JP2024030473A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a configuration that can prevent a reduction in image quality after replacement of a fixing device 100.

SOLUTION: A fixing device 100 has a memory 29 that stores identification information stored during shipment. A control circuit part 21 of an image forming apparatus, when the fixing device 100 is replaced, reads, by a reading unit 31, the identification information stored in the memory 29 in the fixing device 100 after the replacement, and determines temperature adjustment control according to the fixing device 100 after the replacement.

SELECTED DRAWING: Figure 3

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile machine, and a multifunctional device having multiple functions thereof.

The image forming apparatus includes a fixing device that heats a toner image carried on a recording material and fixes the toner image to the recording material. Conventionally, such a fixing device has a configuration in which, for example, a thermistor detects the temperature of a heater that heats the fixing belt, and controls the temperature of the heater so that the temperature detected by the thermistor becomes a target temperature. (For example, Patent Document 1).

Japanese Patent Application Publication No. 2001-282040

Here, when the fixing device is replaced, the materials of the parts constituting the fixing device may have been changed for various reasons before and after the replacement. For example, if the material of the fixing belt is changed, the heat transfer characteristics of the fixing belt may change. In such a case, if you control the temperature of the heater in the replaced fixing device in the same way as before the replacement, the surface temperature of the fixing belt may not be able to be controlled to the desired temperature and the image quality of the product may deteriorate. be.

SUMMARY OF THE INVENTION An object of the present invention is to provide a configuration that can suppress deterioration in image quality after replacing a fixing device.

The image forming apparatus of the present invention includes an endless fixing belt and a nip portion forming a nip portion for fixing the toner image on the recording material by sandwiching and conveying a recording material carrying a toner image between the fixing belt and the fixing belt. a fixing device having a member, a heating section that heats the fixing belt, a temperature detection section that detects the temperature of the heating section, and a storage section that stores identification information; and a temperature detected by the temperature detection section. an image forming apparatus in which the fixing device is replaceable, the image forming apparatus comprising: a control unit that controls the temperature of the heating unit based on the identification information; and a reading unit that reads identification information stored in the storage unit; is information stored at the time of shipment of the fixing device, and when the fixing device is replaced, the control section updates the identification information stored in the storage section of the replaced fixing device with the The target temperature in the temperature adjustment control corresponding to the replaced fixing device is determined by reading by a reading unit.

According to the present invention, it is possible to suppress the image quality from deteriorating after replacing the fixing device.

1 is a schematic cross-sectional view of an image forming apparatus according to an embodiment. FIG. 1 is a control block diagram of an image forming apparatus according to an embodiment. FIG. 1 is a schematic cross-sectional view of a fixing device according to an embodiment. 7 is a graph showing temperature changes of a thermistor and a fixing film during temperature control in a comparative example. FIG. 7 is a table showing the relationship between the target temperature control temperature and the fixing film in a comparative example and an embodiment. FIG. 7 is a table showing the relationship between the target temperature control temperature and the correction coefficient before and after replacing the fixing film of the embodiment. 5 is a flowchart of image forming processing in the embodiment. 3 is a graph showing the temperature changes of the thermistor and the fixing film when the temperature control of the comparative example is performed on the fixing film of the current product (Comparative Example 1). 7 is a graph showing the temperature changes of the thermistor and the fixing film when the temperature control of the comparative example is performed on the fixing film having a higher thermal conductivity than the current product (Comparative Example 2). 12 is a graph showing the temperature changes of the thermistor and the fixing film when the temperature control of the comparative example is performed on the fixing film whose thermal conductivity is lower than that of the current product (Comparative Example 3). 2 is a graph showing the temperature changes of the thermistor and the fixing film when the temperature control of the example is performed on the fixing film of the current product (Embodiment Example 1). 12 is a graph showing the temperature changes of the thermistor and the fixing film when the temperature control of the embodiment is performed on the fixing film having higher thermal conductivity than the current product (Embodiment Example 2). 12 is a graph showing the temperature changes of the thermistor and the fixing film when the temperature control of the embodiment is performed on the fixing film whose thermal conductivity is lower than that of the current product (Embodiment Example 3). A table summarizing the results of Comparative Examples 1 to 3 and Practical Examples 1 to 3. FIG. 7 is a table showing the relationship between the number of corrected hairs in combinations of a fixing film and a pressure roller.

An embodiment will be described using FIGS. 1 to 15. First, the schematic configuration of the image forming apparatus of this embodiment will be described using FIG. 1.

[Image forming device]
FIG. 1 is a cross-sectional configuration diagram of an image forming apparatus 200 according to the present embodiment, and the image forming apparatus 200 forms images using an electrophotographic process. Further, the image forming apparatus 200 of the present embodiment forms a full-color toner image using toner of four colors: yellow (y), magenta (m), cyan (c), and black (k). For this reason, the image forming apparatus 200 includes a plurality of image forming units Py and Pm that form toner images of each color. It has Pc and Pk. Each of the image forming portions Py to Pk is labeled with suffixes y, m, c, and k corresponding to the toner image of each color.

