JP6981304B2 - Image forming device - Google Patents

Description

The present invention relates to an image forming apparatus.

Conventionally, an image forming apparatus such as a printer, a copying machine, a facsimile, or a compound machine, for example, an electrophotographic printer is provided with an image forming unit, and a toner image is formed on the surface of a photoconductor drum in the image forming unit. The toner image is transferred to the paper by the transfer roller, and the toner image is fixed on the paper in the fuser.

Therefore, the fuser includes a heating roller as a first fixing member heated by a heater and a pressurizing roller as a second fixing member to be pressed against the heating roller, and the heating roller and the pressurizing roller. The paper is passed through the nip portion formed between the and, and the toner image on the paper is heated and pressurized.

In this case, the temperature of the heating roller is detected by the temperature sensor, and the supply of electric power from the power supply to the heater is controlled so that the detected temperature becomes a preset temperature, that is, a fixing temperature.

By the way, as the temperature sensor, there is provided a printer that uses a non-contact temperature sensor arranged close to the heating roller without contacting the heating roller.

In this type of printer, while the paper on which the toner image is transferred is conveyed toward the fuser, it is fixed on the paper under the influence of the behavior of the paper and the static electricity generated in each part of the device body. The toner before it is made to be charged, that is, unfixed toner, paper dust, etc. may be scattered. If a paper jam occurs while the paper is being conveyed, the top cover that covers the device body is opened and the paper is removed, but even then, the paper rubs against or vibrates with each part of the device body. Unfixed toner, paper dust, etc. may scatter as a result.

In that case, if unfixed toner, paper dust, or the like adheres to the temperature sensor, the temperature of the heating roller cannot be detected accurately.

Therefore, when it is necessary to rotatably dispose the temperature sensor in the storage cover and cover it with the storage cover to detect the temperature of the heating roller, the detection surface of the temperature sensor is passed through the opening of the storage cover. When it is not necessary to detect the temperature of the heating roller, the temperature sensor is rotated so that the detection surface is retracted to a position not facing the heating roller (see, for example, Patent Document 1). .).

Japanese Unexamined Patent Publication No. 2006-17773

However, in the conventional printer, since the storage cover is not sealed, unfixed toner, paper dust, etc. may enter the storage cover through the opening and adhere to the temperature sensor.

Further, since the temperature sensor is surrounded by the storage cover, the heat radiated from the heating roller may be trapped in the storage cover, and in that case, the temperature sensor is deteriorated.

As a result, the temperature sensor cannot accurately detect the temperature of the heating roller.

An object of the present invention is to solve the problems of the conventional printer and to provide an image forming apparatus capable of accurately detecting the temperature of a fixing member.

Therefore, the image forming apparatus of the present invention includes an image forming unit that forms a developer image on the image carrier, a transfer unit that transfers the developer image on the image carrier to a medium, and a fixing member. A fixing device for fixing the developer image transferred to the medium, a ventilation device arranged adjacent to the fixing device and extending in the width direction of the medium, and an air flow sent to the ventilation device. It has a blower.

The ventilation device is a duct that forms the air flow from one end side to the other end side in the width direction of the medium by the ventilation device, and is disposed in the duct to detect the temperature of the fixing member. It is provided with a shutter that is movably arranged between the vessel and the duct and the temperature detector and selectively opposes the temperature detector and the fixing member.
Further, a duct opening is formed at a position corresponding to the temperature detector on the side wall arranged between one end side and the other end side of the duct.

According to the present invention, the image forming apparatus includes an image forming unit that forms a developer image on an image carrier, a transfer unit that transfers a developer image on the image carrier to a medium, and a fixing member. A fixing device for fixing the developer image transferred to the medium, a ventilation device arranged adjacent to the fixing device and extending in the width direction of the medium, and an air flow sent to the ventilation device. It has a blower.

The ventilation device is a duct that forms the air flow from one end side to the other end side in the width direction of the medium by the ventilation device, and is disposed in the duct to detect the temperature of the fixing member. It is provided with a shutter that is movably arranged between the vessel and the duct and the temperature detector and selectively opposes the temperature detector and the fixing member.
Further, a duct opening is formed at a position corresponding to the temperature detector on the side wall arranged between one end side and the other end side of the duct.

