JP2008046263A - Belt traveling device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a belt traveling device capable of suppressing thermal influence on an endless belt, even when the belt traveling device is arranged adjacent to or close to a heat source. <P>SOLUTION: The belt traveling device 1 includes: the endless belt 5 stretched to be laid among a driving roller 2, driven rollers 3 and 4; a belt driving motor 6; and a control means 7 for controlling the belt driving motor 6. The belt traveling device 1 is arranged adjacent to the heat source 8, and a temperature detecting means 9 for detecting the surface temperature of the endless belt 5 in the surface area (a1) adjacent to the heat source 8 is disposed. A fan 10 as a cooling means is disposed in an area (a2) of the endless belt, receiving less influence from the heat source 8. During non-traveling of the endless belt 5, the initial value of the surface temperature of the endless belt 5 in the area (a1) is measured by the temperature detecting means 9, thereafter, whether or not the temperature rise value (temperature rise width from the initial value) exceeds a prescribed value X is checked, and when the rise value exceeds the prescribed value X, the belt driving motor 6 is operated for a prescribed time so as to shift the area (a1) to the area (a2) and cool the endless belt. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image of a belt traveling device having an endless belt, a copying machine, a printer, a facsimile, a multifunction device having at least two of these functions, a plotter, etc., which includes the belt traveling device as an intermediate transfer device or a direct transfer device. The present invention relates to a forming apparatus.

In recent years, in an image forming apparatus such as a copying machine, a larger amount of heat is required for a fixing device for fixing an image onto a sheet as the performance of the apparatus increases and the speed of image formation increases. For this reason, since the amount of heat used in the fixing device has increased, there is a concern that the temperature inside the apparatus will rise.
Furthermore, since the fixing device and other devices are arranged close to each other in order to save space, the heat of the fixing device may affect the operation and performance of other devices in the vicinity. That is, when heat is transmitted to a photoconductor or a developing unit involved in image formation, there is a possibility that problems such as image deterioration, toner scattering, and toner solidification may occur.
In a so-called tandem type image forming apparatus in which a plurality of photosensitive drums are juxtaposed, heat is transferred to the transfer unit, so that the transfer belt expands due to heat. In order to achieve high image quality, when a thermal expansion or the like occurs in a part of the transfer belt, a speed abnormality occurs, which may cause color misregistration of each color in a color machine.

Patent Document 1 discloses a technique for suppressing a temperature difference generated between photosensitive drums without using a heater or a fan in a tandem type image forming apparatus.
This is because the surface temperature of each photosensitive drum is detected by a temperature sensor, and when the maximum temperature difference between the photosensitive drums exceeds a predetermined value, the image forming operation is prohibited and the intermediate transfer with the photosensitive drum is prohibited. The belt is rotationally driven in contact with the belt, heat is exchanged between the two, and the temperature difference is reduced.

JP 2003-280320 A

However, the configuration described in Patent Document 1 has a problem that heat from the intermediate transfer belt is transmitted to the photosensitive drum, and there is a concern about the influence of heat on the toner and the like.
In the belt traveling device, when the operation accuracy of the device is affected by the position accuracy of the endless belt, a decrease in accuracy is inevitable due to the expansion of the endless belt due to heat.

  An object of the present invention is to provide a belt traveling device that can suppress the influence of heat on an endless belt even if it is disposed adjacent to or close to a heat source, and an image forming apparatus having the belt traveling device.

  In order to achieve the above object, according to the first aspect of the present invention, there is provided a belt travel device for traveling an endless belt rotatably supported by a plurality of support members by a drive source, which is disposed adjacent to the heat source. In the belt traveling apparatus, temperature detecting means for detecting the surface temperature of the endless belt in a range adjacent to the heat source is provided, and cooling means for cooling the surface of the endless belt is provided in a range where the influence of the heat source is small. When the detection result of the temperature detecting means exceeds a predetermined temperature rise value while the endless belt is stopped running, the influence of the heat source with the cooling means is small in the range adjacent to the heat source of the endless belt. It has the control means to move to the range, It is characterized by the above-mentioned.

