JP7354595B2 - Image forming device and control program for the image forming device - Google Patents

Description

The present invention relates to an image forming apparatus and a control program for the image forming apparatus.

2. Description of the Related Art In image forming apparatuses, a technique is known in which control is performed in accordance with the torque of a motor that drives a pressure member included in a fixing section. For example, Patent Document 1 discloses a technology that detects the rotational torque of a motor that drives rollers included in a fixing unit, and reduces the contact pressure between the rollers when the amount of change (rate of variation) in the rotational torque is equal to or greater than a predetermined threshold. is disclosed.

Japanese Patent Application Publication No. 2018-155850

However, in the image forming apparatus described in Patent Document 1, there is a problem that the contact pressure cannot be reduced unless a space is secured to install a mechanism that directly controls the contact pressure between the rollers. be. That is, the image forming apparatus described in Patent Document 1 may have to be increased in size.

On the other hand, since the rubber used for the roller (pressure member) included in the fixing section deteriorates due to changes in physical properties, decrease in hardness, etc., the width of the nip formed by the roller changes over time. When the width of the nip changes, the time that the paper passes through the nip also changes, and the amount of heat applied to the paper changes, which changes the quality of the image formed on the paper, mainly the gloss. In the image forming apparatus described in Patent Document 1, an increase in size is allowed, and unless the above-mentioned mechanism is installed, the contact pressure between the rollers related to the width of the nip between the rollers will not be controlled, resulting in heating of the paper. The quantity is also not controlled. Therefore, the quality of the image formed on the paper may change over time.

The present invention has been made in view of the above-mentioned problems. SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an image forming apparatus that can maintain the quality of an image formed on paper without using a special mechanism even if a pressure member included in a fixing section deteriorates, and control of the image forming apparatus. The goal is to provide programs.

The above objects of the present invention are achieved by the following means.

(1) It has an image forming section that forms an image on paper, a heating member, and a pressure member, and the image forming section heats and presses the paper on which the image has been formed to form the image on the paper. a fixing unit for fixing, a detection unit for detecting the torque of a drive motor that drives the pressure member, and information regarding the torque detected by the detection unit, and based on the amount of change from a reference value of the torque. an image forming apparatus, comprising: a control section that controls the heating member;

(2) The image forming apparatus according to (1), wherein the control unit controls a control temperature of the heating member as the control of the heating member.

(3) The image forming apparatus according to (1) or (2), wherein the control unit controls a lighting rate of the heating member as the control of the heating member.

(4) Image formation according to any one of (1) to (3) above, wherein the control unit acquires information regarding the torque detected in an initial state of the pressure member as information regarding the reference value. Device.

(5) The control unit periodically acquires information regarding the torque and stores it in a storage unit, and compares the reference value and the current value of the torque based on the information stored in the storage unit. The image forming apparatus according to any one of (1) to (4) above, wherein the amount of change is calculated.

(6) The pressure member can be changed into a press-contact state and a separated state, and the control unit acquires information regarding the torque detected when the pressure member is press-contact. The image forming apparatus according to any one of 5).

(7) The control unit further acquires information regarding the torque detected when the pressure member is separated, and combines the torque detected when the pressure member is pressed and the time when the pressure member is separated. The image forming apparatus according to (6) above, which analyzes the cause of the change in the torque based on the torque detected in the image forming apparatus.

(8) The image forming apparatus according to any one of (1) to (7), wherein the control section controls the heating member for each type and basis weight of the paper.

(9) It has an image forming section that forms an image on paper, a heating member, and a pressure member, and heats and presses the paper on which the image is formed by the image forming section to form the image on the paper. A control program for an image forming apparatus including a fixing unit that performs fixing, and a detection unit that detects torque of a drive motor that drives the pressure member, the program acquiring information regarding the torque detected by the detection unit. A control program for causing a computer to execute a process including an acquisition step and a control step of controlling the heating member based on the amount of change in the torque from a reference value.

