JP2014238556A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To determine the abnormality of a cooling device, even when adopting such a configuration that a heating device and the cooling device are separated.SOLUTION: An image forming apparatus includes a fixing device and the cooling device separated from the fixing device. The cooling device includes an upper belt, a heat sink, and a heater heating the upper belt. A control part turns on the heater (S140), to heat the upper belt and the heat sink, according to the start of a first abnormality detection mode (S100 to S120), during warming-up. Then, the control part obtains the temperature of the upper belt and the temperature of the heat sink (S160) and determines whether or not the respective obtained temperatures are reference temperatures T1 and T2 or more (S170). When the respective obtained temperatures are the reference temperatures T1 and T2 or more, the control part determines that a contact state between the heat sink and the upper belt is not abnormal (S180). When at least one of the respective obtained temperatures is less than a reference, the control part determines that the contact state between the heat sink and the upper belt is abnormal (S210).

Description

  The present invention relates to an image forming apparatus.

  2. Description of the Related Art Conventionally, an image forming apparatus having a cooling function for cooling a sheet after fixing is known in order to prevent the wax on the surface of the sheet after fixing from becoming uneven. The image forming apparatus includes an endless belt, a heating device disposed on the upstream side of the belt, and a cooling device including a heat sink disposed on the downstream side of the belt, in addition to the image forming unit and the like. . The heating device melts the toner on the paper after fixing and causes the paper to adhere to the belt. The cooling device prevents unevenness by cooling the toner on the sheet conveyed in close contact with the belt.

  Here, in order to surely prevent the unevenness of the wax, it is necessary to solidify the toner by cooling the belt to a target temperature while the toner and the belt are in close contact with each other. Therefore, the adhesion between the cooling device for cooling the belt and the belt is important. However, there is a case where the belt is partially separated from the heat sink due to the occurrence of waving in the belt due to the accuracy of the belt itself, deterioration over time, the accuracy of attaching the belt, or the like.

  In Patent Document 1, the temperature of the heat sink and the belt temperature after passing through the heat sink are acquired, and the contact quality between the heat sink and the belt is determined based on whether the temperature difference between them is equal to or higher than a predetermined temperature. An image forming apparatus is described that determines whether there is a contact failure abnormality between the heat sink and the belt based on the determination. According to this image forming apparatus, in a portion where the heat sink and the belt are not in contact, the cooling function by the heat sink does not operate normally and the belt temperature becomes high. Can be accurately determined.

JP 2012-194391 A

  However, the image forming apparatus described in Patent Document 1 has the following problems. That is, in the image forming apparatus of Patent Document 1, the heating device and the heat sink share a single belt. For this reason, the heating device and the heat sink each exchange heat with respect to a single belt, so that there is a problem that the thermal efficiency is poor.

  In order to solve this thermal efficiency problem, an image forming apparatus has been proposed in which separate belts are used for the heating device and the cooling device. According to this image forming apparatus, each belt is heated and cooled, so that the problem of thermal efficiency can be improved.

  However, when separate belts are used for the heating device and the cooling device, the heating device and the cooling device are separated. For this reason, the belt cannot be heated with the configuration of only the cooling device when judging the abnormality of poor contact, so check whether the cooling device is operating normally by looking at the relationship between the belt temperature and the heat sink temperature. I couldn't. As a result, there is a problem that a large amount of copy paper is wasted because a large amount of printing is performed in an actual printing operation and it is found that there is an abnormality such as a contact failure only when the cooling device is warmed.

  Accordingly, the present invention has been made in view of the above problems, and an object of the present invention is to provide an image forming apparatus capable of determining an abnormality of a cooling device even when the heating device and the cooling device are separated. Is to provide.

  In order to solve the above problems, an image forming apparatus according to the present invention is provided separately from a fixing device that heats and fixes toner on a sheet, and cools a sheet conveyed from the fixing device. A cooling unit, and a control unit that performs a first abnormality detection mode for detecting an abnormality of the cooling unit. The cooling unit conveys a sheet fixed by the fixing unit to the downstream side, and contacts the belt. A cooling unit that cools the sheet conveyed by the belt, a heating unit that heats at least one of the belt and the cooling unit, a first measurement unit that measures the temperature of the cooling unit, and a belt temperature And a control unit, based on the measurement results of the first and second measurement units, after starting the heating unit in accordance with the start of the first abnormality detection mode. Abnormal cooling device It determines, in which the determination is to stop the activation of the heating portion when finished.

  According to the present invention, even when the fixing device (heating device) and the cooling device are separated, the belt and the cooling unit are heated in the first abnormality detection mode by providing the heating device in the cooling device. Therefore, it is possible to determine whether or not there is an abnormality in the cooling device before starting the printing operation. Thereby, it is possible to prevent the abnormality of the cooling device from being detected during the printing operation.

1 is a diagram illustrating a schematic configuration example of an image forming apparatus according to a first embodiment of the present invention. It is a figure which shows the structural example of a cooling device. 1 is a diagram illustrating a block configuration example of an image forming apparatus. 6 is a flowchart illustrating an operation example of the image forming apparatus in an abnormality detection mode (No. 1). 6 is a flowchart illustrating an operation example of the image forming apparatus in an abnormality detection mode (part 2). It is a figure which shows the example of schematic structure of the image forming apparatus which concerns on the 2nd Embodiment of this invention. It is a figure which shows the example of schematic structure of the image forming apparatus which concerns on the 3rd Embodiment of this invention. 1 is a diagram illustrating a block configuration example of an image forming apparatus. It is a figure which shows the example of schematic structure of the image forming apparatus which concerns on the 4th Embodiment of this invention. 1 is a diagram illustrating a block configuration example of an image forming apparatus.

  Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In addition, the dimensional ratios in the drawings are expanded for convenience of explanation, and may differ from actual ratios.

[Configuration example of image forming apparatus]
The image forming apparatus 100A according to the present invention includes a first abnormality detection mode for confirming whether the heat sink 210 and the upper belt 220 of the cooling device 200A are in normal contact when the printing operation is not performed, and the cooling device 200A. By executing the second abnormality detection mode for confirming whether the cooling function is functioning normally, the abnormality of the cooling device 200A can be grasped before the printing operation.

  FIG. 1 shows an example of a schematic configuration of an image forming apparatus 100A according to the present invention. As shown in FIG. 1, the image forming apparatus 100 is called a tandem type image forming apparatus, and includes an automatic document feeder 80 and an apparatus main body 102. The automatic document conveyance unit 80 is attached to the upper part of the apparatus main body 102 and sends out the paper set on the conveyance table to the image reading unit 90 of the apparatus main body 102 by a conveyance roller or the like. The automatic document feeder 80 is provided with an operation display unit 70.

  The apparatus main body 102 includes an image reading unit 90, an image forming unit 10, an intermediate transfer belt 8, a paper feeding unit 20, a fixing device 44, and an automatic paper reversal conveyance unit 60 (hereinafter referred to as “ADU”). And a cooling device 200A.

  The image reading unit 90 scans and exposes a document placed on a document table by an optical system of a scanning exposure device, photoelectrically converts an image of the document scanned by a CCD (Charge Coupled Devices) image sensor, and outputs an image information signal. Generate. The image information signal is output to the image forming unit 10 after being subjected to analog processing, analog / digital (hereinafter referred to as A / D) conversion processing, pseudo correction, image compression processing, and the like by an image processing unit (not shown).

