JP4566042B2 - Image forming apparatus - Google Patents

Description

The present invention relates to an image forming apparatus that forms a visible image on a recording medium, and more particularly to an image forming apparatus having a temperature control function inside the image forming apparatus.

2. Description of the Related Art Today, electrophotographic apparatuses are increasing in color, such as color copiers and color printers, according to market demands. A color electrophotographic apparatus is provided with a developing device of a plurality of colors around one photoconductor, and a toner is attached by these developing devices to form a composite toner image on the photoconductor, and the toner image is transferred. Recording a color image on a sheet, so-called 1
A drum type and a plurality of photoconductors arranged side by side are each provided with a developing device, and a single color toner image is formed on each photoconductor, and the single color toner images are sequentially transferred to form a composite color image on a sheet. There is a so-called tandem type recording.

Comparing the 1-drum type and the tandem type, the former has only one photoconductor, so that there is an advantage that it can be relatively downsized and cost can be reduced. (4 times) Since image formation is repeated to form a full-color image, it is difficult to speed up image formation. The latter, on the contrary, has the disadvantage of increasing the size and cost, but it is easy to speed up image formation. There is an advantage that is.

Recently, tandem type has been attracting attention because the demand for full-color monochrome speed is desired. In the tandem type electrophotographic apparatus, as shown in FIG.
An image visualized by the developing roller 500 on 0 (hereinafter, Y, C, M, and K are given for each color in the figure, but omitted in this description) is transferred to the registration roller 700 by the transfer device. In the direct transfer system in which the sheet fed by the sheet is conveyed by the sheet conveying belt 250 and sequentially transferred to the sheet, as shown in FIG. 5, the images on each photoconductor 100 are temporarily transferred to the intermediate transfer belt by the primary transfer device. After sequentially transferring to 200, the image on the intermediate transfer belt 200 is transferred to 2
There is an indirect transfer method in which a next transfer device performs batch transfer onto a sheet. Secondary transfer device 30
Although 0 is a roller shape in the figure, there is also a belt shape.

Comparing the direct transfer type with the indirect transfer type, the former is that the sheet fluctuates on the sheet conveying belt 250 in order to transfer the conveyed sheet directly from each photosensitive member 100. There is a drawback that the image written on each photoconductor 100 is shifted. On the other hand, in the latter, the secondary transfer position can be set relatively freely, and even when the speed of the conveyed sheet fluctuates, the image is transferred to the sheet by each photoconductor 100. Since the images already match, the image does not shift even if the sheet speed fluctuates. In view of the above, recently, an indirect transfer type of tandem type electrophotographic apparatus has attracted attention.

At this time, from the viewpoint of reducing the size of the machine, it is configured such that the fixing device 800 is pulled down to the lower side of the intermediate transfer belt 200 together with the higher density inside the machine.
On the other hand, the fixing device 800 was close. In addition, the amount of heat generated inside the machine also increases due to the increase in the speed of the machine, and the fixing device 800, which is a heating element, causes the belt device, which is an image forming unit, to be thermally affected, causing image defects such as color misregistration. It has come to end.

Furthermore, the conditions are more severe during double-sided printing. Here, an indirect transfer type machine will be described, but after an image is formed on one side of a recording sheet, an image is formed on the back side. That is, since the recording paper heated by the fixing unit 800 passes through the duplex unit and comes into contact with the intermediate transfer belt 200 again at the secondary transfer unit, the temperature of the intermediate transfer belt 200 increases due to heat transfer from the recording paper. In addition, heat is transmitted to the drum in contact with the intermediate transfer belt 200 and further to the developing unit, and image defects due to belt deformation and problems such as solidification of toner are more likely to occur.

As a countermeasure, there are many devices that transport heat directly from the cooling section through a duct and exhaust it from the exhaust port by a fan. However, as mentioned above, the heat generation section found in high-speed color copiers has increased. It is becoming very difficult to solve the above problems due to downsizing of the high density device in the device.

However, an expensive cooling device cannot be mounted within a limited cost, and the in-machine cooling during operation must be performed while making full use of cooling by a fan. And even if the temperature inside the machine can be reduced by using multiple fans when the machine is operating, the fan cannot be used under the same conditions as during operation due to noise and power restrictions during standby. The fan is stopped or the number of rotations is reduced. For this reason, even when the fixing temperature is lower than that at the time of operation, the in-machine temperature becomes stricter than that at the time of operation because this continues for a long time. Therefore, especially in a machine having a small size, high density, and high heat generation part such as a high-speed color electrophotographic apparatus, a countermeasure against temperature rise during standby becomes a very big problem.

