JP6474663B2 - Heat generating device, fixing device, and image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus using an electrophotographic recording system, and more particularly to an image forming apparatus having a plurality of temperature detecting elements and a fixing device for fixing toner transferred to a recording medium by heat.

  In a conventional fixing device of an image forming apparatus, when the protection member is peeled off from a plurality of temperature detection elements that are covered with a protection member and are in contact with a heating body, a detection temperature detected by the temperature detection element Malfunctions and errors may be detected incorrectly. Therefore, when a failure occurs, once the heater is turned on and the temperature rise of all the temperature detection units can be recognized, it is determined that the protection member has been peeled off, and the temperature detected by the temperature detection element is corrected. The temperature correction memorizes the temperature difference between the temperature detection units at both ends of the fixing device, determines that the protective member has been peeled off the higher temperature detection unit, and sets the temperature to the detection temperature of the higher temperature detection unit. The difference is subtracted and corrected. As a result, the extent to which the protective member of the temperature detection unit is peeled off is not a failure enough to replace the fixing device. Therefore, unnecessary fixing device replacement can be eliminated and the burden on the user can be reduced.

  Japanese Patent Application Laid-Open No. 2011-48331 (Patent Document 1) describes a fixing device that corrects the detection temperature of a temperature detection unit from which a protective member has been peeled off to prevent erroneous detection of a failure or error. According to Patent Literature 1, when there is a difference in temperature detected by the temperature detection unit, there is a case in which it may be erroneously detected that the paper is not properly transported despite the fact that the protective member is peeled off. In order to solve this problem, the detected temperature is corrected.

JP 2011-48331 A

  However, according to the prior art, in order to perform temperature correction when temperature abnormality is detected, the temperature difference has to be stored. In addition, it is necessary to have a fixing device configuration in which the temperature detection units at both ends are the same distance from the heater, and temperature correction cannot be performed unless detected by the temperature detection units at both ends. . Therefore, when there is a change in the configuration of the fixing device, when there is a difference in the way the protective member is peeled off, which is the cause of false detection, or because of a failure due to other causes in the temperature detector. Depending on the situation, there is a problem that the temperature correction becomes difficult in the method of correcting by subtracting the temperature difference as it is.

  The problem to be solved by the present invention is that when an abnormality is detected in any one of a plurality of temperature detection elements, the temperature for the temperature detection is not corrected, and the temperature for temperature correction is not performed. It is possible to provide a fixing device that does not require a storage unit for storing the difference.

Heating apparatus according to the invention in order to solve the above problems, performing a heat generating means of several, a plurality of temperature detection elements for detecting the temperature of the pre-Symbol heat generating means, the control based on the detected temperature of said temperature sensing element A control unit, and the control unit sets a temperature error threshold for determining that the detected temperature is abnormal when the detected temperature exceeds a predetermined value, and the control unit uses the temperature error threshold to set the temperature error threshold. When the abnormality of one temperature detection element among the plurality of temperature detection elements is determined, a heat generation inspection is performed by the heat generation means, and when the temperature increase of the one temperature detection element can be recognized, the determination is an erroneous detection. The temperature error threshold relating to the one temperature detecting element is changed so that the detected temperature of the one temperature detecting element falls within a normal range by determination .

According to the present invention having the above-described configuration, when temperature abnormality is detected in one temperature detection element among a plurality of temperature detection elements, the detection temperature from the temperature detection element adjacent in the starting direction of the one temperature detection element is calculated. Since it is used as the detection temperature from one temperature detection element, there is no need to perform temperature correction of the detection temperature detected by the one temperature detection element, so a storage unit for storing a temperature difference for temperature correction is provided. It is possible to provide a fixing device as a heat generating device that does not need to be provided. Furthermore, the present invention can be implemented even in situations where there are various causes for the change in the configuration of the fixing device as the heat generating device, the failure and the erroneous detection. Furthermore, it is possible to reduce the burden on the user by eliminating unnecessary replacement of the heat generating device or the fixing device. Furthermore, even when there is a failure in the temperature detecting element that cannot detect the temperature, the heat generating device or the fixing device can be used.