According to an image forming apparatus according to an embodiment of the present invention, the torque of the drive motor that drives the pressure member included in the fixing unit is detected, and the heating member is controlled based on the amount of change in torque from a reference value. . As a result, even if the pressure member included in the fixing unit deteriorates and the fixing nip width increases, the image forming apparatus can quickly control the heating member based on the amount of change in torque, and the amount of heat applied to the paper will not change. That's enough. Therefore, the image forming apparatus can maintain the quality of the image formed on the paper without using a special mechanism that directly controls the fixing nip width.

1 is a diagram showing a schematic configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 3 is a diagram illustrating an example of a schematic configuration of a fixing section. FIG. 3 is a diagram showing an example of a change in fixing nip width. FIG. 3 is a diagram illustrating an example of the relationship between the fixing nip width and the glossiness of an image. FIG. 3 is a diagram showing an example of the relationship between fixing nip width and motor torque. FIG. 3 is a block diagram showing the functional configuration of a control section. 3 is a flowchart illustrating an example of a processing procedure of an image forming apparatus. FIG. 3 is a diagram illustrating an example of the relationship between control temperature and image glossiness. It is a figure which shows an example of the relationship between control temperature and heater average lighting rate. FIG. 6 is a diagram showing an example of a change in motor torque during pressure contact and separation.

Embodiments of the present invention will be described below with reference to the attached drawings. In addition, in the description of the drawings, the same elements are given the same reference numerals, and redundant description will be omitted. Further, the proportions of dimensions in the drawings are exaggerated for convenience of explanation and may differ from the actual proportions.

(Image forming device)
FIG. 1 is a diagram showing a schematic configuration of an image forming apparatus according to an embodiment of the present invention.

As shown in FIG. 1, the image forming apparatus 1 includes a control section 10, a storage section 20, a communication section 30, an operation panel 40, a paper feeding section 50, a transport section 60, an image forming section 70, and a fixing section 80. Each component is interconnected via a bus for exchanging signals.

The control unit 10 includes a CPU (Central Processing Unit), and controls each of the above-described components and performs various calculation processes according to a program. The functional configuration of the control unit 10 will be described later with reference to FIG.

The storage unit 20 includes a ROM (Read Only Memory) that stores various programs and various data in advance, a RAM (Random Access Memory) that temporarily stores programs and data as a work area, a hard disk that stores various programs and various data, etc. Equipped with

The communication unit 30 includes an interface for communicating with other devices such as a user's PC (Personal Computer) via a network such as a LAN (Local Area Network). The communication unit 30 receives a print job from, for example, a user's PC.

The operation panel 40 includes a touch panel, a numeric keypad, a start button, a stop button, etc., and displays various information as a display section, and accepts various operations as an operation reception section.

The paper feed unit 50 includes a paper feed tray that stores paper as a recording material used for printing, and feeds the paper stored in the paper feed tray one by one.

The conveyance unit 60 includes a conveyance path, a plurality of conveyance rollers arranged along the conveyance path, and a drive motor (not shown) that drives the conveyance rollers, and transports the paper fed by the paper feed unit 50 to the conveyance path. Transport along.

The image forming section 70 forms an image on the paper conveyed by the conveying section 60 using a well-known image forming process such as an electrophotographic process.

The fixing unit 80 heats and presses the paper on which the image is formed by the image forming unit 70 and is transported by the transport unit 60 to fix the image on the paper. Details of the fixing section 80 will be described later with reference to FIGS. 2 to 5.

Note that the image forming apparatus 1 may include components other than the above-mentioned components, or may not include some of the above-mentioned components.

(Fusing part)
Next, details of the fixing section 80 will be explained. FIG. 2 is a diagram illustrating an example of a schematic configuration of a fixing section. FIG. 3 is a diagram showing an example of a change in fixing nip width. FIG. 4 is a diagram illustrating an example of the relationship between the fixing nip width and the glossiness of an image. FIG. 5 is a diagram showing an example of the relationship between fixing nip width and motor torque.

As shown in FIG. 2, the fixing unit 80 includes an upper pressure roller 81 and a lower pressure roller 82 as pressure members that press the paper, a drive motor 83, a torque sensor 84, a heating roller 85, a fixing belt 86, and A temperature sensor 87 is provided.