In this case, in the ventilation device arranged adjacent to the fixing device, the temperature detector and the fixing member are selectively opposed to each other by the shutter arranged between the duct and the temperature detector, so that the developer is used. Prevents unfixed toner, paper dust, etc. scattered when removing the medium that caused the paper jam from adhering to the temperature detector while the medium on which the image is transferred is conveyed toward the fixing device. can do.

Moreover, since the air flow generated by the blower passes through the duct, the heat radiated from the fixing member does not stay in the duct, and the temperature detector does not deteriorate.

Therefore, the temperature of the fixing member can be detected with high accuracy by the temperature detector.

It is a figure which shows the arrangement state of the ventilation apparatus in 1st Embodiment of this invention. It is a conceptual diagram of the printer in 1st Embodiment of this invention. It is a control block diagram of the printer in 1st Embodiment of this invention. It is a 1st figure which shows the state in the duct when the shutter in the 1st Embodiment of this invention is placed in the 1st position. It is a 2nd figure which shows the state in the duct when the shutter in the 1st Embodiment of this invention is placed in the 1st position. It is a figure which shows the state in the duct when the shutter in the 1st Embodiment of this invention is placed in the 2nd position. It is a figure which shows the state in the duct when the shutter in the 2nd Embodiment of this invention is placed in the 1st position. It is a figure which shows the control device of the printer in the 2nd Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In this case, an electrophotographic printer as an image forming apparatus will be described.

FIG. 2 is a conceptual diagram of the printer according to the first embodiment of the present invention, and FIG. 3 is a control block diagram of the printer according to the first embodiment of the present invention.

In the figure, 10 is a printer, Cs is a housing of the printer 10, Cst is a top cover as a cover member which is openably and closably arranged at the top of the housing Cs, and 11Bk, 11Y, 11M, and 11C are printers. It is an image forming unit (ID unit) of each color of black, yellow, magenta, and cyan that is detachably attached to the main body of 10, that is, the device main body Bd. Each of the image forming units 11Bk, 11Y, 11M, 11C is arranged around the photoconductor drum 13 as an image carrier and the photoconductor drum 13, none of which is shown, a charging roller as a charging device, and development. A developing roller as a agent carrier, a cleaning device, and the like are provided, and a toner image as a developer image of each color is formed on the photoconductor drum 13.

Four arms am are formed so as to project downward on the top cover Cst, and an LED head 12 as an exposure device is attached to the tip of each arm am. Each of the LED heads 12 is opposed to the photoconductor drum 13 of each image forming unit 11Bk, 11Y, 11M, 11C with the top cover Cst closed, and the photoconductor is opened with the top cover Cst open. It is evacuated from the drum 13.

Further, reference numeral 14 denotes a paper cassette as a medium accommodating portion for storing paper (not shown) as a medium, and the paper in the paper cassette 14 placed on the paper loading platform 14a is placed at the tip of the paper cassette 14. A pickup roller 15 to be fed out to the paper transport path Rt1 as the medium transport path of No. 1 is arranged, and the paper fed by the pickup roller 15 is composed of a paper feed roller 16 and a separation roller 17 adjacent to the pickup roller 15. A separation device 18 for separating one by one is arranged.

Then, a transport roller pair 19 for transporting the paper is arranged on the downstream side of the separation device 18 in the paper transport path Rt1, and the paper is temporarily stopped on the downstream side of the transport roller pair 19. A resist roller pair 20 for correcting skew is arranged.

Further, a transfer unit u1 is arranged along the image forming units 11Bk, 11Y, 11M, and 11C on the downstream side of the resist roller pair 20 in the paper transport path Rt1.

The transfer unit u1 includes a drive roller R1 rotatably arranged below the image forming unit 11Bk, a driven roller R2 rotatably arranged below the image forming unit 11C, a driving roller R1 and a driven roller R2. Each photoconductor drum is provided with a transfer belt 21 stretched rotatably by the transfer belt 21 and a transfer roller 22 as a transfer member rotatably arranged so as to face the photoconductor drum 13 via the transfer belt 21. A color toner image is formed on the paper by sequentially superimposing and transferring the toner image on the 13 on the paper sent from the resist roller pair 20.