  Furthermore, if the machine is left in an abnormally high temperature environment exceeding the operating environment temperature and turned on, the internal temperature will be raised by the amount exceeding the operating environment temperature, so the internal temperature will be higher. In a machine with a small margin with respect to temperature, the possibility of occurrence of a failure is very high. Note that the standby here refers to a standby state in which the machine is not performing a printing operation, and the fixing unit maintains a certain high temperature due to a balance between the machine rise time and the power consumption during standby. In addition, since the noise regulation is severe during standby, cooling means such as a fan cannot be operated so much.

Moreover, the invention disclosed in Patent Document 1 is known as an example in which a temperature sensor is provided in a cooling required portion and the fan control is changed depending on the temperature. According to the present invention, in addition to the thermistor of the fixing unit, temperature sensors are also provided at portions where the temperature is weak, such as a toner storage portion, and the control of the fan is changed based on these.
JP 2001-75460 A

However, the scanner unit, writing unit, toner replenishing unit, waste toner collecting unit,
Locations that are vulnerable to heat such as developer, motor, and electrical component temperatures are dispersed, and it is difficult to cover all locations. For this reason, the sensor installation position is limited depending on the location having the smallest margin with respect to the most permissible temperature and the content of the trouble at high temperatures, and in some cases, a large number of temperature sensors are required. However, in any of these cases, several dedicated temperature sensors are required, resulting in an expensive machine.

The present invention has been made in view of such a background, and the object thereof is to suppress an increase in the in-machine temperature in spite of an increase in the density in the apparatus, and in particular, in terms of the in-machine temperature. Even when the machine is placed in a high temperature environment during severe standby, it is possible to reliably prevent an increase in the temperature inside the machine and prevent image defects such as toner solidification and color misregistration. is there.

In order to achieve the above object, the first means includes a temperature detection means for detecting an in-machine temperature of the apparatus main body having an image forming means, an internal cooling means for lowering the in-machine temperature, and a standby state where no image is formed. The detected temperature detected by the temperature detecting means is compared with a preset temperature, and if the detected temperature is equal to or higher than the set temperature, the operation of the internal cooling means is controlled so as to lower the internal temperature. Control means, and heat insulation means for blocking between the temperature detection means and the paper feed cassette of the paper feed device in the machine, and the temperature detection means is provided at the lowest position in the machine away from the heat source. The set temperature is an upper limit temperature of a use environment temperature range determined in use of the image forming apparatus .

Thus, during the standby, the detected temperature (T) detected by the temperature detecting means is compared with the preset temperature (T1), and when T is detected as T1 or more, the operation of the internal cooling means is performed. Since it was started, the internal temperature during standby is prevented from rising excessively, toner deterioration (melting, sticking, etc.) handled in the image forming unit is prevented, and malfunction such as malfunction caused by high temperature of mechanism members and electronic parts Can be prevented, and the reliability of the image forming apparatus is improved.
Also, with this setting, the temperature sensor is less affected by the heat of fixing, so the detected temperature is close to the outside temperature,
Set temperature = upper limit temperature of the operating environment temperature range
As a result, the internal cooling means operates only when the operating environment temperature range is exceeded, that is, only under an abnormally high temperature environment, eliminating unnecessary operations, reducing standby power consumption, and achieving low noise. it can.
Further, since the temperature detecting means is provided at the lowermost part in the apparatus, the temperature detecting means is not affected by the fixing heat at all, so that the detected temperature becomes equal to the outside air temperature, and the outside air environment can be accurately recognized. As a result, abnormally high temperature environments can be reliably detected, malfunctions such as toner alteration (melting, sticking, etc.), malfunctions due to high temperatures of mechanism members and electronic components can be reliably prevented, and low noise and A low-power image forming apparatus can be provided. Further, the fixing temperature can be accurately controlled according to the environment by using the temperature detection means, for example, the temperature detected by the temperature sensor, and the cost can be reduced.
Furthermore, even when the heater for eliminating the influence of the humidity of the recording paper in the paper feeder is activated, the heat insulation means can prevent the influence of the heater heat on the temperature detection means, so that the detected temperature = outside air It becomes possible to maintain the temperature relationship, and it is possible to reliably prevent problems in an abnormally high temperature environment.

