JP7363241B2 - Image forming device and fixing device - Google Patents

Description

The present invention relates to an image forming apparatus and a fixing device.

Conventionally, in an electrophotographic image forming apparatus, an image is formed on a sheet of paper by forming a toner image on a sheet of paper and fixing the toner image on the sheet with a fixing device included in the image forming apparatus. The fixing device is, for example, a fixing nip formed by pressing two fixing rollers, and fixes the toner image on the paper by pressurizing and heating the paper and conveying it by the rotation of the fixing rollers. .

When the fixing device fixes the toner image, wax, which is a releasing agent contained in the toner image, oozes out and adheres to the fixing roller, etc., and then the fixing roller goes around once, leaving the toner on the paper where the wax adheres. When it comes into contact with an image, the fixation state differs between the areas where the wax is attached and the other areas, causing unevenness in the image. This phenomenon is called glossy memory. The occurrence of gloss memory can be suppressed by removing wax by pressing a cleaning roller against a rotating fixing roller or the like.

However, if a jam occurs in the fixing device, a relatively large amount of toner on the paper will be transferred to the fixing roller etc. when the jam is cleared, and further toner carried by the fixing roller etc. will be transferred onto the cleaning roller. The cleaning roller becomes dirty, which deteriorates the effectiveness of removing wax from the fixing roller, etc. As a countermeasure to this problem, there is a known technology in which after a jam occurs, switching to cleaning mode stops fixing the toner image on the paper, and removes the toner adhering to the cleaning roller with a web (nonwoven fabric) in contact with it. It is being

In the cleaning mode, the toner adhering to the fixing roller, etc. is removed by the cleaning roller that is in pressure contact with the fixing roller, etc., thereby preventing the toner from staining the toner image formed on the paper after the cleaning mode. . However, wax oozes out from the toner adhering to the cleaning roller and transfers to the fixing roller, which may cause gloss memory. In order to suppress the gloss memory that occurs in this way, it is necessary to reduce the amount of toner adhering to the cleaning roller, which increases the time in the cleaning mode in which the toner on the cleaning roller is removed by the web. Productivity decreases.

The following prior art is disclosed in the following patent document. During the recovery operation after clearing a jam in the image heating device, the pressure of the web sliding against the collection roller is applied to the collection roller, which collects the toner on the fixing roller by coming into contact with the rotating fixing roller. Execute a cleaning mode lower than that during fixing processing. This prevents a large amount of toner from adhering to the collection roller, which increases the frictional resistance between the collection roller and the web, causing slack in the web, which reduces the cleaning effectiveness of the collection roller. .

Patent Application No. 2015-169855

However, in the above-mentioned prior art, since the pressing force of the web against the collection roller, which is a cleaning roller, is reduced, the nip width between the collection roller and the web is reduced, and the adhesion between the two is reduced, resulting in poor cleaning performance of the web against the collection roller. There is a possibility that it will decrease. Therefore, when a relatively large amount of toner adheres to the collection roller, it takes time to collect the toner to the extent that gloss memory does not occur, which increases the time spent in cleaning mode and may reduce productivity. There is a problem.

On the other hand, if the pressure of the web against the cleaning roller is increased, the rotation of the cleaning roller will be inhibited, and a speed difference will occur between the cleaning roller and the fuser belt, etc., which rotate in pressure contact, resulting in damage to the surface of the fuser belt, etc. The problem is that it is possible.

The present invention has been made to solve such problems. That is, it is an object of the present invention to provide an image forming apparatus and a fixing device that can prevent the occurrence of gloss memory and suppress a decrease in productivity without damaging the fixing member.

The above-mentioned problems of the present invention are solved by the following means.

(1) An image forming unit that forms a toner image on a recording medium contacts the toner image formed on the recording medium, pressurizes the toner image, and heats the toner image at a predetermined fixing temperature. a fixing member that performs a fixing process to fix an image on the recording medium; a first cleaning member that comes into pressure contact with the fixing member and cleans the fixing member; and a first cleaning member that comes into pressure contact with the first cleaning member and cleans the fixing member. a second cleaning member that cleans a member; a pressure separation drive unit that presses and separates the fixing member and the first cleaning member; a rotation drive unit that rotationally drives the first cleaning member; and the first cleaning member. In the normal mode in which the heating unit heats the member and the fixing process to the recording medium is performed, the set temperature for heating the first cleaning member by the heating unit is set to a predetermined first temperature, and the pressure separation drive a cleaning mode in which the first cleaning member is brought into pressure contact with the fixing member to clean the fixing member, the first cleaning member is cleaned by the second cleaning member, and the fixing process to the recording medium is not performed; Then, a set temperature for heating the first cleaning member by the heating unit is set to a predetermined second temperature higher than the first temperature, and the first cleaning member is separated from the fixing member by the pressure separation drive unit. , a control unit that controls the first cleaning member to be rotated by the rotation drive unit and the first cleaning member to be cleaned by the second cleaning member; 1. Heating of the first cleaning member by the heating unit is controlled based on the temperature measured by a temperature sensor that measures the temperature of the end of the first cleaning member, and in the cleaning mode, the heating of the first cleaning member by the heating unit is controlled. The image forming apparatus increases the set temperature stepwise to the second temperature according to the time from the start of heating to bring the cleaning member to the second temperature.