Further, the fixing device 31 is a fixing device as a fixing device arranged on the downstream side of the image forming units 11Bk, 11Y, 11M, 11C and the transfer unit u1 in the paper transport path Rt1, and the fixing device 31 is rotatable. A heating belt 32 as a first fixing member arranged in the above, and a pressure roller 33 as a second fixing member rotatably arranged and pressed against the heating belt 32 are provided, and a color toner image is displayed. Fix it on the paper. A heater 34 as a heat source is arranged inside the heating belt 32.

On the downstream side of the fuser 31 in the paper transport path Rt1, the paper transport path Rt2 as the second medium transport path is branched from the paper transport path Rt1, and a switch 35 for switching the paper transport path is arranged at the branch point. Will be set up. Further, on the downstream side of the switch 35 in the paper transport path Rt2, the paper transport path Rt3 as the third medium transport path is branched from the paper transport path Rt2.

Then, a transport roller pair 37 for transporting the paper is arranged on the downstream side of the switch 35 in the paper transport path Rt1, and a discharge roller for discharging the paper to the outside of the apparatus main body Bd on the downstream side of the transport roller pair 37. A pair 38 is arranged, and a stacker 39 for loading the discharged paper is arranged outside the apparatus main body Bd.

Further, a transport roller pair 41 for transporting paper is arranged on the downstream side of the switch 35 in the paper transport path Rt1, and the paper is inverted and fed to the paper transport path Rt3 on the downstream side of the transport roller pair 41. A pair of reversing rollers 42 for transporting the inverted paper is arranged, and a pair of transport rollers 43 to 45 for transporting the inverted paper are arranged in the paper transport path Rt3.

Next, the operation of the printer 10 will be described.

In each image forming unit 11Bk, 11Y, 11M, 11C, the photoconductor drum 13 is rotated by a drive unit (not shown), and the charging roller uniformly charges the surface of the photoconductor drum 13. Next, the LED head 12 irradiates the photoconductor drum 13 with light corresponding to the image signal, and forms an electrostatic latent image as a latent image on the photoconductor drum 13. Subsequently, the developing roller develops the electrostatic latent image and attaches toner as a developer on the photoconductor drum 13 to form a toner image.

The paper contained in the paper cassette 14 is unwound by the pickup roller 15, separated one by one by the paper feed roller 16 and the separation roller 17, fed to the paper transport path Rt1, and transported by the transport roller pair 19. The skew is corrected by the resist roller pair 20, and is conveyed between the image forming units 11Bk, 11Y, 11M, 11C and the transfer unit u1 as the transfer belt 21 travels. Then, the toner image on each photoconductor drum 13 is sequentially superimposed on the paper and transferred, and a color toner image is formed on the paper. Subsequently, the paper is sent to the fuser 31 and passed through the nip portion formed between the heating belt 32 and the pressure roller 33 in the fuser 31, and the color toner image on the paper is displayed. It is heated and pressurized to fix it on the paper. In this way, a color image is formed on the paper.

In the case of single-sided printing, the paper on which the color image is formed is conveyed on the paper transport path Rt1 by the transport roller pair 37, discharged to the outside of the apparatus main body Bd by the discharge roller pair 38, and loaded on the stacker 39.

On the other hand, in the case of double-sided printing, the paper on which the color image is formed is fed to the paper transport path Rt2 by the switch 35, transported by the transport roller pair 41, and then inverted by the reversing roller pair 42 and the paper transport path. It is sent to Rt3, is conveyed by the transport roller pairs 43 to 45, and is sent to the paper transport path Rt1 again.

A temperature sensor 51 as a temperature detector is arranged in the fuser 31, and the temperature of the heating belt 32 is detected by the temperature sensor 51, and the detected temperature, that is, the detected temperature is a predetermined temperature of the apparatus main body Bd. It is designed to be sent to the control unit 46 arranged at the location. In the control unit 46, the detection temperature is compared with the preset fixing temperature, and when a control signal is generated and sent to the fuser control unit 47, the detection temperature of the fuser control unit 47 becomes the fixing temperature. As such, the power supplied to the heater 34 from a power source (not shown) is controlled.