The photosensitive drums 101y to 101k, which serve as image carriers, are cylindrical photosensitive members, and are rotationally driven in the counterclockwise direction of the arrow at a predetermined process speed (peripheral speed). During their rotation, the photosensitive drums 101y to 101k are charged to a predetermined polarity by charging devices 102y to 102k such as charging rollers.

Next, exposure processing based on the input image information is performed on the charged surfaces of the photosensitive drums 101y to 101k by laser beams 103y to 103k output from laser optical systems (exposure devices) 110y to 110k. Laser optical systems 110y to 110k output laser beams 103y to 103k modulated (on/off) in response to time-series electric digital pixel signals of target image information from an image signal generator such as an image reading device (not shown). Then, the surfaces of the photosensitive drums 101y to 101k are scanned and exposed. As a result, electrostatic latent images corresponding to image information are formed on the surfaces of the photosensitive drums 101y to 101k by this scanning exposure. Output laser beams 103y to 103k from laser optical systems 110y to 110k are deflected to exposure positions of photosensitive drums 101y to 101k by mirrors 109y to 109k.

The electrostatic latent image formed on the photosensitive drum 101y in the image forming portion Py is visualized with yellow toner by the developing device 104y. This yellow toner image is transferred onto the surface of the intermediate transfer member 105 at the primary transfer portion 111y, which is a contact portion between the photosensitive drum 101y and the intermediate transfer member (intermediate transfer belt in this embodiment) 105. Note that toner remaining on the surface of the photosensitive drum 101y is cleaned by a cleaner 107y.

The above-described cycle of charging, exposure, development, primary transfer, and drum cleaning is similarly repeated in other image forming portions pm, Pc, and Pk to form magenta toner images, cyan toner images, and black toner images, Toner images of each color are sequentially transferred onto the intermediate transfer member 105 in an overlapping manner.

The multicolor toner image formed on the intermediate transfer body 105 is secondarily transferred all at once onto a sheet P (recording material) in a secondary transfer section 106 . The sheet P is a sheet of paper, plastic film, or the like, and is conveyed from the cassette 114 to the secondary transfer section 106 via the sheet conveyance section 113. Toner remaining on the intermediate transfer body 105 is cleaned by a cleaner 108.

The sheet P that has passed through the secondary transfer section 106 is introduced into the fixing device 100 as an image heating device, and undergoes a fixing process (image heating process) for the unfixed toner image carried thereon. The sheet P that has undergone the fixing process is then discharged outside the machine, and the series of image forming operations is completed.

As shown in FIG. 2, the image forming apparatus 200 includes a control circuit section (control section) 21 typified by a CPU, and an operation panel section 112 that serves as an interface for communicating with users and external devices and accessing the device. etc. are provided. The control circuit section 21 includes image forming sections Py and Pm. It monitors and controls the status of various parts within the apparatus, including Pc, Pk, sheet conveyance section 113, and fixing device 100, and also coordinates the command chain between each apparatus to coordinate the operations of the entire image forming apparatus. .

[Fusing device]
Next, the fixing device 100 will be described using FIG. 3 while referring to FIG. 2. The fixing device 100 of this embodiment is removably attachable to the image forming apparatus main body 201 of the image forming apparatus 200. That is, the image forming apparatus 200 of this embodiment has a structure in which the fixing device 100 is replaceable.

The fixing device 100 includes a fixing film 20 as an endless fixing belt, a pressure roller 22 as a nip forming member, a fixing heater 16 as a heating section, and a heater back thermistor 19 as a temperature detection section and a first temperature detection section. , and a film back thermistor 18 as a second temperature detection section. The fixing film 20 is a cylindrical endless belt provided with an elastic layer. The pressure roller 22 is a pressure member that forms a fixing nip 27 with the fixing film 20 . The fixing nip section 27 is a nip section for nipping and conveying a sheet (recording material) P carrying a toner image and fixing the toner image on the recording material. The fixing heater 16 is a heater that heats the fixing film 20, and in this embodiment, it is a plate-shaped heater arranged inside (back side) of the fixing film 20 in the fixing nip portion 27. The fixing heater 16 is held in a heat-resistant heater holder 17 having a substantially gutter-shaped cross section. Specifically, the fixing heater 16 is adhesively fixed to the lower surface of the heater holder 17 along the longitudinal direction (in the direction of the rotational axis of the pressure roller 22), and is configured to be able to slide on the fixing film 20. Furthermore, the fixing film 20 is fitted around the heater holder 17 . Each configuration will be explained in detail below.

