JP2006308654A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an image forming apparatus where temperature is appropriately detected by cleaning a temperature detection part to which dust or dirt such as a toner or a paper powder adheres by a simple mechanism in a non-contact type surface temperature detection means. <P>SOLUTION: The image forming apparatus 1 is equipped with an opening/closing part 11 to expose a paper conveying path 4 inside on the left side surface of its main body 2. The device is also equipped with the surface temperature detection means 54 above a heating roller 51 being a fixing member. The device is also equipped with the temperature detection part 54a for detecting infrared on the bottom face of the surface temperature detection means 54, and a cleaning means 80 provided with a cleaning member 81 capable of taking both positions, that is, a contact position where it comes into contact with the temperature detection part 54a and a retreat position where it retreats therefrom. The cleaning means 80 keeps the cleaning member 81 at the retreat position when the opening/closing part 11 is closed, and the cleaning member 81 is positionally changed to the contact position linked with the opening of the opening/closing part 11. Thus, just by opening the opening/closing part 11, the cleaning member 81 is automatically brought into contact with the temperature detection part 54a so as to clean, while preventing a user from directly touching the temperature detection part 54a with his (her) hand. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus represented by a copying machine or a printer.

  In an electrophotographic image forming apparatus typified by a copying machine or a printer, a thermal fixing method is widely used as a method for fixing an unfixed toner image transferred onto a sheet by a transfer unit. In this heat fixing method, two rotating members composed of rollers and belts are pressed against each other to form a nip, and a heating means is arranged near one or both of these rotating members to rotate. By heating the member and inserting a paper carrying an unfixed toner image in the nip, the toner is fixed on the paper.

  As a heat fixing type fixing device, a roller that directly contacts an unfixed toner image on a sheet of two rollers constituting a pair of rollers that are in pressure contact with each other is a heat roller (fixing member). A built-in heating means such as a halogen heater is generally used. In order to obtain a stable fixing property, the surface temperature of the heat roller is monitored by a temperature detection means composed of a temperature sensor such as a thermistor, and the amount of heat generated by the heating means such as a halogen heater is controlled to control the surface of the heat roller. Maintain the temperature at the proper temperature.

Conventionally, the surface temperature of the heat roller has been detected by contact-type temperature detecting means that contacts the surface. That is, a temperature sensor such as a thermistor is brought into contact with the non-sheet passing area of the surface of the heat roller, and the temperature control of the heat roller by the heating means is performed based on the surface temperature of the non-sheet passing area. However, when the temperature sensor is brought into contact with the surface of the heat roller, the surface of the heat roller is damaged, or toner or paper dust remaining around the temperature detection means adheres to the temperature detection part of the sensor, so that an appropriate temperature detection is possible. There was a problem that could not be done. Therefore, in order to solve such a problem, a non-contact type temperature detecting means that is provided at a position slightly away from the surface of the heat roller and detects the surface temperature is proposed. it can.
JP-A-6-194994 (page 3-5, Fig. 1-3)

  Here, in the vicinity of the surface of the heat roller, it is known that a slight air flow is generated in the circumferential direction by the rotation of the heat roller. The air flow may cause toner or paper dust remaining around the temperature detection unit to scatter and reach the temperature detection unit of the temperature detection unit. There is a concern that dust or dirt such as toner or paper dust may adhere to the temperature detection unit, which may be an obstacle to obtaining thermal energy from the surface of the heat roller and may adversely affect the temperature detection of the surface of the heat roller. .

  In the fixing device described in Patent Document 1, a thermistor cover is provided in the temperature detection device, and a roller that contacts the surface of the heat roller is attached to the thermistor cover to maintain a predetermined gap with the surface of the heat roller. However, it cannot be denied that toner or paper dust may enter the thermistor (temperature detection means) inside the cover from the gap between the thermistor cover and the heat roller surface. Furthermore, there is a possibility that toner or paper dust adheres to the roller and accumulates, so that the gap between the thermistor cover and the surface of the heat roller is widened, and the toner and paper dust can easily enter the thermistor cover. It is done. When toner or paper dust enters the location of the thermistor (temperature detection means) in this way, it is necessary to remove the temperature detection device from the surface of the heat roller, which is very inconvenient for cleaning the location. Therefore, in order to continuously perform appropriate temperature detection, it is desirable to clean the temperature detection unit of the temperature detection unit appropriately with a simple mechanism.

  The present invention has been made in view of the above points, and when detecting the surface temperature of a member using a non-contact type surface temperature detection unit, the toner or paper powder remaining around the temperature detection unit in the fixing device is used. An object of the present invention is to provide an image forming apparatus that can clean an appropriate temperature detection by a simple mechanism even when dust or dirt is scattered and adheres to a temperature detection unit. And

  In order to solve the above-mentioned problems, the present invention can take a non-contact type surface temperature detecting means for detecting the surface temperature of a member and a position of both contact and retraction with respect to a temperature detecting portion of the surface temperature detecting means. A cleaning unit provided with a cleaning member; and an opening / closing unit that allows the paper conveyance path to be exposed, and the cleaning unit holds the cleaning member in the retracted position when the opening / closing unit is closed, The cleaning member is changed to the contact position in conjunction with the opening of.