In the present embodiment, as the temperature sensor 51, a non-contact temperature sensor arranged in the vicinity of the heating belt 32 without contacting the heating belt 32 is used.

By the way, while the paper on which the toner image is transferred is conveyed toward the fuser 31, it is affected by the behavior of the paper, static electricity generated in each part of the apparatus main body Bd, and the like before it is fixed on the paper. Toner, that is, unfixed toner, paper dust, etc. may be scattered. Further, if a paper jam occurs while the paper is being conveyed, the top cover Cst is opened by the operator and the paper is removed, but even at that time, the paper rubs against each part in the device main body Bd or vibrates. Unfixed toner, paper dust, etc. may scatter as a result of this.

In that case, if unfixed toner, paper dust, or the like adheres to the temperature sensor 51, the temperature of the heating belt 32 cannot be detected accurately.

Therefore, in the present embodiment, a ventilation device 50 having a tubular shape is arranged adjacent to the fixing device 31 between the image forming unit 11C and the fixing device 31 in the paper transport path Rt1, and the ventilation is provided. The temperature sensor 51 is arranged in a duct 52 as an air flow path of the device 50, and the temperature sensor 51 and the heating belt 32 are selectively (according to the operation of the top cover Cst) by a shutter 53 described later. ) It is designed to be opposed.

Further, a fan 55 as a ventilation device is arranged adjacent to the ventilation device 50, and the air flow generated by operating the fan 55 is sent to the ventilation device 50 and applied to the temperature sensor 51. It has become.

Next, the ventilation device 50 will be described.

FIG. 1 is a diagram showing an arrangement state of the ventilation device according to the first embodiment of the present invention, and FIG. 4 is a duct when the shutter according to the first embodiment of the present invention is placed at the first position. 1st figure showing the inside state, FIG. 5 is a second figure showing the state inside the duct when the shutter is placed in the first position in the first embodiment of the present invention, FIG. 6 is. It is a figure which shows the state in the duct when the shutter in the 1st Embodiment of this invention is placed in the 2nd position.

In the figure, 31 is a fuser, 32 is a heating belt, 33 is a pressure roller, Np is a nip portion formed between the heating belt 32 and the pressure roller 33, and Hg is a case as an outer casing of the fuser 31. The heating belt 32 is run in the case Hg, and the pressure roller 33 is rotated. Further, h1 is formed on the side wall Ws on the side facing the image forming unit 11C (FIG. 2) in the case Hg, and the opening as a medium inlet for introducing the paper on which the color toner image is transferred, and h2 is the side wall. It is an opening as a fuser opening for transmitting the radiant heat of the heating belt 32 to the temperature sensor 51, which is formed above the opening h1 in Ws.

The ventilation device 50 is arranged above the opening h1 in the side wall Ws and downstream of the fuser 31 in the paper transport path Rt1 so as to extend in the width direction of the paper, and the duct 52 of the ventilation device 50. One end, in the present embodiment, the fan 55 is disposed so as to face the front end in FIG. The air flow generated by the fan 55 enters the duct 52 through the air inlet Ei, passes through the duct 52, and exits from the air outlet Eo.

The duct 52 has a "U" -shaped cross section, a duct cover 57 as a first box-shaped body with the fuser 31 side open, and a "U" -shaped cross section. A duct plate 58 as a second box-shaped body with the image forming unit 11C side open is provided, and by fitting the duct plate 58 into the duct cover 57, the cross section has a substantially rectangular shape. A space Sp with both ends open is formed, and in the space Sp (inside the duct 52), a temperature sensor 51, a shutter 53 that selectively opposes the temperature sensor 51 and the heating belt 32, and the top cover Cst. A shutter opening / closing mechanism 60 or the like that moves the shutter 53 with opening / closing is arranged.

The duct cover 57 includes a bottom wall 57b, a side wall 57s and a top wall 57t, a duct plate 58 has a bottom wall 58b, a side wall 58s and a top wall 58t, and the duct plate 58 is fitted in the duct cover 57 and has a bottom. The wall 58b is placed on the bottom wall 57b and the top wall 58t is placed below the top wall 57t. Then, an opening h3 as a duct opening for transmitting the radiant heat of the heating belt 32 to the temperature sensor 51 is formed at a position corresponding to the opening h2 of the side wall Ws on the side wall 58s of the duct plate 58.