(2) The image forming apparatus according to (1) above, wherein the second temperature is higher than the fixing temperature.

(3) The image forming apparatus according to (2) above, wherein the second temperature is set for each type of recording medium.

(4) The controller further includes a moving unit that moves the second cleaning member at a predetermined feed speed, and in the normal mode, the controller moves the second cleaning member that is pressed against the first cleaning member to the The second cleaning member is moved by the moving unit at a first feed rate, and in the cleaning mode, the second cleaning member pressed against the first cleaning member is moved by the moving unit at a second feed rate faster than the first feed rate. The image forming apparatus according to any one of (1) to (3) above.

(5) The image forming apparatus according to any one of (1) to (4) above, wherein the surface layer of the first cleaning member is made of polyimide.

( 6 ) The control unit changes the initial set temperature that is raised in stages according to the temperature measured by the temperature sensor when the heating unit starts heating the first cleaning member. The image forming apparatus according to ( 1 ).

( 7 ) A fixing member that performs a fixing process to fix the toner image on the recording medium by contacting the toner image formed on the recording medium, pressurizing the toner image, and heating the toner image at a predetermined fixing temperature; , a first cleaning member that comes into pressure contact with the fixing member to clean the fixing member, a second cleaning member that comes into pressure contact with the first cleaning member and cleans the first cleaning member, and the fixing member; a pressure-separation drive unit that presses and separates the first cleaning member; a rotation drive unit that rotationally drives the first cleaning member; a heating unit that heats the first cleaning member; and the fixing unit on the recording medium. In the normal mode in which the processing is performed, a set temperature for heating the first cleaning member by the heating unit is set to a predetermined first temperature, and the first cleaning member is brought into pressure contact with the fixing member by the pressure separation drive unit. In a cleaning mode in which the fixing member is cleaned and the first cleaning member is cleaned by the second cleaning member, and the fixing process to the recording medium is not performed, heating of the first cleaning member by the heating unit is set. setting the temperature to a predetermined second temperature higher than the first temperature, separating the first cleaning member from the fixing member by the pressure separation drive unit, and rotating the first cleaning member by the rotation drive unit; a control unit configured to control the first cleaning member to be cleaned by the second cleaning member, and the control unit includes a temperature sensor that measures the temperature at an end of the first cleaning member. heating of the first cleaning member by the heating unit is controlled based on the temperature, and in the cleaning mode, the time from the start of heating by the heating unit to bring the first cleaning member to the second temperature; The fixing device increases the set temperature stepwise up to the second temperature in accordance with the set temperature .

In the cleaning mode, the first cleaning member is separated from the fixing member, and the first cleaning member is heated to a higher temperature than in the normal mode and rotated, thereby cleaning with the second cleaning member pressed against the first cleaning member. do. This prevents the occurrence of gloss memory and prevents a decrease in productivity without damaging the fixing member.

1 is a schematic diagram showing the configuration of an image forming apparatus. FIG. 2 is a block diagram showing the configuration of an image forming apparatus. FIG. 3 is a schematic diagram showing the configuration of a fixing section. FIG. 3 is a schematic diagram of the fixing unit showing the positions of each member of the fixing unit in a cleaning mode. FIG. 7 is a diagram showing the temperatures at the ends and center of the cleaning roller with respect to the time from the start of heating the cleaning roller when stepwise temperature control is not performed. FIG. 7 is a diagram showing the temperatures at the ends and center of the cleaning roller with respect to time from the start of heating the cleaning roller when stepwise temperature control is performed. FIG. 6 is a diagram showing the relationship between the temperature range of the cleaning roller at the start of heating and the set temperature of the heater that is raised stepwise. FIG. 6 is a diagram illustrating an example of the temperature at the end and center of the cleaning roller when the set temperature of the heater is increased in stages according to the temperature of the cleaning roller at the start of heating. FIG. 7 is a diagram illustrating another example of the temperatures at the ends and center of the cleaning roller when the set temperature of the heater is increased in stages according to the temperature of the cleaning roller at the start of heating. 3 is a flowchart showing the operation of the image forming apparatus. FIG. 7 is a diagram showing a second configuration of the fixing section.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An image forming apparatus according to an embodiment of the present invention will be described below with reference to the drawings. In addition, in the drawings, the same elements are given the same reference numerals, and overlapping explanations will be omitted. Furthermore, the dimensional ratios in the drawings are exaggerated for convenience of explanation and may differ from the actual ratios.

FIG. 1 is a schematic diagram showing the configuration of an image forming apparatus 100. FIG. 2 is a block diagram showing the configuration of the image forming apparatus 100. FIG. 3 is a schematic diagram showing the configuration of the fixing section 50.

Image forming apparatus 100 can be connected via a network by communication unit 130 to one or more terminals (not shown) for issuing various instructions such as printing instructions to image forming apparatus 100 . Image forming apparatus 100 forms an image on paper 900 based on the print job received from the terminal.