The fixing film 20 has a silicone rubber layer (elastic layer) with a thickness of about 300 μm formed on a cylindrical base material made of cylindrical stainless steel with a thickness of about 30 μm, and a PFA resin tube (the outermost layer) with a thickness of about 30 μm on the surface layer. ) has a covered structure. The pressure roller 22 has a structure in which a silicone rubber layer with a thickness of about 2.5 mm and a PFA resin tube with a thickness of about 50 μm are laminated on a metal core made of Fe. Both ends of the core metal of this pressure roller 22 are rotatably held between both side plates of the fixing device 100.

A fixing unit 30 including a fixing heater 16 , a heater holder 17 , and a fixing film 20 is installed above the pressure roller 22 . In addition to these, the fixing unit 30 also includes a film back thermistor 18 and a heater back thermistor 19. The fixing unit 30 is installed parallel to the pressure roller 22 such that the fixing heater 16 side is in contact with the pressure roller 22.

The heater holder 17 is made of a highly heat-resistant liquid crystal polymer resin, and plays the role of holding the fixing heater 16 and guiding the orbit of the fixing film 20. Both ends of the heater holder 17 are urged toward the axis of the pressure roller 22 by a pressure mechanism (not shown) provided on the frame 24 of the fixing device 100 with a force of 157N on one side and a total pressure of 314N. There is. As a result, the surface of the fixing heater 16 is brought into contact with the elastic layer of the pressure roller 22 with a predetermined pressing force through the fixing film 20, thereby forming a fixing nip portion 27 having a predetermined width necessary for fixing. ing.

The fixing heater 16 has a resistance heating element in which a conductive paste containing a silver-palladium alloy is applied to a ceramic substrate made of alumina or aluminum nitride in the form of a uniform film with a thickness of about 10 μm by screen printing. ing. Furthermore, a glass coating is applied on the heating element to ensure pressure resistance.

The heater back thermistor 19 is installed on a surface (referred to as a back surface) opposite to the sliding surface of the fixing heater 16 and has a function of detecting the temperature of the back surface of the fixing heater 16 . That is, the heater back thermistor 19 detects the temperature of the surface of the fixing heater 16 opposite to the fixing film 20. The film back thermistor 18 detects the temperature of the fixing film 20. That is, the film back thermistor 18 is installed above the heater holder 17 so as to be in elastic contact with the inner peripheral surface of the fixing film 20, and has the function of detecting the inner surface temperature of the fixing film 20. Specifically, a temperature detection thermistor was attached to the tip of a stainless steel arm 25 fixedly supported by the heater holder 17, and the arm 25 elastically swung, making the movement of the inner surface of the fixing film 20 unstable. Even in this state, the thermistor is kept in constant contact with the inner surface of the fixing film 20.

The heater back thermistor 19 and the film back thermistor 18 are connected to the control circuit section 21 via A/D converters 64 and 65, respectively. The control circuit section 21 is configured to sample the output from each thermistor at a predetermined period, and to reflect the temperature information obtained in this way in temperature control. That is, the control circuit section 21 determines the temperature control content of the fixing heater 16 based on the outputs of the film back thermistor 18 and the heater back thermistor 19, and controls the fixing heater 16 by the heater drive control section 28, which is a power supply section. Controls energization to.

The temperature control method of the fixing device 100 mainly determines the power supply value to the heater so that the temperature value detected by the film back thermistor 18 can be stably maintained at a desired temperature. The specific method is to calculate the temperature from the target temperature of the film back thermistor 18, the detected temperature, the amount of temperature change per unit time, the heater input power value, and the PI control parameters, so that the temperature reaches the target temperature early. Change the power to maintain stability. At this time, since the direct heat source is the fixing heater 16, the temperature detected by the thermistor 19 on the back of the heater and the amount of temperature change are also auxiliary PI controlled to prevent the temperature of the fixing film 20 from fluctuating too suddenly. , the inner temperature of the fixing film 20 is stabilized more quickly.

The fixing device 100 also includes a memory 29 as a storage section. The memory 29 stores identification information such as individual information regarding thermal responsiveness. In this embodiment, a nonvolatile memory such as NVRAM is used as the memory 29, but it may also be in the form of an IC tag such as RFID, a two-dimensional barcode, or the like. When the fixing device 100 is installed in the image forming apparatus 200, the stored information in the memory 29 is read by the reading unit 31 provided in the image forming apparatus main body 201 of the image forming apparatus 200. The memory 29 communicates with the control circuit section 21 of the image forming apparatus 200 via the reading section 31. In this embodiment, by reading the identification information stored in the memory 29 with the reading section 31, the temperature control of the heater 16 is determined as described later. The identification information stored in the memory 29 is information stored when the fixing device 100 was shipped. This identification information will be described later.