According to a second aspect of the present invention, in the belt running device according to the first aspect, the cooling means is controlled to start by the control means.
According to a third aspect of the present invention, in the belt travel device according to the first or second aspect, the region of the endless belt cooled by the cooling means is the next, and the detection result of the temperature detection means has a predetermined temperature rise value. The position of the said cooling means is set so that it may not come again in the range adjacent to the said heat source when it exceeds.

According to a fourth aspect of the present invention, in the image forming apparatus, the belt travel device according to any one of the first to third aspects is provided as an intermediate transfer device.
According to a fifth aspect of the present invention, the image forming apparatus includes the belt traveling device according to any one of the first to third aspects as a direct transfer device.

According to a sixth aspect of the present invention, in the image forming apparatus according to the fourth or fifth aspect, a plurality of photosensitive drums are juxtaposed along the endless belt surface, and the photosensitive drum is rotated. A drum drive source for driving is provided, and the control means activates the drum drive source simultaneously when the endless belt is driven.
According to a seventh aspect of the present invention, in the image forming apparatus according to the fourth or fifth aspect, a plurality of photosensitive drums are juxtaposed along the endless belt surface, with respect to the photosensitive drum. A contact / separation mechanism for contacting / separating the endless belt, and the control means controls the contact / separation mechanism to move the endless belt away from the photosensitive drum when the endless belt travels. To do.

According to the first aspect of the present invention, the amount of expansion and contraction of the endless belt due to heat can be suppressed, and the influence of speed abnormality during travel of the endless belt can be reduced.
According to invention of Claim 2, unnecessary energy consumption can be suppressed.
According to the invention described in claim 3, it is possible to suppress belt deterioration caused by heating and cooling the same portion of the endless belt many times.
According to the fourth aspect of the present invention, in the intermediate transfer type image forming apparatus, it is possible to suppress color misregistration due to an abnormality in the conveyance speed of the intermediate transfer belt.
According to the fifth aspect of the present invention, in the direct transfer type image forming apparatus, it is possible to suppress color misregistration due to an abnormality in the conveyance speed of the paper conveyance belt.
According to the sixth aspect of the present invention, frictional contact with the photosensitive drum during running of the belt in the cooling control can be avoided.
According to the seventh aspect of the present invention, it is possible to avoid frictional contact with the photosensitive drum during running of the belt in the cooling control and to suppress the heat of the belt from being transmitted to the photosensitive drum.

Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 and 2.
The belt travel device 1 according to the present embodiment includes a driving roller 2 and driven rollers 3 and 4 as support members, an endless belt 5 wound around these rollers, and a driving source for rotationally driving the driving roller 2. Belt drive motor 6 and control means 7 for controlling the belt drive motor 6.
The belt traveling device 1 is disposed adjacent to the heat source 8, and is provided with temperature detection means 9 that detects the surface temperature of a range a 1 adjacent to the heat source 8 of the endless belt 5. A fan 10 as a cooling means is arranged in a range a2 where the influence of the heat source 8 of the endless belt 5 is small.
Here, the “range where the influence of the heat source is small” refers to a relatively low temperature region away from the heat source 8 and is not limited to the range a2. Moreover, the cooling by the cooling means here means air cooling by blowing air having a relatively low temperature compared with the vicinity of the heat source 8 in this region.

While the endless belt 5 is stopped traveling, a part of the endless belt 5 expands and contracts due to the expansion caused by the temperature rise due to heat in the range adjacent to the heat source 8, so that speed abnormality may occur when the endless belt 5 travels. There is.
By cooling the range and reducing the amount of expansion and contraction, it is possible to suppress adverse effects due to speed abnormalities.
In the present embodiment, when the range adjacent to the heat source 8 exceeds a predetermined temperature rise value, the endless belt 5 is driven to travel, and conveyed to a range where the influence of the heat source provided with the cooling means is small, The amount of expansion and contraction of the endless belt 5 is reduced by forcibly cooling at that position.