A print job is a general term for print commands to the image forming apparatus 100, and includes print data and print settings. Print data is data of a document to be printed, and may include various data such as image data, vector data, and text data. Specifically, the print data may be PDF (Portable Document Format) data, PDL (Page Description Language) data, or TIFF (Tagged Image File Format) data. The print settings are settings related to image formation on the paper 900, and include various settings such as the number of pages, the number of copies to be printed, paper type, selection of color or monochrome, and page layout.

The image forming apparatus 100 includes a control section 110, a storage section 120, a communication section 130, an operation display section 140, an image reading section 150, an image control section 160, and an image forming section 170. These components are communicatively coupled to each other by a bus. Image forming apparatus 100 may be configured by, for example, an MFP (MultiFunction Peripheral).

The control unit 110 includes a CPU (Central Processing Unit) and various types of memory, and controls each of the above units and performs various calculation processes according to a program. The details of the operation of the control unit 110 will be described later.

The storage unit 120 is configured with an SDD (Solid State Drive), an HDD (Hard Disc Drive), or the like, and stores various programs and various data.

Communication unit 130 is an interface for communicating between image forming apparatus 100 and external devices. As the communication unit 130, a network interface based on standards such as Ethernet (registered trademark), SATA, and IEEE1394 is used. Further, as the communication unit 130, various local connection interfaces such as wireless communication interfaces such as Bluetooth (registered trademark) and IEEE802.11 are used.

The operation display unit 140 includes a touch panel, a numeric keypad, a start button, a stop button, etc., and is used to display various information and input various instructions.

The image reading unit 150 includes a light source such as a fluorescent lamp and an image sensor such as a CCD (Charge Coupled Device) image sensor. The image reading unit 150 illuminates a document set at a predetermined reading position with light from a light source, photoelectrically converts the reflected light with an image sensor, and generates image data from the electrical signal.

The image control unit 160 performs layout processing, screening, rasterization processing, etc. of the print data included in the print job etc. received by the communication unit 130, and generates image data in bitmap format. The image data is CMYK values or RGB values for each pixel.

Image forming section 170 includes image forming section 40 , fixing section 50 , paper feeding section 60 , and paper transport section 70 .

The image forming section 40 includes image forming units 41Y, 41M, 41C, and 41K corresponding to toner of each color of Y (yellow), M (magenta), C (cyan), and K (black). Each of the image forming units 41Y, 41M, 41C, and 41K forms a toner image on the photoreceptor drum 47 through charging, exposure, and development processes based on image data (image data after color conversion). Exposure is performed by scanning the photoreceptor drum 47 with laser light. The toner image formed on the photoreceptor drum 47, which is an image carrier, is transferred to the intermediate transfer belt 42 by the driving force of the drive roller 45, which is pressed between the photoreceptor drum 47 and the primary transfer roller 48 via the intermediate transfer belt 42. As the toner images rotate and travel, they are sequentially superimposed on the intermediate transfer belt 42 to form color toner images. The intermediate transfer belt 42 runs in the sub-scanning direction (the direction of the straight arrow in FIG. 1). The color toner image formed on the intermediate transfer belt 42 is transferred onto the conveyed paper 900 by the secondary transfer roller 43 and the opposing roller 44 being pressed together via the intermediate transfer belt 42 .

The fixing unit 50 includes a fixing roller 51a, a fixing belt 51b, a heating roller 51c, a pressure roller 52, a cleaning roller 54, a web 56a, a pressure roller 56b, an original winding roller 56c, a winding roller 56d, a cleaning roller drive mechanism 57, and A pressure roller drive mechanism 58 is included. The fixing belt 51b constitutes a fixing member. The cleaning roller 54 constitutes a first cleaning member. The web 56a constitutes a second cleaning member. The cleaning roller drive mechanism 57 includes a gear, a cam, a motor, etc. (all not shown), and constitutes a pressure separation drive section and a rotation drive section.

The fixing belt 51b is an endless belt, and is stretched between a heating roller 51c and a fixing roller 51a. The fixing belt 51b rotates clockwise in FIG. 3 following the rotation of a fixing roller 51a that is rotationally driven by the driving force of a drive motor (not shown). The fixing roller 51a and the pressure roller 52 are pressed against each other via the fixing belt 51b, thereby forming a fixing nip N between the fixing belt 51b and the pressure roller 52. The paper 900 conveyed to the fixing unit 50 is heated at a predetermined fixing temperature in the fixing nip N and pressurized to fix (melt and fix) the toner image. It is conveyed by the rotation of the The fixing temperature is set, for example, to 160 to 200°C. The fixing temperature can be varied depending on the type of paper 900 and the like. The fixing belt 51b is, for example, a 70 μm thick PI (polyimide) base whose outer peripheral surface is covered with an elastic layer. As the elastic layer, for example, heat-resistant silicone rubber (hardness JIS-A 30°) with a thickness of 200 μm is used. As the heat-resistant resin, for example, PFA (perfluoroalkoxy) having a thickness of 30 μm is used.