  The cleaning means includes a slide mechanism that changes the position of the slide member provided with the cleaning member between the contact position and the retracted position, and an urging force that urges the slide member toward the contact position. Means.

  Further, the surface temperature detecting means is provided for detecting the surface temperature of the fixing member and / or the pressure member of the fixing device.

  In the image forming apparatus provided with the surface temperature detecting means in the fixing device, a paper counter for counting the cumulative number of printed sheets of paper, and information from the paper counter is received, and the temperature detecting unit is cleaned by the cleaning member. And informing means for prompting.

  In the image forming apparatus provided with the surface temperature detecting means in the fixing device, a time measuring means for measuring the cumulative driving time of the fixing device, and the temperature detecting portion by the cleaning member in response to information from the time measuring means. And informing means for prompting the cleaning of.

  In the image forming apparatus provided with the surface temperature detecting means in the fixing device, an in-machine temperature detecting means for detecting the temperature in the image forming apparatus and an informing means for prompting cleaning of the temperature detecting portion by the cleaning member. And when the temperature obtained by the surface temperature detecting means immediately after power-on and before starting the fixing device is lower than the temperature obtained by the in-machine temperature detecting means by a predetermined temperature, the notification means It was decided to prompt the cleaning of the detector.

  Further, in the image forming apparatus provided with the surface temperature detecting means in the fixing device, the storage means for storing in advance the surface temperature increase value per unit time with respect to a predetermined amount of heat of the fixing member and / or the pressure member; A notification means for prompting cleaning of the temperature detection unit by a cleaning member, and when the fixing device is started with the predetermined amount of heat after the power is turned on, per unit time obtained by the surface temperature detection means When the surface temperature rise value is lower by a predetermined temperature than the surface temperature rise value stored in advance by the storage means, the notification means prompts the temperature detection unit to be cleaned.

  According to the configuration of the present invention, the non-contact type surface temperature detecting means for detecting the surface temperature of the member and the cleaning member capable of taking both the contact and retreat positions with respect to the temperature detecting portion of the surface temperature detecting means are provided. The cleaning means and an opening / closing part that exposes the paper conveyance path, and the cleaning means keeps the cleaning member in the retracted position when the opening / closing part is closed, and interlocks with the opening of the opening / closing part. Therefore, the cleaning member is automatically brought into contact with the temperature detection unit without directly touching the temperature detection unit of the surface temperature detection means by simply opening the opening / closing unit. Can be cleaned. Therefore, even when dust or dirt is scattered and adheres to the temperature detection unit, it is possible to clean these with a simple mechanism and perform appropriate temperature detection.

  Further, the cleaning means includes a slide mechanism for changing the position of the slide member provided with the cleaning member between the contact position and the retracted position, and an urging means for urging the slide member toward the contact position. Therefore, the position of the cleaning member can be easily changed by opening the opening / closing part. Therefore, the mechanism for cleaning the temperature detection unit of the surface temperature detection means can be made a simpler configuration, and the temperature detection accuracy can be improved by appropriately performing the cleaning.

  Further, since the surface temperature detecting means is provided for detecting the surface temperature of the fixing member and / or the pressure member of the fixing device, dust and dust such as toner and paper dust are scattered. Thus, even when attached to the temperature detection unit, it is possible to obtain a high-performance image forming apparatus equipped with a fixing device capable of cleaning these with a simple mechanism and performing appropriate temperature detection. .

  Further, in the image forming apparatus having the surface temperature detecting means in the fixing device, a paper counter for counting the cumulative number of printed sheets of paper and information from the paper counter are received to prompt the cleaning member to clean the temperature detecting unit. In response to the fact that the toner and paper dust remaining in the vicinity increases as the cumulative number of printed sheets increases, the temperature detection unit is urged to clean the apparatus. be able to. As a result, even if the cumulative number of printed sheets of paper increases and toner or paper dust remaining in the vicinity increases, the temperature detection unit can be cleaned each time, and appropriate temperature detection performance can be maintained. .

  Further, in the image forming apparatus provided with the surface temperature detecting means in the fixing device, the time detecting means for measuring the cumulative driving time of the fixing device, and the temperature detecting portion is cleaned by the cleaning member in response to the information from the time measuring means. In response to the increase in the cumulative driving time of the fixing device, the toner and paper dust remaining in the vicinity also increase as the cumulative driving time of the fixing device increases. Can be reminded. As a result, even if the cumulative driving time of the fixing device increases and toner or paper dust remaining in the vicinity increases, the temperature detection unit can be cleaned each time, and appropriate temperature detection performance can be maintained. Become.