The upper pressure roller (fixing roller) 81 is arranged so as to be inscribed in the fixing belt 86, which is an endless belt. The lower pressure roller 82 is configured to press against the upper pressure roller 81 facing with the fixing belt 86 in between, with a predetermined load. ). The upper pressure roller 81 and the lower pressure roller 82 can be changed into a pressed state and a separated state.

The drive motor 83 drives the lower pressure roller 82 to rotate at a predetermined speed. More specifically, the drive motor 83 is connected to the rotating shaft of the lower pressure roller 82 via a plurality of gears (not shown), and applies the torque of the drive motor 83 (hereinafter referred to as "motor torque"). By transmitting the signal to the lower pressure roller 82, the lower pressure roller 82 is driven. However, the object to be driven by the drive motor 83 is not limited to the lower pressure roller 82 , and the drive motor 83 drives the upper pressure roller 81 in addition to or instead of the lower pressure roller 82 . It may be driven.

A torque sensor 84 serving as a detection unit detects motor torque. As described above, the drive motor 83 rotates the lower pressure roller 82 at a predetermined speed, so when the motor torque increases, the duty ratio in the PWM control performed on the electric power supplied to the drive motor 83 also increases. Rise. For this reason, the torque sensor 84 detects the motor torque that is correlated with the duty ratio by detecting the duty ratio in PWM control, for example. Alternatively, the torque sensor 84 may detect a motor torque that is correlated with the current supplied to the drive motor 83 by detecting the current. In this embodiment, the torque sensor 84 detects the motor torque when the upper pressure roller 81 and the lower pressure roller 82 are in pressure contact.

The heating roller 85 includes a heater 851 as a heating member therein, and is arranged so as to be spaced apart from the upper pressure roller 81 and inscribed in the fixing belt 86 to heat the fixing belt 86 . The heated fixing belt 86 passes through the fixing nip together with the paper that has been conveyed to the fixing section 80, thereby heating the paper. Temperature sensor 87 detects the temperature of heated fixing belt 86 . In the fixing unit 80, the power supply to the heater 851, that is, the lighting rate of the heater 851 (hereinafter referred to as "heater lighting rate") is controlled so that the temperature detected by the temperature sensor 87 becomes a predetermined control temperature (fixing temperature). be done.

The upper pressure roller 81 and the lower pressure roller 82 are configured to have, for example, an elastic layer made of rubber such as silicone rubber around the outer periphery of a core metal. Further, examples of the heater 851 include a halogen lamp, a resistance heating element, an electromagnetic induction heating (IH) heating means, and the like. However, the configurations of the upper pressure roller 81, the lower pressure roller 82, the heater 851, etc. are not limited to the example described above. For example, the lower pressure roller 82 may be configured to have a release layer such as a PFA tube on the outer periphery of a metal base material, or may be configured to have a temperature lower than that of the heater 851 included in the heating roller 85. Other heaters may be provided externally or internally.

When at least one of the upper pressure roller 81 and the lower pressure roller 82 has an elastic layer as described above, the elastic layer deteriorates due to changes in physical properties, decrease in hardness, etc. over time. Therefore, the fixing nip width (width of the fixing nip along the paper conveyance direction) increases over time, as shown in FIG. 3, for example. As the fusing nip width increases, the time it takes the paper to pass through the fusing nip becomes longer, and the amount of heat applied to the paper increases, which changes the quality of the image formed on the paper, especially the gloss, as shown in FIG. 4, for example. I end up. Therefore, in this embodiment, even if the upper pressure roller 81 and/or the lower pressure roller 82 deteriorate and the fixing nip width increases, the heater 851 is controlled so that the amount of heat applied to the paper does not increase.

Further, as the fixing nip width increases, the motor torque when the upper pressure roller 81 and the lower pressure roller 82 are in pressure contact increases, for example, as shown in FIG. 5. Therefore, in this embodiment, the heater 851 is controlled based on the amount of change in motor torque that changes depending on the fixing nip width.