The second means is the first means, wherein the image forming means includes an image forming section including a photoconductor for forming a toner image, a toner replenishing section for supplying toner to the image forming section, and the image forming section. A transfer unit that transfers the toner image formed on the recording sheet supplied from the paper feeding device, a fixing unit that fixes the transferred toner image on the recording sheet, and a recording sheet that is fixed by the fixing unit is discharged. And a paper discharge means.

Since the electrophotographic image forming apparatus includes a fixing unit (fixing device) as a heat source, it is particularly effective for this type of image forming apparatus having a heat source in the apparatus.

The third means is characterized in that, in the second means, the fixing means is the heat source .

The provision of temperature detecting means to the position of the flight lowermost away from the heat source, there is no the temperature detecting means thereby to detect the temperature of normal operation emanating naturally from the fixing means, is possible to improve the reliability it can.

A fourth means is characterized in that, in any one of the first to third means, the lowermost position in the apparatus is a lower portion of a waste toner bottle installed at a position across the heat insulating means .

Since the temperature detecting means is provided in the lower part of the waste toner bottle that is easily affected by heat, it is possible to reliably prevent the temperature of a portion that is vulnerable to heat, for example, the toner supply unit.

The fifth means is characterized in that in any one of the first to fourth means, there is provided an informing means for informing a current in-flight situation and / or an operating state of the internal cooling means.

The sixth means sets the second set temperature in the fifth means, and when the temperature detecting means detects that the in-machine temperature exceeds the second set temperature, the notifying means Notification is made that the cooling operation by the cooling means is started.

Notifying means, for example, displaying the current in-flight situation or the operating status of the cooling means on the display unit of the operation panel to inform the user of the countermeasures to be performed internally, so that the user can understand that there is no abnormality This makes it possible to provide a user-friendly image forming apparatus.

If such notification is given, the user can be informed in advance that the fan will suddenly start rotating during standby and the wind noise will increase, so that the user can understand that there is no abnormality, so that a more friendly image forming apparatus can be provided. it can.

The seventh means includes a measurement means for measuring the time during which the standby has continued in the fifth means, and when the time measured by the measurement means has passed a preset time, the notification means increases the standby time. Since it became, it notifies that it starts cooling operation, It is characterized by the above-mentioned.

Since the fan operation is started after the user is informed in advance that the fan suddenly starts rotating during standby and the wind noise increases, a more friendly image forming apparatus can be provided.

The eighth means is characterized in that, in the sixth or seventh means, the cooling operation by the internal cooling means is started if the user does not operate the machine for a certain period during the notification.

The ninth means is characterized in that, in the eighth means, during the execution of the cooling operation by the internal cooling means, the informing means is displayed on the notification means.

Since the user can understand that the fan is rotating and the wind noise is loud during standby, and that the current state of the machine is not abnormal, a more friendly image forming apparatus can be provided.

According to a tenth means, in the second means, an intermediate transfer belt is provided as the transfer means, and a part of the intermediate transfer belt is stretched over a fixing means provided with a heat source. It is characterized by.

Since the temperature inside the apparatus can be lowered by the internal cooling means, thermal change, material and deterioration of the intermediate transfer belt can be prevented, and an image forming apparatus free from image defects such as color misregistration can be provided.

The eleventh means is characterized in that, in the tenth means, a heat transfer suppressing member that prevents heat propagation is provided above the fixing means and below the intermediate transfer belt.

The heat generated from the fixing unit is exhausted outside the apparatus without being transferred to the intermediate transfer belt side by the heat transfer suppressing member, so that a thermal change to the intermediate transfer belt can be prevented, and a highly reliable image forming apparatus Can be provided.

A twelfth means includes a toner replenishing unit for storing toner to be supplied to the image forming unit above the intermediate transfer belt in the eleventh means, and the toner replenishing unit is over the heat transfer suppressing member. It is arrange | positioned in the lapped position, It is characterized by the above-mentioned.