1 is a configuration diagram illustrating an image forming apparatus according to a first embodiment. FIG. 3 is a configuration diagram illustrating a configuration of a fixing unit according to the first embodiment. FIG. 6 is an explanatory diagram illustrating a positional relationship between a heater and a temperature sensor of the fixing unit according to the first embodiment. FIG. 3 is a block diagram of a control relationship of the printing apparatus according to the first embodiment. It is a block diagram which shows the principal part of the main control part regarding 1st Embodiment. FIG. 3 is a functional block diagram of a fixing control unit according to the first embodiment. 3 is a flowchart illustrating an operation of a fixing unit according to the first embodiment. FIG. 6 is a sequence diagram illustrating a processing procedure from an initial operation of a printing unit to a printing operation. FIG. 6 is a sequence diagram illustrating a processing procedure from an initial operation of a printing unit to a printing operation. FIG. 10 is a functional block diagram of a fixing control unit according to a second embodiment. 6 is a flowchart illustrating an operation of a fixing unit according to a second embodiment. FIG. 10 is a functional block diagram of a fixing control unit according to a third embodiment. 10 is a flowchart illustrating an operation of a fixing unit according to a third embodiment.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described. FIG. 1 is a configuration diagram illustrating an image forming apparatus according to the first embodiment. In FIG. 1, a printing apparatus 1 as an image forming apparatus can form an image by thermally melting a developer such as toner and thermally fixing it on a recording medium 31. The recording medium 31 is stored in a roll before printing, and is drawn out by a drawing roller 33 to be fed. The cut sensor 32 measures the timing for cutting the recording medium 31. The cutter 34 cuts the recording medium 31 into a predetermined length at the timing measured by the cut sensor 32. The cutter 34 cuts the recording medium 31 by being slid or clamped by a movable blade and a fixed blade. The cut recording medium 31 is nipped by a conveyance roller 35, a secondary transfer roller 39, a fixing unit 40 as a heat generating device or a fixing device, and a discharge roller 41, and is conveyed along the direction of arrow A.

  The ID unit 38 forms a developer image on the photosensitive drum 38-1 as an image carrier. Here, the ID unit 38 is provided for each process color (cyan, yellow, magenta, black) when the printing apparatus 1 is a color printing apparatus, and when the printing apparatus 1 is a monochrome printing apparatus, It is composed of a black ID unit 38. In the present embodiment, it is assumed that the printing apparatus 1 is a monochrome printing apparatus and the ID unit 38 is black. The primary transfer roller 37 transfers a developer image (not shown) formed on the photosensitive drum 38-1 onto the transfer belt 36 that temporarily moves along the arrow B direction. The conveyance of the recording medium 31 is adjusted so that the head of the developer image transferred onto the transfer belt 36 and the writing position of the recording medium 31 overlap with the secondary transfer roller 39. As a result, the developer image on the transfer belt 36 is transferred to the recording medium 31 by the secondary transfer roller 39.

  The recording medium 31 to which the developer image has been transferred is then sent to a fixing unit 40 as a fixing device. The developer image transferred onto the recording medium 31 is fixed on the recording medium 31 by the fixing unit 40. Finally, the printing apparatus 1 is configured such that the recording medium 31 on which the developer image is fixed is discharged out of the printing apparatus 1 by a discharge roller 41. The display unit 2 displays the state of the printing apparatus 1, and the operation unit 4 receives a print command by an operator's operation.

  FIG. 2 is a configuration diagram showing the configuration of the fixing unit according to the first embodiment. The fixing unit 40 as a fixing device includes a fixing belt 51 and a pressure belt 52, and heat-melts the developer image on the recording medium 31 and thermally fixes it on the recording medium 31. The fixing unit 40 passes the recording medium 31 in the transport direction indicated by the arrow A between the fixing belt 51 rotated and heated in the direction of the arrow C and the pressure belt 52 rotated in the direction of the arrow D. As a result, the developer image is melted by heat and pressure, and is thermally fixed on the recording medium 31. The fixing belt 51 includes a plurality of heaters 61 to 65 serving as heat generation means to be described below, and a plurality of temperature sensors 53 to 59 serving as temperature detection elements that detect the temperatures of the heaters 61 to 65. The pressure belt 52 is a heater. 66 and a temperature sensor 60.

  FIG. 3 is an explanatory diagram showing the positional relationship between the heater and the temperature sensor of the fixing unit according to the first embodiment. FIG. 3A shows the positional relationship between the heater and the temperature sensor when the fixing belt 51 shown in FIG. 2 is viewed from above (y-axis), and FIG. 3B is the same as the pressure belt 52 shown in FIG. The positional relationship between the heater and the temperature sensor when viewed from above (y-axis) is shown.

  As shown in FIGS. 2 and 3, the fixing belt 51 and the pressure belt 52 have a cylindrical shape having a rotation axis parallel to the width direction (z axis) of the recording medium 31. A plurality of heaters 61 to 65 as heat generating means are arranged inside the circumference of the cylindrical fixing belt 51, and a plurality of temperatures for detecting the surface temperature of the fixing belt 51 are arranged outside the circumference of the cylindrical fixing belt 51. Sensors 53 to 59 are linearly arranged in the cylindrical axial direction. A heater 66 is disposed on the inner side of the circumference of the cylindrical pressure belt 52 over the entire width direction of the recording medium 31, and a temperature sensor for detecting the surface temperature of the pressure belt 52 on the outer side of the circumference. 60 is disposed at the center of the recording medium 31 in the width direction.

