JPH06230617A - Image forming device - Google Patents

Abstract

PURPOSE:To provide an image forming device whose reliability is improved by enhancing heat exhausting efficiency in the whole device without preventing the image forming device from being made light in weight. CONSTITUTION:An air intake port 66 taking air inside a printer main body and an air exhausting port 67 exhausting the air to the outside of the printer main body are provided. A fan device 65 is arranged in an air passage to the port 67 from the port 66. Besides, a controller unit 56, a power source part 81 and a fixing unit 37 are successively arranged from the upstream side to the downstream side of the air flow generated by the fan device 65.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming device, and more particularly to an image forming device having improved heat exhaust efficiency.

[0002]

2. Description of the Related Art An image forming apparatus for forming a toner image on a recording sheet by an electrophotographic copying method such as a laser beam printer is provided with an optical system device inside a frame of an image forming apparatus body.
A large number of mechanical devices such as electric devices and rollers are stored. These devices are arranged in consideration of mutual functionality in the frame, but maintainability or safety,
It is placed in consideration of reliability.

For example, an optical system unit that outputs a laser beam in response to a control signal such as image data from a host computer, and an image forming cartridge that transfers a toner image to a recording paper by being exposed to the laser beam from the optical system unit are used. Generally, functionally, they are arranged adjacent to each other substantially in the center of the frame. Then, a fixing unit that heats the transferred toner image to the recording sheet and has a high temperature is provided downstream of the recording sheet being conveyed through the image forming cartridge. Further, a controller unit is provided in the image forming device, and thereby various rollers, the optical system unit and the like are controlled. Since this controller unit has a substrate on which electrical components such as a CPU and a memory are attached, it generates a certain amount of heat, but it is necessary to keep it within a certain temperature range to ensure reliability. Need to consider. For this reason, the controller unit is arranged at the end of the frame and is provided with a ventilation hole so that it is cooled by natural convection with the outside air. Furthermore, in order to enhance the cooling effect,
In many cases, a fan device for forcibly blowing air is provided. Further, the power supply unit for supplying external electric power further generates heat than the controller unit, and although its heat resistance is higher than that of the controller unit, it must be arranged so that it can be used within a certain temperature range. Therefore, in consideration of the cooling effect and the safety when an operator puts his / her hand from the outside, the power supply unit is arranged at a lower position in the frame which is not directly touched by the hand.

[0004]

However, in recent years, in order to downsize the entire image forming apparatus, it is inevitable that the devices are collectively arranged in a limited space in the frame body. The heat generated in the image device tends not only to directly affect each other, but also heat is likely to be collected. For example, heat generated in the fixing unit, which is extremely high in function, flows into the vicinity of the power supply unit or the controller unit, or heat generated in the power supply unit flows into the vicinity of the controller unit. In such a case, a sufficient cooling effect cannot be expected only by natural convection by the external air. Also, providing independent cooling fan devices near the controller unit and power supply unit that require cooling leads to an increase in the number of parts, which not only increases costs but also reduces the weight of the image forming apparatus as a whole. Even above is not preferable.

The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to improve the heat dissipation efficiency of the entire image forming apparatus without hindering the weight reduction of the image forming apparatus. It is an object of the present invention to provide an image forming apparatus having improved property.

[0006]

SUMMARY OF THE INVENTION To achieve the above object, the present invention comprises an image forming means for forming a toner image on a recording paper,
In an image forming apparatus having a heat fixing unit for thermally fusing the toner image to a recording sheet, a control unit for controlling these operations, and a power supply unit for supplying external power, an air is formed in the image forming unit. An air inlet for taking in air and an air outlet for discharging air to the outside of the image forming apparatus, and an air blower is arranged in an air passage extending from the air inlet to the air outlet. The image forming apparatus is characterized in that the control unit, the power supply unit, and the heat fixing unit are arranged in order from the upstream side to the downstream side of the air flow generated by.

[0007]

The air blower is arranged in the air passage extending from the air intake to the air outlet, and the control means, the power source, and the heat fixing are arranged in order from the upstream side to the downstream side of the air flow generated by the air blower. By arranging the means, the external air taken in flows from the control means having a small heat generation amount to the power source part having a large heat generation amount and the heat fixing means in order, and is discharged to the outside. With this arrangement, since the device arranged on the upstream side has a small amount of heat generation, all the devices are always efficiently cooled without adversely affecting the device arranged on the downstream side.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 is a perspective view showing the entire structure of a laser beam printer according to an embodiment of the present invention, FIG. 2 is a sectional view schematically showing the internal structure of the printer body shown in FIG. 1, and FIG.
FIG. 3 is a left side view showing the printer body shown in FIG. 1.