Since the toner for replenishment is disposed at a position overlapping with the heat transfer suppressing member, it is possible to prevent the toner from being thermally changed (melting, fixing, etc.) along with the operation of the internal cooling means, and more reliable. An image forming apparatus with high performance can be provided.

A thirteenth means is characterized in that, in the eleventh or twelfth means, the internal cooling means that operates when the detected temperature exceeds a preset set temperature is a fan for cooling the heat transfer suppression member. .

  When the fan for cooling the heat transfer suppression member is used in this way, efficient in-machine cooling is performed, and an image forming apparatus having energy saving and high reliability can be provided.

A fourteenth means is characterized in that, in the thirteenth means, a developing cooling fan is operated in addition to the heat transfer suppressing member cooling fan.

  Developers generate a lot of heat, especially in high-speed machines, due to self-heating due to friction. Therefore, the toner in the image forming unit may be solidified, which affects the output image. Accordingly, by operating not only the fan for cooling the heat transfer control member but also the fan for developing cooling, an image forming apparatus with higher reliability can be provided more reliably.

According to the present invention, the detected temperature detected by the temperature detecting means is compared with a preset temperature set in advance, and if the detected temperature is equal to or higher than the set temperature, the operation of the internal cooling means is controlled so as to lower the internal temperature. Therefore, it is possible to reliably prevent the temperature inside the apparatus from rising and to prevent image defects such as toner solidification and color misregistration.

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

1 and 2 are schematic configuration diagrams showing the entire image forming apparatus according to the embodiment of the present invention.
Is a view seen from the front side, and FIG. 2 is a view seen from the side.

The image forming apparatus is the indirect transfer tandem color image forming apparatus described above,
In FIG. 1, reading unit 1, writing unit 2, and image forming unit 3 from above to below.
A paper feeding unit 4 is arranged.

The reading unit 1 is a so-called scanner, and is guided by an illumination lamp and a first mirror for reading a document mounted on the first traveling body, second and third mirrors mounted on the second traveling body, and these mirrors. The lens has a known configuration including a lens for condensing the light beam, and a photoelectric conversion element such as a CCD for photoelectrically converting the light imaged on the image forming surface by the lens. It is also possible to mount an automatic document feeder on the upper part of the scanner and read the document surface while automatically feeding the document.

The writing unit 2 modulates the laser diode based on the image information read by the reading unit 1, deflects the laser beam emitted from the laser diode by a polygon mirror, and passes through an optical element provided for each color. The data is written on the photosensitive drum 31 provided for each color.

The image forming unit 3 develops the latent image formed on the photosensitive drum 31 by optical writing performed by the writing unit 2, and transfers the developed visible image to the intermediate transfer belt 33 by the primary transfer roller 32. The image superimposed on the transfer belt 33 is transferred onto the recording paper by the secondary transfer roller 34. The recording sheet on which the image has been transferred is conveyed to the fixing unit 5 via the conveyance belt 35. The recording paper heat-fixed by the fixing unit 5 passes through the paper discharge unit 6,
It is discharged outside the machine. The toner remaining on the photosensitive drum 31 and the intermediate transfer belt 33 is cleaned by cleaning units 36 and 37, respectively, to prepare for the next image formation. The intermediate transfer unit 30 is configured by the intermediate transfer belt 33, the primary and secondary transfer rollers 32 and 34.

Further, as shown in FIG. 2, a toner replenishing unit (toner cartridge) for storing toner to be supplied to the image forming unit 3 on the front side of the image forming unit and above the fixing unit 5.
36 is provided. The toner replenishing unit 39 is disposed at a position overlapping with a heat transfer suppression unit 84 (see FIG. 1) described later. Therefore, heat transfer from the fixing unit 5 to the toner replenishing unit 39 side can be suppressed, and thermal change of the toner can be prevented. A known electrophotographic image forming element including a charging unit, a developing unit, a transfer unit, a cleaning unit, and a charge eliminating unit is disposed on the outer peripheral portion of each photosensitive drum 31.

A duplex unit 7 is provided below the intermediate transfer belt 33, the conveyance belt 35 and the fixing unit 5, and a recording sheet on which an image is formed on one side is switched by the paper discharge unit 6 to the duplex unit 7 side. As a result, it is guided again to the position of the registration roller 38. Then, the image is sent to the secondary transfer roller 34 side in synchronization with the image on the other side formed on the intermediate transfer belt 33. As a result, image formation is performed on both sides, and the paper is discharged again through the fixing unit 5.