  In addition, the image forming apparatus provided with the surface temperature detecting means in the fixing device includes an in-machine temperature detecting means for detecting the temperature in the image forming apparatus and a notifying means for prompting cleaning of the temperature detecting portion by the cleaning member. When the temperature obtained by the surface temperature detecting means immediately after turning on the power and before starting the fixing device is lower than the temperature obtained by the in-machine temperature detecting means, the notification means cleans the temperature detecting portion. In response to the fact that the temperature detection performance decreases as dust or dust such as toner or paper dust adheres to the temperature detection part of the surface temperature detection means, the temperature inside the machine before the fixing device is started. Based on this, it is possible to know the cleaning time of the temperature detector. Therefore, even when toner or paper dust adheres to the temperature detection unit and the performance of the surface temperature detection unit deteriorates, the temperature detection unit is cleaned based on the internal temperature before the fixing device is started. And proper temperature detection performance can be maintained.

  Further, in the image forming apparatus provided with the surface temperature detecting means in the fixing device, the storage means for storing in advance the surface temperature increase value per unit time with respect to a predetermined amount of heat of the fixing member and / or the pressure member; A notification means for prompting cleaning of the temperature detection unit by a cleaning member, and when the fixing device is started with the predetermined amount of heat after the power is turned on, per unit time obtained by the surface temperature detection means When the surface temperature rise value is lower than the surface temperature rise value stored in advance by the storage means by a predetermined temperature, the notification means prompts the temperature detection unit to clean. Corresponding to the decrease in temperature detection performance as dust and dust such as toner and paper dust adhere, it is based on the temperature rise per unit time after starting the fixing device. There it is possible to know the cleaning time of the temperature detection unit. Therefore, even when toner or paper dust adheres to the temperature detection unit and the performance of the surface temperature detection means deteriorates, this is grasped based on the temperature increase value per unit time after the fixing device is started. The detection unit can be cleaned, and proper temperature detection performance can be maintained.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  First, an image output operation of an image forming apparatus according to an embodiment of the present invention will be described while explaining an outline of the structure with reference to FIG. FIG. 1 is a schematic vertical sectional front view of an image forming apparatus. Note that solid line arrows in the figure indicate the sheet conveyance path and conveyance direction, and alternate long and short dash line arrows indicate the laser beam L.

  As shown in FIG. 1, a paper feed unit 3 is disposed at the lower part of the main body 2 of the image forming apparatus 1. Inside the paper feed unit 3, paper P such as cut paper before printing is stacked and stored, and the paper P is separated and sent out one by one.

  A paper transport unit 20 is provided inside the main body 2 and on the left side of the paper feed unit 3. The paper P sent out from the paper supply unit 3 is transported by the paper transport unit 20 on a paper transport path 4 formed vertically upward along the left side surface of the main body 2 and is transferred to a transfer unit 40 described later. It reaches.

  On the other hand, a document feeding unit 5 is provided on the upper surface of the image forming apparatus 1, and a document image reading unit 6 is provided below the document feeding unit 5. When a user copies a document, a document on which an image such as a character, a figure, or a pattern is drawn is stacked on the document feeding unit 5. The document feeding unit 5 separates the documents one by one and sends the document, and the document image reading unit 6 reads the image data. The information of the image data is sent to the laser irradiation unit 7 disposed above the paper feed unit 3 and in the center of the main body 2. Laser light L controlled based on the image data is irradiated by the laser irradiation unit 7 toward the image forming unit 30 described later.

  An image forming unit 30 and a transfer unit 40 are provided above the paper transport unit 20 and to the left of the laser irradiation unit 7. In the image forming unit 30, an electrostatic latent image of a document image is created by the laser light L irradiated by the laser irradiation unit 7. A toner image is formed from the electrostatic latent image, and the toner image is transferred by the transfer unit 40 to the pre-printing paper P sent in synchronization by the paper transport unit 20.

  Above the transfer unit 40, a fixing unit 50 as a fixing device is provided. The sheet P carrying the unfixed toner image in the transfer unit 40 is sent to the fixing unit 50, where the toner image is heated and pressed by a heat roller as a fixing member and a pressure roller as a pressure member. It is fixed.

  A branching unit 60 is provided above the fixing unit 50. The sheet P discharged from the fixing unit 50 is discharged from the branching unit 60 to the in-body sheet discharge tray 8 provided in the cylinder of the image forming apparatus 1 when double-sided printing is not performed. It is also possible to convey the paper P from the branch portion 60 toward the left side of the image forming apparatus 1 and discharge it to the side paper discharge tray 9 outside the left side surface of the main body 2.