The heating roller 51c heats the fixing belt 51b by transmitting heat generated by the built-in heater 53 to the fixing belt 51b. The heating roller 51c is, for example, a cylindrical metal core made of metal such as aluminum, and the outer peripheral surface thereof is coated with a fluororesin or the like. The heater 53 is, for example, a halogen heater.

The fixing roller 51a rotates clockwise in FIG. 3 by the driving force of a drive motor (not shown). The circumferential speed of the fixing roller 51a is set to, for example, about 200 mm/s. The fixing roller 51a is indirectly heated by the heater 53 via the fixing belt 51b. For example, the fixing roller 51a includes, in order from the inside, a cylindrical metal core, an elastic layer formed on the surface of the core made of a material such as silicone rubber or foamed silicone rubber, and a release layer made of fluororesin or the like. .

The pressure roller 52 presses the fixing roller 51a via the fixing belt 51b. The pressure roller 52 includes, for example, in order from the inside, a cylindrical metal core, a foamed silicone rubber elastic layer formed on the surface of the core, and a release layer made of fluororesin or the like.

(Normal mode)
In the normal mode in which the fixing unit 50 performs a fixing process in which a toner image is fixed onto the paper 900, the cleaning roller 54 is brought into pressure contact with the fixing belt 51b by the cleaning roller drive mechanism 57. FIG. 3 shows the positions of each member of the fixing section 50 in the normal mode. The cleaning roller 54, which is in pressure contact with the fixing belt 51b, cleans the fixing belt 51b by removing toner and wax that have been transferred and attached to the paper 900 during fixing from the rotating fixing belt 51b. At this time, the cleaning roller 54 follows the rotation of the fixing belt 51b and rotates counterclockwise in FIG. 3. Note that the cleaning roller 54 may be rotated by the driving force of the cleaning roller drive mechanism 57 at the same speed as the fixing belt 51b. The web 56a is supplied from the original winding roller 56c, is pressed against the cleaning roller 54 by the pressing force of the stretched pressing roller 56b, and is wound around the winding roller 56d. The press roller drive mechanism 58 causes the press roller 56b to press against the cleaning roller 54 via the web 56a, so that the web 56a is constantly pressed against the cleaning roller 54. The web 56a cleans the cleaning roller 54 by removing toner and wax attached to the cleaning roller 54 from the cleaning roller 54 by being transferred from the fixing belt 51b when cleaning the fixing belt 51b. At this time, the cleaning roller 54 is heated to a predetermined first temperature by the built-in heater 55. The heater 55 constitutes a heating section. The first temperature may be set to the same temperature as the fixing temperature, or may be set to a higher temperature than the fixing temperature. The first temperature is, for example, 170°C. The heater 55 is, for example, a halogen heater. The temperature of the cleaning roller 54 is measured by a temperature sensor 59. The temperature sensor 59 is a non-contact sensor and can measure the temperature of the end of the cleaning roller 54 (specifically, the surface of the end of the roller). The temperature sensor 59 is, for example, an infrared detection type sensor that includes a detection element (thermistor) for measuring the temperature of the cleaning roller 54 and a detection element (thermistor) for temperature compensation. The temperature sensor 59 may be arranged on a mounting plate fixed to the casing of the image forming apparatus 100 so that its detection surface faces the end of the cleaning roller 54 . The take-up roller 56d is rotated by a motor (not shown) to take up the web 56a. The take-up roller 56d constitutes a moving section. As the web 56a is wound up by the take-up roller 56d, the feeding speed of the web 56a is set to a predetermined first feeding speed. The first feed rate is, for example, 0.10 mm/s. The nip width of the nip portion formed when the web 56a is pressed against the cleaning roller 54 is set to a predetermined first width. The first width is, for example, 3 mm.

The cleaning roller 54 is, for example, a cylindrical metal core made of a metal such as aluminum, and its outer peripheral surface is coated with PI (polyimide) as a surface layer. By making the surface layer of the cleaning roller 54 PI with low mold releasability, the wax adhering to the fixing belt 51b is easily removed, improving the cleaning efficiency of the fixing belt 51b and effectively suppressing the occurrence of gloss memory. can. By using PI on the surface layer of the cleaning roller 54 with a contact angle (pure water) of 80° to 90°, an average surface roughness of 0.2 μm or less, and a nip width of 1.5 mm or more, the PI adhered to the fixing belt 51b. Wax can be removed more effectively.

The web 56a is, for example, a nonwoven fabric using heat-resistant fibers such as aramid fibers.

(cleaning mode)
If a jam or the like occurs in the fixing unit 50, after the jam is handled such as removing the paper that caused the jam, the fixing unit 50 shifts to a cleaning mode in which the fixing process to the paper 900 is not performed.

FIG. 4 is a schematic diagram of the fixing section 50 showing the positions of each member of the fixing section 50 in the cleaning mode.