  The image forming unit 10 forms an image by electrophotography, and includes an image forming unit 10Y that forms a yellow (Y) image, an image forming unit 10M that forms a magenta (M) image, The image forming unit 10C forms a cyan (C) color image, and the image forming unit 10K forms a black (K) color image. In this example, common function names, for example, Y, M, C, and K indicating colors to be formed are added to the back of the reference numeral 10.

  The image forming unit 10Y includes a photosensitive drum 1Y, a charging unit 2Y, an exposure unit (optical writing unit) 3Y, a developing unit 4Y, and a cleaning unit 6Y disposed around the photosensitive drum 1Y. The image forming unit 10M includes a photosensitive drum 1M, and a charging unit 2M, an exposure unit 3M, a developing unit 4M, and a cleaning unit 6M disposed around the photosensitive drum 1M. The image forming unit 10C includes a photosensitive drum 1C, and a charging unit 2C, an exposure unit 3C, a developing unit 4C, and a cleaning unit 6C disposed around the photosensitive drum 1C. The image forming unit 10K includes a photosensitive drum 1K, and a charging unit 2K, an exposure unit 3K, a developing unit 4K, and a cleaning unit 6K disposed around the photosensitive drum 1K.

  Respective photosensitive drums (image carriers) 1Y, 1M, 1C, and 1K in the image forming units 10Y, 10M, 10C, and 10K, charging units 2Y, 2M, 2C, and 2K, exposure units 3Y, 3M, 3C, and 3K, development The parts 4Y, 4M, 4C, and 4K and the cleaning parts 6Y, 6M, 6C, and 6K have a common content configuration. In the following description, Y, M, C, and K are not used unless particularly distinguished.

  The charging unit 2 charges the surface of the photosensitive drum 1 almost uniformly. The exposure unit 3 is composed of, for example, an LPH (LED Print Head) having an LED array and an imaging lens, or a polygon mirror type laser exposure scanning device, and the photosensitive drum 1 is irradiated with laser light based on an image information signal. Scan to form an electrostatic latent image. The developing unit 4 develops the electrostatic latent image formed on the photosensitive drum 1 with toner. As a result, a toner image which is a visible image is formed on the photosensitive drum 1.

  The intermediate transfer belt 8 is stretched by a plurality of rollers and supported so as to be able to run. When the primary transfer roller operates, the intermediate transfer belt 8 travels, and the toner image formed on each photosensitive drum 1 is transferred to the image transfer position of the intermediate transfer belt 8 (primary transfer).

  The paper feed unit 20 has a plurality of paper feed trays 20A and 20B in which paper P such as A3 and A4 is accommodated. The paper P transported from the paper feed trays 20A, 20B by the transport rollers 22, 24, 26, 28, etc. is transported to the registration roller 32 via the loop creation roller 30. Note that the number of paper feed trays is not limited to three. Further, a single or a plurality of large-capacity paper feeders that can accommodate a large-capacity paper P may be connected as necessary.

  The registration roller 32 includes a driving roller and a driven roller, and forms a loop when the leading edge of the paper P is abutted by the loop creation roller 30 to correct the skew of the paper P. The paper P is conveyed to the secondary transfer unit 34 at a predetermined timing. In the secondary transfer unit 34, the color image transferred to the image forming position of the intermediate transfer belt 8 is collectively transferred onto the surface of the paper P conveyed from the paper supply unit 20 (secondary transfer). The sheet P that has been secondarily transferred is conveyed to the fixing device 44.

  The fixing device 44 is provided downstream of the secondary transfer unit 34 in the paper conveyance direction (hereinafter simply referred to as the downstream side), and includes a pressure roller and a heating roller. The fixing device 44 fixes the toner image on the paper P to the paper P by performing pressure and heat treatment on the paper P on which the toner image is transferred by the secondary transfer unit 34.

  On the downstream side of the fixing device 44, a conveyance path switching unit 48 for switching the conveyance path of the paper P to the discharge path side or the ADU 60 side is provided. The conveyance path switching unit 48 includes, for example, a solenoid and a motor, and performs conveyance path switching control based on a set printing mode (single-sided printing mode, double-sided printing mode, or the like).

  The paper P on which single-sided printing has been completed in the single-sided printing mode or the paper P on which double-sided printing has been completed in the double-sided printing mode is provided on the downstream side of the fixing device 44 after being subjected to fixing processing by the fixing device 44. It is transported to the cooling device 200A by the transport roller 46.

  When the paper P is re-fed to the image forming unit 10 in the duplex printing mode, the paper P having an image formed on the front side is conveyed to the ADU 60 via the conveyance path switching unit 48. The paper P transported to the ADU 60 is transported to the switchback path via the transport roller 62 and the like. In the switchback path, the ADU roller 64 is reversely controlled to be transported to the U-turn path section with the trailing edge of the paper P as the head, and to the registration roller 32 by the transport rollers 66 and 68 provided in the U-turn path section. The paper P is fed again in a state where the front and back sides are reversed. The paper P that has been re-fed to the registration roller 32 is subjected to the same image forming process as that on the front side of the paper P. The sheet P on which the image is transferred to the back surface by the image forming unit 10 is transported to the cooling device 200A via the transport path switching unit 48 and the transport roller 46 after the fixing process is performed by the fixing device 44.

  The cooling device 200 </ b> A is disposed downstream of the fixing device 44 and cools the paper P heated by the fixing device 44. Thereby, the toner image on the paper P is also cooled to a certain temperature, and problems such as the toner image adhering to the paper discharge roller 74 and the like when the paper P is discharged can be prevented. The paper P cooled by the cooling device 200 </ b> A is discharged by a paper discharge roller 74 onto a paper discharge tray (not shown). Details of the cooling device 200A will be described later.

[Configuration example of cooling device]
Next, a configuration example of the cooling device 200A according to the present invention will be described. FIG. 2 shows an example of the configuration of the cooling device 200A according to the present invention. As shown in FIG. 2, the cooling device 200 </ b> A includes an upper belt 220, a lower belt 230, a heat sink 210, a cooling fan 250, and a heater 240.

  The upper belt 220 is an endless belt, and is stretched by four rollers 222, 224, 226, and 228 provided on the upper side of the transport path R <b> 1 (one-dot chain line). In this example, for example, the roller 222 is configured as a driving roller, and the upper belt 220 moves clockwise (in the direction of the arrow) as the roller 222 is driven. The roller 228 functions as a peeling roller for peeling the paper P from the upper belt 220. Note that the driving roller may be configured other than the roller 222.

  The lower belt 230 is an endless belt, and is stretched by four rollers 232, 234, 236, and 238 provided on the lower side of the conveyance path R1. In this example, for example, the roller 232 is configured as a driving roller, and the lower belt 230 moves counterclockwise (in the direction of the arrow) as the roller 232 is driven. Further, conveyance rollers 242, 244, 246 and 248 for conveying the lower belt 230 are provided inside the lower belt 230 and at positions facing the heat sink 210. With such a configuration, the paper P discharged from the fixing device 44 is transported along the transport path R <b> 1 while being sandwiched between the upper belt 220 and the lower belt 230. Note that the drive roller may be configured other than the roller 232.