  The plurality of heaters 61 to 65 as the heat generating means are heaters having different lengths extending from the starting point E to the other end in the width direction from the position of one end (left end in the figure) of the recording medium 31 in the width direction. is there. A plurality of heaters 61 to 65 are provided according to the size of the available recording medium 31 in the width direction. This is because they are selectively used depending on the size and environment of the recording medium 31 and the state of the fixing device.

  Among the plurality of temperature sensors 53 to 59 as temperature detection elements, the temperature sensor 59 is disposed at one place on the circumference corresponding to the starting point E, which is one end in the width direction of the recording medium 31. Further, the other temperature sensors 53 to 58 are arranged in a straight line from the position of the temperature sensor 59 toward the other end in the width direction of the recording medium 31. Further, the arrangement of the temperature sensors 54 to 58 is provided in the vicinity of the other ends of the heaters 61 to 65. This is a case where the recording medium 31 travels in a biased manner, and if there is an end portion through which the recording medium 31 does not pass, the temperature may continue to rise without being deprived of heat by the recording medium 31 at that end portion. Because.

As shown in FIG. 3A, with respect to the longest heater 65, all of the temperature sensors 53 to 59 are arranged at positions where the temperature rise of the heater 65 can be detected. Regarding the second longest heater 64, the temperature sensors 53 to 57 and 59 are arranged at positions where the temperature rise of the heater 64 can be detected. Similarly, for the shortest heater 61, the temperature sensors 53, 54 and 59 are arranged at positions where the temperature rise of the heater 61 can be detected. Thus, the plurality of temperature sensors 53 to 59 are arranged corresponding to the plurality of heaters 61 to 65 having different lengths.
Note that the number of heaters and temperature sensors installed is not limited to the number shown in FIGS. 2 and 3, and is appropriately determined depending on the application and configuration of the printing apparatus 1.

  FIG. 4 is a block diagram of the control relationship of the printing apparatus according to the first embodiment. The main control unit 5 of the printing apparatus 1 controls the status display and printing operation of the printing apparatus 1. Regarding the status display of the printing apparatus 1, the display unit 2 performs display according to the control of the main control unit 5. As for the printing operation of the printing apparatus 1, a print command is sent from the operation unit 4 or the personal computer 3 to the data receiving unit 9 by the operation of the operation unit 4 by the operator or the operation of the personal computer 3. When the main control unit 5 receives a print command from the data receiving unit 9, the main control unit 5 controls the transport control unit 16, the image formation control unit 17, and the fixing control unit 18 based on the information of the print command to perform a printing operation.

  The sensor unit 10 includes various sensors such as the temperature sensors 53 to 60 and the cut sensor 32. The sensor unit 10 transmits information from various sensors to the main control unit 5. The main control unit 5 sends this to the conveyance control unit 16, the image formation control unit 17, and the fixing control unit 18. Each control unit of the conveyance control unit 16, the image formation control unit 17, and the fixing control unit 18 receives information from the sensor unit 10 via the main control unit 5, and uses this to control a control target to be described next. Do.

  When each control unit of the conveyance control unit 16, the image formation control unit 17, and the fixing control unit 18 determines that there is an abnormality in the control from the information of the sensor unit 10, it notifies the main control unit 5 of this abnormality. Receiving this, the main control unit 5 performs control such as displaying on the display unit 2. As will be described later, in the present embodiment, the fixing control unit 18 serving as a control unit that performs control based on the temperature detected by the temperature sensors 53 to 60 causes an abnormality in the temperature sensors 53 to 60 from the information of the temperature sensors 53 to 60. The main control unit 5 is notified.

  The transport control unit 16 controls the transport unit 26 as a control target based on a command and information from the main control unit 5 and performs medium transport. The transport unit 26 as a control target includes the above-described drawing roller 33, cutter 34, transport roller 35, discharge roller 41, and the like.

  The image formation control unit 17 controls the process unit 27 as a control target based on a command and information from the main control unit 5 to perform image formation. The process unit 27 as a control target includes the transfer belt 36, the primary transfer roller 37, the ID unit 38, the secondary transfer roller 39, and the like described above.