In the cleaning mode, the cleaning roller 54 is separated from the fixing belt 51b by the cleaning roller drive mechanism 57, and is moved counterclockwise in FIG. 4 at the same speed as the fixing belt 51b by the driving force of the cleaning roller drive mechanism 57. be rotated. Even in the cleaning mode, the web 56a is maintained in pressure contact with the cleaning roller 54 by the pressing roller drive mechanism 58. The web 56a is supplied from the original winding roller 56c, is pressed against the cleaning roller 54 by the pressing force of the stretched pressing roller 56b, and is wound around the winding roller 56d. The web 56a is in pressure contact with the cleaning roller 54 and is transferred from the fixing belt 51b when cleaning the fixing belt 51b, thereby removing toner and wax attached to the cleaning roller 54. conduct. At this time, the cleaning roller 54 is heated by the built-in heater 55 to a predetermined second temperature higher than the predetermined first temperature. The second temperature is set to a temperature higher than the fixing temperature. This prevents the toner from becoming relatively hard due to the low temperature of the cleaning roller 54 and being unable to be removed by the web 56a, and allows the toner and wax to be effectively removed from the cleaning roller 54. The second temperature can be set for each type of paper 900 as the fixing temperature is changed depending on the type of paper 900. The second temperature may be set to a constant temperature regardless of the type of paper 900. The second temperature can be set to an appropriate value through experiments from the viewpoint of suppressing gloss memory and shortening the cleaning mode time. The second temperature is, for example, 210°C. The upper limit of the second temperature may be the allowable temperature limit of the web 56a.

As the web 56a is wound up by the take-up roller 56d, the feeding speed of the web 56a is set to a predetermined second feeding speed that is faster than the first feeding speed. In the cleaning mode, it is necessary to more effectively reduce the amount of toner (and wax) attached to the cleaning roller 54 than in the normal mode. In the cleaning mode, increasing the feed speed of the web 56a can effectively reduce the amount of toner (and wax) adhering to the cleaning roller 54. Further, by increasing the feeding speed of the web 56a only during the cleaning mode, it is possible to suppress an increase in the amount of the web 56a used. The second feed rate is, for example, 1 mm/s. The nip width of the nip portion formed when the web 56a is pressed against the cleaning roller 54 is set to a predetermined second width that is larger than the first width. The second width is, for example, 4 mm.

Note that in the normal mode, the temperature of the fixing belt 51b may be relatively high, such as when a toner image formed on a relatively thick paper 900 is fixed. In this case, if the temperature of the cleaning roller 54 immediately before the jam occurs is already high (for example, if the temperature of the cleaning roller 54 is 210° C.), there is no need to raise the temperature of the cleaning roller 54 during the cleaning mode. (It may be maintained at 210°C).

The paper 900 on which the toner image has been fixed by the fixing unit 50 is discharged to the paper discharge tray 90 as a printed matter.

The paper feed unit 60 has a plurality of paper feed trays 61 and 62, and sends out the sheets of paper 900 stored in the paper feed trays 61 and 62 one by one to a downstream conveyance path.

The paper transport section 70 has a plurality of transport rollers for transporting the paper 900, and transports the paper 900 between the image forming section 40, the fixing section 50, and the paper feeding section 60. The plurality of transport rollers include a registration roller 71 for correcting the inclination of the paper 900 and a loop roller 72 for forming a predetermined amount of loops on the paper 900.

The paper transport unit 70 discharges the paper 900 on which the image has been formed to the paper discharge tray 90 .

Next, the operation of the control section 110 will be explained in detail.

When the control unit 110 receives the print job through the communication unit 130, the image control unit 160 performs rasterization processing on the print data to generate image data, and the image creation unit 40 creates a toner image on the paper 900 based on the image data. Form. If no jam is detected, the control unit 110 sets the fixing unit 50 to the normal mode. In the normal mode, the control unit 110 fixes the toner image on the paper 900, cleans the fixing belt 51b with the cleaning roller 54 heated to a first temperature, and cleans the fixing belt 51b with the web 56a moved at the first feed speed. Clean 54.

When the control unit 110 detects a jam in the fixing unit 50, it determines whether or not the jam processing has been completed. For example, the control unit 110 may control the position of the paper 900 detected by a position sensor (not shown) provided on the transport path of the paper 900, even though the paper transport unit 70 is controlling the transport of the paper 900. A jam is detected by not changing. For example, the control unit 110 detects that all of the sheets of paper 900 whose positions on the conveyance path do not change even though the conveyance of the sheets of paper 900 is controlled (for example, the paper that caused the jam) are no longer detected by the position sensor. It is determined that the jam processing has been completed.

When the control unit 110 determines that the jam processing has been completed, the control unit 110 shifts the fixing unit 50 to the cleaning mode. In the cleaning mode, the control unit 110 heats the cleaning roller 54 separated from the fixing belt 51b to a second temperature higher than the first temperature and rotates the cleaning roller 54. As a result, the control unit 110 cleans the cleaning roller 54 with the web 56a that is pressed against the cleaning roller 54 and moved at the second feed speed faster than the first feed speed.