  The discharge port portion from which the paper P is discharged from the branch portion 60 toward the in-body paper discharge tray 8 functions as the switchback portion 70. When performing duplex printing, the switchback unit 70 switches the transport direction of the paper P discharged from the fixing unit 50. Then, the paper P is sent downward through the double-sided printing paper conveyance path 10 provided on the left side of the fixing unit 50 and on the left side of the transfer unit 40, and again passes through the paper conveyance unit 20 to the transfer unit 40. Sent.

  Next, a detailed configuration of a portion from the sheet conveyance unit 20 to the switchback unit 70 of the image forming apparatus 1 will be described with reference to FIGS. 2 and 3 in addition to FIG. 2 is a schematic vertical sectional partial enlarged view showing a portion from the paper conveying portion to the switchback portion and a schematic diagram of the control circuit, and FIG. 3 is a model showing a portion from the paper conveying portion to the switchback portion similar to FIG. FIG. 2 is a partially enlarged vertical sectional view showing a state where the opening / closing part is opened.

  The paper transport unit 20 includes a transport roller 21 and a registration roller 22. The conveyance roller 21 and the registration roller 22 are configured by a pair of rollers that are in contact with each other. The transport roller 21 is rotated by a motor (not shown), and transports the paper P sent from the paper feed unit 3 (see FIG. 1) toward the registration roller 22. The registration roller 22 is rotated by a motor (not shown), and feeds the paper P in synchronization with the toner image formed by the image forming unit 30 toward the transfer unit 40 that transfers the toner image onto the paper P.

  The image forming unit 30 is provided with a photosensitive drum 31 that is an image carrier, and a main charging device 32, a developing device 33, and a cleaning device 34 are arranged in this order along the rotation direction of the photosensitive drum 31. Has been.

  The photosensitive drum 31 is rotated by a motor (not shown) so that the peripheral speed thereof is the same as the paper transport speed. Then, the surface of the photosensitive drum 31 is uniformly charged with a predetermined polarity and potential by the main charging device 32, and an electrostatic latent image of the original image is formed by the laser light L irradiated by the laser irradiation unit 7. . The developing device 33 charges the toner, which is a developer, and supplies the toner to the surface of the photosensitive drum 31 to develop the electrostatic latent image to form a toner image. After the toner image is transferred to the paper P, the cleaning device 34 scrapes and collects the toner remaining on the surface of the photosensitive drum 31.

  In the vicinity of the main charging device 32 and the developing device 33, an in-machine temperature detecting means 35 for detecting the in-machine temperature of the image forming apparatus 1 in the image forming unit 30 is provided.

  The transfer unit 40 is provided with a transfer roller 41. The transfer roller 41 abuts on the photosensitive drum 31 to form a transfer nip through which the paper P is inserted. The transfer roller 41 is rotated by a motor (not shown) so that its peripheral speed is the same as the peripheral speed of the photosensitive drum 31. Further, a transfer bias and a cleaning bias are applied to the transfer roller 41 as necessary.

  The fixing unit 50 as a fixing device includes a heat roller 51 as a fixing member and a pressure roller 52 as a pressure member. The paper P is inserted through a nip formed by the contact between the heat roller 51 and the pressure roller 52. The heat roller 51 is rotated by a motor (not shown) so that the peripheral speed thereof is the same as the paper transport speed. The pressure roller 52 is rotated according to the rotation of the heat roller 51 by contacting the heat roller 51. Inside the heat roller 51, a halogen heater 53 as a heat source is disposed. Further, the fixing unit 50 is provided with non-contact type surface temperature detecting means 54 for detecting the surface temperature of the heat roller 51. The cleaning means 80 is provided in the vicinity of the surface temperature detection means 54. Further, in the vicinity of the fixing unit 50, a paper counter 55 that counts the cumulative number of printed sheets of paper P and a timer 56 that counts the cumulative driving time of the fixing unit 50 are provided.

  The branching unit 60 includes a first switching guide 61 and a second switching guide 62. The first switching guide 61 distributes the paper P in the direction of the switchback portion 70 which is also a discharge port portion for discharging the paper P to the in-body paper discharge tray 8 (see FIG. 1) and the direction of the second switching guide 62. Is. The second switching guide 62 feeds the paper P downward through the side paper discharge tray 9 (see FIG. 1) direction, the left side of the fixing unit 50, and the left side of the transfer unit 40. The paper P is sorted into 10 directions. The first switching guide 61 and the second switching guide 62 are rotatably mounted, and the angle can be changed by a solenoid or the like (not shown).

  The switchback unit 70 includes a discharge roller 71 and a discharge port 72. The discharge roller 71 is composed of a pair of rollers in contact with each other, and is provided in the vicinity of the discharge port 72 through which the paper P is discharged toward the in-body paper discharge tray 8. The paper P is inserted into a nip formed by contact with a pair of rollers constituting the discharge roller 71, and is sent out to the in-body paper discharge tray 8 by rotating the discharge roller 71. The discharge roller 71 is rotated by a motor or the like (not shown). Further, in the switchback unit 70, the paper P can be switched back by reversing the rotation of the discharge roller 71, and the transport direction of the paper P can be switched. Thereby, double-sided printing can be performed on one sheet of paper P.