The laser beam printer 11 shown in FIG.
A printer main body 12 as an image forming device having a built-in sheet storage portion 22 (see FIG. 2) for storing recording paper, and a paper feed unit 13 auxiliary attached to the bottom side of the printer main body 12.

The printer body 12 is connected to a host computer (not shown) via an interface cable, receives image data and control signals sent from the host computer, and forms a toner image on a recording sheet. still,
Reference numeral “16” in FIG. 1 denotes a power switch of the printer body 12.

The paper feeding unit 13 includes a paper feeding cassette 14 that holds recording paper, and this paper feeding cassette 14 is the printer 1.
1 and a unit main body 15 loaded from the front side (the front left side in the drawing). The paper feed cassette 14 usually contains recording paper of a size different from the paper size of the recording paper held in the sheet storage unit 22, and the recording paper manually selected by the operator or a control signal from the host computer. A toner image is formed on the recording sheet automatically selected according to the above. In the illustrated example, the number of sheet feeding units 13 is only one, but it is also possible to attach a plurality of sheet feeding units 13 to the printer body 12 in a stacked state.

The internal structure of the printer body 12 is as shown in FIG. 2, and the machine frame body (frame) 2 forming the image forming apparatus body is shown.
1 is composed of a bottom wall 21a, a front wall 21b, a back wall 21c, a right side wall 21d (see FIG. 1) and a left side wall 21e. On the bottom wall 21a side of the machine frame 21, a seat accommodating portion 22 is built in, which is inclined downward toward the rear of the machine frame 21,
Recording sheets are stacked and held on the sheet storage section 22. The front end of the sheet storage portion 22 can be projected to the outside of the machine frame body 21, and when holding a long recording sheet of legal size or the like, the front end portion of the sheet storage portion 22 is projected. Become. Further, in order to regulate the width direction of the recording paper, the sheet containing portion 22 is provided with a width regulating plate 23.

In order to facilitate the loading of the recording paper into the sheet accommodating portion 22, the printer body 12 has a paper loading port 42 for loading the recording paper into the sheet accommodating portion 22 of the sheet accommodating portion 22. It is provided in the upper position. The paper loading port 42 is provided with a paper feed cover 24 for opening and closing the loading port 42. Paper feed cover 2
4 is formed of a resin material and extends from the substantially central portion of the upper surface of the machine frame 21 toward the front side of the printer body 12. Further, the paper feed cover 24 is attached to the machine frame 21 so as to be openable and closable in the vertical direction around a hinge portion 29 provided at a substantially central portion of the machine frame 21. Further, as shown in FIGS. 1 and 2, the paper feed cover 24 also has a function of a paper discharge tray for holding the recording paper P on which an image is formed and discharged, and the upper surface of the recording paper is covered. A sheet receiving surface 24a for holding the sheet is formed.

A top cover 27 is attached so as to be swingable about a hinge portion 26 provided at the rear end of the machine frame 21,
The printer body 12 has a clamshell type structure. The image forming means 8 is provided at the center of the machine frame 21.
5 (see FIG. 4) is provided, and the image forming means 85 is provided.
Has a laser beam scanning optical system unit 25 and an image forming cartridge 30. Image forming cartridge 30
Is located below the top cover 27 and is detachably attached. When the image forming cartridge 30 is loaded in the machine frame 21, the image forming cartridge 30 is pressed by a pressing member or a spring member (not shown) attached to the inner surface of the top cover 27. Also, the top cover 2
7 is provided with a lock mechanism (not shown), and when the upper cover 27 is closed, the upper cover 27 can be locked to the machine frame 21 by the lock mechanism, while an opening / closing lever provided on the upper surface of the upper cover 27. When the lock is released by operating 28 (see FIG. 1), the top cover 27 can be opened.

The recording sheets placed on the sheet accommodating portion 22 are fed one by one by the sheet feeding roller 31 and the cam 32 and the pinch roller 33 contacting them, and are guided while being guided by the guide member. Then, the sheet is discharged from the sheet discharge port 34 formed in the upper cover 27 onto the upper cover 27 and the paper feed cover 24 in the front direction of the printer.
In order to discharge the recording paper P on which an image is formed through the paper discharge port 34, a pair of paper discharge rollers 4 is provided inside the top cover 27.
1 is attached.

A photosensitive drum 35 is rotatably incorporated in the image forming cartridge 30, and a developing sleeve 51 is provided adjacent to the photosensitive drum 25. For the developing sleeve 51, the toner tank 5
The toner accommodated in 2 is supplied. Photoconductor drum 3
A charging brush (not shown) is in contact with the outer peripheral surface of 5, and the outer peripheral surface is charged to a predetermined potential by this charging brush. The image forming cartridge 30 having such a structure is also referred to as an image cartridge, an image forming unit or a process cartridge, and is replaced with a new one by the life of the photosensitive drum 35 or the use of toner. A transfer roller 36 for transferring the latent image formed on the photosensitive drum 35 onto the recording paper is rotatably attached to the machine frame 21.

