a is applied. The electrostatic latent image is visualized as a magenta toner image. The magenta toner image is obtained by applying a primary transfer bias having a polarity opposite to that of the toner to the intermediate transfer belt 7 by the transfer roller 5a at the primary transfer portion (transfer nip portion) between the photosensitive drum 2a and the transfer roller 5a. The primary transfer is performed on the intermediate transfer belt 7 which is rotationally driven in the direction of the arrow in FIG.

  Thus, the intermediate transfer belt 7 on which the magenta toner image has been primarily transferred as described above moves to the next cyan image forming unit 1C. In the cyan image forming unit 1C as well, the cyan toner image formed on the photosensitive drum 2b is transferred to the magenta toner image on the intermediate transfer belt 7 in the primary transfer portion in the same manner as described above.

  Similarly, yellow and black toners respectively formed on the photosensitive drums 2c and 2d of the yellow and black image forming units 1Y and 1K on the magenta and cyan toner images superimposed and transferred on the intermediate transfer belt 7, respectively. The images are sequentially superimposed at each primary transfer portion, and a full-color toner image is formed on the intermediate transfer belt 7. The transfer residual toner which is not transferred onto the intermediate transfer belt 7 and remains on the photosensitive drums 2a to 2d is removed by the drum cleaning devices 6a to 6d, and the photosensitive drums 2a to 2d are prepared for the next image formation. It is done.

  On the other hand, the pickup roller 15 and the feed roller 15 are fed from the paper feed cassette 14 in accordance with the timing at which the leading end of the full color toner image on the intermediate transfer belt 7 reaches the secondary transfer portion (transfer nip portion) between the roller 8 and the secondary transfer roller 10. The sheet sent to the conveyance path L by the roller 16 and the retard roller 17 is conveyed to the secondary transfer unit by the registration roller pair 19. Then, a full-color toner image is collectively transferred from the intermediate transfer belt 7 to the sheet conveyed to the secondary transfer unit by the secondary transfer roller 10 to which a secondary transfer bias having a polarity opposite to that of the toner is applied. .

  Thus, the sheet on which the full-color toner image has been transferred is conveyed to the fixing device 22, and the sheet on which the full-color toner image has been fixed by being heated and pressurized and thermally fixed on the surface of the sheet. The paper discharge roller pair 23 discharges the paper from the lower discharge port onto the paper discharge tray 21, thereby completing a series of image forming operations. The transfer residual toner that is not transferred onto the sheet and remains on the intermediate transfer belt 7 is removed by the belt cleaning device 11, and the intermediate transfer belt 7 is prepared for the next image formation.

  The image forming operation in the case of single-sided printing in which an image is formed on one side of the paper has been described above. However, in the case of double-sided printing in which an image is formed on both sides of the paper, an image is formed on one side through the above-described process. The transported paper is switched in the transport direction by the flapper 30 and a part thereof is discharged from the upper discharge port 26a of the paper discharge unit 26, and then switched back to be guided to another transport path L ′. By passing through the conveyance path L ′, the front and back are reversed and conveyed to the registration roller pair 19. Thereafter, an image is formed on the back side through the same process as described above, and the paper on which the image is formed on both sides is transferred from the discharge port 26b on the lower side of the paper discharge unit 26 to the discharge tray 21 in the same manner as single-sided printing. Discharged.

  Next, a cooling structure of the paper discharge unit 26 constituting the gist of the present invention will be described.

<Embodiment 1>
6 is a partial perspective view showing the fan and lever provided in the vicinity of the paper discharge unit, FIG. 7 is a front perspective view of the lever, FIGS. 8 and 9 are rear perspective views of the lever, and FIG. 10 is the same lever. It is a rear view of the lever which shows the flow of the wind.

  As shown in FIG. 6, a fan 29 for cooling the motor 28 and the like disposed in the vicinity of the lever 27 on one side (left side in the present embodiment) of the front cover 101 is provided on the back side (back side). Air is blown out from the fan 29 toward the back of the lever 27 (backward).