The control unit 110 can set the set temperature at which the cleaning roller 54 is heated by the heater 55 as follows, based on the temperature measured by the temperature sensor 59 provided at the end of the cleaning roller 54. The control unit 110 increases the set temperature of the heater 55 stepwise to the second temperature in accordance with the time since the heater 55 starts heating the cleaning roller 54 to the second temperature. Hereinafter, control for increasing the set temperature of the heater 55 stepwise to the second temperature will be referred to as "stepped temperature control."

FIG. 5 is a diagram showing the temperature at the ends and center of the cleaning roller 54 with respect to time from the start of heating the cleaning roller 54 when stepwise temperature control is not performed. FIG. 6 is a diagram showing the temperature at the ends and center of the cleaning roller 54 with respect to time from the start of heating the cleaning roller 54 when stepwise temperature control is performed. 5 and 6, the broken line graph is a graph of the temperature at the center of the cleaning roller 54, and the solid line graph is a graph of the temperature at the end of the cleaning roller 54. The upper limit temperature is the upper limit value of the temperature of the cleaning roller 54. The upper limit temperature is set below the melting point of the web 56a.

As shown in FIG. 5, when stepwise temperature control is not performed, if the set temperature of the heater 55 is controlled based on the temperature detected by the temperature sensor 59 provided at the end of the cleaning roller 54, The temperature may rise excessively and exceed the upper limit temperature. As a result, depending on the upper limit temperature, problems such as melting of the web 56a that is in pressure contact with the cleaning roller 54 may occur.

As shown in FIG. 6, when the set temperature is gradually increased in the order of the first set temperature, second set temperature, and third set temperature according to the time from the start of heating of the cleaning roller 54, the center of the cleaning roller 54 It is possible to prevent the temperature from rising excessively. This allows the center temperature of the cleaning roller 54 to be lower than the upper limit temperature. The first set temperature to the third set temperature are such that the temperature at the end of the cleaning roller 54 (temperature measured by the temperature sensor 59) reaches the second temperature without the center temperature of the cleaning roller 54 reaching the upper limit temperature. It can be determined experimentally from the viewpoint of minimizing the time required.

The control unit 110 changes the set temperature of the heater 55 to be raised in stages according to the temperature measured by the temperature sensor 59 when the heater 55 starts heating the cleaning roller 54 .

FIG. 7 is a diagram showing the relationship between the temperature range of the cleaning roller 54 at the start of heating and the set temperature of the heater 55, which is gradually increased.

In the example of FIG. 7, if the temperature of the cleaning roller 54 at the start of heating is lower than or equal to the first set temperature, the first set temperature, second set temperature, and 3. Raise the set temperature step by step in the order of set temperature. If the temperature of the cleaning roller 54 at the start of heating is higher than the first set temperature and lower than the second set temperature, the temperature is set in the order of the second set temperature and the third set temperature depending on the time from the start of heating of the cleaning roller 54. Increase the set temperature in stages. If the temperature of the cleaning roller 54 at the start of heating is higher than the second set temperature and lower than the third set temperature, the set temperature is set to the third set temperature.

FIG. 8 is a diagram illustrating an example of the temperature at the ends and center of the cleaning roller 54 when the set temperature of the heater is increased in stages according to the temperature of the cleaning roller 54 at the start of heating. FIG. 9 is a diagram illustrating another example of the temperature at the ends and center of the cleaning roller 54 when the set temperature of the heater is increased in stages according to the temperature of the cleaning roller 54 at the start of heating.

FIG. 8 shows an example where the end temperature of the cleaning roller 54 at the start of heating is higher than the first set temperature and lower than the second set temperature. In this case, the time required to raise the temperature of the cleaning roller 54 can be shortened by increasing the set temperature of the heater 55 at the start of heating stepwise to a second temperature higher than the end temperature of the cleaning roller 54 at the start of heating.

FIG. 9 shows an example in which the end temperature of the cleaning roller 54 at the start of heating is higher than the second set temperature and lower than or equal to the third set temperature. In this case, by setting the set temperature of the heater 55 at the start of heating to a third temperature higher than the end temperature of the cleaning roller 54 at the start of heating, the time for heating up the cleaning roller 54 can be shortened.

The operation of image forming apparatus 100 will be explained.

FIG. 10 is a flowchart showing the operation of image forming apparatus 100. This flowchart can be executed by the control unit 110 according to a program stored in the storage unit 120.

The control unit 110 determines whether or not the jam has been processed (S101). That is, the control unit 110 determines whether a jam has occurred in the fixing unit 50 and the jam processing has been completed. If the control unit 110 determines that the jam has not been processed (S101: NO), the process proceeds to step S103.

When the control unit 110 determines that the jam has been processed (S101: YES), the control unit 110 shifts the fixing unit to the cleaning mode. That is, the control unit 110 separates the cleaning roller 54 from the fixing roller 51a, heats it to the second temperature, and rotates the cleaning roller 54. As a result, the cleaning roller 54 is cleaned by the web 56a pressed against the cleaning roller 54.