4 and 6 show the space Sp seen from the direction of arrow A in FIG. 1 when the duct plate 58 is removed in the duct 52, and FIG. 5 shows the space Sp when the duct cover 57 is removed in the duct 52. The space Sp seen from the direction of arrow B in FIG. 1 is shown, and the air inlet Ei is formed on the side facing the fan 55 and the air outlet Eo is formed on the opposite side.

Since the temperature sensor 51 receives the radiant heat of the heating belt 32 and detects the temperature, the heat receiving surface 51s is arranged so as to be slightly inclined downward toward the heating belt 32 in the present embodiment. To. Therefore, a pair of posts pt1 and pt2 are formed on the side wall 58s of the duct plate 58 so as to project toward the side wall 57s of the duct cover 57, and the holding plate 61 extends between the posts pt1 and pt2. The temperature sensor 51 is arranged so as to be inclined downward, and the temperature sensor 51 is attached to the holding plate 61 via a pair of holders 62.

Further, the shutter 53 is movably arranged between the duct 52 and the temperature sensor 51, that is, between the duct plate 58 and the holding plate 61 in the direction of arrow C. The shutter 53 is placed in the first position shown in FIGS. 4 and 5 in the normal state where the top cover Cst is closed, and the second position shown in FIG. 6 with the top cover Cst open. Placed in.

Therefore, a long groove m1 as a first locking portion having an oval shape is provided at one end of the shutter 53 in the longitudinal direction, and a second engagement having a U-shaped shape is provided at the other end. The U-groove m2 as a stop is formed, and the post pt1 is fitted in the long groove m1 and the post pt2 is fitted in the U-groove m2. Therefore, the shutter 53 is moved so that the posts pt1 and pt2 are guided by the long groove m1 and the U groove m2, respectively.

Then, the shutter 53 is formed with an opening h4 as a pair of shutter openings for facing the temperature sensor 51 and the heating belt 32 at a predetermined position, and the shutter 53 is placed at the first position. When the temperature sensor 51 and the heating belt 32 are opposed to each other via the openings h2 to h4 and the shutter 53 is placed at the second position, the temperature sensor 51 and the heating belt 32 are shut off by the shutter 53.

Sealing materials 65 and 66 are arranged on the upper and lower edges of the shutter 53 along the longitudinal direction of the shutter 53, and the space Sx between the side wall 58s of the duct plate 58 and the shutter 53 is above the shutter 53. The edges and lower edges are sealed by sealants 65, 66. The sealing materials 65 and 66 are slid with respect to the duct plate 58 as the shutter 53 is moved.

Further, the shutter opening / closing mechanism 60 is arranged on the arm 71 as an interlocking member disposed swingably around the post pt2 and the top cover Cst, and serves as an operation unit for opening / closing the top cover Cst. The lever 72, the slider 73 as a moving member moved in the vertical direction by operating the lever 72, the guide 74 for guiding the slider 73, the shutter 53, and the shutter 53 are arranged between the holding plate 61. A tension spring 75 or the like is provided as an urging member that urges the shutter 53 toward the air outlet Eo side, that is, in the direction of moving the shutter 53 from the first position to the second position.

The lever 72 includes an engaging protrusion 72a formed so as to project downward, and the slider 73 includes a pressed portion 73a at the upper end and a pressing portion 73b at the lower end. The arm 71 is provided with a pressing portion 71a at a predetermined location and a pressed portion 71b at another predetermined location. The shutter 53 includes a pressed portion 53a at an end on the air outlet Eo side.

Then, the engaging projection 72a of the lever 72 and the pressed portion 73a of the slider 73 are brought into contact with each other in the groove 74a formed in the guide 74, and the pressing portion 73b of the slider 73 and the arm 71 are outside the groove 74a. The pressed portion 71b of the arm 71 is brought into contact with the pressed portion 71b, and the pressed portion 71a of the arm 71 and the pressed portion 53a of the shutter 53 are brought into contact with each other.