The control operation will be described with reference to FIG. First, while the endless belt 5 is stopped running, the initial value of the surface temperature of the endless belt 5 in the range a1 is measured by the temperature detecting means 9 (S1). Thereafter, the surface temperature of the endless belt 5 is measured while the vehicle is stopped (S2), and a temperature increase value (temperature increase width from the initial value: temperature deviation) is stored in a memory (not shown) of the control means 7 in advance. It is checked whether or not the value X is exceeded (S3), and if it exceeds, the belt drive motor 6 is moved for a predetermined time (S4).
Here, the “predetermined time” is a rotation time during which the portion of the endless belt 5 located in the range a1 is located in the range a2. In this case, the time based on the traveling speed of the endless belt 5 is obtained in advance and stored in the memory of the control means 7. When the belt drive motor 6 is a stepping motor, it can be positioned in the range a2 by managing the number of steps.
The endless belt 5 may be moved based on the detection mark.

A second embodiment will be described based on FIGS. 3 and 4. In addition, the same part as the said embodiment is shown with the same code | symbol, The description on the structure and function which were already demonstrated is abbreviate | omitted as long as there is no special need, and only the principal part is demonstrated (same in other following embodiment).
In the above embodiment, the fan 10 as the cooling means is always turned on. However, in the present embodiment, when the cooling is not necessary, the fan 10 is stopped to suppress wasteful energy consumption. The fan 10 is connected to the control means 7, and ON / OFF of the fan 10 is controlled by the control means 7.
As shown in FIG. 4, at first, the fan 10 is stopped, and when it is determined that the temperature rise value exceeds X, the belt drive motor 6 is moved for a predetermined time and the fan 10 is started (S4).
Therefore, the fan 10 can be stopped until a predetermined temperature rise occurs, and the amount of power used can be reduced.

Next, a third embodiment will be described based on FIG. When the region of the endless belt that has been cooled once again comes into the range adjacent to the heat source, the same region is heated and cooled many times, and the deterioration of the endless belt is accelerated. The present embodiment aims to prevent this.
In order to cool the region of the endless belt 5 that was in the range a1, after moving to the range a2, if the detection result of the temperature detection means 9 then exceeds a predetermined temperature rise, the control means 7 is also in the same range. The belt drive motor 6 is controlled so as to move the region of the endless belt 5 in a1 to the range a2. In this case, the region previously in the range a2 is located in the range a3 and is adjacent to the heat source 8. I will not come to a1. The same applies to FIGS. 1 and 3.
In this embodiment, the fan 10 as a cooling means is disposed between the driving roller 2 and the driven roller 4. However, the region (part) once cooled as described above is again in the range a 1 adjacent to the heat source 8. If it does not come, the fan 10 can be disposed at an arbitrary position within a range that satisfies this requirement.

A fourth embodiment will be described with reference to FIGS. In this embodiment, the belt traveling device is applied to an intermediate transfer device of an image forming apparatus.
In an image forming apparatus, with a high density due to space saving of an apparatus, a fixing device as a heat source and an intermediate transfer device as an endless belt traveling device may be adjacent to each other. Even in a state where image formation is not performed, since the inside of the fixing device is heated for the next image formation, the heat of the fixing device raises the temperature of the region adjacent to the fixing device of the intermediate transfer belt.
Due to the thermal expansion of the area affected by the heat in the intermediate transfer belt, the peripheral length of the intermediate transfer belt changes, causing an abnormality in the conveyance speed of the intermediate transfer belt during the next image formation, and color misregistration of each color. Therefore, it is necessary to reduce the temperature increase of the intermediate transfer belt.