The relationships illustrated in FIGS. 3 and 5 are as follows: the diameter of the upper pressure roller and the diameter of the lower pressure roller are both 60 mm, the power of the halogen lamp as a heater is 2700 W, the control temperature is 192° C., and the fixing speed is 340 mm/s. This was obtained from experimental results when a sheet of paper with a thickness of 0.15 mm was passed through a fixing section that was set to have a thickness of 0.15 mm. Furthermore, the relationship illustrated in FIG. 4 is based on the blue solid color fixed to paper (manufactured by Oji Paper Co., Ltd., paper type: POD gloss coat, basis weight: 128 g/m ² ) by the fixing unit set as described above. The glossiness of the image was measured using a gloss meter (manufactured by Konica Minolta, Inc., model: GM-60A) at a measurement angle of 60°. In the example shown in FIG. 3, the fixing nip width at the end of the durability period is increased by 4 mm compared to the initial fixing nip width. Furthermore, in the examples shown in FIGS. 4 and 5, when the fixing nip width increases by 2 mm, the gloss level increases by about 3 and the motor torque increases by about 0.04 Nm.

(control unit)
Next, the functional configuration of the control unit 10 will be explained. FIG. 6 is a block diagram showing the functional configuration of the control section.

As shown in FIG. 6, the control unit 10 functions as a heater control unit 11, an acquisition unit 12, a storage control unit 13, and a calculation unit 14 by reading programs and executing processes.

The heater control unit 11 controls the heater 851. For example, the heater control unit 11 sets a predetermined control temperature and controls the heater lighting rate so that the temperature detected by the temperature sensor 87 becomes the predetermined control temperature. More specifically, the heater control unit 11 increases the heater lighting rate when the temperature detected by the temperature sensor 87 is less than the control temperature, and decreases the heater lighting rate when the detected temperature exceeds the control temperature. Alternatively, the heater control unit 11 may control the heater lighting rate regardless of the control temperature. The heater control unit 11 may perform on/off control to control the heater lighting rate to 100% or 0%, or may perform duty control to control the heater lighting rate in multiple stages.

The acquisition unit 12 acquires information regarding the motor torque detected by the torque sensor 84. For example, the acquisition unit 12 periodically acquires information regarding the motor torque detected by the torque sensor 84 under the same conditions. More specifically, the acquisition unit 12 acquires the motor detected when the upper pressure roller 81 and the lower pressure roller 82 are in pressure contact, for example, during warm-up immediately after power-on of the image forming apparatus 1 every morning. Get information about torque. Alternatively, the acquisition unit 12 may obtain the temperature of the core of the upper pressure roller 81 or the temperature of the fixing unit 80 from an arbitrary temperature sensor provided in the image forming apparatus 1, which is useful for determining the warm-up state of the image forming apparatus 1. Information regarding ambient temperature, etc. may also be acquired. Then, the acquisition unit 12 may correct the information regarding the motor torque based on the temperature of the core metal, the ambient temperature, etc., and acquire the information as information regarding the motor torque detected under the same conditions.

In this embodiment, the acquisition unit 12 acquires information regarding the reference value (initial value) and current value of the motor torque. The acquisition unit 12 obtains, for example, the initial state of the upper pressure roller 81 and the lower pressure roller 82 (for example, immediately after the upper pressure roller 81 and/or the lower pressure roller 82 are replaced) as information regarding the reference value of the motor torque. Information regarding motor torque detected during a predetermined period) is acquired.

The storage control unit 13 causes the storage unit 20 to store information regarding motor torque. The storage control unit 13 causes the storage unit 20 to store, for example, information regarding the reference value of the motor torque detected in the initial state of the upper pressure roller 81 and the lower pressure roller 82.

The calculation unit 14 compares the reference value and the current value of the motor torque, and calculates the amount of change in the motor torque from the reference value.

(process)
Next, the processing procedure of the image forming apparatus 1 will be explained. The processing of the image forming apparatus 1 maintains the quality of the image formed on the paper even if the upper pressure roller 81 and/or the lower pressure roller 82 included in the fixing unit 80 deteriorate and the fixing nip width increases. It is controlled as follows.