  Here, on the back surface of the lever 27, as shown in FIGS. 8 and 9, a longitudinally long air passage S1 is defined in the longitudinal ribs 27a and 27b parallel to each other. This air passage S1 is open on the back side of the lever 27 (the surface on the near side in FIG. 8), and the air passage S1 is laterally disposed above the air passage S1 by a flat wall 27c provided away from the back surface of the lever 27. A directional air passage S2 (see FIG. 10) is formed, and the air passage S2 and the air passage S1 communicate with each other. As shown in FIGS. 7, 9, and 10, the air passage S2 is opened as an air exhaust port 27d on the inner end surface of the lever 27. The air exhaust port 27d has an opening width at a lower portion thereof directed downward. It has an opening shape that spreads out.

  Thus, the wind blown from the fan 29 toward the back surface of the lever 27 flows upward through the air passage S1 formed in the lever 27 as shown by the arrow in FIG. The wind that flows into the path S2 and flows into the wind path S2 collides with the lateral ribs 27e forming a part of the wind path S2 and bends in the flow direction at a right angle, and then flows in the lateral direction in the wind path S2. Then, the air is discharged from the air discharge port 27d toward the paper discharge unit 26.

  In the paper discharge unit 26, the wind is blown from the lateral direction, so that in the case of single-sided printing, the paper discharged from the lower discharge port 26b is effectively cooled by the wind. In double-sided printing, the paper once partially discharged from the upper discharge port 26a is cooled by the wind, and finally the paper having an image formed on both sides is discharged from the lower discharge port 26b. When being done, the paper is effectively cooled by the wind.

  As described above, in the present embodiment, the existing fan 29 is used, and the wind from the fan 29 is guided to the paper discharge unit 26 by the existing lever 27 as a guide member. Even when the sheet is close to the fixing device 22, the sheet discharged from the sheet discharge unit 26 can be effectively cooled by the wind from the fan 29, and steam is generated from the discharged sheet, or the apparatus main body. Problems such as sticking of a plurality of sheets discharged to the outside of the paper 100 and stocked on the paper discharge tray 21 can be solved without increasing the number of parts, increasing the cost, and increasing the size of the apparatus. In particular, in the present embodiment, since the existing lever 27 for opening and closing the front cover 101 is used as a guide member, there is no need to separately provide components, and an increase in the number of components and the associated cost increase can be avoided. it can.

<Embodiment 2>
Next, a second embodiment of the present invention will be described with reference to FIGS.

  11 is a front perspective view of the lever, FIG. 12 is a rear perspective view of the lever, FIG. 13 is a rear view of the lever showing the flow of wind in the lever, and FIG. 14 is a flow of wind in the discharge section. FIG. 11 is a front view of the discharge portion of the color laser printer shown, and in these drawings, the same elements as those shown in FIGS. 6 to 10 are denoted by the same reference numerals, and description thereof will be omitted below. To do.

  In the present embodiment, a partition rib 27f is projected as a branching portion on the air passage S2 formed inside the lever 27 that is a guide member, and the air passage S2 is divided into upper and lower portions by the partition rib 27f. The other features are the same as those of the above-described embodiment.

  Thus, in the present embodiment, the wind blown from the fan 29 (see FIG. 6) toward the back surface of the lever 27 moves upward through the air passage S1 formed in the lever 27 as in the first embodiment. The air flowing into the upper air passage S2 collides with the lateral rib 27e and bends in the flow direction at a right angle, and is divided vertically by the partition rib 27f. Each of the diverted winds flows in the horizontal direction as indicated by arrows in FIG. 13 through the upper and lower divided air paths S21 and S22 in the air path S2, and the paper is discharged from the air outlet 27d as shown in FIGS. It is discharged toward the upper and lower discharge ports 26a and 26b of the part 26, respectively.

  In the paper discharge unit 26, the wind is blown from the lateral direction, so in the case of single-sided printing, the paper discharged from the lower discharge port 26b is blown from the divided air path S22 below the air path S2 of the lever 27. Cooled effectively by wind. In double-sided printing, the paper once partially discharged from the upper discharge port 26a is cooled by the wind blown from the divided air path S21 above the air path S2 of the lever 27, and finally double-sided. The sheet on which the image is formed is effectively cooled by the wind blown from the divided air path S22 below the air path S2 of the lever 27.