When the image forming operation is started, the pressure roller 22 is rotationally driven in the direction of the arrow at a predetermined circumferential speed by the motor 32 as a fixing drive section. The motor 32 is controlled by a fixing drive control section 33 of the control circuit section 21. The fixing film 20, which is in pressure contact with the pressure roller 22, follows the rotation of the pressure roller 22 and rotates at a predetermined speed. At this time, the fixing film 20 is brought into a state of driven rotation around the outer circumference of the heater holder 17 in the direction of the arrow while sliding with its inner peripheral surface in close contact with the sliding surface of the fixing heater 16. Heat-resistant grease is applied to the inner circumferential surface of the fixing film 20 to ensure slidability between the heater holder 17 and the inner surface of the fixing film 20.

When the pressure roller 22 is rotationally driven and the cylindrical fixing film 20 is brought into a driven rotation state, the fixing heater 16 is energized. Then, when the fixing film 20 reaches a desired temperature, the sheet P carrying the unfixed toner image t is guided along the entrance guide 23 and introduced into the fixing nip portion 27 . In the fixing nip portion 27, the toner image bearing surface side of the sheet P is in close contact with the outer peripheral surface of the fixing film 20, and the sheet moves together with the fixing film 20. While the sheet is nipped and conveyed in the fixing nip section 27, the heat of the fixing film 20 is applied to the sheet P, and the unfixed toner image is melted and fixed onto the sheet P. The sheet P that has passed through the fixing nip portion 27 is curvature separated from the fixing film 20 and is discharged by the fixing discharge roller 26 .

[Comparative example]
FIG. 4 shows, as a comparative example, a change in the surface temperature of the fixing film 20 when using the fixing device 100 in which an arbitrary fixing film 20 is built into the image forming apparatus 200. The measurement conditions in this example are a stable room temperature condition (21°C or higher and 29°C or lower), specifically, measurement starts at 23°C, startup power of the fixing heater 16 is 500W ± 3%, and the thermistor 19 on the back side of the heater is The temperature control temperature was 206° C., and the measurement time was an average value for 20 seconds from 40 seconds after reaching the temperature control temperature to 60 seconds after reaching the temperature control temperature. First, in the case of the fixing device 100 incorporating the fixing film 20a (hereinafter referred to as the current fixing film) using current materials, the average surface temperature (hereinafter referred to as surface temperature) of the fixing film 20a (film A) was 195°C. Next, the surface temperature of the fixing film 20 containing a fixing film 20b (hereinafter referred to as a modified fixing film, film B) made of a different material was 199°C. This means that when the current fixing film 20a and the modified fixing film 20b are used together under the current control, the modified fixing film 20b is used at an excessive temperature. As a result, there is a risk of image defects, transportation defects, or reduced component life.

[Identification information]
Therefore, in this embodiment, in order to reduce such risks, information called identification information 01 indicating that the fixing film 20b is the fixing film 20b is written in the memory 29 as the identification information of the fixing device 100 when the fixing device 100 is shipped. Then, when the fixing device 100 is replaced and the fixing device 100 having the fixing film 20b is attached to the image forming apparatus 200, the control circuit section 21 uses the identification information 01 read out from the memory 29 by the reading section 31. Determine the temperature control temperature to be controlled. That is, in the present embodiment, when the fixing device 100 is replaced, the control circuit section 21 uses the reading section 31 to read the identification information stored in the memory 29 of the replaced fixing device 100, and Temperature control according to the fixing device 100 is determined. In this embodiment, the surface temperature of the current fixing film 20a is controlled at a temperature that can be reproduced by the modified fixing film 20b. FIG. 5 summarizes the results under the conditions shown in FIG. 4.

In this embodiment, when using the fixing device 100 incorporating the modified fixing film 20b in a stable room temperature state (21° C. or higher and 29° C. or lower), the temperature control information α stored in the memory 29 is used. This means controlling the temperature by multiplying the current temperature by a certain 0.990. That is, the temperature control information α is a correction coefficient depending on the fixing device 100. In the present embodiment, this temperature adjustment temperature control information α is stored in the memory 29, and the control circuit unit 21 multiplies the standard target temperature in the temperature adjustment control by a correction coefficient corresponding to the replaced fixing device 100. The temperature is set as the target temperature in temperature control.

In FIGS. 4 and 5, information α for temperature control in a stable room temperature state is stored, but as shown in FIG. The usage information α may be changed and stored separately. Further, the temperature control temperature control information α reflects the confirmation result when the specifications of the modified fixing film 20b are determined. Note that by loading the following parameters into the temperature control table when the image forming apparatus is placed on the market, this patent can be applied without changing the software of the image forming apparatus even after the image forming apparatus is placed on the market.