  The fixing control unit 18 controls the fixing drive control unit 21 and the fixing temperature control unit 22 as control targets based on commands and information from the main control unit 5. Further, the fixing drive control unit 21 controls the fixing roller unit 28 as a control target, and the fixing temperature control unit 22 controls the heater unit 29 as a control target to operate the fixing unit 40. The fixing roller unit 28 as a control target includes the fixing belt 51 and the pressure belt 52 described above, and the heater unit 29 as a control target includes the heaters 61 to 66 described above.

  FIG. 5 is a block diagram illustrating a main part of the main control unit according to the first embodiment. The main control unit 5 is provided with a ROM 6 in which a control method and the like are stored, and a RAM 7 for sequentially storing data necessary for operation. The CPU 8 controls the main control unit 5 using the RAM 7 while referring to and acquiring the ROM 6.

  FIG. 6 is a functional block diagram of the fixing control unit according to the first embodiment. FIG. 6 shows the main functions of the fixing controller 18 relating to the present embodiment, and other functions are omitted. The unit controller 70 of the fixing controller 18 controls each part. The warm-up operation unit 71 controls the warm-up operation of the fixing drive control unit 21 and the fixing temperature control unit 22 under the control of the unit control unit 70. The heater lighting unit 72 lights the heater unit 29, that is, the heaters 61 to 66, under the control of the unit control unit 70. The main control unit notifying unit 73 notifies the main control unit 5 under the control of the unit control unit 70. The main control unit 5 that has received the notification performs storage in the ROM 6 described later, display on the display unit 2, and the like.

  The temperature sensor abnormality determination unit 75 determines whether an abnormality is detected in any one of the temperature sensors 53 to 60 under the control of the unit control unit 70. When an abnormality is detected in one of the temperature sensors 53 to 60 as described later, the adjacent temperature sensor temperature increase determination unit 76 determines whether a temperature increase is recognized in the temperature sensor adjacent to the temperature sensor.

  Here, the adjacent temperature sensor is a temperature sensor adjacent to the origin E direction, which is one end of the recording medium 31 in the width direction, among the plurality of temperature sensors 53 to 59 arranged in a straight line in the width direction of the recording medium 31. There are temperature sensors adjacent to each other in the direction of the other end. However, the temperature sensor adjacent to the starting point E direction is preferable. For example, when an abnormality is detected in the temperature sensor 54 when the heater 61 is in use, either the temperature sensor 53 adjacent to the origin E direction or the temperature sensor 55 adjacent to the other end direction may be used. However, the temperature sensor 53 adjacent to the starting point E direction is preferable. This is related to the length of the heaters 61 to 65 in use. The temperature sensor 53 adjacent to the origin E direction covers the heater 61, but the temperature sensor 55 adjacent to the other end direction covers the heater 61. Because it is not always.

  Next, the operation of the fixing unit 40 relating to the first embodiment will be described. FIG. 7 is a flowchart showing the operation of the fixing unit according to the first embodiment. The flowchart shown in FIG. 7 shows a control procedure and a heater control processing procedure when an abnormality is detected in the temperature sensor. First, the printing apparatus 1 performs an initial operation such as a power-on operation (not shown), a sleep return operation, or a printing operation after power saving.

S101: The fixing control unit 18 of the printing apparatus 1 instructs the fixing temperature control unit 22 in the initial operation to turn on the heater unit 29 by the heater lighting unit 72 and to perform the warming up operation by the warming up operation unit 71.

S102: The fixing controller 18 determines whether the temperature sensor abnormality determination unit 75 detects an abnormality in any one of the temperature sensors 53 to 60 of the sensor unit 10 during the warm-up operation. If no abnormality is detected, the process proceeds to step 108, and if an abnormality is detected, the process proceeds to step 103. Here, there are the following methods for determining whether an abnormality is detected in one of the temperature sensors 53 to 60 of the sensor unit 10.

(1) When the temperature sensor detects a remarkably low temperature (for example, when −5 ° C. or less is detected as the temperature error threshold S1), it is determined that there is an abnormality.

(2) When the temperature sensor detects a remarkably high temperature (for example, when 280 ° C. or more is detected as the temperature error threshold S2), it is determined that there is an abnormality.

(3) When the temperature difference detected by two adjacent temperature sensors is a certain level or more (for example, when the certain temperature difference is 100 ° C. or more, the temperature sensor 53 is 50 ° C. and the temperature sensor 54 is 180 ° C. If the temperature difference is 130 ° C. as a result, it is determined that there is an abnormality.

(4) If no temperature rise is observed even after a certain time has passed since the heater was turned on, it is determined that the temperature sensor is abnormal. Regarding the abnormality determination of the temperature sensors 53 to 60 of the sensor unit 10, the temperature error thresholds S <b> 1 and S <b> 2 and the abnormality determination methods (1) to (4) can be changed depending on the application and configuration of the printing apparatus 1.