An outline of the configuration of an intermediate transfer type color image forming apparatus (tandem type copying machine) will be described with reference to FIG. Here, reference numeral 1 denotes an intermediate transfer device as a belt traveling device, 5 denotes an intermediate transfer belt as an endless belt, and 8 denotes a fixing device as a heat source.
Four photosensitive drums 16K (black), 16C (cyan), 16M (magenta), and 16Y (yellow) as image carriers are juxtaposed along the extended surface of the intermediate transfer belt 5. Around each photosensitive drum 16, a charging unit 17, a developing unit (not shown), an exposure unit, a cleaning unit, a neutralizing unit, and the like are arranged to form a known image forming configuration. The color order of K, C, M, and Y is not limited to this.

The toner images formed on the respective photosensitive drums 16 are transferred onto the intermediate transfer belt 5 while being superimposed by a primary transfer unit (not shown). The sheet P as the sheet-like recording medium fed from the selected one of the sheet feeding cassettes 15A and 15B provided in the lower part of the apparatus main body 14 is temporarily stopped by the registration roller pair 11 to correct the oblique displacement. After that, the toner image is conveyed at a predetermined timing by the registration roller pair 11, and the superimposed toner images on the intermediate transfer belt 5 are collectively transferred by the secondary transfer unit 12.
The sheet P on which the superimposed toner image has been transferred is sent to the fixing device 8 where the toner image is fixed by heat and pressure. After the fixing, the paper P is discharged to the paper discharge tray 13 by a pair of discharge rollers (not shown).

As shown in FIG. 7, each photosensitive drum 16 is driven by a drum drive motor 18 as a drum drive source, and the drum drive motor 18 is controlled by the control means 7.
In the tandem type copying machine, the intermediate transfer device 1 and the fixing device 8 may be adjacent to each other. In such a configuration, by rotating and cooling the intermediate transfer belt 5, it is possible to provide the intermediate transfer belt 5 that is small in local expansion and contraction due to heat, and at the time of color matching for each color, which is a problem unique to the tandem machine It is possible to provide an image forming apparatus with a small color shift.
FIG. 8 shows the control operation in this embodiment. In this embodiment, since there is no contact / separation mechanism between each photosensitive drum 16 and the intermediate transfer belt 5, it is checked whether or not the temperature rise value exceeds a predetermined value X (S3). While moving for a predetermined time, the fan 10 is started, and the drum drive motor 18 is moved for a predetermined time (S4). That is, the belt drive motor 6 and the drum drive motor 18 are rotated synchronously to avoid the trouble of each photosensitive drum 16 in the movement of the intermediate transfer belt 5.

A fifth embodiment will be described with reference to FIGS.
In the present embodiment, the tandem intermediate transfer type image forming apparatus includes a contact / separation mechanism for each photosensitive drum 16 and the intermediate transfer belt 5.
As shown in FIG. 9, the contact / separation mechanism includes a contact / separation member 20 provided inside the intermediate transfer belt 5 so as to be movable up and down in a region facing each photoconductor drum 16, and the contact / separation member 20 up and down. And a cam 21 for moving the cam 21 in rotation. The contact / separation member 20 includes a base plate 23 supported by a support member (not shown) so as to be movable up and down, and a roller 24 that is rotatably supported on the left and right ends of the base plate 23 and rotates along with the intermediate transfer belt 5. Have.
In this embodiment, not the drum drive motor 18 but the contact / separation cam drive motor 22 is controlled by the control means 7.

As shown in FIG. 11, it is checked whether or not the temperature rise value exceeds a predetermined value X (S3). If it exceeds, the belt drive motor 6 is moved for a predetermined time, the fan 10 is started, and the contact and separation are performed. The cam drive motor 22 is activated (S4).
When the contact / separation cam drive motor 22 is started to rotate by a predetermined angle, as shown in FIG. 10, the intermediate transfer belt 5 is separated from each photoconductive drum 16, and the influence of each photoconductive drum 16 is influenced in the travel. I will not receive it.