  An opening / closing unit 11 is provided at a location on the left side of the sheet conveying path 4 in FIG. 2 from immediately downstream of the image forming unit 30 to downstream of the fixing unit 50. The opening / closing part 11 can rotate in a vertical plane around a shaft part 11 a provided at the lower end thereof, and can take both open and closed postures with respect to the left side surface of the main body 2. 2 shows a state when the opening / closing part 11 is in a closed position, and FIG. 3 shows a state when it is in an open position. By opening the opening / closing section 11, the sheet conveying path 4 from immediately downstream of the image forming section 30 to downstream of the fixing section 50 can be exposed, and it is possible to deal with troubles such as sheet jam and other maintenance. .

  1 and 2, an operation panel 12 is provided on the upper front side of the image forming apparatus 1. The user of the image forming apparatus 1 can input and set various printing conditions such as the printing paper size and thickness, the number of printed sheets, and the presence / absence of double-sided printing from the operation panel 12. Further, from the display unit of the operation panel 12, it is possible to confirm various printing conditions and to know the occurrence status of troubles such as paper shortage and jam.

  Further, the image forming apparatus 1 includes a storage unit 90 and a notification unit 100 as shown in FIG. The storage unit 90 stores in advance a surface temperature increase value per unit time for a predetermined amount of heat obtained by the halogen heater 53 of the heat roller 51 in the fixing unit 50. The surface temperature rise value data per unit time stored in advance in the storage means 90 is data accurately measured by the surface temperature detection means 54 without being affected by dust or dust such as toner or paper dust. It is. Then, the information in the above-described in-machine temperature detection means 35, surface temperature detection means 54, paper counter 55, time measurement means 56, and storage means 90 is sent to the notification means 100. The notification means 100 prompts the user to clean the surface temperature detection means 54 by using the display panel 12, LEDs, buzzer, and sound based on information from each of these means.

  Next, the detailed configuration of the surface temperature detecting means 54 and the cleaning means 80 provided above the fixing unit 50 will be described with reference to FIGS. FIG. 4 is a partially enlarged front view of a model vertical section showing the periphery of the fixing portion, and FIG. 5 is a top view of the model partially enlarged view. 6 is a partially enlarged front view of a model vertical cross section similar to FIG. 4 and shows a state in which the opening / closing part is opened, and FIG. 7 is also a model partially enlarged top view of the same.

  As shown in FIG. 4, a surface temperature detection unit 54 is provided above the heat roller 51 of the fixing unit 50. The surface temperature detecting means 54 is a non-contact type temperature detecting means for detecting the surface temperature of the heat roller 51, and is arranged with a predetermined gap from the heat roller 51 at a substantially upper center in the axial direction of the heat roller 51. Has been. The surface temperature detecting means 54 is composed of a thermistor or the like, and detects the temperature by obtaining infrared rays or the like emitted from the surface of the heat roller 51 as heat energy. The temperature detector 54 a that actually detects the temperature is provided on the bottom surface of the surface temperature detector 54.

  The cleaning unit 80 is provided at a gap between the heat roller 51 and the surface temperature detection unit 54. The cleaning unit 80 includes a cleaning member 81, a slide mechanism 110, and a spring 82. As shown in FIG. 5, the slide mechanism 110 includes a slide member 111, a guide pin 112, and a stay 113.

  The cleaning member 81 is composed of a bristle brush, sponge, non-woven fabric, felt or the like, and cleans the temperature detection part 54a of the surface temperature detection means 54. The cleaning member 81 is located at a substantially central portion in the axial direction of the heat roller 51 and immediately below the surface temperature detecting means 54, that is, a portion corresponding to the temperature detecting portion 54 a of the surface temperature detecting means 54, and the upper surface of the slide member 111. Is provided.

  As shown in FIG. 4, the slide member 111 of the slide mechanism 110 is provided substantially horizontally above the heat roller 51. As shown in FIG. 5, the slide member 111 is a thin plate-like member having a substantially U shape when viewed from above, and the sheet conveyance path 4 passes through an inner portion of the U shape. As described above, in the slide member 111, the cleaning member 81 is provided on the upper surface of the substantially central portion in the axial direction of the heat roller 51. Further, one guide pin 112 is provided on each end of the upper surface of the slide member 111 in the axial direction of the heat roller 51. The guide pin 112 passes through a guide groove 113 a of a stay 113 provided on a frame (not shown) of the main body 2. The stay 113 is provided substantially horizontally as shown in FIG. 4, and the guide groove 113 a is perpendicular to the axial direction of the heat roller 51.