S103: In step S102, when the fixing control unit 18 determines that one of the temperature sensors 53 to 60 of the sensor unit 10 is abnormal, the heater lighting unit 72 notifies the fixing temperature control unit 22 of each of the heaters 61 to 61. The heaters 61 to 66 are instructed to be lit to inspect the state of 66. All the heaters 61 to 66 may be turned on, or only the longest heater 65 arranged at a position where the temperature rise of all the temperature sensors 53 to 59 can be detected may be turned on.

S104: The fixing controller 18 determines whether the adjacent temperature sensor temperature increase determination unit 76 can recognize the temperature increase of the temperature sensor adjacent to one of the temperature sensors 53 to 60 in which the abnormality is detected in step S102. For example, if abnormality is detected in the temperature sensor 53 shown in FIG. 3A in step S102, whether or not the temperature sensor 54 adjacent to the temperature sensor 53 and / or the temperature sensor 59 can recognize that there is a temperature increase. judge. If the temperature difference detected by the two temperature sensors in the abnormality determination method (3) is greater than or equal to a certain value, a plurality of combinations of temperature sensors are provided and compared, and a threshold value is provided for the temperature difference to determine an abnormality. One of the detected temperature sensors 53 to 60 is specified.

  If the temperature rise of the adjacent temperature sensor cannot be recognized, the process proceeds to step S105, and if the temperature rise of the adjacent temperature sensor can be recognized, the process proceeds to step S106. In step S104, if there is no adjacent temperature sensor such as the temperature sensor 60 shown in FIG. 3A, even if it is determined that the temperature sensor 60 is abnormal, an increase in the adjacent temperature sensor cannot be recognized. The process proceeds to S105.

S <b> 105: If the temperature rise of the adjacent temperature sensor cannot be recognized, the fixing control unit 18 sets an error as a problem of the fixing unit 40 and notifies the main control unit 5 by the main control unit notification unit 73. In response to this, the main control unit 5 instructs the display unit 2 to display a message.

S106: If the temperature increase of the adjacent temperature sensor can be recognized in step S104, the fixing control unit 18 determines that one of the temperature sensors 53 to 59 in which the abnormality has been detected is erroneously detected, and the main control unit notification unit. The main control unit 5 is notified by 73. In response to this, the main controller 5 stores the information in the nonvolatile ROM 6.

S107: The fixing control unit 18 performs a warming-up operation using a temperature sensor adjacent to the warming-up operation unit 71 instead of one of the temperature sensors 53 to 59 in which an abnormality is detected. As described above, adjacent temperature sensors used as an alternative are a temperature sensor adjacent to the origin E direction, which is one end in the width direction of the recording medium 31, and adjacent to the other end direction among the plurality of temperature sensors 53 to 59. There is a temperature sensor that does, but any may be used. However, the temperature sensor adjacent to the starting point E direction is preferable.

S108: When it is determined in step S102 that there is no temperature sensor in which the abnormality is detected in the temperature sensors 53 to 60 of the sensor unit 10 during the warm-up operation, the fixing control unit 18 uses the warm-up operation unit 71 to perform a normal warm-up operation. I do. Thereafter, the following operation is performed.

  That is, when the temperature sensor 53 to 59 determined as abnormal is the temperature sensor 53, the adjacent temperature sensor is the temperature sensor 54, the temperature sensor 59, or both. Even if the temperature sensor determined to be abnormal is the central portion or the end portion of the heater unit 29 including the heaters 61 to 66, correction is not performed. If the temperature sensor determined to be abnormal is the temperature sensor 53, control is performed by replacing the detected temperature of the adjacent single temperature sensor 54 or the detected temperature of the single temperature sensor 59 with the detected temperature of the temperature sensor 53. Continue.

  Alternatively, the average value of the detected temperatures of the plurality of temperature sensors 54 and 59, which are both of them, is calculated and used to replace the detected temperature of the temperature sensor 53 and control is continued. When the power is turned OFF / ON, the information detected by the temperature sensor erroneously, that is, the information of the temperature sensor 53 is stored in the ROM 6, so steps 101 and 102 are performed using the temperature sensors 54 and 59 adjacent to the temperature sensor 53. .

  Next, a processing sequence relating to the first embodiment will be described. 8A and 8B are sequence diagrams showing the processing procedure from the initial operation of the printing unit to the printing operation. First, as shown in FIG. 8A, the main control unit 5 starts an initial operation S201 of the printing unit 1. In the initial operation, the main control unit 5 notifies the image formation control unit 17 of an image control initial start request S202, the conveyance control unit 16 of a conveyance control initial start request S203, and the fixing control unit 18 of a fixing control initial start request S204. To do.