  The heat sink 210 has a liquid flow path inside and a plurality of fins on the upper surface. The heat sink 210 is disposed so as to be in contact with the inner peripheral surface of the upper belt 220, and cools the fixed sheet P conveyed by the upper belt 220 and the lower belt 230 by releasing heat. The heat sink 210 constitutes an example of a cooling unit.

  The cooling fan 250 is provided on the upper surface of the heat sink 210 and directly cools the heat sink 210 by blowing air to the heat sink 210 during the normal printing operation and in the second abnormality detection mode. The number of installed cooling fans 250 is not limited to one, and a plurality of cooling fans 250 may be provided. Although FIG. 2 shows an example in which the cooling fan 250 is arranged on the upper surface portion of the heat sink 210, disposing the cooling fan 250 between the fins of the heat sink 210 improves the flow of air accumulated between the fins and dissipates heat. You may make it raise an effect.

  The heater 240 is composed of, for example, a halogen heater and is built in the roller 226. The heater 240 is turned on by energization in the first abnormality detection mode to heat the inner peripheral surface of the upper belt 220 and to heat the heat sink 210 that is in contact with the upper belt 220. The heater 240 is built in the roller 226, but can be built in the other rollers 222, 224, and 228. Further, the heater 240 can be brought into direct contact with the upper belt 220 without being incorporated in the roller 226, or the heat sink 210 and the upper belt 220 can be heated by arranging the heater 240 in contact with the heat sink 210. The heater 240 constitutes an example of a heating unit.

  The thermistor 252 is attached to the upper surface portion of the heat sink 210, and measures the temperature T1 of the surface portion of the heat sink 210. The thermistor 254 is attached to the inner peripheral surface of the upper belt 220, and measures the temperature T2 of the surface portion of the upper belt 220. The thermistor 252 constitutes an example of a first measurement unit, and the thermistor 254 constitutes an example of a second measurement unit.

[Block Configuration Example of Image Forming Apparatus]
Next, a block configuration example of the image forming apparatus 100A according to the present invention will be described. FIG. 3 shows an example of a block configuration of the image forming apparatus 100A.

  As shown in FIG. 3, the image forming apparatus 100A includes a control unit 50 that controls the operation of the entire apparatus. The control unit 50 includes a CPU (Central Processing Unit) 52, a ROM (Read Only Memory) 54, and a RAM 56 (Random Access Memory). The CPU 52 executes the first and second abnormality detection modes, the printing operation, and the like by developing the control software and data read from the ROM 54 on the RAM 56 and starting the software to control each unit of the image forming apparatus 100. .

  The control unit 50 is connected to the cooling device 200A, the operation display unit 70, the image forming unit 10, the fixing device 44, and the memory unit 72. The cooling device 200 </ b> A includes a heater 240, a fan motor 274, an upper belt motor 276, a lower belt motor 278, a thermistor 252, and a thermistor 254.

  The heater 240 is turned on / off based on on / off switching control by the control unit 50. The heater 240 is turned on by the on control of the control unit 50 in the first abnormality detection mode to heat the upper belt 220 and the heat sink 210 to a predetermined temperature.

  The fan motor 274 is turned on / off based on on / off switching control by the control unit 50. The fan motor 274 is turned on by the on control of the control unit 50 to cool the heat sink 210 during normal printing operation or in the second abnormality detection mode.

  The upper belt motor 276 is driven under the control of the control unit 50 to rotate and move the upper belt 220 (see FIG. 2). The upper belt motor 276 is connected to the roller 222, for example, via a transmission means such as a gear. The lower belt motor 278 is driven under the control of the control unit 50 to rotate and move the lower belt 230 (see FIG. 2). The lower belt motor 278 is connected to, for example, the roller 232 via a transmission unit such as a gear.

  The thermistor 252 measures the temperature of the heat sink 210 and supplies temperature information T1 obtained by the measurement to the control unit 50. The thermistor 254 measures the temperature of the upper belt 220 and supplies temperature information T2 obtained by the measurement to the control unit 50.

  The operation display unit 70 is configured by combining a touch panel type position input device and a display unit. For example, selection of the first abnormality detection mode or the second abnormality detection mode, image forming conditions such as paper type and size, and the like. And an operation signal corresponding to the receiving operation is supplied to the control unit 50. The operation display unit 70 displays an operation screen including a dedicated icon for selecting the first abnormality detection mode, the second abnormality detection mode, or the like, or displays the first abnormality detection mode or the second abnormality detection mode. When it is determined that there is an abnormality in the cooling device 200A, an error message is displayed. The operation display unit 70 constitutes an example of a notification unit and an operation unit.

  The image forming unit 10 adjusts the laser output, the developing bias voltage, and the like based on the control of the control unit 50 and transfers a predetermined image onto the paper P. The fixing device 44 melts the toner transferred onto the paper P by turning on the internal heater and heating the paper P under the control of the control unit 50.

  The memory unit 72 is configured by, for example, a nonvolatile semiconductor memory, an HDD (Hard Disk Drive), or the like. The memory unit 72 stores threshold values such as reference temperatures X1 and X2 used in the first abnormality detection mode and a reference temperature X1 used in the second abnormality detection mode, for example.

[Operation example of image forming apparatus]
Next, an operation example of the image forming apparatus 100 in the first and second abnormality detection modes will be described. 4 and 5 are flowcharts illustrating an example of the operation of the image forming apparatus 100 in the first and second abnormality detection modes. As shown in FIG. 4, in step S100, the image forming apparatus 100 is powered on based on a power-on operation by the user. The power-on of the image forming apparatus 100 includes recovery from the sleep mode and the power saving mode.

  In step S110, when the power of the image forming apparatus 100 is turned on, the control unit 50 starts warming up. In step S120, when the warm-up is started, the control unit 50 starts the first abnormality detection mode during the warm-up. That is, in order to grasp the abnormality of the cooling device 200A before the printing operation, the first abnormality detection mode is executed before the printing operation (print job) is performed. The execution of the first abnormality detection mode can be arbitrarily set by the user as needed.

  When starting the first abnormality detection mode in step S130, the control unit 50 turns off the cooling fan 250. In step S140, the control unit 50 turns on the heater 240 when starting the first abnormality detection mode. At the same time, the control unit 50 drives the upper belt 220 and the lower belt 230. Thus, the entire upper belt 220 is heated by the heater 240, and the heat of the upper belt 220 is transmitted to the heat sink 210 in contact with the belt surface, whereby the heat sink 210 is also heated.

  In step S150, the control unit 50 determines whether or not an elapsed time from the start of the first abnormality detection mode has exceeded a predetermined time S1 set in advance. When the control unit 50 determines that the elapsed time from the start of the first abnormality detection mode does not exceed the predetermined time S1, the control unit 50 proceeds to step S160. The case where the elapsed time from the start of the first abnormality detection mode exceeds the predetermined time S1 will be described later.

  When the elapsed time from the start of the first abnormality detection mode does not exceed the predetermined time S1, the control unit 50 acquires the temperature T1 of the heat sink 210 from the thermistor 252 and the upper belt 220 from the thermistor 254 in step S160. Temperature T2 is obtained.