The paper feed unit 4 has a plurality of paper feed stages 41 a, 41 b, 41 c, 41 d (hereinafter generally indicated by reference numeral 41), and a waste toner bottle 42 is provided on the side of the apparatus. A temperature sensor 43 is provided below the waste toner bottle 42, and a heat insulating material 44 is disposed between the paper feed stage 41 and the temperature sensor 43. Further, a heater 45 for controlling the humidity of the recording paper is provided below the paper feed stage 41.

In FIG. 1, a heat control unit 8 is provided above the paper discharge unit 6. The heat control unit 8 includes a heat control unit 81, heat radiating fins 82, and a duct 83.
1 controls the driving of a plurality of fans (not shown).

Further, a heat transfer suppressing portion 84 that prevents heat propagation is provided above the fixing unit 5 and below the intermediate transfer belt 33. The heat transfer suppression unit 84 is a combination of a shielding plate and a heat pipe, and is provided in a small gap between the fixing unit 5 as a heat source and the image forming unit (here, the intermediate transfer belt 33) 3 as a cooling required unit. ing. The heat pipe is a radiation fin 82
The heat is released from the radiating fins 82. In other words, the heat transfer suppression unit 4 prevents heat from entering the image forming unit 3 side, and further, the heat released from the fixing unit 5 is carried to the heat radiating fins 82 by the heat pipes. It is discharged out of the machine by a cooling fan (not shown) that generates

Further, in FIG. 2, a control unit 9 including a drive control unit and an electrical unit that control driving of the entire device is provided at the rear of the device. In addition, an operation panel that functions as a notification means is provided in the upper part of the front of the apparatus. The control unit 9 controls the apparatus in response to an instruction from the control panel, and displays a necessary display on the display unit of the operation panel. And function as a user interface. As the display content of the display unit, for example, “the standby state continues and the in-machine temperature is rising.

Rotate the fan and start cooling. "," In-flight cooling is in progress. "

In the present embodiment, as can be seen from FIG. 1, the color image forming apparatus includes four photosensitive drums 31 and an intermediate transfer belt 33, but is formed in the image forming unit 3 by toner supplied from a toner replenishing unit 39. The toner image is intermediately transferred from the photosensitive drum 31 to the intermediate transfer belt 33. Thereafter, the toner image is transferred onto the recording paper conveyed from the paper feed cassette of the paper feed stage 41 by the secondary transfer roller 34. Further, the recording paper is conveyed on the conveying belt 35, and the toner image is thermally fixed by the fixing unit 5 and discharged from the paper discharge unit 6. During operation of the machine, a plurality of unillustrated fans are used to keep the in-machine temperature below an allowable value.

In addition, during standby, the fan cannot be used under the same conditions as during operation due to noise and power restrictions, so it will be considerably limited, so please stop the rotation of the fan or reduce the number of rotations. Yes. Note that the standby here refers to a standby state in which the machine is not performing a printing operation, and the fixing unit maintains a certain high temperature due to a balance between the machine rise time and the power consumption during standby. In addition, since the noise regulation is severe during standby, cooling means such as a fan cannot be operated so much.

Furthermore, a temperature sensor 43 is provided in the machine, and the detected temperature T is compared with a preset set temperature T1, and when T is detected to be equal to or higher than T1, the operation of internal cooling means such as a fan is performed so as to lower the machine temperature. Is controlling. Specifically, control is performed such as increasing the number of operating fans or increasing the number of rotations. Thereafter, when the detected temperature detects, for example, (T1-2) ° C., the operation of the internal cooling means returns to the normal standby control. As a result, the internal cooling means that has started to operate once due to an increase in the internal temperature operates stably until the internal temperature decreases to some extent.

The control procedure at this time is shown in the flowchart of FIG. That is, in this control procedure, first, the detected temperature T ° C. is checked, and if T ° C ≧ T1 ° C. (step S101), the temperature control lowering control is started by the thermal control unit 8 which is an internal cooling means (step S102). ),
When the detected temperature falls to (T1-2) ° C. (step S103), the fan operation is returned to the normal standby state (step S104).