  As shown in FIGS. 4 and 5, the spring 82 is provided on the right side of the slide member 111. This spring 82 is provided between the slide member 111 and the frame of the main body 2, and is a biasing means that biases the slide member 111 to the left in FIGS. 4 and 5, that is, toward the opening / closing part 11. . Thereby, when the opening / closing part 11 is in the closed posture shown in FIGS. 4 and 5, the left end of the slide member 111 is kept in contact with the upper right side surface 11 b of the opening / closing part 11.

  The cleaning means 80 configured as described above performs a cleaning operation as follows.

  When the normal printing operation is performed in the image forming apparatus 1, the opening / closing unit 11 is in the closed posture shown in FIGS. 4 and 5. When the opening / closing part 11 is in the closed position, the upper right side surface 11 b abuts against the slide member 111, and the slide member 111 is displaced to the right against the elastic force of the spring 82. As a result, the cleaning member 81 provided on the upper surface of the slide member 111 is held at the retracted position retracted to the right with respect to the temperature detecting portion 54a of the surface temperature detecting means 54. Since there is nothing that shields the heat roller 51 below the temperature detection unit 54a, the surface temperature detection means 54 can detect the temperature of the surface of the heat roller 51.

  Here, when the opening / closing part 11 is opened, the opening / closing part 11 takes the open posture shown in FIGS. 6 and 7. As a result, the restriction on the displacement of the slide member 111 is released, and the slide member 111 is biased by the spring 82 and displaced to the left. As a result, the cleaning member 81 provided on the upper surface of the slide member 111 is repositioned to a contact position where it comes into contact with the temperature detection unit 54a of the surface temperature detection means 54. By the contact of the cleaning member 81, the temperature detection unit 54a can be cleaned. At this time, the left end of the guide groove 113a of the stay 113 serves as a stopper for the guide pin 112 provided on the slide member 111, and the slide member 111 moves to the left beyond the position of FIGS. Never jump out.

  By the operation as described above, the cleaning unit 80 slides the cleaning member 81 at right angles to the axial direction of the heat roller 51 within a horizontal plane. In other words, the cleaning member 81 can take both the retracted position shown in FIGS. 4 and 5 and the contact position shown in FIGS. 6 and 7 with respect to the temperature detecting portion 54a of the surface temperature detecting means 54. .

  In this way, the non-contact type surface temperature detecting means 54 for detecting the surface temperature of the member and the cleaning member 81 capable of taking both the contact and retreat positions with respect to the temperature detecting portion 54a of the surface temperature detecting means 54 are provided. The cleaning unit 80 is provided, and the opening / closing unit 11 that allows the sheet conveyance path 4 to be exposed. The cleaning unit 80 holds the cleaning member 81 in the retracted position when the opening / closing unit 11 is closed, and the opening / closing unit 11. Since the cleaning member 81 is repositioned to the contact position in conjunction with the opening, the cleaning is automatically performed only by opening the opening / closing part 11 without directly touching the temperature detecting part 54a of the surface temperature detecting means 54. The member 81 can be cleaned by contacting the temperature detecting portion 54a. Therefore, even when dust or dust such as toner or paper dust scatters and adheres to the temperature detection unit 54a, it is possible to clean these with a simple mechanism and perform proper temperature detection. .

  Further, the cleaning unit 80 includes a slide mechanism 110 that changes the position of the slide member 111 provided with the cleaning member 81 between the contact position and the retracted position, and a bias that biases the slide member 111 in the direction of the contact position. Since the spring 82 as a means is provided, the position of the cleaning member 81 can be easily changed by opening the opening / closing part 11. Therefore, the mechanism for cleaning the temperature detection unit 54a of the surface temperature detection means 54 can be made simpler, and the temperature detection accuracy can be improved by appropriately performing the cleaning.

  Since the surface temperature detecting means 54 is provided for detecting the surface temperature of the heat roller 51 that is a fixing member of the fixing unit 50 that is a fixing device, dust or dust such as toner or paper dust is provided. Even when the toner scatters and adheres to the temperature detection unit 54a, the high-performance image forming apparatus 1 including the fixing unit 50 that can clean these with a simple mechanism and perform appropriate temperature detection. Can be obtained.

  Subsequently, in the image forming apparatus 1 as described above, a cleaning method for the temperature detection unit 54a of the surface temperature detection unit 54 corresponding to various situations when printing is performed in addition to FIG. 9 will be used for explanation. FIG. 8 is a graph showing the in-machine temperature immediately after the image forming apparatus is turned on, obtained by the in-machine temperature detecting means and the surface temperature detecting means. FIG. 9 is a graph showing the temperature obtained by the surface temperature detecting means at the power on of the image forming apparatus. It is a graph which shows the transition from time. In each case, the horizontal axis represents time and the vertical axis represents temperature.