  In step S170, the controller 50 determines whether or not the temperature T1 of the heat sink 210 is equal to or higher than a preset reference temperature X1, and the temperature T2 of the upper belt 220 is equal to or higher than a preset reference temperature X2. To do. If the contact state between the heat sink 210 and the upper belt 220 is normal, the heat sink 210 also rises with the temperature rise of the upper belt 220 due to the heating of the heater 240, and both temperatures T1, T2 are the reference temperature X1. , X2 or more. Here, the reference temperatures X1 and X2 are threshold values used when determining whether or not an abnormality has occurred in the contact state between the upper belt 220 of the cooling device 200A and the heat sink 210, and is a target of the heater 240, for example. It is appropriately set according to the temperature.

  When the temperature T1 of the heat sink 210 is equal to or higher than the reference temperature X1 and the temperature T2 of the upper belt 220 is equal to or higher than the reference temperature X2, the control unit 50 proceeds to step S180. On the other hand, when the temperature T1 of the heat sink 210 is lower than the reference temperature X1 or when the temperature T2 of the upper belt 220 is lower than the reference temperature X2, the control unit 50 determines that both the temperatures T1 and T2 are the reference temperatures X1 and X2. If it is less, the process returns to step S150.

  In step S180, control unit 50 determines that there is no abnormality in cooling device 200A when both temperature T1 of heat sink 210 and temperature T2 of upper belt 220 satisfy the criteria. That is, it is determined that the heat sink 210 is in normal contact (adherence) with the upper belt 220.

  In step S190, when the determination of whether there is an abnormality in the contact state between the heat sink 210 and the upper belt 220 is completed, the control unit 50 turns off the heater 240 in order to end the first abnormality detection mode. If the heater 240 is turned off in step S200, the control unit 50 ends the first abnormality detection mode, and proceeds to step S240 shown in FIG.

  If at least one of the temperature T1 of the heat sink 210 and the temperature T2 of the upper belt 220 does not satisfy the reference in step S170, the control unit 50 determines that the elapsed time from the start of the first abnormality detection mode is a predetermined time S1 in step S150. It is judged whether it is over. When it is determined that the elapsed time from the start of the first abnormality detection mode exceeds the predetermined time S1, the control unit 50 proceeds to step S210.

  In step S210, the control unit 50 determines that an abnormality has occurred in the cooling device 200A when at least one of the temperature T1 of the heat sink 210 and the temperature T2 of the upper belt 220 does not satisfy the reference. That is, the upper belt 220 and the heat sink 210 are not in normal contact due to problems such as aging deterioration, design accuracy, and mounting accuracy of the upper belt 220 and the like, that is, between the upper belt 220 and the heat sink 210. It is determined that there is a part that is spaced apart.

  When determining that the cooling device 200A has an abnormality in step S220, the control unit 50 turns off the heater 240 in order to end the first abnormality detection mode.

  If the control unit 50 determines in step S230 that there is an abnormality in the cooling device 200A, an error display indicating that an abnormality has occurred in the cooling device 200A is displayed on the operation screen of the operation display unit 70. At this time, details indicating that a contact failure has occurred between the heat sink 210 and the upper belt 220 may be displayed. This error display can also be displayed on the screen of a display unit of a computer connected to the image forming apparatus 100 via a network. Further, instead of the error display, a warning by sound may be performed, or a warning by both error display and sound may be performed.

  As shown in FIG. 5, when the first abnormality detection mode is finished and it is determined that there is no abnormality such as poor contact between the heat sink 210 and the upper belt 220 of the cooling device 200A, the control unit 50 performs the second abnormality in step S240. Start detection mode. The second abnormality detection mode is also executed before performing the printing operation in order to grasp the abnormality of the cooling function of the cooling device 200A before the printing operation. The execution of the second abnormality detection mode can be arbitrarily set by the user as needed.

  In step S250, the control unit 50 turns on the cooling fan 250 with the start of the second abnormality detection mode. By driving the cooling fan 250, air (outside air) is blown to the heat sink 210 to cool the heat sink 210. For example, the heat sink 210 is cooled to substantially the same temperature as the outside air temperature.

  In step S260, the control unit 50 determines whether or not the elapsed time since turning on the cooling fan 250 has exceeded a preset predetermined time S2. When the controller 50 determines that the elapsed time since the cooling fan 250 is turned on does not exceed the predetermined time S2, the controller 50 proceeds to step S270. A case where the elapsed time after turning on the cooling fan 250 exceeds the predetermined time S2 will be described later.

  If the elapsed time since turning on the cooling fan 250 does not exceed the predetermined time S2, the control unit 50 acquires the temperature T3 of the heat sink 210 measured by the thermistor 252 in step S270.

  In step S280, the control unit 50 determines whether the temperature T3 of the heat sink 210 is equal to or lower than a preset reference temperature X3. Here, the reference temperature X3 is a threshold value used when determining whether the cooling function of the cooling device 200A is normal, and is appropriately set based on, for example, the outside air temperature. When the temperature T3 of the heat sink 210 is equal to or lower than the reference temperature X3, the control unit 50 proceeds to step S290. On the other hand, when the temperature T3 of the heat sink 210 exceeds the reference temperature X3, the control unit 50 returns to step S260.

  In step S290, when the temperature T3 of the heat sink 210 is equal to or lower than the reference temperature X3, the control unit 50 determines that the cooling function of the cooling device 200A is normal and ends the second abnormality detection mode. For example, it is determined that there is no defect or failure in the cooling fan 250, the fan motor 274, the heat sink 210, or the like.

  In step S300, the control unit 50 ends the warming up. As described above, in this example, the first and second abnormality detection modes are executed during the warm-up before starting the printing operation.

  On the other hand, when the temperature T3 of the heat sink 210 exceeds the reference temperature X3, in step S260, the control unit 50 determines whether or not the elapsed time since turning on the cooling fan 250 has exceeded a predetermined time S2. . When the control unit 50 determines that the elapsed time since the cooling fan 250 is turned on exceeds the predetermined time S2, the control unit 50 proceeds to step S310.

  In step S310, control unit 50 determines that there is an abnormality in the cooling function of cooling device 200A. For example, it is determined that some defect or failure has occurred in the cooling fan 250, the fan motor 274, the heat sink 210, etc., and the heat sink 210 cannot be cooled to the reference temperature X3. However, even when the control unit 50 determines that the cooling function of the cooling device 200 </ b> A is abnormal, the heat sink 210 itself has no abnormality, and the number of printed sheets (print job) is a small number of printed sheets that can be cooled by the heat sink 210. Sometimes printing is allowed. This is because there is no abnormality in the contact state between the heat sink 210 and the upper belt 220, and in the case of a small number of printed sheets, even if the cooling fan 250 or the like is out of order, the cooling can be made with just the heat sink 210. is there.

  If the control unit 50 determines in step S320 that there is an abnormality in the cooling function of the cooling device 200A, an error display indicating that an abnormality has occurred in the cooling function of the cooling device 200A is displayed on the operation screen of the operation display unit 70. I do. This error display can also be displayed on the screen of a display unit of a computer connected to the image forming apparatus 100 via a network. Further, instead of the error display, a warning by sound may be performed, or a warning by both error display and sound may be performed.