Here, the temperature control temperature is a target temperature relative to the temperature detected by the heater back thermistor 19, and is referred to as the "target temperature T", the reference temperature control temperature as the basic temperature control temperature Tx, and the memory 29 of a certain fixing device 100 as the "target temperature T". When the identification information stored in is "temperature adjustment temperature control information αx", the determined temperature adjustment temperature T is expressed by the following formula. Note that the [basic temperature control temperature Tx] is a temperature control temperature that is a reference temperature control that is set in advance according to the image forming mode, and is stored when the image forming apparatus 200 is shipped.
[Temperature control temperature T] = [Basic temperature control temperature Tx] x [Temperature control temperature control information αx]

It has been found that the temperature difference between the inner circumferential surface and the outer circumferential surface of the fixing film 20 under predetermined conditions is mainly influenced by the following factors. The elastic layer thickness and surface layer thickness of the fixing film 20, the detection sensitivity of the film back thermistor 18, the shape and contact pressure of the arm (backup member) 25, the characteristics of the heat-resistant grease initially applied to the inner peripheral surface of the fixing film 20, etc. be. The temperature control temperature control information αx is a correction coefficient that takes these factors into account, and includes information regarding the heat transfer characteristics of the fixing film 20. The identification information is not limited to a correction coefficient such as the temperature control information αx, but may be one or more pieces of information described above. Further, as information regarding the heat transfer characteristics of the fixing film 20, for example, the thermal conductivity of the fixing film 20 may be included in the identification information in advance.

Here, when changing the material of parts such as the fixing film of the replacement fixing device, it is possible to make the factors related to these parts the same as those of the fixing device currently used (current product). This requires the development of new materials, which leads to increased costs. In order to reduce costs, general-purpose materials are often used, resulting in narrower options for material selection, and in some cases it may not be possible to match the characteristic values of the above factors to the current product. In this embodiment, by accepting the difference in the characteristic values of the above-mentioned factors between the member after the material change and the member of the current product, the temperature control temperature, which is a control factor, and the fixing film, which is a control characteristic value, are determined by the difference in the characteristic values. By quantifying the difference from the surface temperature of 20 mm and using it for temperature control, basic fixing functions (image quality, transportability) and durability are improved.

The temperature control temperature, which is the target temperature in temperature control, is determined as follows, for example. That is, the control circuit unit 21 determines that the thermal conductivity of the fixing film 20 of the replaced fixing device 100 is the first value based on the information regarding the heat transfer characteristics included in the identification information read by the reading unit 31. In this case, the target temperature (temperature control temperature) in the temperature control control is determined to be the first temperature. On the other hand, if the thermal conductivity of the fixing film 20 of the replaced fixing device 100 is a second value larger than the first value, the control circuit unit 21 controls the temperature control temperature to be lower than the first temperature. Decide on a lower second temperature.

[Image formation processing]
Next, the outline of the flow of the image forming process of this embodiment, including the determination of the temperature control temperature as described above, will be described using FIG. 7. First, when the control circuit unit 21 receives an image forming signal of an image forming job (S1), it sets a print mode (image forming mode) (S2). Here, we will explain the basics for controlling the temperature of the fixing film 20 using the film back thermistor 18 based on sheet information (type, basis weight, size) used for image formation, image information (monochrome mode/color mode), and outside temperature information. The controlled temperature Tx is determined from the internal table.

For example, in the case of plain paper (basis weight: 64 g/m ² ), color mode, and 23° C. environment, Tx is set to 206° C. Since toner peeling is more likely to occur as the basis weight is higher and the outside air temperature is lower, the target temperature control temperature is set higher. Therefore, the value of Tx is generally set based on the sheet information (type, basis weight, size), image information (monochrome mode/color mode), and outside temperature information described above.

Next, the control circuit unit 21 reads out the unique temperature control information αx from the memory 29 of the fixing device 100 (S3). Here, the fixing device 100 incorporating the fixing film 20b (film B) after the material change described in the previous section will be described using as an example the fixing device 100 in which αx=0.990 in a stable room temperature environment. The basic temperature control temperature Tx and the print temperature control temperature T at which printing is actually performed are determined according to the following equation based on the read αx value (S4).
T=Tx×αx=206℃×0.990=204℃
Tx=206°C: Basic target temperature control temperature αx=0.990 under these conditions: Temperature control information linked to the fixing film 20b

In this manner, in this embodiment, 204° C. is determined as the temperature control temperature during printing. Then, the control circuit section 21 starts driving the pressure roller 22 and starts energizing the fixing heater 16 via the heater drive control section 28 (S5).

When the detected temperature Tnow of the film back thermistor 18 satisfies the conditional expression (Tnow>T-12°C) (Yes in S6), the control circuit unit 21 allows the sheet P to be fed and is fed onto the photosensitive drums 101y to 101k. An image forming command is sent (S7). That is, the image forming operation is started.

This conditional expression is determined by the length of the conveyance path of the sheet in the image forming apparatus. This conditional expression is set based on the fact that the sheet P carrying the toner image enters the fixing nip portion 27 at the timing when the fixing film 20 reaches the temperature T when the forming operation is started. In this example, a fixed conditional expression is used, but a plurality of conditional expressions may be provided depending on printing conditions (sheet type, basis weight, image information).