In order to heat-fuse the transfer image on which the latent image formed on the photosensitive drum 35 is transferred onto the recording paper, a fixing unit 37 as a heat fixing means is provided at the upper rear part of the machine frame 21. Is provided. In the casing 38 of the fixing unit 37, a fixing roller 39 which is heated by a heater amplifier (not shown) and a pressure roller 40 which is in pressure contact with the fixing roller 39 are rotatably mounted. This fixing unit 37 consumes 400 watts of power,
This is the highest temperature portion in the machine frame 21 due to the functional requirement of heat fixing. The temperature is about 160 ° C during standby and reaches 180 ° C to 190 ° C during printing.

The optical system unit 25 has a Bolgon mirror 45 which is irradiated with light from a light source composed of a semiconductor laser and a collimator lens (not shown), and further includes known members such as a folding mirror 46 and a toroidal mirror 47. Have From the optical system unit 25, the laser beam that has passed through the glass 48 provided in the window is applied to the photosensitive drum 35 in the image forming cartridge 30.

The bottom wall 21a of the machine frame 21 is provided with a paper feed port 53 for taking the recording paper contained in the paper feed unit 13 into the printer body 12. A space below the sheet storage portion 22 in the machine frame 21 is defined as a controller storage chamber 55, which serves as a control unit for controlling image data processing from the host computer and various rollers and the optical system unit 25. The controller unit 56 is stored.

The controller unit 56 is a CPU
It has a substrate 57 to which electrical components such as a memory and a memory are attached, and a support plate 58 to which one end of the substrate 57 is fixed. As shown in FIG. 3, the support plate 58 is provided with two types of connectors, a parallel interface connector 83 and a serial interface connector 82, in order to match the type of interface used and various communication parameters with those of the host computer. There is. The controller unit 56 is set in the machine frame 21 by being inserted into the machine frame 21 from a mounting opening 60 formed on the left side wall 21e of the machine frame 21 and screwing a support plate 58 to the left wall 21e. To be done. The mounting opening 60 is closed by the support plate 58 when the controller unit 56 is set. In FIG. 2, reference numeral “61” is attached to the bottom wall 21 a and is the printer body 1
2 shows a guide plate extending in the left-right direction, and the guide plate guides the substrate 57 when the controller unit 56 is inserted into the machine frame 21. Further, reference numeral "62" indicates a font cartridge connector provided on the substrate 57, and a font cartridge 63 used as an auxiliary is inserted from a slot 64 formed in the front wall 21b and connected to the connector 62. To be done. Since the controller unit 56 has semiconductor elements such as a CPU and a memory, it consumes about 10 watts and generates a small amount of heat, but the ambient temperature is 70 ° C. to 80 ° C. or lower from the viewpoint of operational reliability. There is a need to.
For this reason, the support plate 58 is formed with an air intake 66 composed of a large number of intake holes. Then, the outside air is taken in through the air intake port 66, and the air is distributed on the board 57 to which electric components such as the CPU and the memory are attached to cool it.

Further, in consideration of safety, a power source section 81 (see FIG. 4) is provided along the right side wall 21d on the bottom wall 21a of the machine frame 21 which is not directly touched by the hand. From the outside, external power is supplied to the fixing unit 37, the controller unit 56, the roller driving motor, and the like. The power supply unit 81 consumes 40 to 50 watts of electric power and generates more heat than the controller unit 56. Although the heat resistance of the power supply unit 81 is higher than that of the controller unit 56, it is necessary to consider so that it can be used within a temperature range of about 90 ° C. or lower.

On the rear wall 21c of the machine frame 21, a fan device 65 as a blowing means is attached which is composed of a fan and a fan motor for driving the fan. When the power switch 16 is turned on, the fan device 65 is also supposed to operate, and heat generated in the machine frame 21 is supplied from the air outlet 67 provided on the rear wall 21c to the machine frame 21.
The air is blown out to the outside.

Next, the heat exhausting action of the printer body 12 according to this embodiment will be described. FIG. 4 shows the printer body 12
FIG. 5 is a schematic vertical sectional view showing the flow of air in the printer body 12, and FIG. 5 is a plan view schematically showing the flow of air in the printer body 12. According to this embodiment, as shown in FIG.
An air discharge port 67 for discharging air from the air intake port 66 that takes in air into the printer body 12 to the outside of the printer body 12.
An air passage D having a substantially U-shape is formed (direction A in the drawing). That is, as also shown in FIG. 4, the external air taken in through the air intake 66 provided in the support plate 58 of the controller unit 56 in accordance with the operation of the fan device 65 is directly moved upward by the sheet accommodation portion 22. It is prevented from flowing (see FIG. 4) and is sent to the right side wall 21d along the front wall 21b while passing over the substrate 57 of the controller unit 56. The air is further sent rearward along the side wall 21d, passes through the power supply unit 81, reaches the rear surface wall 21c, and goes around to the fixing unit 37. An air passage D that is discharged to the outside is formed. The fixing unit 37 does not need to be actively cooled in terms of its function, and is arranged so that the generated heat is discharged to the outside of the printer main body without flowing into other devices. Some air flow in the B direction will also occur. Here, the air passage D is not a passage formed by being partitioned in the main body, but since the air resistance is significantly smaller than that of other portions, the air flow as described above is generated. ing.