  As described above, according to the first embodiment, even when the fixing device (heating device) 44 and the heat sink 210 constituting the cooling device 200A are separated, the heater 240 is provided in the cooling device 200A. Thus, the first and second abnormality detection modes can be executed. Further, since the first and second abnormality detection modes are executed, for example, during warming up before the printing operation is started, the abnormality of the cooling device 200A can be confirmed before the printing operation is started. Thereby, it is possible to prevent the abnormality of the cooling device 200A from being detected during the printing operation, and it is possible to prevent a large amount of copy paper from being wasted.

  Further, since the abnormality of the cooling device 200A can be detected before the start of the printing operation, the toner after fixing is not sufficiently cooled, and the toner adheres to the paper discharge roller 74 on the downstream side of the fixing device 44. This problem can also be avoided. As a result, it is possible to prevent a decrease in productivity due to a failure or the like of the image forming apparatus 100A, and it is possible to improve reliability.

  Further, according to the first embodiment, when the first abnormality detection mode is executed, the cooling fan 250 is turned off, so that the heat sink 210 and the upper belt 220 can be heated faster. Thereby, the time until the abnormality detection of the cooling device 200A can be shortened, and the execution time of the first abnormality detection mode can be shortened. As a result, the printing operation can be started without delay.

  In addition, according to the first embodiment, the dedicated icon for selecting the first and second abnormality detection modes is displayed on the operation screen of the operation display unit 70, so that the serviceman performs the work. It is possible to easily set the first and second abnormality detection modes.

  Also, by executing the first abnormality detection mode, the temperature of the cooling device 200A can be raised to some extent before the printing operation, so the temperature difference between the cooling device 200A at the beginning and the end of the printing operation (print job) is reduced. can do. Even when the second abnormality detection mode is executed, when the cooling temperature of the cooling device 200A is adjusted to a predetermined temperature during the printing operation without lowering to the outside temperature when the image forming apparatus 100A is turned on, for example, The temperature difference between the cooling devices 200A at the beginning and the end of the printing operation can be reduced. Thereby, the image nonuniformity of the printing paper P due to the temperature difference of the cooling device 200A can be reduced.

  Furthermore, according to the first embodiment, since the second abnormality detection mode is executed, in addition to the abnormality of the contact failure between the heat sink 210 and the upper belt 220, the abnormality of the cooling function of the cooling device 200A is also confirmed. be able to. Thereby, the reliability of the image forming apparatus 100A can be further improved.

<Second Embodiment>
The second embodiment is different from the first embodiment in that the sheet P heated by the fixing device 44 is used as the heating unit used in the first abnormality detection mode. Since the configuration and operation of the other image forming apparatus 100B are the same as those of the image forming apparatus 100A of the first embodiment, common constituent elements are denoted by the same reference numerals and detailed description thereof is omitted. To do.

[Configuration example of image forming apparatus]
First, a configuration example of an image forming apparatus 100B according to the second embodiment will be described. FIG. 6 shows an example of the configuration of an image forming apparatus 100B according to the second embodiment. As shown in FIG. 6, the image forming apparatus 100 </ b> B includes a circulation path R <b> 2, a cooling device 200 </ b> B, and a switching unit 294.

  The circulation path R2 is a path for circulating the paper P that has passed through the cooling device 200B in the first abnormality detection mode to the fixing device 44 again. The circulation path R <b> 2 extends downward from the downstream portion of the cooling device 200 </ b> B in the transport path R <b> 1 so as to be folded back toward the fixing device 44, and its end side is connected to the ADU 60. A plurality of rollers 290, 292 and the like are provided in the circulation path R2. The switching unit 294 is provided at a branch portion between the transport path R1 and the circulation path R2, and switches the transport path of the paper P to the transport path R1 or the circulation path R2 based on the switching control of the control unit 50.

  The cooling device 200B has the same configuration as the cooling device 200A except that it does not have the heater 240. In this example, the paper P heated by the fixing device 44 is used as the heating unit used in the first abnormality detection mode. By conveying the paper P heated by the fixing device 44 in contact with the upper belt 220 of the cooling device 200B, the heat of the paper P can be transmitted to the upper belt 220 and the heat sink 210. Thereby, the upper belt 220 and the heat sink 210 can be warmed to a predetermined temperature.

[Operation example of image forming apparatus]
Next, an operation example of the image forming apparatus 100B in the first and second abnormality detection modes according to the second embodiment will be described. When the image forming apparatus 100B is powered on, the control unit 50 starts warming up and starts the first abnormality detection mode during the warming up. With the start of the first abnormality detection mode, test paper P (hereinafter referred to as test paper PT) is taken out from the paper supply unit 20, and the taken out test paper PT passes through the image forming unit 10. It is conveyed to the fixing device 44. The test paper PT conveyed to the fixing device 44 is heated to a predetermined temperature and then conveyed to a cooling device 200B provided on the downstream side.

  The test paper PT conveyed to the cooling device 200B is conveyed along the conveyance path R1 while being sandwiched between the upper belt 220 and the lower belt 230. During the transport of the test paper PT, the upper belt 220 is heated by the heat of the test paper PT, and the heat sink 210 that is in contact with the upper belt 220 is also heated.

  The test paper PT that has passed through the cooling device 200B is conveyed to the circulation path R2 by switching control of the switching unit 294, and is conveyed to the ADU 60 by rollers 290, 292 and the like. The test paper PT conveyed to the ADU 60 is conveyed back to the fixing device 44 via the secondary transfer unit 34 by being switched back. The test paper PT conveyed to the fixing device 44 is heated again by the fixing device 44 and then conveyed to the cooling device 200B.

  The test paper PT transported to the cooling device 200B is transported along the transport path R1 while being sandwiched between the upper belt 220 and the lower belt 230, and the upper belt 220 is heated by the heat of the test paper PT. The heat sink 210 in contact with 220 is also heated. In this way, the control unit 50 controls the conveyance so that the test paper PT circulates a plurality of times between the fixing device 44 and the cooling device 200B, thereby effectively and quickly heating the heat sink 210 and the upper belt 220. It can be carried out. The number of circulations can be arbitrarily set according to the target heating temperature.

  Further, in the first abnormality detection mode, the control unit 50, when the test paper PT passes through at least one of the fixing device 44 and the cooling device 200B, the paper passing speed is slower than the paper passing speed during the normal printing operation. The conveyance control is performed as follows. Accordingly, heat exchange can be performed between the fixing device 44 and the cooling device 200B for a long time, and the heat sink 210 and the upper belt 220 can be heated more efficiently.

  When a predetermined time has elapsed from the start of the first abnormality detection mode, the controller 50 acquires the temperature T1 of the surface portion of the heat sink 210 and also acquires the temperature T2 of the surface portion of the upper belt 220. The controller 50 determines whether the temperature T1 is equal to or higher than the reference temperature X1 and the temperature T2 is equal to or higher than the reference temperature X2. When the temperature T1 is equal to or higher than the reference temperature X1 and the temperature T2 is equal to or higher than the reference temperature X2, the control unit 50 determines that there is no abnormality in the cooling device 200B. On the other hand, when the temperature T1 is less than the reference temperature X1 or the temperature T2 is less than the reference temperature X2, the control unit 50 determines that there is an abnormality in the cooling device 200B and displays an error message to the user. Inform.