  The image forming control unit 17 performs the initial operation of the process unit 27 (see FIG. 4) according to the request. When the initial operation of the process unit 27 ends, the image formation control unit 17 notifies the main control unit 5 of an image control initial end notification S205. Similarly, the transport control unit 16 performs the initial operation of the transport unit 26 (see FIG. 4) according to the request. When the initial operation of the transport unit 26 ends, the transport control unit 16 notifies the main control unit 5 of a transport control initial end notification S206.

  The fixing control unit 18 performs an initial operation of the fixing drive control unit 21 (see FIG. 4) and the fixing temperature control unit 22 (see FIG. 4) according to a request. The fixing drive control unit 21 performs an initial operation of the fixing roller unit 28. The fixing temperature control unit 22 performs an initial operation of the heater unit 29. When the temperature sensor abnormality determination S207 is performed (S102) and no abnormality is detected in the temperature sensor, the fixing control unit 18 similarly notifies the main control unit 5 of the fixing control initial end notification S208 when the initial operation is completed. To do.

  When an abnormality is detected in the temperature sensor, the main control unit 5 notifies the fixing control unit 18 of a heater state inspection request S209. The fixing control unit 18 turns on the longest heater 65 (see FIG. 3) arranged at a position where all the temperature sensors 53 to 59 can detect a temperature rise, and performs a state inspection S210 of the heater unit 29 (S103). . Here, only the longest heater 65 is used.

  Therefore, if there is a temperature rise in one of the temperature sensors 53 to 59 in which an abnormality is detected, the fixing control unit 18 notifies the main control unit 5 of a heater abnormality erroneous detection notification S211. Upon receiving the heater abnormality error detection notification S211, the main control unit 5 stores the error detection information S212 in the ROM 6 (S106). After performing the heater abnormality error detection notification S211, the fixing control unit 18 performs the sensor abnormality error detection control S213. The sensor abnormality error detection control S213 here is the operation of step S107 in FIG. That is, the fixing control unit 18 performs the warming-up operation using the temperature sensor adjacent to the warming-up operation unit 71 instead of one of the temperature sensors 53 to 59 in which the abnormality is detected.

  As shown in FIG. 8B, if there is no temperature rise in one of the temperature sensors 53 to 59 in which an abnormality is detected, the fixing control unit 18 sends a heater abnormality detection notification S214 to the main control unit 5 as an error. Notice. The main control unit 5 displays this on the display unit 2 (S105). At the same time, the main control unit 5 sends an image control stop request S215 to the image formation control unit 17 to stop the operation of the image formation control unit 17. Similarly, the main control unit 5 sends a conveyance control stop request S216 to the conveyance control unit 16 to stop the operation of the conveyance control unit 16. Further, the main control unit 5 sends a fixing control stop request S217 to the fixing control unit 18 to stop the operation of the fixing control unit 18.

  Here, as described above, when the fixing control unit 18 ends the initial operation and no abnormality is detected in the temperature sensors 53 to 60, the fixing control initial end notification S208 to be notified to the main control unit 5 is renewed. This is illustrated as an end notification S218. After the initialization, the main control unit 5 requests the image control standby request S219 from the image formation control unit 17, the conveyance control standby request S220 from the conveyance control unit 16, and the fixing control standby request S221 from the fixing control unit 18, respectively. The printing apparatus 1 is put into a standby state.

  Subsequently, when the main control unit 5 receives a print request S222 from the operation unit 4 via the data receiving unit 9, the main control unit 5 sends an image control print start request S223 to the image formation control unit 17 and a conveyance control print start request S224. Is requested to the conveyance control unit 16, and a fixing control printing start request S225 is requested to the fixing control unit 18, respectively.

  Then, the main control unit 5 sends a paper feed start request S226 to the transport control unit 16 and starts paper feeding. When the paper feeding is completed, the conveyance control unit 16 notifies the main control unit 5 of a paper feeding completion notification S227. After completing the printing operation, the image formation control unit 17 notifies the main control unit 5 of an image control printing completion notification S228. Similarly, the conveyance control unit 16 notifies the main control unit 5 of a conveyance control print completion notification S229 after the printing operation is completed. Similarly, the fixing control unit 18 notifies the main control unit 5 of a fixing control printing completion notification S230 after the printing operation is completed.

  When printing is completed, the main control unit 5 requests the image control standby request S231 to the image formation control unit 17, the conveyance control standby request S232 to the conveyance control unit 16, and the fixing control standby request S233 to the fixing control unit 18, respectively. Then, the printing apparatus 1 is put into a standby state.