By controlling in this way, if the internal temperature is detected to be higher than the preset temperature during standby, the internal cooling means operates to lower the internal temperature, thus preventing an excessive increase in the internal temperature. As a result, the toner handled in the image forming unit 3 can be prevented from being melted and fixed, and malfunctions such as malfunction caused by the high temperature of the mechanism members and electronic parts can be prevented. It is possible to provide an improved image forming apparatus.

In this embodiment, the temperature sensor 43 is provided below the fixing unit 5 that is a heat source. Therefore, the temperature sensor 43 does not detect the normal temperature generated by the original heat fixing function, and can further improve the reliability.

The temperature sensor 43 is provided in the vicinity of a portion that is vulnerable to heat, that is, a portion that stores toner or handles toner. Therefore, it is possible to accurately detect the temperature of the part that is vulnerable to heat,
Since the internal cooling means operates at a certain set temperature or higher, the temperature of the portion that is vulnerable to heat can be lowered, and problems due to heat can be reliably prevented.

In the present embodiment, the set temperature at which the cooling control of the internal cooling means is started is set as the upper limit temperature of the use environment temperature range determined for use of the machine. For this reason, the temperature detected by the temperature sensor 43 that is not significantly affected by the fixing heat is close to the outside air temperature,
By setting the set temperature = the upper limit temperature of the use environment temperature range, it can be determined whether or not the machine is used within the environment temperature range permitted for use. The internal cooling means operates only when the environmental temperature exceeds the upper limit of the temperature range, that is, when it is determined that the environment is in an abnormally high temperature environment. Reduction and low noise can be realized.

  In the present embodiment, the temperature sensor 43 is provided at the lowest position in the machine. Therefore, the temperature sensor 43 is not affected by fixing heat at all, and the detected temperature becomes equal to the outside air temperature, so that the outside air environment can be accurately recognized. As a result, abnormally high temperature environments can be reliably detected, and malfunctions such as malfunctions due to high temperatures of mechanical members and electronic components such as toner alteration and melting can be reliably prevented. The image forming apparatus can be provided. Further, since this temperature sensor can accurately detect the temperature outside the apparatus, the fixing temperature can be accurately controlled by the environment using this detected temperature, and the cost can be reduced.

  Further, the temperature sensor 43 can be provided at the lowest position in the machine, and further at a position 43 'where the linear distance is farthest from the heat source in the machine (arrow A in FIG. 1). In this case, since the temperature sensor 43 ′ is located farthest from the heat source, it is more reliably not affected by the fixing heat, and the detected temperature becomes equal to the outside air temperature, so that the outside air environment can be recognized more accurately. Can do. Therefore, the above-described effects can be obtained more reliably.

In this embodiment, a heat insulating material 44 is provided between the temperature sensor 43 and the paper feed stage (paper feed cassette) 41. Therefore, even when the heater 45 for preventing the humidity effect of the recording paper provided in the paper feed cassette is activated, the influence of the heater heat on the temperature sensor 43 can be prevented. This
The detected temperature = the outside air temperature can be maintained, and the malfunction under the abnormally high temperature environment can be surely prevented.

Since the thermal control unit 8 detects the current in-flight situation or the operating status of the cooling means, these situations are displayed and notified by a display device (not shown). This allows the user or service person to be informed about the internal situation and actions taken internally, that is, that the internal cooling means is operating, and grasps whether the current situation is abnormal or not abnormal. be able to.

In the present embodiment, the second set temperature T2 is set, for example, T2 = (T1-1) ° C.
When the temperature detected by the temperature sensor 43 reaches T2, as indicated by reference numeral 42 in FIG. 2, "standby continues and the temperature inside the machine rises on the display means such as the machine display, LED, or connected personal computer display". "The fan is rotated to start cooling" is displayed, and the internal cooling means is activated only when the detected temperature reaches T1. As a result, if the fan suddenly starts rotating due to cooling inside the machine during standby and the wind noise increases, it will not be surprised because the user has been informed in advance and the machine state is not abnormal. Therefore, a more friendly image forming apparatus can be provided.