A protrusion 73c is formed on the slider 73 so as to project toward the side wall 57s side of the duct cover 57 so that the slider 73 does not fall out of the groove 74a when the slider 73 is moved upward. When the stopper 74b is formed on the guide 74 and the slider 73 is moved upward by a predetermined amount, the protrusion 73c comes into contact with the stopper 74b and the slider 73 is stopped.

Next, the operation of the shutter opening / closing mechanism 60 will be described.

First, the operation of the opening / closing mechanism 60 when the operator operates the lever 72 from the state where the top cover Cst is opened to close the top cover Cst will be described.

When the top cover Cst is closed by the operator, the engaging projection 72a is inserted into the groove 74a, the slider 73 is pushed, and the slider 73 is moved downward. As a result, that is, with the movement of the slider 73, the arm 71 is rotated in the clockwise direction in FIG. 4 (counterclockwise direction in FIG. 5), and the shutter 53 urges the tension spring 75 (tensile force). ) Is moved to the air inlet Ei side and placed in the first position.

As a result, as shown in FIG. 1, the heating belt 32 and the temperature sensor 51 are opposed to each other via the opening h4 of the shutter 53, the opening h3 of the duct plate 58, and the opening h2 of the side wall Ws of the fuser 31. , The radiant heat of the heating belt 32 can be sufficiently transmitted to the temperature sensor 51.

Further, during this period, that is, while the paper on which the toner image is transferred is conveyed toward the fuser 31, it is not fixed due to the influence of the behavior of the paper, the static electricity generated in each part in the apparatus main body Bd, and the like. Toner, paper dust, etc. may be scattered, but not only the temperature sensor 51 is surrounded by the duct 52, but also the sealing materials 65 and 66 are attached to the upper and lower edges of the shutter 53. Arranged along the longitudinal direction, the space Sx between the side wall 58s of the duct plate 58 and the shutter 53 is sealed by the sealing materials 65 and 66, so that scattered unfixed toner, paper dust, etc. are opened. Even if it enters the duct 52 via h3, it only slightly enters the temperature sensor 51 side through the opening h4 of the shutter 53, and the air flow generated by the fan 55 passes through the duct 52. Since it passes through, it is possible to prevent unfixed toner, paper dust, and the like from adhering to the temperature sensor 51.

Since the air flow passes through the duct 52, the heat radiated from the heating belt 32 does not stay in the duct 52, and the temperature sensor 51 does not deteriorate.

Therefore, the temperature of the heating belt 32 can be accurately detected by the temperature sensor 51.

Next, the operation of the shutter opening / closing mechanism 60 when the operator operates the lever 72 from the state where the top cover Cst is closed to open the top cover Cst will be described.

If a paper jam occurs while the paper is being conveyed, the operator operates the lever 72 to clear the paper and the top cover Cst is opened, at which time the engagement protrusion 72a is placed outside the groove 74a. Then, the urging force of the tension spring 75 causes the arm 71 to be rotated in the counterclockwise direction in FIG. 4, and the slider 73 is pushed and moved upward.

As a result, as shown in FIG. 6, the shutter 53 is moved to the air outlet Eo side and placed in the second position, and the opening h4 of the shutter 53 is the opening h3 of the duct plate 58 and the side wall of the fuser 31. It is placed at a different position with respect to the opening h2 of Ws, and the heating belt 32 and the temperature sensor 51 are shut off by the shutter 53.

Therefore, when the operator removes the paper that has caused the paper jam, the unfixed toner, paper dust, etc. scattered as the paper rubs against or vibrates with each part in the device main body Bd opens. Even if it enters the duct 52 via h3, it is prevented from entering the temperature sensor 51 side through the opening h4 of the shutter 53, so that unfixed toner, paper dust, etc. adhere to the temperature sensor 51. Can be further prevented.

As a result, the temperature of the heating belt 32 can be accurately detected by the temperature sensor 51.

Next, a second embodiment of the present invention will be described. The same reference numerals are given to those having the same structure as that of the first embodiment, and the effects of the same embodiment are used for the effects of the invention due to having the same structure.