The control unit 110 determines whether a print instruction has been received (S103). For example, the control unit 110 determines that a print instruction has been received when the communication unit 130 receives a print job. If the control unit 110 determines that it has not received a print instruction (S103: NO), it waits until it receives a print instruction.

When the control unit 110 determines that a print instruction has been received (S103: YES), the control unit 110 shifts (sets) the fixing unit to the normal mode. That is, the control unit 110 cleans the fixing belt 51b by bringing the cleaning roller 54 heated to the first temperature into pressure contact with the fixing belt 51b, and cleans the cleaning roller 54 with the web 56a. At the same time, the control unit 110 pressurizes and heats the paper 900 at the fixing nip N between the fixing belt 51b and the pressure roller 52, thereby fixing the toner image on the paper 900 to the paper 900.

(Modified example)
The fixing unit 50 includes a fixing roller 51a having a built-in heater 53 and a pressure roller instead of the first configuration (the configuration shown in FIG. 3) including a fixing roller 51a, a fixing belt 51b, a heating roller 51c, and a pressure roller 52. A second configuration including 52 may also be used.

FIG. 11 is a diagram showing a second configuration of the fixing section 50. FIG. 11 shows the positions of each member of the fixing section 50 in the cleaning mode.

In the modified example, the fixing roller 51a and the pressure roller 52 are pressed against each other to form a fixing nip N.

In the normal mode, the cleaning roller 54 is pressed against the fixing roller 51a by the cleaning roller drive mechanism 57. The cleaning roller 54, which is in pressure contact with the fixing roller 51a, cleans the fixing belt 51b by removing toner and wax that have been transferred from the rotating fixing roller 51a and adhered to the paper 900 during fixing. At this time, the cleaning roller 54 follows the rotation of the fixing roller 51a and rotates counterclockwise in FIG. 11. Note that the cleaning roller 54 may be rotated by the driving force of the cleaning roller drive mechanism 57 at the same speed as the fixing belt 51b. The web 56a is constantly pressed against the cleaning roller 54 by the pressing roller drive mechanism 58, which presses the pressing roller 56b against the cleaning roller 54 via the web 56a. The web 56a cleans the cleaning roller 54 by removing toner and wax attached to the cleaning roller 54 from the cleaning roller 54 by being moved from the fixing roller 51a when cleaning the fixing belt 51b. At this time, the cleaning roller 54 is heated to the first temperature by the built-in heater 55.

In the cleaning mode, the cleaning roller 54 is separated from the fixing roller 51a by the cleaning roller drive mechanism 57, and is moved counterclockwise in FIG. 11 at the same speed as the fixing roller 51a by the driving force of the cleaning roller drive mechanism 57. be rotated. Even in the cleaning mode, the web 56a is maintained in pressure contact with the cleaning roller 54 by the pressing roller drive mechanism 58. The web 56a is in pressure contact with the cleaning roller 54 and is transferred from the fixing belt 51b when cleaning the fixing belt 51b, thereby removing toner and wax attached to the cleaning roller 54. conduct. At this time, the cleaning roller 54 is heated to the second temperature by the built-in heater 55.

The embodiment described above has the following effects.

In the cleaning mode, the first cleaning member is separated from the fixing member, and the first cleaning member is heated to a higher temperature than in the normal mode and rotated, thereby cleaning with the second cleaning member pressed against the first cleaning member. do. This prevents the occurrence of gloss memory and prevents a decrease in productivity without damaging the fixing member.

The second temperature is set higher than the fixing temperature. Thereby, wax can be effectively removed from the first cleaning member.

A second temperature is set for each type of recording medium. Thereby, by optimizing the second temperature, it is possible to reduce the heating time of the second cleaning member and prevent the occurrence of gloss memory.

The feeding speed of the second cleaning member pressed against the first cleaning member in the cleaning mode is made faster than the feeding speed of the second cleaning member pressed against the first cleaning member in the normal mode. Thereby, wax can be removed from the first cleaning member more quickly and effectively.

The surface layer of the first cleaning member is made of polyimide. As a result, wax adhering to the fixing member can be easily removed by lowering the mold releasability of the first cleaning member, thereby improving the cleaning efficiency of the fixing member and effectively suppressing the occurrence of gloss memory.

When heating the first cleaning member in the cleaning mode, the set temperature for heating the first cleaning member is gradually increased to a second temperature based on the temperature measured by the temperature sensor provided at the end of the first cleaning member. Make it expensive. As a result, even if it is difficult to install a non-contact temperature sensor or the like to measure the temperature at the center of the first cleaning member, the 1. The temperature of the cleaning member can be increased.

The initial set temperature, which is increased stepwise, is changed in accordance with the temperature measured by the temperature sensor at the time of starting heating of the first cleaning member. Thereby, it is possible to shorten the temperature rising time of the first cleaning member while suppressing excessive temperature rise in the central portion of the first cleaning member.

The invention is not limited to the embodiments described above.

For example, in the embodiment, paper is used as an example of the storage medium, but the recording medium is not limited to paper, and may be a resin film or the like.