Further, the time for which the standby has continued is counted, and when a certain time is exceeded, the display means that “the standby has continued and the temperature inside the machine has increased. The fan is rotated and cooling is started” is displayed. Even if the temperature inside the machine can be suppressed by using a plurality of fans when the machine is in operation, the fan cannot be used under the same conditions as during operation due to noise and power restrictions during standby. In other words, the driving conditions are considerably limited during standby, and the fan is stopped or the rotational speed is reduced. For this reason, even during standby when the set temperature for fixing is lower than during operation, if the standby continues for a long time, the internal temperature will become higher than during operation and the cooling conditions will be severe, so the duration of standby is counted. And inform the user. Because of this, even if the fan suddenly starts rotating for cooling the inside of the aircraft during standby and the wind noise increases, the user is notified in advance, so the user is not surprised and the state of the machine is not abnormal Therefore, a more friendly image forming apparatus can be obtained.

Furthermore, if the user does not operate the machine for a certain period during the warning, the operation of the internal cooling means is started. Also, if there is a user operation and the machine is running,
Since all the in-machine cooling means operate, there is no problem because the in-machine temperature is lowered. Also in this case, even if the fan suddenly starts rotating for cooling the inside of the machine during standby and the wind noise increases, the user is notified in advance, so that the user is not surprised and the state of the machine is not abnormal Can be understood.

During the operation of the internal cooling device, a message “in-machine cooling is in progress” is displayed on the display means. For this reason, the user can understand that the fan suddenly starts rotating due to cooling in the machine during standby and the wind noise is loud, and that the current state of the machine is not abnormal.

In this embodiment, the intermediate transfer belt 33 is stretched and stretched above a fixing device having a heat source. As a result, the intermediate transfer belt 33 is heated. Since the heat control unit 8 is provided and cooled by a plurality of fans, the internal cooling means is operated even during standby to prevent the temperature inside the apparatus from rising. As a result, thermal change of the belt and deterioration of the material can be prevented. Thereby, it is possible to suppress the occurrence of problems in image formation such as color misregistration.

Further, the heat transfer suppression unit 84 suppresses heat transfer from the fixing unit 5 to the image forming unit 3, particularly the intermediate transfer belt 33, and prevents the temperature inside the apparatus from rising along with the operation of the internal cooling means during standby. It is also possible to prevent thermal changes of the belt and deterioration of the material.

Further, a toner replenishing unit (toner cartridge) 39 for storing toner to be supplied to the image forming unit 3 is provided above the fixing unit 5, and is disposed at a position overlapping the heat transfer suppressing unit 84. Therefore, heat transfer from the fixing unit 5 to the toner supply unit 39 side is suppressed, and thermal change of the toner can be prevented. By providing the cooling means in this mechanical configuration, it becomes possible to prevent the temperature of the toner from rising along with the operation of the internal cooling means during standby, and to prevent thermal change melting and sticking of the toner. . As a result, a more reliable image forming apparatus can be provided.

  FIG. 6 is a diagram showing details of the heat transfer control unit according to the present embodiment. In the figure, 85 is a suction fan, 86 is an exhaust fan, 87 is an aluminum plate, 88 is a heat pipe, and 89 is a shielding plate. There is a duct that winds over the heat sink, but it is omitted in this figure. The transfer of heat generated by the fixing unit 5 to the image forming unit 3 and the intermediate transfer belt 33 which are cooling units and further to the toner replenishing unit 39 is shielded by a shielding plate 89. Further, the heat is transferred to the heat sink (radiation fin) 82 by the combination of the aluminum plate 87 and the heat pipe 88, and the heat is released to the outside by the suction fan 85 and the exhaust fan 86 that cool the portion. Therefore, when all the fans cannot be turned due to power or noise restrictions, by operating only the fans 85 and 86 in this portion, it is possible to efficiently prevent heat due to fixing from being transmitted to the cooling required portion. Can be released out of the plane. As a result, an image forming apparatus with high reliability can be provided with minimum power and noise.

  FIG. 7 is a diagram showing details of the development cooling unit according to the present embodiment. In the figure, 105 is a frame, 111 and 112 are ducts, 113 is an exhaust fan, 114 is a roller drive motor, and 115 is an exhaust fan drive motor. Heat generated by self-heating due to development friction is exhausted by the exhaust fan 113 through the ducts 111 and 112 from the vents (not shown) of the frame on the development. Accordingly, by operating not only the heat transfer suppression member cooling fans 85 and 86 but also the development cooling fan 113, the occurrence of white streaks due to toner coagulation in the image forming unit 3 can be suppressed. Image forming apparatus with high image quality can be provided.