  When the first abnormality detection mode ends, the control unit 50 starts the second abnormality detection mode. The controller 50 turns off the fixing device 44 and turns on the cooling fan 250 with the start of the second abnormality detection mode. As a result, air (outside air) is blown onto the heat sink 210 to cool the heat sink 210.

  When a predetermined time has elapsed from the start of the second abnormality detection mode, the control unit 50 acquires the temperature T3 of the surface portion of the heat sink 210, and determines whether the acquired temperature T3 is equal to or lower than the reference temperature X3. . When it is determined that the temperature T3 is equal to or lower than the reference temperature X3, the control unit 50 determines that there is no abnormality in the cooling function of the cooling device 200B. On the other hand, when determining that the temperature T3 exceeds the reference temperature X3, the control unit 50 determines that there is an abnormality in the cooling function of the cooling device 200B, and notifies the user of this by displaying an error.

  As described above, according to the second embodiment, the same operational effects as those of the first embodiment can be obtained. That is, even when the fixing device (heating device) 44 and the cooling device 200B are configured separately, the first and second abnormality detection modes can be executed, and the abnormality of the cooling device 200A is detected before the start of the printing operation. Can be confirmed. Further, according to the second embodiment, since the paper P heated by the fixing device 44 is used as the heating unit, the first abnormality detection mode can be executed without providing heating means such as a heater. .

<Third Embodiment>
The third embodiment is different from the first and second embodiments in that exhaust heat of the fixing device 44 is used as a heating unit used in the first abnormality detection mode. Since the configuration and operation of the other image forming apparatus 100C are the same as those of the image forming apparatus 100A of the first embodiment, common constituent elements are denoted by the same reference numerals and detailed description thereof is omitted. To do.

[Configuration example of image forming apparatus]
First, a configuration example of a cooling device 200C according to the third embodiment will be described. FIG. 7 shows an example of the configuration of a cooling device 200C according to the third embodiment. As shown in FIG. 7, the cooling device 200 </ b> C does not have the heater 240 (see FIG. 2), but includes the blower fan 260 and the pair of guide plates 262 a and 262 b, the cooling device 200 </ b> A described in the first embodiment. This is the same as the configuration. Therefore, only the configuration different from the cooling device 200A will be described below.

  The blower fan 260 is provided between the pair of guide plates 262 a and 262 b and in the peripheral part (near the vicinity) of the fixing device 44. The blower fan 260 is driven in the first abnormality detection mode, sucks heat discharged from the fixing device 44, and blows the sucked heat onto the upper belt 220 of the cooling device 200C as warm air.

  The pair of guide plates 262a and 262b are made of, for example, a sheet metal, and are arranged to face each other at a predetermined interval so as to straddle between the upper roller of the fixing device 44 and the rollers 224 and 222 of the cooling device 200C. Is provided. The guide plates 262a and 262b have a function of adjusting the direction of the warm air so that the warm air blown by the blower fan 260 is efficiently blown to the upper belt 220 of the cooling device 200C.

  In this example, the blower fan 260, the guide plates 262a and 262b, and the fixing device 44 function as an example of a heating unit for heating the heat sink 210 and the upper belt 220. In addition, the guide plates 262a and 262b are used as members for restricting the direction of the warm air. However, the guide plates 262a and 262b are not limited to this, and a tubular member such as a tube may be used. Further, the hot air of the blower fan 260 may be blown directly to the heat sink 210, or the hot air may be blown to both the heat sink 210 and the upper belt 220.

[Block Configuration Example of Image Forming Apparatus]
Next, a block configuration example of an image forming apparatus 100C according to the third embodiment will be described. FIG. 8 shows an example of a block configuration of an image forming apparatus 100C according to the third embodiment. As shown in FIG. 8, the image forming apparatus 100 </ b> C has the same configuration as that of the image forming apparatus 100 </ b> A described in the first embodiment except that a blower fan motor 280 is added. Therefore, only the configuration different from the image forming apparatus 100C will be described below.

  The blower fan motor 280 is turned on / off based on on / off switching control by the control unit 50. The blower fan motor 280 is turned on by the ON control of the control unit 50 in the first abnormality detection mode, sucks heat discharged from the fixing device 44, and blows the sucked heat onto the heat sink 210.

  The fixing device 44 is heated to a predetermined temperature by turning on the internal heater based on the energization control of the control unit 50 during the normal printing operation or the first abnormality detection mode.

[Operation example of image forming apparatus]
Next, an operation example of the image forming apparatus 100C in the first and second abnormality detection modes according to the third embodiment will be briefly described. When the image forming apparatus 100C is powered on, the controller 50 starts warming up, and starts the first abnormality detection mode during the warming up. When the fixing device 44 is turned on at the start of the first abnormality detection mode, the controller 50 turns on the heater inside the fixing device 44 and heats the fixing roller to a predetermined temperature. At this time, heat during heating is discharged from the fixing device 44 to the outside.

  Further, the controller 50 drives the blower fan motor 280 to rotate the blower fan 260 and drives the upper belt motor 276 to rotate the upper belt 220 with the start of the first abnormality detection mode. Let The blower fan 260 takes in the heat discharged from the fixing device 44 and blows the taken-in heat onto the belt surface of the upper belt 220 as warm air. The upper belt 220 is heated by the blown warm air, and the heat sink 210 in contact with the upper belt 220 is also heated.

  On the other hand, the control unit 50 places the cooling fan 250 in a stopped state with the start of the first abnormality detection mode. Thereby, the heat sink 210 and the upper belt 220 can be heated more quickly.

  When a predetermined time has elapsed from the start of the first abnormality detection mode, the controller 50 acquires the temperature T1 of the surface portion of the heat sink 210 and also acquires the temperature T2 of the surface portion of the upper belt 220. The controller 50 determines whether the temperature T1 is equal to or higher than the reference temperature X1 and the temperature T2 is equal to or higher than the reference temperature X2. When the temperature T1 is equal to or higher than the reference temperature X1 and the temperature T2 is equal to or higher than the reference temperature X2, the control unit 50 determines that there is no abnormality in the cooling device 200C. On the other hand, when the temperature T1 is lower than the reference temperature X1 or the temperature T2 is lower than the reference temperature X2, the control unit 50 determines that the cooling device 200C has an abnormality and displays an error message to the user. Inform.

  When the first abnormality detection mode ends, the control unit 50 starts the second abnormality detection mode. The controller 50 turns off the fixing device 44 and turns off the blower fan 260 with the start of the second abnormality detection mode. On the other hand, the controller 50 turns on the cooling fan 250 with the start of the second abnormality detection mode. As a result, air (outside air) is blown onto the heat sink 210 to cool the heat sink 210.

  When a predetermined time has elapsed from the start of the second abnormality detection mode, the control unit 50 acquires the temperature T3 of the surface portion of the heat sink 210, and determines whether the acquired temperature T3 is equal to or lower than the reference temperature X3. . When it is determined that the temperature T3 is equal to or lower than the reference temperature X3, the control unit 50 determines that there is no abnormality in the cooling function of the cooling device 200C. On the other hand, when determining that the temperature T3 exceeds the reference temperature X3, the control unit 50 determines that there is an abnormality in the cooling function of the cooling device 200C, and notifies the user of this by displaying an error.