In this way, the control circuit unit 21 repeats the image forming operation while controlling the inner surface detection temperature of the fixing film 20 (S7), and when the last sheet of the image forming job is detected (Yes in S8), the image forming After completing the forming operation completion process (stopping temperature control, turning down high pressure equipment, stopping drive mechanism), the series of flows ends.

As explained above, by optimally controlling the film temperature during printing, it is possible to stabilize and improve the quality (transportability, fixed image quality, fixing member life, etc.) related to the surface temperature of the fixing member. In particular, when the fixing device 100 is replaced with a fixing device 100 made of a material of at least some parts different from the fixing device before replacement, it is possible to suppress the image quality from deteriorating after the fixing device 100 is replaced.

[Comparative example]
Next, in order to explain the above-mentioned effects, a comparative example and a practical example will be used. First, a comparative example will be explained. Here, with regard to the above-described fixing device 100, it has been found through preliminary studies that the following problems occur when using plain paper (basis weight: 64 g/m ² ), color mode, and a 23° C. environment.

That is, if an image forming operation is performed when the surface temperature of the fixing film 20 is 199° C. or higher, image quality deterioration on the high temperature side (hot offset, gloss reduction) occurs. Furthermore, if the image forming operation is performed at a temperature of 206° C. or higher, which is a high surface temperature of the fixing film 20, sheet conveyance failures (jams due to curling of the sheet, folding of the leading edge of the sheet) occur. On the other hand, if the image forming operation is performed when the surface temperature of the fixing film 20 is 189° C. or lower, the image quality deteriorates on the low temperature side (defective fixing). Therefore, the temperature at which image quality deterioration does not occur on the high temperature side (high temperature side image quality permissible temperature) is 198°C, the temperature at which transport failure does not occur (transfer failure permissible temperature) is 205°C, and the temperature at which image quality deterioration does not occur on the low temperature side (low temperature side). (side image quality permissible temperature) is set to 190°C.

FIGS. 8, 9, and 10 show temperature changes in the case of control in a comparative example in which the control according to the present embodiment described above is not applied. In the comparative example, Step 3 (reading of temperature control information αx) and Step 4 (setting process of printing temperature control temperature T) of the control flow in FIG. 7 are not included. Therefore, the printing temperature T controlled by the film back thermistor 18 is uniformly set to 206° C. even if the types of fixing films 20 in the fixing device are different.

[Comparative example 1]
FIG. 8 shows the change over time in the surface temperature (hereinafter referred to as surface temperature) of the fixing film 20a in the fixing device 100 incorporating the fixing film 20a (hereinafter referred to as the fixing film 20a) using the material of the current product. The surface temperature was an average value for 20 seconds from 40 seconds to 60 seconds after reaching the temperature control temperature. The surface temperature was 195°C, and even in the section 60 seconds after reaching the target temperature control temperature, the film surface temperature could be maintained between 190°C and 198°C, which is the film surface temperature at which no abnormal phenomenon occurs.

[Comparative example 2]
FIG. 9 shows the surface temperature of the fixing film 20b (hereinafter referred to as surface temperature) in a fixing device 100 incorporating a fixing film 20b (hereinafter referred to as the fixing film 20b) made of a film material with higher thermal conductivity than the material of the current product. This is a change over time. The surface temperature was an average value for 20 seconds from 40 seconds to 60 seconds after reaching the temperature control temperature. The surface temperature was 199°C, and the film surface temperature could not be maintained between 190°C and 198°C, which is the film surface temperature at which no abnormal phenomenon occurs, even in the period 60 seconds after reaching the target temperature control temperature.

[Comparative example 3]
FIG. 10 shows the surface temperature (hereinafter referred to as surface temperature) of the fixing film 20c in a fixing device 100 incorporating a fixing film 20c (hereinafter referred to as the fixing film 20c) made of a film material with lower thermal conductivity than the material of the current product. This is a change over time. The surface temperature was an average value for 20 seconds from 40 seconds to 60 seconds after reaching the temperature control temperature. The surface temperature was 189°C, and the film surface temperature could not be maintained between 190°C and 198°C, which is the film surface temperature at which no abnormal phenomenon occurs, even in the section 60 seconds after reaching the target temperature control temperature.

[Example of implementation]
Next, FIGS. 11, 12, and 13 show temperature changes in the case of control according to a specific example to which the control according to the present embodiment is applied. In the practical example, unlike the comparative example, Step 3 (reading of temperature control information αx) and Step 4 (setting process of print temperature control temperature T) of the control flow shown in FIG. 7 are performed. For this reason, the printing temperature T controlled by the film back thermistor 18 is changed depending on the type of fixing film 20 in the fixing device.