FIG. 7 is a diagram showing a state inside the duct when the shutter in the second embodiment of the present invention is placed in the first position, and FIG. 8 is a diagram showing a state inside the duct, and FIG. 8 is a control of the printer in the second embodiment of the present invention. It is a figure which shows the apparatus.

In the figure, 81 is a motor as a drive unit for moving the shutter 53 in the direction of arrow C, gr1 is a gear attached to an output shaft (not shown) of the motor 81, and gr2 is meshed with gear gr1 to rotate the motor 81. It is a gear (idle gear) that decelerates.

Further, the 73 is a slider as a moving member that is moved in the vertical direction with the driving of the motor 81, and a rack 73d is formed at the edge of the slider 73 on the air outlet Eo side, and the rack 73d and the gear are formed. It is meshed with gr2.

The rack 73d and the gear gr2 form a motion direction changing member, and the rotational motion of the gear gr2 is converted into a linear motion of the rack 73d.

Therefore, when the motor 81 is driven in the forward direction, in the present embodiment, in the counterclockwise direction, the slider 73 can be moved downward, and the motor 81 is moved in the reverse direction, in the present embodiment, the clock. When driven in the clockwise direction, the slider 73 can be moved upward.

The 82 is a cover sensor as an open / close detector that detects the opening / closing of the top cover Cst as a cover member by the operator operating the lever 72 (FIG. 1) as the operation unit, and controls the sensor output. Send to 46. When the control unit 46 generates a control signal based on the sensor output and sends it to the fuser control unit 47, the fuser control unit 47 turns the motor 81 in the clockwise direction when the top cover Cst is opened. , And when the top cover Cst is closed, the motor 81 is driven in the counterclockwise direction.

Further, reference numeral 60 denotes a shutter opening / closing mechanism, in which the shutter opening / closing mechanism 60 includes an arm 71 as an interlocking member oscillatingly arranged around a post pt2, the motor 81, a cover sensor 82, gears gr1, gr2, and the like. A slider 73, a guide 74 for guiding the slider 73, a tension spring 75 as an urging member arranged between the shutter 53 and the holding plate 61 and urging the shutter 53 toward the air outlet Eo side, and the like are provided. .. The arm 71 moves the shutter as the slider 73 moves.

In the present embodiment, the engagement protrusion 72a (FIG. 4) is not formed on the lever 72, and the pressed portion 73a of the slider 73 has the engagement protrusion 72a in the groove 74a formed in the guide 74. Will not be brought into contact with.

Next, the operation of the shutter opening / closing mechanism 60 will be described.

When the top cover Cst is closed by the operator, the fuser control unit 47 drives the motor 81 in the counterclockwise direction and moves the slider 73 downward. As a result, the arm 71 is rotated in the counterclockwise direction in FIG. 7, and the shutter 53 is moved toward the air inlet Ei side against the urging force (tensile force) of the tension spring 75, and is in the first position. Placed in.

As a result, as shown in FIG. 1, the opening h4 as the shutter opening of the shutter 53, the opening h3 as the duct opening of the duct plate 58 as the second box-shaped body, and the fixing device 31 as the fixing device. Since the heating belt 32 as the first fixing member and the temperature sensor 51 as the temperature detector are opposed to each other through the opening h2 as the fixing opening of the side wall Ws, the radiant heat of the heating belt 32 is transferred to the temperature sensor 51. Can be fully communicated to.

Further, during this period, that is, while the paper as the medium to which the toner image as the developer image is transferred is conveyed toward the fuser 31, the behavior of the paper, static electricity generated in each part in the apparatus main body Bd, etc. The unfixed toner, paper dust, etc. may be scattered due to the influence of the above, but it is possible to prevent the scattered unfixed toner, paper dust, etc. from adhering to the temperature sensor 51.

Further, the heat radiated from the heating belt 32 does not stay in the duct 52 as an air flow path, and the temperature sensor 51 does not deteriorate.

Therefore, the temperature of the heating belt 32 can be accurately detected by the temperature sensor 51.