A sixth embodiment will be described based on FIGS. 12 and 13.
The present embodiment is an example in which the belt traveling device is applied to a direct transfer device of an image forming apparatus.
In an image forming apparatus, with a high density due to space saving of equipment, a fixing device as a heat source and a direct transfer device as an endless belt traveling device may be adjacent to each other. Even in a state where image formation is not being performed, since the inside of the fixing device is heated for the next image formation, the heat of the fixing device directly controls the temperature of the area adjacent to the fixing device of the paper conveying belt in the transfer device. Raise.
When the area affected by heat in the paper transport belt expands, the circumference of the paper transport belt changes, causing an abnormality in the transport speed of the paper transport belt during the next image formation, and color misregistration of each color. Therefore, it is necessary to reduce the temperature rise of the sheet conveying belt.

The outline of the structure of a direct transfer type color image forming apparatus (tandem type copying machine) will be described with reference to FIG. Here, reference numeral 30 denotes a direct transfer device as a belt traveling device, and the direct transfer device 30 includes a driving roller 31, a driven roller 32, a sheet conveying belt 33 as an endless belt, and the like.
Four photosensitive drums 16Y (yellow), 16M (magenta), 16C (cyan), and 16K (black) serving as image carriers are juxtaposed along the extended surface of the paper transport belt 33. Around each photosensitive drum 16, a charging unit 17, a developing unit (not shown), an exposure unit, a cleaning unit, a neutralizing unit, and the like are arranged to form a known image forming configuration. The color order of Y, M, C, and K is not limited to this.

The toner images formed on the respective photosensitive drums 16 are directly and sequentially transferred onto the sheet P conveyed by the sheet conveying belt 33 by a transfer unit (not shown).
The sheet P to which the toner image has been transferred is sent to the fixing device 8 where the toner image is fixed by heat and pressure. After the fixing, the paper P is discharged to the paper discharge tray 13 by a pair of discharge rollers (not shown).

  In the tandem type copying machine, the direct transfer device 30 and the fixing device 8 may be adjacent to each other. In such a configuration, by rotating and cooling the paper conveyance belt 33, it is possible to provide the paper conveyance belt 33 with small local expansion and contraction due to heat, and at the time of color matching of each color, which is a problem unique to the tandem machine It is possible to provide an image forming apparatus with a small color shift.

When the range a4 adjacent to the fixing device 8 exceeds a predetermined temperature rise value, the sheet conveying belt 33 is driven to travel to the range a5 where the influence of the heat source provided with the cooling means 10 is small. Cooling.
In this embodiment, since there is no contact / separation mechanism between each photosensitive drum 16 and the paper transport belt 33, the control for cooling the temperature rise value exceeds the predetermined value X, as shown in FIG. The belt drive motor 6 is moved for a predetermined time, the fan 10 is started, and the drum drive motor 18 is moved for a predetermined time.

The seventh embodiment will be described based on FIGS. 14 and 15.
In the present embodiment, the tandem direct transfer type image forming apparatus includes a contact / separation mechanism for each photosensitive drum 16 and the intermediate transfer belt 5.
As shown in FIG. 14, the contacting / separating mechanism includes an contacting / separating member 20 provided inside the sheet conveying belt 33 so as to be movable up and down in an area facing each photosensitive drum 16, and the contacting / separating member 20 being moved up and down. And a cam 21 for moving the cam 21 in rotation. The contact / separation member 20 includes a base plate 23 supported by a support member (not shown) so as to be movable up and down, and a roller 24 that is rotatably supported on the left and right ends of the base plate 23 and rotates along with the paper conveying belt 33. Have.
In this embodiment, not the drum drive motor 18 but the contact / separation cam drive motor 22 is controlled by the control means 7.