  As described above, according to the third embodiment, the same operational effects as those of the first embodiment can be obtained. That is, even when the fixing device (heating device) 44 and the cooling device 200C are configured separately, the first and second abnormality detection modes can be executed, and the abnormality of the cooling device 200C is detected before the start of the printing operation. Can be confirmed.

<Fourth embodiment>
In the fourth embodiment, the first and second embodiments are used in that the exhaust heat of the fixing device 44 is used as the heating unit used in the first abnormality detection mode and the water-cooled cooling device 200D is used. Is different. Since the configuration and operation of the other image forming apparatus 100D are the same as those of the image forming apparatus 100A according to the first embodiment, common constituent elements are denoted by the same reference numerals and detailed description thereof is omitted. To do.

[Configuration example of image forming apparatus]
First, a configuration example of a cooling device 200D according to the fourth embodiment will be described. FIG. 9 shows an example of the configuration of a cooling device 200D according to the fourth embodiment. As shown in FIG. 9, the cooling device 200 </ b> D does not have a heater 240 (see FIG. 2), and includes a blower fan 260, a pair of guide plates 262 a and 262 b, a radiator 270, and a tube (water-cooled hose) 272. The configuration is the same as that of the cooling device 200A described in the embodiment. Therefore, only the configuration different from the cooling device 200A will be described below.

  The blower fan 260 is provided between the pair of guide plates 262 a and 262 b and in the peripheral part (near the vicinity) of the fixing device 44. The blower fan 260 is driven in the first abnormality detection mode, sucks the heat discharged from the fixing device 44, and blows the sucked heat to the downstream radiator 270 as warm air.

  The pair of guide plates 262a and 262b are made of, for example, a sheet metal, are disposed to face each other at a predetermined interval, and are provided so as to straddle between the upper roller of the fixing device 44 and the radiator 270. The guide plates 262a and 262b have a function of adjusting the direction of the warm air so that the warm air blown by the blower fan 260 is efficiently blown to the radiator 270.

  The radiator 270 is arrange | positioned in the downstream of the wind direction of the ventilation fan 260, and the tube 272 is connected to the attaching part which is not shown in figure. The radiator 270 heats the internal liquid by exchanging heat with warm air blown from the blower fan 260 in the first abnormality detection mode, or cools the internal liquid by dissipating heat in the second abnormality detection mode. Or

  The tube 272 is disposed so as to contact the upper surface portion of the heat sink 210. For example, the tube 272 is disposed so as to pass between the fins of the heat sink 210. In the first abnormality detection mode, the heat sink 210 is heated by the liquid heated by the radiator 270 flowing into the tube 272. In the second abnormality detection mode, the liquid cooled by the radiator 270 or a cooling fan 250 described later flows into the tube 272, thereby cooling the heat sink 210.

  The cooling fan 250 is disposed above the tube 272 and cools the liquid flowing in the tube 272 in the second abnormality detection mode and in the printing operation. Note that the cooling fan 250 may be attached to the radiator 270 and the liquid flowing through the tube 272 may be cooled by cooling the radiator 270.

  In this example, the blower fan 260, the guide plates 262a and 262b, the radiator 270, and the fixing device 44 function as an example of the heating unit. In addition, the guide plates 262a and 262b are used as members for restricting the direction of the warm air. However, the guide plates 262a and 262b are not limited to this, and a tubular member such as a tube may be used. Further, the hot air of the blower fan 260 may be blown directly to the heat sink 210, or the hot air may be blown to both the heat sink 210 and the upper belt 220.

[Block Configuration Example of Image Forming Apparatus]
Next, a block configuration example of an image forming apparatus 100D according to the fourth embodiment will be described. FIG. 10 shows an example of a block configuration of an image forming apparatus 100D according to the fourth embodiment. As shown in FIG. 10, the image forming apparatus 100 </ b> D has the same configuration as that of the cooling device 200 </ b> A described in the first embodiment except that a blower fan motor 280 and a circulation motor 282 are added. Therefore, only the configuration different from that of the image forming apparatus 100D will be described below.

  The blower fan motor 280 is turned on / off based on on / off switching control by the control unit 50. The blower fan motor 280 is turned on by the ON control of the control unit 50 in the first abnormality detection mode, sucks heat discharged from the fixing device 44, and blows the sucked heat to the radiator 270.

  Circulation motor 282 is turned on / off based on on / off switching control by controller 50. The circulation motor 282 is turned on by the on control of the control unit 50 in the second abnormality detection mode and in the printing operation, and circulates the liquid inside the tube 272 cooled by the radiator 270. The circulation motor 282 constitutes an example of a drive unit.

  The fixing device 44 is heated to a predetermined temperature by turning on the internal heater based on the energization control of the control unit 50 during the normal printing operation or the first abnormality detection mode.

[Operation example of image forming apparatus]
Next, an operation example of the image forming apparatus 100D in the first and second abnormality detection modes according to the fourth embodiment will be briefly described. When the image forming apparatus 100C is powered on, the controller 50 starts warming up, and starts the first abnormality detection mode during the warming up. The controller 50 turns on the fixing device 44 with the start of the first abnormality detection mode. When the fixing device 44 is turned on, the heater inside the fixing device 44 is turned on to heat the fixing roller to a predetermined temperature. At this time, heat during heating is discharged from the fixing device 44 to the outside.

  Further, the controller 50 drives the blower fan motor 280 to rotate the blower fan 260 and drives the upper belt motor 276 to rotate the upper belt 220 with the start of the first abnormality detection mode. Let The blower fan 260 takes in the heat discharged from the fixing device 44 and blows the taken-in heat onto the radiator 270 as warm air. In the radiator 270 to which the warm air is blown, the liquid inside the tube 272 is also warmed by warming the liquid inside. As a result, the heat sink 210 in contact with the tube 272 is heated, and the heat sink 210 in contact with the heat sink 210 is also heated.

  On the other hand, with the start of the first abnormality detection mode, the controller 50 stops the circulation motor 282 and puts the cooling fan 250 in a stopped state. Thereby, the heat sink 210 and the upper belt 220 can be heated more quickly. It should be noted that the radiator 270 is also warmed when a certain period of time has elapsed since the start of the first abnormality detection mode, so that the liquid heated by the radiator 270 is circulated in the tube 272 by re-driving the circulation motor 282. Anyway. Thereby, the heat sink 210 and the upper belt 220 can be heated more efficiently.

  When a predetermined time has elapsed from the start of the first abnormality detection mode, the controller 50 acquires the temperature T1 of the surface portion of the heat sink 210 and also acquires the temperature T2 of the surface portion of the upper belt 220. The controller 50 determines whether the temperature T1 is equal to or higher than the reference temperature X1 and the temperature T2 is equal to or higher than the reference temperature X2. When the temperature T1 is equal to or higher than the reference temperature X1 and the temperature T2 is equal to or higher than the reference temperature X2, the control unit 50 determines that there is no abnormality in the cooling device 200D. On the other hand, when the temperature T1 is less than the reference temperature X1 or the temperature T2 is less than the reference temperature X2, the control unit 50 determines that the cooling device 200D is abnormal and displays an error message to the user. Inform.