FIG. 7 is a flowchart illustrating an example of a processing procedure of the image forming apparatus. The algorithm shown in the flowchart of FIG. 7 is stored as a program in the storage unit 20 and executed by the control unit 10.

As shown in FIG. 7, the control unit 10 first starts an image forming process, and while controlling the heater lighting rate as the heater control unit 11, the control unit 10 uses the motor torque detected by the torque sensor 84 as the acquisition unit 12. Information regarding the reference value of is acquired (step S101). For example, the control unit 10 acquires information regarding the motor torque detected in the initial state of the upper pressure roller 81 and the lower pressure roller 82 as information regarding the reference value of the motor torque. Then, the control unit 10, as the storage control unit 13, causes the storage unit 20 to store information regarding the motor torque reference value acquired in step S101 (step S102).

After that, the control unit 10, as the acquisition unit 12, acquires information regarding the current value of the motor torque detected by the torque sensor 84 (step S103). Then, the control unit 10, as the storage control unit 13, causes the storage unit 20 to store the information regarding the current value of the motor torque acquired in step S103 (step S104).

Next, the control unit 10, as the calculation unit 14, compares the reference value and the current value of the motor torque based on the stored information, and calculates the amount of change in the current value from the reference value of the motor torque (step S105). Then, the control unit 10, as the heater control unit 11, controls the heater 851 based on the amount of change calculated in step S105 (step S106), and ends the process. The control unit 10 controls (changes) the control temperature of the heater 851, for example, as the control of the heater 851. Hereinafter, control of the control temperature will be explained with reference to FIG. 8.

FIG. 8 is a diagram showing an example of the relationship between control temperature and image glossiness.

As shown in FIG. 8, when the control temperature of the heater 851 decreases, the glossiness of the image decreases. The relationship illustrated in FIG. 8 was obtained from the experimental results when the glossiness of an image was measured under the same measurement conditions as those under which the relationship illustrated in FIG. 5 was obtained, as described above. In the example shown in FIG. 8, when the control temperature decreases by 5° C., the glossiness decreases by about 3 degrees. Considering the relationships illustrated in FIGS. 4 and 5, for example, if the fixing nip width increases by 2 mm and the motor torque increases by 0.04 Nm, and the control temperature decreases by 5 degrees Celsius, the gloss level will increase by about 3 as the standard. Return to value. Therefore, when the motor torque increases, the control unit 10 lowers the control temperature, for example, based on the relationships exemplified in FIGS. 4, 5, and 8 that have been confirmed in advance. Thereby, the control unit 10 can quickly control the control temperature based on the amount of change in the motor torque, return the glossiness to the reference value, and maintain the quality of the image formed on the paper.

Note that if the control temperature of the heater 851 is set to a different temperature for each paper type and basis weight, the control unit 10 controls the control temperature for each paper type and basis weight. Further, after executing the process in step S106, the control unit 10 may return to the process in step S101 and repeatedly execute the processes in steps S101 to S106. In this case, the control unit 10 may acquire information regarding the motor torque detected immediately after the control temperature is controlled as information regarding the new reference value of the motor torque in step S101 from the second time onwards.

This embodiment has the following effects.

The image forming apparatus 1 detects the torque (motor torque) of the drive motor 83 that drives the upper pressure roller 81 and/or the lower pressure roller 82 included in the fixing unit 80, and determines the amount of change in the motor torque from a reference value. Based on this, the heater 851 is controlled. As a result, even if the upper pressure roller 81 and/or the lower pressure roller 82 included in the fixing unit 80 deteriorate and the fixing nip width increases, the image forming apparatus 1 can control the heater 851 based on the amount of change in motor torque. can be quickly controlled, and there is no need to change the amount of heat applied to the paper. Therefore, the image forming apparatus 1 can maintain the quality of the image formed on the paper without using a special mechanism that directly controls the fixing nip width.

Further, the image forming apparatus 1 controls the control temperature of the heater 851 to control the heater 851 . The image forming apparatus 1 can maintain the quality of the image formed on the paper by controlling the temperature of the heater 851.