[Example 1 of implementation]
FIG. 11 shows the change over time in the surface temperature (hereinafter referred to as surface temperature) of the fixing film 20a in the case of a fixing device 100 incorporating a fixing film 20a (hereinafter referred to as the fixing film 20a) using the material of the current product. The results of reading out the temperature adjustment temperature control information αx in step 3 of the control flow in FIG. 7 and calculating the target temperature adjustment temperature in step 4 are as follows.
T=Tx×αx=206℃×1.000=206℃
Tx=206°C: Basic target temperature control temperature αx=1.000 under these conditions: Temperature control information linked to the fixing film 20a

In this way, in this example, 206° C. is determined as the temperature control temperature during printing. The surface temperature was an average value for 20 seconds from 40 seconds to 60 seconds after reaching the temperature control temperature. The surface temperature was 195°C, and even in the section 60 seconds after reaching the target temperature control temperature, the film surface temperature could be maintained between 190°C and 198°C, which is the film surface temperature at which no abnormal phenomenon occurs.

[Specific implementation example 2]
FIG. 12 shows the surface temperature (hereinafter referred to as surface temperature) of the fixing film 20b in a fixing device 100 incorporating a fixing film 20b (hereinafter referred to as the fixing film 20b) made of a film material with higher thermal conductivity than the material of the current product. This is a change over time. The results of reading out the temperature control information αx in step 3 of the control flow in FIG. 7 and calculating the target temperature control in step 4 are as follows.
T=Tx×αx=206℃×0.990=204℃
Tx=206°C: Basic target temperature control temperature αx=0.990 under these conditions: Temperature control information linked to the fixing film 20b

In this way, in this example, 204° C. is determined as the temperature control temperature during printing. The surface temperature was an average value for 20 seconds from 40 seconds to 60 seconds after reaching the temperature control temperature. The surface temperature was 195°C, and even in the section 60 seconds after reaching the target temperature control, the film surface temperature could be maintained between 190°C and 198°C, which is the film surface temperature at which no abnormal phenomenon occurs.

[Specific implementation example 3]
FIG. 13 shows the surface temperature of the fixing film 20c (hereinafter referred to as the surface temperature ) is the change over time. The results of reading out the temperature control information αx in step 3 of the control flow in FIG. 7 and calculating the target temperature control in step 4 are as follows.
T=Tx×αx=206℃×1.034=213℃
Tx=206°C: Basic target temperature control temperature αx=1.034 under these conditions: Temperature control information linked to the fixing film 20c

In this way, in this example, 213° C. is determined as the temperature control temperature during printing. The surface temperature was an average value for 20 seconds from 40 seconds to 60 seconds after reaching the temperature control temperature. The surface temperature was 195°C, and even in the section 60 seconds after reaching the target temperature control temperature, the film surface temperature could be maintained between 190°C and 198°C, which is the film surface temperature at which no abnormal phenomenon occurs.

FIG. 14 summarizes the results of Comparative Examples 1, 2, and 3 and Practical Examples 1, 2, and 3 in a list. In Comparative Example 2, a hot offset occurred that degraded the image quality on the high temperature side, and in Comparative Example 3, a fixing failure occurred that degraded the image quality on the low temperature side. On the other hand, in Practical Example 1, Practical Example 2, and Practical Practical Example 3 using the control of this embodiment, abnormal phenomena and conveyance defects that degrade the image quality on the high temperature side and the image quality on the low temperature side do not occur under all conditions. It did not occur.

From the above results, according to the present embodiment, when changing the materials and processes of each part constituting the fixing device for various reasons, it is difficult to completely match the conventional physical property values such as dimensions and thermal properties. Even in such cases, the image forming device can recognize the type of fixing unit in the fixing device and the information associated with that type, allowing optimal fixing temperature control to be performed, thereby preventing sheet conveyance defects and image defects. It was found that it was possible to suppress

In the above explanation, only the fixing film was changed, but as shown in FIG. It is also possible to operate it. That is, the identification information stored in the memory of the fixing device may include not only information about the fixing film but also information about other members such as the pressure roller.

For example, as a fixing member such as a fixing film, "A" is the current product, "B" is a material different from the current product, and as a pressure member such as a pressure roller, "A" is the current product, "A" is the current product and the material is different from the current product. Suppose there is a "B" with different values. In this case, if both the fixing member and the pressure member are A, if one of the fixing member and the pressure member is A and the other is B, if both the fixing member and the pressure member are B By making αx different from each other, it is possible to perform appropriate temperature control according to each case.

[Other embodiments]
In each of the above-described embodiments, the fixing belt uses a fixing film, which is a film-like member, but it may be a belt in which an elastic layer or a surface layer is provided on a base layer made of resin, for example. Further, the fixing unit may have a configuration in which the fixing belt is stretched by a plurality of stretching members. Further, the nip portion forming member may be a belt other than a roller, and is preferably a rotating body.