  As shown in FIG. 2, the notification unit 100 obtains the number information of the accumulated number of printed sheets P from a sheet counter 55 provided near the fixing unit 50. When the information from the paper counter 55 is received and the cumulative number of printed sheets reaches a predetermined number, the notifying means 100 displays the fact on the operation panel 12, turns on the LED, uses a buzzer or sound, and so on. The user of the image forming apparatus 1 is urged to clean the temperature detection unit 54a. Thereby, the user can open the opening / closing part 11 immediately and clean the temperature detection part 54a.

  In this way, it is possible to prompt the user of the apparatus to clean the temperature detector 54a in response to the increase in the toner and paper dust remaining in the vicinity as the cumulative number of printed sheets P increases. As a result, even if the cumulative number of printed sheets of paper P increases and toner or paper dust remaining in the vicinity increases, the temperature detection unit 54a can be cleaned each time, and appropriate temperature detection performance can be maintained. It becomes.

  Further, as shown in FIG. 2, regarding the cumulative driving time of the fixing unit 50, the notification unit 100 obtains the time information from the time measuring unit 56 provided near the fixing unit 50. When the information from the time measuring means 56 is received and the accumulated driving time reaches a predetermined time, the notifying means 100 displays the fact on the operation panel 12, turns on the LED, uses a buzzer or sound, and the like. The user of the image forming apparatus 1 is urged to clean the temperature detection unit 54a. Thereby, the user can open the opening / closing part 11 immediately and clean the temperature detection part 54a.

  In this way, it is possible to prompt the user of the apparatus to clean the temperature detection unit 54a in response to the increase in the toner and paper dust remaining in the vicinity as the cumulative driving time of the fixing unit 50 increases. . As a result, even if the cumulative driving time of the fixing unit 50 increases and toner or paper dust remaining in the vicinity increases, the temperature detection unit 54a can be cleaned each time, and appropriate temperature detection performance can be maintained. It becomes possible.

  Further, as shown in FIG. 2, the notifying unit 100 includes an in-machine temperature detecting unit 35 provided in the vicinity of the main charging device 32 and the developing device 33, and a fixing unit regarding the in-machine temperature immediately after the image forming apparatus 1 is turned on. The temperature information is received from both the surface temperature detecting means 54 provided near the portion 50. With respect to these temperatures before starting the fixing unit 50, as shown in FIG. 8, the in-machine temperature obtained by the surface temperature detecting means 54 (broken line in FIG. 8) is the in-machine temperature obtained by the in-machine temperature detecting means 35. When the temperature is lower than the predetermined temperature (the solid line in FIG. 8), the notification unit 100 displays the fact on the operation panel 12, turns on the LED, uses a buzzer or sound, and the like, and thereby forms the image forming apparatus 1. The user is urged to clean the temperature detector 54a. Thereby, the user can open the opening / closing part 11 immediately and clean the temperature detection part 54a.

  In this way, in response to the deterioration of the temperature detection performance as dust or dust such as toner or paper dust adheres to the temperature detection section 54a of the surface temperature detection means 54, the inside of the apparatus before starting the fixing section 50 Based on the temperature, the cleaning time of the temperature detector 54a can be known. Therefore, even when toner or paper dust adheres to the temperature detection unit 54a and the performance of the surface temperature detection unit 54 deteriorates, the temperature is detected by grasping this based on the internal temperature of the fixing unit 50 before starting. The part 54a can be cleaned, and appropriate temperature detection performance can be maintained.

  As for the surface temperature rise per unit time of the heat roller 51 with respect to a predetermined heat quantity, as shown in FIG. 2, the notification means 100 includes a storage means 90 in which the surface temperature rise value is stored in advance, and a surface temperature detection means 54. And temperature information from both. When the fixing unit 50 is started with a predetermined amount of heat by the halogen heater 53 after the power is turned on, as shown in FIG. 9, the surface temperature increase value per unit time obtained by the surface temperature detecting means 54 (broken line in FIG. 9). ) Is a predetermined temperature lower than the surface temperature rise value (solid line in FIG. 9) stored in advance by the storage means 90, the notification means 100 displays that fact on the operation panel 12, turns on the LED, The user of the image forming apparatus 1 is prompted to clean the temperature detection unit 54a by using a buzzer or sound. Thereby, the user can open the opening / closing part 11 immediately and clean the temperature detection part 54a.

  In this way, the unit time after starting the fixing unit 50 corresponds to the fact that the temperature detection performance decreases as dust or dust such as toner or paper dust adheres to the temperature detection unit 54a of the surface temperature detection unit 54. The cleaning time of the temperature detector 54a can be known based on the perceived temperature rise value. Therefore, even when toner or paper dust adheres to the temperature detection unit 54a and the performance of the surface temperature detection unit 54 deteriorates, this is grasped based on the temperature increase value per unit time after the fixing unit 50 is started. Thus, the temperature detection unit 54a can be cleaned, and appropriate temperature detection performance can be maintained.