  Therefore, also in the present embodiment, as in the first embodiment, the existing fan 29 and lever 27 are used to blow air to the paper discharge section 26, and the paper discharged from the paper discharge section 26 is blown into the wind. Therefore, steam is generated from the discharged paper or is discharged out of the apparatus main body 100 and placed on the discharge tray 21 without increasing the number of parts, increasing the cost, and increasing the size of the apparatus. Problems such as sticking of a plurality of stocked sheets can be solved.

  In the above, the embodiment in which the present invention is applied to a color laser printer has been described. However, the present invention is similarly applied to other arbitrary image forming apparatuses such as a copying machine, a facsimile machine, and a multifunction machine in addition to a printer. Of course, it is possible.

1 is a perspective view of a color laser printer according to the present invention. 1 is a perspective view of a color laser printer according to the present invention. It is a perspective view of the paper discharge part of the color laser printer which concerns on this invention. The state which opened the front cover of the color laser printer concerning this invention is shown. 1 is a cross-sectional view of a color laser printer according to the present invention. It is a fragmentary perspective view which shows the fan and lever provided in the paper discharge part vicinity of the color laser printer which concerns on this invention. It is a surface side perspective view of the lever which concerns on Embodiment 1 of this invention. It is a back side perspective view of the lever which concerns on Embodiment 1 of this invention. It is a back side perspective view of the lever which concerns on Embodiment 1 of this invention. It is a rear view of the lever which shows the flow of the wind in the lever which concerns on Embodiment 1 of this invention. It is a surface side perspective view of the lever which concerns on Embodiment 2 of this invention. It is a back side perspective view of the lever which concerns on Embodiment 2 of this invention. It is a rear view of the lever which shows the flow of the wind in the lever which concerns on Embodiment 2 of this invention. It is a front view of the discharge part of the color laser printer which shows the flow of the wind in the discharge part in Embodiment 2 of this invention.

Explanation of symbols

1M Magenta image forming unit 1C Cyan image forming unit 1Y Yellow image forming unit 1K Black image forming unit 2a to 2d Photosensitive drum (image carrier)
3a to 3d charger 4a to 4d developing device 5a to 5d transfer roller 6a to 6d drum cleaning device 7 intermediate transfer belt (transfer belt)
8,9 Roller 10 Secondary transfer roller 11 Belt cleaning device 12a to 12d Toner container 13 Laser scanner unit (LSU)
DESCRIPTION OF SYMBOLS 14 Paper feed cassette 15 Pickup roller 16 Feed roller 17 Retard roller 18 Conveyance roller pair 19 Registration roller pair 20 Conveyance roller pair 21 Paper discharge tray 22 Fixing device (fixing part)
23 Paper discharge roller pair 24, 25 Auxiliary roller 26 Paper discharge part 26a, 26b Paper discharge part discharge port 27 Lever (guide member)
27a, 27b Lever vertical rib 27c Lever flat wall 27d Lever air exhaust port 27e Lever lateral rib 27f Partition rib 28 Motor 29 Fan 30 Flapper 100 Image forming apparatus body 101 Front cover L, L 'Conveyance path S1, S2 Air path S21, S22 Split air path

Claims (4)

An apparatus for discharging a sheet on which a toner image is fixed from a sheet discharge unit to the outside of the apparatus main body after fixing the toner image transferred on the sheet in the image forming unit by heating and pressurizing in the fixing unit. In the image forming apparatus comprising a fan for discharging the heat inside to the outside in the vicinity of the paper discharge unit,
An image forming apparatus comprising a guide member for guiding wind from the fan to the paper discharge unit.   An openable / closable front cover having the paper discharge portion, and a device for arranging a lever for opening and closing the front cover beside the paper discharge portion, wherein the lever is configured as the guide member. 2. An image forming apparatus according to claim 1, wherein an air passage for guiding the wind from the fan to the paper discharge section is formed therein.   The paper discharge portion is provided with two upper and lower discharge ports, and a branch portion is formed inside the guide member so that the wind from the fan is divided vertically and guided to each discharge port. The image forming apparatus according to claim 1 or 2.   4. The image forming apparatus according to claim 3, wherein at least one of the upper and lower two-stage discharge ports is a reverse discharge port.

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