  As described above, when temperature abnormality is detected in one temperature sensor 53 among a plurality of sensors, the temperature detected from the temperature sensors 54 and 59 adjacent to the one temperature sensor is used to detect the temperature from one temperature detection element. Therefore, since it is not necessary to perform temperature correction of the detected temperature detected by the one temperature sensor, it is not necessary to provide a storage unit for storing a temperature difference for temperature correction.

  Furthermore, according to the first embodiment, the temperature situation can be recognized by using the temperature sensor adjacent to the failed temperature sensor even in the situation where the cause of the fixing device configuration, failure, and false detection is various. it can. As a result, fine correction is not performed and accuracy is lowered, but it can be used without performing temperature correction. In addition, since control related to temperature correction is eliminated, control complexity can be avoided. As a result, unnecessary replacement of the fixing device can be eliminated and the burden on the user can be reduced. Furthermore, even if there is a failure in the temperature detecting element that cannot be detected in the first place, the fixing device can be used according to the first embodiment.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. FIG. 9 is a functional block diagram of the fixing control unit according to the second embodiment. The difference from the functional block diagram of the fixing control unit 18 relating to the first embodiment is that the heater lighting prohibiting unit 77 is provided. The rest of the configuration is the same as in FIG. As will be described later, the heater lighting prohibition unit 77 prohibits lighting and disables the heater corresponding to the temperature sensor determined to be abnormal under the control of the unit control unit 70. As a result, the recording medium 31 having a size corresponding to the heater cannot be used.

  FIG. 10 is a flowchart showing the operation of the fixing unit according to the second embodiment. The flowchart shown in FIG. 10 shows a control procedure and a heater control processing procedure when it is determined that there is an abnormality in the temperature sensor. Steps S301 to S306 are the same as steps S101 to S106 in the flowchart relating to the first embodiment, and steps S309 and S310 are the same as steps S107 and S108. Only steps S307 and S308 (indicated by *) that are different from the steps in the flowchart relating to the first embodiment will be described below.

S307: When the temperature rise of the adjacent temperature sensor can be recognized in step 306, the fixing control unit 18 determines that one of the temperature sensors 53 to 59 in which the abnormality is detected has been erroneously detected, and the main control unit 5 Stores in the nonvolatile ROM 6 the error information of the temperature sensor that has been erroneously detected. Thereafter, the fixing control unit 18 prohibits lighting of the corresponding heater for one of the temperature sensors 53 to 59 in which the abnormality is detected by the heater lighting prohibiting unit 77. For example, when an abnormality is detected in the temperature sensor 54 that monitors the temperature of the right end portion of the heater 61 shown in FIG.

S308: The fixing control unit 18 notifies the main control unit 5 that the lighting of the corresponding heater is prohibited by the main control unit notification unit 73. In response to this, the main control unit 5 displays on the display unit 2 a notification that the specific recording medium 31 cannot be printed unless the heater is used. For example, when the heater 61 has a length suitable for the width of the A4 size recording medium 31 and an abnormality is detected in the temperature sensor 54, the display unit 2 is notified that the A4 size recording medium 31 cannot be printed. Will do. The notification timing may be when there is a print request for a specific recording medium width. The heaters 61 to 65 and the recording medium are selected depending on the configuration of the heater and the temperature sensor.

The processing sequence related to the second embodiment is the same as FIG. 8 showing the processing sequence related to the first embodiment.
As described above, according to the second embodiment, in addition to the effects of the first embodiment, the lighting of the heater related to the temperature sensor in which the abnormality is detected is prohibited, and the recording medium using the corresponding heater is used. Since it indicates that the width cannot be printed, it can operate safely.

(Third embodiment)
Next, a third embodiment of the present invention will be described. FIG. 11 is a functional block diagram of the fixing control unit according to the third embodiment. The difference from the functional block diagram of the fixing control unit 18 relating to the first embodiment is that it includes a corresponding temperature sensor temperature rise determination unit 78 and a temperature error threshold change unit 79. The rest of the configuration is the same as in FIG.

  As will be described later, the corresponding temperature sensor temperature increase determination unit 78 determines whether the temperature increase can be recognized by one of the temperature sensors 53 to 60 in which an abnormality has been detected, under the control of the unit control unit 70. Further, the temperature error threshold changing unit 79 detects an abnormality when one of the temperature sensors 53 to 60 is detected by the control of the unit control unit 70 and an increase in temperature of the temperature sensor is confirmed. The temperature error threshold value of one of the temperature sensors 53 to 60 is changed.