  The configurations described in claims 4 to 7 are not exclusive, and can be implemented in combination with each other as shown in the embodiment of the present invention.

  Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the invention.

  For example, the object whose temperature is detected by the surface temperature detecting means 54 is not limited to the heat roller 51 as a fixing member, but may be the pressure roller 52 as a pressure member. One surface temperature detecting means 54 may be provided for each of these members. Furthermore, the attachment position of the surface temperature detection means 54 is not limited to the upper side of the heat roller 51, and may be the lower side.

  Further, the target member whose temperature is detected by the surface temperature detecting means 54 is not limited to the member constituting the fixing unit 50 as in the present embodiment, and may be a constituent member of another device. .

  The present invention can be used in an image forming apparatus using a non-contact type surface temperature detecting means for detecting a surface temperature of a member.

1 is a schematic vertical sectional front view of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a schematic vertical cross-sectional partial enlarged view showing a portion from a sheet conveying section to a switchback section of the image forming apparatus of FIG. 1 and a schematic diagram of a control circuit. FIG. 3 is a partially enlarged schematic vertical sectional view showing a portion from a sheet conveying unit to a switchback unit similar to FIG. 2 and showing a state in which the opening / closing unit is opened. FIG. 3 is a schematic vertical sectional partial enlarged front view showing the periphery of the fixing unit in FIG. 2. FIG. 3 is a schematic partial enlarged top view showing the periphery of the fixing unit in FIG. 2. FIG. 5 is a schematic vertical sectional partial enlarged front view showing the periphery of the fixing unit similar to FIG. 4 and shows a state in which the opening and closing unit is opened. FIG. 6 is a model partially enlarged top view showing the periphery of the fixing unit similar to FIG. 5 and shows a state in which the opening and closing unit is opened. 6 is a graph showing the in-machine temperature immediately after the image forming apparatus is turned on, obtained by the in-machine temperature detecting means and the surface temperature detecting means. 6 is a graph showing a transition of the temperature obtained by the surface temperature detection means from when the image forming apparatus is turned on.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 4 Paper conveyance path 11 Opening / closing part 12 Operation panel 20 Paper conveying part 30 Image forming part 35 In-machine temperature detection means 40 Transfer part 50 Fixing part (fixing apparatus)
51 Heat roller (fixing member)
54 Surface temperature detection means 54a Temperature detection section 55 Paper counter 56 Timekeeping means 60 Branching section 70 Switchback section 80 Cleaning means 81 Cleaning member 82 Spring (biasing means)
90 storage means 100 notifying means 110 slide mechanism 111 slide member

Claims (7)

  A non-contact type surface temperature detecting means for detecting the surface temperature of the member; a cleaning means provided with a cleaning member capable of taking both contact and retreat positions with respect to the temperature detecting portion of the surface temperature detecting means; and a paper transport path An opening / closing portion that allows exposure, and the cleaning means holds the cleaning member in the retracted position when the opening / closing portion is closed, and moves the cleaning member in the contact position in conjunction with opening of the opening / closing portion. An image forming apparatus characterized in that the position is changed.   The cleaning means includes a slide mechanism that changes the position of the slide member provided with the cleaning member between the contact position and the retracted position, and an urging means that urges the slide member toward the contact position. The image forming apparatus according to claim 1, further comprising:   The image forming apparatus according to claim 1, wherein the surface temperature detecting unit is provided to detect a surface temperature of a fixing member and / or a pressure member of the fixing device. .   4. The apparatus according to claim 3, further comprising: a paper counter that counts a cumulative number of printed sheets of paper; and a notification unit that receives information from the paper counter and prompts the cleaning of the temperature detection unit by the cleaning member. The image forming apparatus described.   5. A time measuring means for measuring the cumulative driving time of the fixing device, and a notifying means for receiving information from the time measuring means and prompting cleaning of the temperature detection unit by the cleaning member. The image forming apparatus according to 3.   An in-machine temperature detecting means for detecting the temperature in the image forming apparatus and an informing means for prompting cleaning of the temperature detecting portion by the cleaning member, and immediately after turning on the power and before starting the fixing device, The notification means prompts the cleaning of the temperature detection section when the temperature obtained by the surface temperature detection means is a predetermined temperature lower than the temperature obtained by the in-machine temperature detection means. Image forming apparatus.   A storage unit that stores in advance a surface temperature increase value per unit time for a predetermined amount of heat of the fixing member and / or the pressure member; and a notification unit that prompts the cleaning member to clean the temperature detection unit. The surface temperature increase value per unit time obtained by the surface temperature detecting means when the fixing device is started with the predetermined amount of heat after turning on the power is stored in advance by the storage means. The image forming apparatus according to claim 3, wherein when the temperature is lower than a predetermined temperature, the notification unit prompts cleaning of the temperature detection unit.

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