Further, the controller unit 5 is arranged in order from the upstream side to the downstream side of the air flow generated in this way.
6, the power supply unit 81 and the fixing unit 37 are arranged. Therefore, the taken-in external air flows to the power supply unit 81 and the fixing unit 37 having a large heat generation amount in order from the controller unit 56 having a small heat generation amount. It will be discharged to the outside. With such an arrangement, since the device arranged on the upstream side has a small amount of heat generation, all the devices are always efficiently cooled without adversely affecting the device arranged on the downstream side. As a result, the controller unit 56 can always be directly cooled by the external air.
It becomes possible to suppress the temperature to 0 ° C. to 60 ° C. or less. Further, since the air that has passed through the controller unit 56 is not so high in temperature, the power supply unit 81 is also cooled sufficiently and sufficiently. Moreover, the fixing unit 37 which becomes extremely hot
The heat of will not flow into other equipment and have a bad effect. Therefore, reliability is improved by increasing the exhaust heat efficiency. Furthermore, since the above-mentioned air passage is formed, the fan device 65 provided on the rear wall 21c of the machine frame body 21 for exhaust is sufficient to generate the flow of air for exhaust heat, and the controller is used. A fan device dedicated to the unit 56 is not particularly necessary. Therefore, the cost can be reduced and the weight of the printer body can be reduced.

The present invention is not limited to the above-mentioned embodiments, but can be variously modified within the scope of the claims. For example, in the present embodiment, the fan device 65 for exhaust is provided near the air outlet 67, but a fan device for intake is provided near the air inlet 66, or a fan device for blowing air in the air passage. May be provided.

[0026]

As described above, in the image forming apparatus of the present invention, the air blowing means is arranged in the air passage extending from the air intake opening to the air exhaust opening, and the air flow generated by the air blowing means is upstream. By arranging the control unit, the power supply unit, and the heat fixing unit in this order from the downstream side to the downstream side, the external air taken in has a large heat generation amount in order from the control unit having a small heat generation amount, and the heat fixing unit. Will be discharged to the outside. With this arrangement, since the device arranged on the upstream side has a small amount of heat generation, all the devices are always efficiently cooled without adversely affecting the device arranged on the downstream side. As a result, the control means can always be cooled directly by the external air and can be kept at a predetermined temperature. Further, since the air that has passed through the control means is not so high in temperature, the power supply section is also cooled sufficiently and sufficiently.
Moreover, the heat of the heat fixing unit, which becomes extremely high, does not flow into other devices and have a bad influence. Therefore, reliability is improved by increasing the exhaust heat efficiency. further,
Since the above-mentioned air passage is formed, it is not necessary to provide a plurality of fan devices to generate the flow of air for exhaust heat, which leads to cost reduction and weight reduction of the image forming device.

[Brief description of drawings]

FIG. 1 is a perspective view showing the overall structure of a laser beam printer according to an embodiment of the present invention.

FIG. 2 is a sectional view schematically showing the internal structure of the printer body shown in FIG.

FIG. 3 is a left side view showing the printer body shown in FIG.

FIG. 4 is a schematic vertical sectional view showing the flow of air in the printer body.

FIG. 5 is a plan view schematically showing the flow of air in the printer body.

[Explanation of symbols]

12 ... Printer main body (image forming device) 21 ... Machine frame (image forming device main body) 37 ... Fixing unit (thermal fixing means) 56 ... Controller unit (control means) 65 ... Fan device (blowing means) 66 ... Air intake Port 67 ... Air outlet 81 ... Power supply unit 85 ... Image forming means P ... Recording paper

Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location B41J 29/377

Claims (1)

[Claims] 1. An image forming unit for forming a toner image on a recording sheet,
An image forming apparatus comprising: a heat fixing unit for thermally fusing the toner image to a recording sheet; a control unit for controlling these operations; and a power supply unit for supplying external power. An air intake port for taking in air and an air exhaust port for exhausting air to the outside of the image forming apparatus, and an air blowing unit is arranged in an air passage extending from the air intake port to the air exhaust port. An image forming apparatus in which the control unit, the power supply unit, and the heat fixing unit are arranged in order from the upstream side to the downstream side of the air flow generated by the above.