In the cooling control, as shown in FIG. 11, it is checked whether or not the temperature rise value exceeds a predetermined value X. If it exceeds, the belt drive motor 6 is moved for a predetermined time and the fan 10 is started. And the contact / separation cam drive motor 22 is started.
When the contact / separation cam drive motor 22 is activated to rotate by a predetermined angle, as shown in FIG. 15, the sheet conveying belt 33 is separated from each photosensitive drum 16, and the influence of each photosensitive drum 16 is influenced in the travel. I will not receive it.

1 is a schematic configuration diagram of a belt traveling device according to a first embodiment of the present invention. It is a flowchart which shows the control operation of cooling in 1st Embodiment. It is a schematic block diagram of the belt traveling apparatus which concerns on 2nd Embodiment. It is a flowchart which shows the control operation of cooling in 2nd Embodiment. It is a schematic block diagram of the belt traveling apparatus which concerns on 3rd Embodiment. It is a schematic block diagram of the image forming apparatus which concerns on 4th Embodiment. FIG. 10 is a control configuration diagram of an image forming apparatus according to a fourth embodiment. It is a flowchart which shows the control operation of cooling in 4th Embodiment. FIG. 10 is a control configuration diagram of an image forming apparatus according to a fifth embodiment. It is a control block diagram of the state which operated the contacting / separating mechanism in 5th Embodiment. It is a flowchart which shows the control operation of cooling in 5th Embodiment. It is a schematic block diagram of the image forming apparatus which concerns on 6th Embodiment. FIG. 10 is a control configuration diagram of an image forming apparatus according to a sixth embodiment. FIG. 10 is a control configuration diagram of an image forming apparatus according to a seventh embodiment. It is a control block diagram of the state which operated the contacting / separating mechanism in 7th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Belt travel apparatus or intermediate transfer apparatus 2, 31 Driving roller as support member 3, 4, 32 Driven roller as support member 5 Endless belt 7 Control means 8 Heat source or fixing device 9 Temperature detection means 10 Fan 16 as cooling means 16 Photosensitive drum 18 Drum drive motor as drum drive source 30 Direct transfer device a1, a4 Range adjacent to heat source a2, a5 Range less affected by heat source

Claims (7)

A belt travel device that travels an endless belt rotatably supported by a plurality of support members using a drive source, and is disposed adjacent to a heat source.
A temperature detecting means for detecting the surface temperature of the endless belt in a range adjacent to the heat source is provided, and a cooling means for cooling the surface of the endless belt is provided in a range where the influence of the heat source is small. Control means for moving the range of the endless belt adjacent to the heat source to a range where the influence of the heat source with the cooling means is small when the detection result of the temperature detection means exceeds a predetermined temperature rise value during stoppage A belt travel device characterized by comprising: The belt travel device according to claim 1,
The belt travel device characterized in that the cooling means is controlled to start by the control means. In the belt travel device according to claim 1 or 2,
In order that the region of the endless belt cooled by the cooling unit does not come again to the range adjacent to the heat source when the detection result of the temperature detection unit exceeds the predetermined temperature rise value, A belt travel device in which the position of the cooling means is set.   An image forming apparatus comprising the belt traveling device according to claim 1 as an intermediate transfer device.   An image forming apparatus comprising the belt traveling device according to claim 1 as a direct transfer device. The image forming apparatus according to claim 4 or 5,
A plurality of photosensitive drums are juxtaposed along the endless belt surface, and a drum drive source that rotationally drives the photosensitive drums is provided, and the control means causes the endless belt to travel. An image forming apparatus characterized in that the drum driving source is activated at the same time. The image forming apparatus according to claim 4 or 5,
The control unit has a configuration in which a plurality of photosensitive drums are juxtaposed along the endless belt surface, and a contact / separation mechanism that contacts and separates the endless belt with respect to the photosensitive drum. An image forming apparatus, wherein when the endless belt is run, the contact / separation mechanism is controlled to separate the endless belt from the photosensitive drum.

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