Further, if a paper jam occurs while the paper is being conveyed, the lever 72 is operated by the operator to remove the paper, and the top cover Cst is opened. However, when the top cover Cst is opened, the fuser control unit 47 drives the motor 81 in the clockwise direction and moves the slider 73 upward. At this time, the urging force of the tension spring 75 causes the arm 71 to rotate in the clockwise direction in FIG. 7.

As a result, as shown in FIG. 6, the shutter 53 is moved to the air outlet Eo side by the urging force of the tension spring 75 and placed in the second position, and the opening h4 of the shutter 53 is the opening of the duct plate 58. The heating belt 32 and the temperature sensor 51 are blocked by the shutter 53 at different positions with respect to the opening h2 of the side wall Ws of the h3 and the fuser 31.

Therefore, when the operator removes the paper that has caused the paper jam, the unfixed toner, paper dust, and the like scattered as the paper rubs against or vibrates with each part in the apparatus main body Bd are the temperature sensor 51. It can be prevented from adhering to.

As a result, the temperature of the heating belt 32 can be accurately detected by the temperature sensor 51.

Although the printer 10 is described in each of the above embodiments, the present invention can be applied to an image forming apparatus such as a copying machine, a facsimile, and a multifunction device.

It should be noted that the present invention is not limited to each of the above-described embodiments, and various modifications can be made based on the gist of the present invention, and these are not excluded from the scope of the present invention.

10 Printer 11Bk, 11Y, 11M, 11C Image forming unit 13 Photoreceptor drum 31 Fuser 32 Heating belt 50 Ventilation device 51 Temperature sensor 52 Duct 53 Shutter 55 Fan u1 Transfer unit

Claims (8)

(A) An image forming unit that forms a developer image on an image carrier, and
(B) A transfer unit that transfers the developer image on the image carrier to a medium, and
(C) A fixing device provided with a fixing member and fixing a developer image transferred to a medium, and a fixing device.
(D) A ventilation device arranged adjacent to the fixing device and extending in the width direction of the medium.
(E) It has a ventilation device that sends an air flow to the ventilation device, and also has a ventilation device.
(F) The ventilation device is a duct that forms the air flow from one end side to the other end side in the width direction of the medium by the ventilation device, and a temperature that is disposed in the duct to detect the temperature of the fixing member. It is provided with a detector and a shutter that is movablely arranged between the duct and the temperature detector and selectively opposes the temperature detector and the fixing member .
(G) an image forming apparatus according to claim Rukoto duct opening is formed at a position corresponding to the temperature detector in disposed sidewalls between one end and the other end of the duct. The image forming apparatus according to claim 1, wherein the space between the side wall of the duct and the shutter is sealed by a sealing material. (A) It has a cover member that can be opened and closed in the housing of the image forming apparatus, and also has a cover member.
(B) A shutter opening is formed at a predetermined position of the shutter, and the shutter opening is formed.
(C) The shutter is placed in the first position with the cover member closed, the temperature detector and the fixing member face each other through the shutter opening, and the cover member is opened. The image forming apparatus according to claim 1, which is placed at a second position and shuts off the temperature detector and the fixing member. Before SL shutter is placed in a first position with the cover member is closed, through the shutter opening and the duct opening is opposed to the fixing member and the temperature detector, wherein the cover member is opened The image forming apparatus according to claim 3 , which is placed in a second position in a state and shuts off the temperature detector and the fixing member. The image forming apparatus according to claim 3 or 4 , wherein the ventilation device includes a shutter opening / closing mechanism for moving a shutter in a duct when the cover member is opened / closed. The fifth aspect of the present invention, wherein the shutter opening / closing mechanism includes a lever of the cover member, a moving member that is moved by the operator operating the lever, and an interlocking member that moves the shutter with the movement of the moving member. Image forming device. The shutter opening / closing mechanism includes a lever of the cover member, a cover sensor that detects opening / closing of the cover member by the operator operating the lever, a motor driven based on the sensor output of the cover sensor, and driving of the motor. The image forming apparatus according to claim 5 , further comprising a moving member that is moved along with the moving member and an interlocking member that moves the shutter with the movement of the moving member. The image forming apparatus according to any one of claims 5 to 7 , wherein the shutter opening / closing mechanism includes an urging member that urges the shutter in a direction of moving the shutter from a first position to a second position.

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