  When the first abnormality detection mode ends, the control unit 50 starts the second abnormality detection mode. The controller 50 turns off the fixing device 44 and turns off the blower fan 260 with the start of the second abnormality detection mode. On the other hand, the controller 50 turns on the cooling fan 250 with the start of the second abnormality detection mode. As a result, air (outside air) is blown onto the heat sink 210 to cool the heat sink 210. The heat sink 210 is also cooled by circulating the liquid inside the tube 272 cooled by the radiator 270.

  When a predetermined time has elapsed from the start of the second abnormality detection mode, the control unit 50 acquires the temperature T3 of the surface portion of the heat sink 210 and determines whether the temperature T3 is equal to or lower than the reference temperature X3. When it is determined that the temperature T3 is equal to or lower than the reference temperature X3, the control unit 50 determines that there is no abnormality in the cooling function of the cooling device 200D. On the other hand, when it is determined that the temperature T3 exceeds the reference temperature X3, the control unit 50 determines that there is an abnormality in the cooling function of the cooling device 200D, and notifies the user of this by performing an error display.

  As described above, according to the fourth embodiment, the same operational effects as those of the first embodiment can be obtained. That is, even when the fixing device (heating device) 44 and the cooling device 200D are configured separately, the first and second abnormality detection modes can be executed, and the abnormality of the cooling device 200D is detected before the start of the printing operation. Can be confirmed.

  It should be noted that the technical scope of the present invention is not limited to the above-described embodiments, and includes those in which various modifications are made to the above-described embodiments without departing from the spirit of the present invention. For example, in the first to fourth embodiments, the cooling devices 200A, 200B, 200C, and 200D (hereinafter referred to as the cooling device 200) are the image forming devices 100A, 100B, 100C, and 100D (hereinafter referred to as the image forming device). However, the present invention is not limited to this. It is also possible to configure the cooling device 200 independently as a post-processing device, and to configure the image forming system by connecting the independently configured cooling device 200 to the downstream side of the image forming device 100. By setting it as such a system structure, the highly convenient system according to a user's request | requirement can be provided.

44 Fixing device 50 Control unit 70 Operation display unit (notification unit, operation unit)
200A, 200B, 200C, 200D Cooling device 210 Heat sink (cooling part)
220 Upper belt (belt)
240 heater (heating unit)
250 Cooling fan 252 Thermistor (first measurement unit)
254 Thermistor (second measuring unit)
260 Blower fan (heating unit)
262a, 262b Guide plate 270 Radiator (heating unit)
272 Tube 282 Circulation motor (drive unit)
P paper PT test paper (heating section)
R2 circulation route

Claims (19)

A fixing device that at least heats and fixes the toner to the paper;
A cooling device that is provided separately from the fixing device and cools the sheet conveyed from the fixing device;
A controller for performing a first abnormality detection mode for detecting an abnormality of the cooling device,
The cooling device is
A belt that conveys the paper fixed by the fixing device downstream;
A cooling unit that is provided in contact with the belt and cools the paper conveyed by the belt;
A heating unit for heating at least one of the belt and the cooling unit;
A first measurement unit for measuring the temperature of the cooling unit;
A second measuring unit for measuring the temperature of the belt,
The controller determines whether the cooling device has an abnormality based on the measurement results of the first and second measurement units after starting the heating unit with the start of the first abnormality detection mode. An image forming apparatus comprising: determining and stopping the activation of the heating unit when the determination is completed. The image forming apparatus according to claim 1, wherein the control unit starts the heating unit and stops a cooling function of the cooling unit with the start of the first abnormality detection mode. The controller reduces the temperature difference of the cooling device during the printing operation by executing the first abnormality detection mode before starting the printing operation and increasing the temperature of the cooling device by starting the heating unit. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. The control unit starts the first abnormality detection mode when the temperature of the cooling unit measured by the first measurement unit or the temperature of the belt measured by the second measurement unit starts. The image forming apparatus according to any one of claims 1 to 3, wherein the cooling device is determined to be abnormal when the temperature does not exceed a predetermined temperature within a predetermined time. The image according to any one of claims 1 to 4, wherein the control unit detects an abnormality in a contact state between the cooling device and the belt in the first abnormality detection mode. Forming equipment. The cooling device includes a fan for cooling the cooling unit,
The said control part stops the cooling function of the said cooling part by stopping the said fan with the start of the said 1st abnormality detection mode. Any one of Claims 1-5 characterized by the above-mentioned. The image forming apparatus described in 1. The cooling device is
A tube provided in contact with the cooling section and having a liquid inside;
A fan for cooling the liquid inside the tube;
A drive unit for circulating the liquid inside the tube,
The controller stops the cooling operation by the cooling unit by stopping the driving unit and stopping the circulation of the liquid in the tube and stopping the fan with the start of the first abnormality detection mode. The image forming apparatus according to claim 1, wherein the image forming apparatus includes: When the control unit determines that the cooling device is normal in the first abnormality detection mode, the control unit performs a second abnormality detection mode for determining whether the cooling function of the cooling device is normal, 8. The image forming apparatus according to claim 1, wherein in the abnormality detection mode of 2, the activation of the heating unit is stopped, and the cooling operation by the cooling unit is performed. . When the temperature of the cooling unit measured by the first measuring unit is not less than or equal to a predetermined temperature within a predetermined time after starting the second abnormality detection mode, the cooling unit The image forming apparatus according to claim 8, wherein the cooling function is determined to be abnormal. The cooling unit is a heat sink;
10. The printing apparatus according to claim 9, wherein the control unit permits printing even when it is determined that there is an abnormality in the cooling function of the cooling device when printing is a small amount of printing that can be cooled by the heat sink. Image forming apparatus. The image forming apparatus according to claim 1, wherein the heating unit includes a heater. The image forming apparatus according to claim 1, wherein the heating unit includes a fan that blows heat discharged from the fixing device to at least one of the belt and the cooling unit. The cooling device is
Provided in contact with the cooling unit, having a tube having a liquid inside,
The heating unit is
A radiator that performs heat exchange of the liquid inside the tube;
A fan that blows heat discharged from the fixing device to the radiator,
As the first abnormality detection mode starts, the control unit drives the fixing device and drives the fan to blow heat discharged from the fixing device to the radiator, thereby The image forming apparatus according to claim 1, wherein the liquid is heated. The image forming apparatus according to claim 1, wherein the heating unit is a sheet heated by the fixing device, and the belt and the cooling unit are heated by conveying the sheet by the belt. A circulation path for returning the paper that has passed through the cooling device to the fixing device;
15. The conveyance control according to claim 14, wherein the control unit performs conveyance control so that the sheet that has passed through the cooling device circulates between the fixing device and the cooling device via the circulation path. Image forming apparatus. The control unit performs conveyance control so that when the paper passes through the fixing device or the cooling device, the paper passing speed of the paper is slower than the paper passing speed when performing a printing operation. The image forming apparatus according to claim 14 or 15. 2. The apparatus according to claim 1, further comprising: a notification unit that notifies that there is an abnormality in the cooling device when the cooling device is abnormal in the first abnormality detection mode or the second abnormality detection mode. Item 17. The image forming apparatus according to any one of Items 16 above. The image forming apparatus according to any one of claims 1 to 17, wherein the control unit performs the first abnormality detection mode and the second abnormality detection mode during warm-up. The image forming apparatus according to any one of claims 1 to 18, further comprising: an operation unit configured to select and execute the first abnormality detection mode or the second abnormality detection mode. .

Images