Further, in the embodiment, in the cleaning mode, when the cleaning roller 54 is heated by the heater 55, the cleaning roller 54 is set to be heated according to the time from the start of heating based on the temperature of the end of the cleaning roller 54. The temperature is increased stepwise to a second temperature. However, in the normal mode as well, the set temperature at which the cleaning roller 54 is heated can be raised stepwise to the first temperature by stepwise temperature control.

Further, in the embodiments, part or all of the processing executed by the program may be executed by replacing it with hardware such as a circuit.

N Fixing nip,
40 Imaging section,
50 fixing section,
51a fixing roller,
51b fixing belt,
51c heating roller,
52 Pressure roller,
53 Heater,
54 cleaning roller,
55 heater,
56a web,
56b pressure roller,
56c main winding roller,
56d take-up roller,
57 Cleaning roller drive mechanism,
58 Press roller drive mechanism,
59 Temperature sensor,
60 paper feed section,
70 paper transport section,
100 image forming device,
110 control unit,
120 storage unit,
130 Communications Department,
140 operation display section,
150 image reading section,
160 image control unit,
170 image forming section,
900 paper.

Claims (7)

an image forming section that forms a toner image on a recording medium;
a fixing member that performs a fixing process to fix the toner image on the recording medium by contacting the toner image formed on the recording medium and applying pressure to the toner image and heating it at a predetermined fixing temperature;
a first cleaning member that cleans the fixing member by coming into pressure contact with the fixing member;
a second cleaning member that is in pressure contact with the first cleaning member and cleans the first cleaning member;
a pressure/separation drive unit that presses and separates the fixing member and the first cleaning member;
a rotational drive unit that rotationally drives the first cleaning member;
a heating unit that heats the first cleaning member;
In the normal mode in which the fixing process to the recording medium is performed, the set temperature for heating the first cleaning member by the heating unit is set to a predetermined first temperature, and the first cleaning member is heated by the pressure separation drive unit. cleaning the fixing member by bringing it into pressure contact with the fixing member, and cleaning the first cleaning member with the second cleaning member;
In a cleaning mode in which the fixing process to the recording medium is not performed, the set temperature for heating the first cleaning member by the heating unit is set to a predetermined second temperature higher than the first temperature, and the pressure separation drive unit a control unit configured to separate the first cleaning member from the fixing member, rotate the first cleaning member by the rotation drive unit, and clean the first cleaning member with the second cleaning member; and ,
The control unit controls heating of the first cleaning member by the heating unit based on a temperature measured by a temperature sensor that measures a temperature at an end of the first cleaning member, and in the cleaning mode, The image forming apparatus may increase the set temperature stepwise to the second temperature in accordance with the time from the start of heating the first cleaning member to the second temperature by the heating unit. The image forming apparatus according to claim 1, wherein the second temperature is higher than the fixing temperature. The image forming apparatus according to claim 2, wherein the second temperature is set for each type of recording medium. further comprising a moving part that moves the second cleaning member at a predetermined feeding speed,
In the normal mode, the control unit causes the moving unit to move the second cleaning member, which is in pressure contact with the first cleaning member, at a first feed speed, and in the cleaning mode, the second cleaning member is in pressure contact with the first cleaning member. moving the second cleaning member at a second feed rate faster than the first feed rate by the moving unit;
The image forming apparatus according to any one of claims 1 to 3. The image forming apparatus according to claim 1, wherein the surface layer of the first cleaning member is made of polyimide. According to claim 1 , the control unit changes the initial set temperature that is increased in stages according to the temperature measured by the temperature sensor when the heating unit starts heating the first cleaning member. The image forming apparatus described above. a fixing member that performs a fixing process to fix the toner image on the recording medium by contacting the toner image formed on the recording medium and applying pressure to the toner image and heating the toner image at a predetermined fixing temperature;
a first cleaning member that cleans the fixing member by coming into pressure contact with the fixing member;
a second cleaning member that is in pressure contact with the first cleaning member and cleans the first cleaning member;
a pressure/separation drive unit that presses and separates the fixing member and the first cleaning member;
a rotational drive unit that rotationally drives the first cleaning member;
a heating unit that heats the first cleaning member;
In the normal mode in which the fixing process to the recording medium is performed, the set temperature for heating the first cleaning member by the heating unit is set to a predetermined first temperature, and the first cleaning member is heated by the pressure separation drive unit. cleaning the fixing member by bringing it into pressure contact with the fixing member, and cleaning the first cleaning member with the second cleaning member;
In a cleaning mode in which the fixing process to the recording medium is not performed, the set temperature for heating the first cleaning member by the heating unit is set to a predetermined second temperature higher than the first temperature, and the pressure separation driving unit a control unit that controls to separate the first cleaning member from the fixing member, rotate the first cleaning member by the rotation drive unit, and clean the first cleaning member with the second cleaning member; , has
The control unit controls heating of the first cleaning member by the heating unit based on a temperature measured by a temperature sensor that measures a temperature at an end of the first cleaning member, and in the cleaning mode, The fixing device is configured to increase the set temperature stepwise to the second temperature in accordance with the time from when the heating unit starts heating the first cleaning member to the second temperature.