1 is a front view illustrating a schematic configuration of an image forming apparatus according to an embodiment of the present invention. 1 is a side view illustrating a schematic configuration of an image forming apparatus according to an embodiment of the present invention. It is a flowchart which shows the cooling control procedure of in-machine temperature. 1 is a diagram illustrating a schematic configuration of a tandem image forming apparatus of a direct transfer method that has been conventionally performed. 1 is a diagram illustrating a schematic configuration of a tandem image forming apparatus of an indirect transfer method that has been conventionally performed. It is the figure which looked at the heat-transfer control part of the image forming apparatus which concerns on embodiment of this invention diagonally from the lower left direction. FIG. 2 is a detailed view of a developing cooling unit of the image forming apparatus according to the embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reading unit 2 Writing unit 3 Image forming unit 30 Intermediate transfer unit 31 Photosensitive drum 32 Primary transfer roller 33 Intermediate transfer belt 4 Paper feed unit 43, 43 'Fixing unit 6 Paper discharge unit 7 Duplex unit 8 Thermal control unit 81 Heat Control unit 82 Radiation fin 83 Duct 84 Heat transfer suppression unit 85, 86, 113 Fan 9 Control unit

Claims (14)

Temperature detecting means for detecting the temperature inside the apparatus main body having the image forming means;
An internal cooling means for lowering the in-machine temperature;
During standby without forming an image, the detected temperature detected by the temperature detecting means is compared with a preset temperature set in advance, and if the detected temperature is equal to or higher than the set temperature, the internal temperature is lowered. Control means for controlling the operation of the internal cooling means;
Thermal insulation means for blocking between the temperature detection means and the paper feed cassette of the paper feed device in the machine;
Equipped with a,
The temperature detecting means is provided at the lowest position in the machine away from the heat source,
The image forming apparatus, wherein the set temperature is an upper limit temperature of a use environment temperature range determined in use of the image forming apparatus. The image forming means is
An image forming unit including a photoconductor for forming a toner image;
A toner replenishing unit for replenishing toner to the image forming unit;
A transfer unit for transferring the toner image formed in the image forming unit to a recording sheet supplied from a paper feeding device;
Fixing means for fixing the transferred toner image on the recording paper;
A paper discharge means for discharging the recording paper fixed by the fixing means;
The image forming apparatus according to claim 1, further comprising: The image forming apparatus according to claim 2, wherein the fixing unit is the heat source . 4. The image forming apparatus according to claim 1 , wherein the lowermost position in the apparatus is a lower portion of a waste toner bottle installed at a position across the heat insulating unit . 5. 5. The image forming apparatus according to claim 1, further comprising a notification unit configured to notify a current in-machine situation and / or an operation state of the internal cooling unit . A second set temperature is set, and when the temperature detecting means detects that the in-machine temperature exceeds the second set temperature, the notifying means notifies that the cooling operation by the internal cooling means is started. The image forming apparatus according to claim 5 . Comprising a measuring means for measuring the wait continues for time, when the elapsed time period measured by said measuring means is preset, claim, characterized in that notification that initiates a cooling operation by said notifying means 5 The image forming apparatus described. 8. The image forming apparatus according to claim 6 , wherein a cooling operation by the internal cooling unit is started if the user does not operate the machine for a certain period during the notification . 9. The image forming apparatus according to claim 8 , wherein during the execution of the cooling operation by the internal cooling unit, the notification unit displays a message indicating that the internal cooling is being performed . 3. The image forming apparatus according to claim 2 , further comprising an intermediate transfer belt as the transfer unit, wherein a part of the intermediate transfer belt is stretched over a fixing unit including a heat source. . The image forming apparatus according to claim 10 , further comprising a heat transfer suppressing member that prevents heat transfer above the fixing unit and below the intermediate transfer belt . A toner replenishing unit for storing toner to be supplied to the image forming unit is provided above the intermediate transfer belt, and the toner replenishing unit is disposed at a position overlapping the heat transfer suppressing member. The image forming apparatus according to claim 11 . 13. The image forming apparatus according to claim 11, wherein the operating internal cooling means is a fan for cooling the heat transfer suppressing member . 14. The image forming apparatus according to claim 13, wherein the internal cooling means is a development cooling fan in addition to the heat transfer suppressing member cooling fan .

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