  FIG. 12 is a flowchart showing the operation of the fixing unit according to the third embodiment. The flowchart shown in FIG. 12 shows a control procedure and a heater control processing procedure when an abnormality is detected in the temperature sensor. Steps S401 to S403 are the same as steps S101 to S103 in the flowchart relating to the first embodiment, and steps S408 and S409 are the same as steps S107 and S108. Only steps S404 to S407 (indicated by *) that are different from the steps in the flowchart relating to the first embodiment will be described below.

S404: In step S403, after the heater unit 29 including the heaters 61 to 66 is turned on to check the state of the heaters 61 to 66, the fixing control unit 18 detects the abnormality by the temperature sensor temperature rise determination unit 78. It is determined whether or not the temperature rise of the temperature sensors 53 to 60 can be recognized. If one of the temperature sensors 53 to 60 in which the abnormality is detected cannot recognize a temperature increase, the process proceeds to step S405. If a temperature increase can be recognized, the process proceeds to step S406.

S405: If one of the temperature sensors 53 to 60 in which the abnormality is detected cannot be recognized, the fixing control unit 18 causes the main control unit notifying unit 73 to determine that there is a problem in the fixing unit 40, and the main control unit 5 To notify. In response to this, the main control unit 5 instructs the display unit 2 to display a message.

S406: In step S404, if one of the temperature sensors 53 to 60 in which the abnormality is detected can be recognized, the fixing control unit 18 has detected that one of the temperature sensors 53 to 60 in which the abnormality has been detected has been erroneously detected. The main control unit notifying unit 73 notifies the main control unit 5 of the determination. In response to this, the main controller 5 stores the information in the nonvolatile ROM 6.

S407: The fixing controller 18 changes the temperature error threshold S of one of the temperature sensors 53 to 60 determined to be erroneously detected by the temperature error threshold changing unit 79. That is, the threshold value is set so that the temperature detected by one temperature sensor in which an abnormality is detected and the temperature rise is confirmed falls within a normal range. For example, the error detection is relaxed by setting the temperature error threshold S, which was set to 100 ° C., to 150 ° C. The temperature error threshold value S to be changed can be changed depending on the configuration of the heater and the temperature sensor. However, the threshold value is set so that the abnormal temperature difference does not exceed 150 ° C.

S408: The fixing control unit 18 performs a warming-up operation using a temperature sensor adjacent to one of the temperature sensors 53 to 59 in which an abnormality is detected by the warming-up operation unit 71.

The processing sequence related to the third embodiment is the same as FIG. 8 showing the processing sequence related to the first embodiment.
As described above, according to the third embodiment, the fixing unit 40 is continuously used by changing the temperature error threshold without replacing one of the temperature sensors 53 to 59 in which an abnormality is detected. be able to. Compared to the first embodiment, one of the temperature sensors 53 to 59 in which an abnormality has been detected is continuously used, so the accuracy of the erroneously detected sensor location is reduced, but error monitoring is continued. Therefore, it can be expected to operate safely. Further, there is no restriction on the printing operation as compared to the second embodiment.

  In the description of the first to third embodiments, the printing apparatus has been described. However, the present invention is not limited to this and can be applied to a copying machine or a facsimile.

DESCRIPTION OF SYMBOLS 1 Printing apparatus 2 Display part 4 Operation part 5 Main control part 18 Fixing control part 21 Fixing drive control part 22 Fixing temperature control part 31 Recording medium 40 Fixing unit 51 Fixing belt 52 Pressure belt 53-60 Temperature sensor 61-65 Heater 70 Unit control unit 71 Warming up operation unit 72 Heater lighting unit 75 Temperature sensor abnormality determination unit 76 Adjacent temperature sensor temperature rise determination unit

Claims (3)

A heating means of multiple,
A plurality of temperature detection elements for detecting the temperature of the pre-Symbol heat generating means,
A control unit that performs control based on the detected temperature of the temperature detection element;
The control unit sets a temperature error threshold for determining an abnormality when the detected temperature exceeds a predetermined value,
Further, when the control unit determines an abnormality of one temperature detection element among the plurality of temperature detection elements using the temperature error threshold, the heat generation inspection is performed by the heat generation unit, and the temperature of the one temperature detection element is determined. When an increase can be recognized, the determination is made as a false detection, and the temperature error threshold for the one temperature detection element is changed so that the detection temperature of the one temperature detection element falls within a normal range. A heat generating device characterized by that. A fixing device for fixing a developer image transferred to a recording medium by heat using the heat generating device according to claim 1 . An image forming apparatus comprising: an image forming unit that forms the developer image on the recording medium; and further comprising a fixing device according to claim 2 .

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