Further, the disclosure of this embodiment includes the following configuration.
(Configuration 1)
An endless fixing belt, a nip part forming member that forms a nip part for sandwiching and conveying a recording material carrying a toner image between the fixing belt and fixing the toner image on the recording material, and heating the fixing belt. a fixing device having a heating section for heating, a temperature detection section for detecting the temperature of the heating section, and a storage section storing identification information;
a control unit that controls the temperature of the heating unit based on the temperature detected by the temperature detection unit;
An image forming apparatus comprising: a reading unit that reads identification information stored in the storage unit, the fixing device being replaceable;
The identification information is information stored when the fixing device was shipped,
When the fixing device is replaced, the control section causes the reading section to read the identification information stored in the storage section of the replaced fixing device, and reads the identification information according to the replaced fixing device. An image forming apparatus characterized in that a target temperature in the temperature adjustment control is determined.
(Configuration 2)
The heating section is arranged inside the fixing belt,
The identification information includes information regarding heat transfer characteristics of the fixing belt,
The control unit is configured to determine, based on information regarding the heat transfer characteristics included in the identification information read by the reading unit, that the thermal conductivity of the fixing belt of the replaced fixing device is a first value. In this case, the target temperature in the temperature control control is determined to be a first temperature, and if the thermal conductivity of the fixing belt is a second value larger than the first value, the target temperature in the temperature control control is determined to be a first temperature. The image forming apparatus according to configuration 1, wherein the temperature is determined to be a second temperature lower than the first temperature.
(Configuration 3)
When the fixing device is replaced, the control section causes the reading section to read the identification information stored in the storage section of the replaced fixing device, and reads the identification information according to the replaced fixing device. The image forming apparatus according to configuration 1, wherein a temperature obtained by multiplying a reference target temperature in the temperature adjustment control by a correction coefficient determined by the correction coefficient is set as a target temperature in the temperature adjustment control.
(Configuration 4)
The heating section is a plate-shaped heater disposed inside the fixing belt in the nip section,
4. The image forming apparatus according to any one of configurations 1 to 3, wherein the temperature detection unit detects the temperature of a surface of the heater opposite to the fixing belt.
(Configuration 5)
The temperature detection section is a first temperature detection section,
further comprising a second temperature detection section that detects the temperature of the inner circumferential surface of the fixing belt,
5. The image forming apparatus according to any one of configurations 1 to 4, wherein the control section performs the temperature adjustment control using the first temperature detection section and the second temperature detection section.

16...Fusing heater (heating section)
18...Film back thermistor (second temperature detection part)
19...Heater back thermistor (temperature detection section, first temperature detection section)
20...Fixing film (fixing belt)
21...Control circuit section (control section)
22... Pressure roller (nip part forming member)
29...Memory (storage unit)
31... Reading unit 100... Fixing device 200... Image forming device

Claims (5)

An endless fixing belt, a nip part forming member that forms a nip part for sandwiching and conveying a recording material carrying a toner image between the fixing belt and fixing the toner image on the recording material, and heating the fixing belt. a fixing device having a heating section for heating, a temperature detection section for detecting the temperature of the heating section, and a storage section storing identification information;
a control unit that controls the temperature of the heating unit based on the temperature detected by the temperature detection unit;
An image forming apparatus comprising: a reading unit that reads identification information stored in the storage unit, the fixing device being replaceable;
The identification information is information stored when the fixing device was shipped,
When the fixing device is replaced, the control section causes the reading section to read the identification information stored in the storage section of the replaced fixing device, and reads the identification information according to the replaced fixing device. An image forming apparatus characterized in that a target temperature in the temperature adjustment control is determined. The heating section is arranged inside the fixing belt,
The identification information includes information regarding heat transfer characteristics of the fixing belt,
The control unit is configured to determine, based on information regarding the heat transfer characteristics included in the identification information read by the reading unit, that the thermal conductivity of the fixing belt of the replaced fixing device is a first value. In this case, the target temperature in the temperature control control is determined to be a first temperature, and if the thermal conductivity of the fixing belt is a second value larger than the first value, the target temperature in the temperature control control is determined to be a first temperature. The image forming apparatus according to claim 1, wherein the temperature is determined to be a second temperature lower than the first temperature. When the fixing device is replaced, the control section causes the reading section to read the identification information stored in the storage section of the replaced fixing device, and reads the identification information according to the replaced fixing device. The image forming apparatus according to claim 1, wherein a temperature obtained by multiplying a reference target temperature in the temperature regulation control by a correction coefficient determined by the above correction coefficient is set as a target temperature in the temperature regulation control. The heating section is a plate-shaped heater disposed inside the fixing belt in the nip section,
The image forming apparatus according to claim 1, wherein the temperature detection section detects the temperature of a surface of the heater on a side opposite to the fixing belt. The temperature detection section is a first temperature detection section,
further comprising a second temperature detection section that detects the temperature of the inner circumferential surface of the fixing belt,
The image forming apparatus according to any one of claims 1 to 4, wherein the control unit performs the temperature adjustment control using the first temperature detection unit and the second temperature detection unit.

Images