Further, the image forming apparatus 1 acquires information regarding the motor torque detected in the initial state of the upper pressure roller 81 and the lower pressure roller 82 as information regarding the reference value of the motor torque. Thereby, the image forming apparatus 1 can continuously maintain the quality of the image based on the quality of the image formed on the paper in the initial state of the upper pressure roller 81 and the lower pressure roller 82.

The image forming apparatus 1 also periodically acquires information regarding the motor torque and stores it in the storage unit 20, compares the reference value and the current value of the motor torque based on the information, and calculates the amount of change in the motor torque. do. Thereby, the image forming apparatus 1 can accurately calculate the amount of change in motor torque based on the information stored in the storage unit 20.

The image forming apparatus 1 also acquires information regarding the motor torque detected when the upper pressure roller 81 and the lower pressure roller 82 are in pressure contact. As a result, the image forming apparatus 1 can accurately determine the reference value and current value of the motor torque detected under the condition where the upper pressure roller 81 and the lower pressure roller 82 are in pressure contact, which is affected by the fixing nip width. Can be compared.

Further, the image forming apparatus 1 controls the heater 851 for each paper type and basis weight. Thereby, the image forming apparatus 1 can maintain the same quality of images formed on various sheets of paper.

Note that the present invention is not limited to the embodiments described above, and various changes and improvements can be made within the scope of the claims. Note that Modifications 1 to 4 below may be used in combination.

(Modification 1)
In the embodiment described above, the case where the control temperature of the heater 851 is controlled is explained as an example of controlling the heater 851, but the heater lighting rate may be controlled as the control of the heater 851.

FIG. 9 is a diagram showing an example of the relationship between the control temperature and the heater average lighting rate.

The relationship illustrated in FIG. 9 is that the diameter of the upper pressure roller and the lower pressure roller are both 60 mm, the power of the halogen lamp as a heater is 2700 W, the fixing nip width is 19 mm, and the fixing speed (paper conveyance speed) is 340 mm/s. This was obtained from experimental results when a sheet of paper with a thickness of 0.15 mm was passed through a fixing section that was set to have a thickness of 0.15 mm. As shown in FIG. 9, the average lighting rate of the heater 851 has a correlation with the control temperature. Therefore, the control unit 10 according to the first modification may control the heater lighting rate as the control of the heater 851 in step S106 shown in FIG. For example, when the motor torque increases by 0.04 Nm and the relationships illustrated in FIGS. 4, 5, 8, and 9 are satisfied, the control unit 10 reduces the heater lighting rate by reducing the control temperature by 5°C. may be reduced by 2.5%. The image forming apparatus 1 can achieve the same effects as the embodiments described above by controlling the heater lighting rate.

Note that the control unit 10 may control only the control temperature, only the heater lighting rate, or may control both the control temperature and the heater lighting rate. For example, when the motor torque increases by 0.08 Nm and the relationships illustrated in FIGS. 4, 7, 8, and 9 are satisfied, the control unit 10 lowers the control temperature by 5°C while increasing the heater lighting rate. It may be reduced by 2.5% to maintain the quality of the image formed on the paper.

(Modification 2)
In the embodiment described above, the case where the information regarding the motor torque detected when the upper pressure roller 81 and the lower pressure roller 82 are in pressure contact with each other is acquired has been described as an example, but the information regarding the motor torque detected when the upper pressure roller 81 and the lower pressure roller 82 are separated, Information regarding motor torque may also be obtained.

FIG. 10 is a diagram showing an example of a change in motor torque during pressure contact and separation. In FIG. 10, it is assumed that the line showing the change in motor torque at the time of separation and the broken line show the same slope.

As shown in FIG. 10, the motor torque during the current pressure contact includes the motor torque during the current separation, an increase in motor torque due to the initial pressure contact, and an increase in motor torque due to changes in the fixing nip width. . The motor torque during separation changes over time due to wear of the gears that transmit the motor torque, deterioration of the bearings, etc. Therefore, by subtracting the motor torque at the time of separation, which indicates current gear wear and deterioration of bearings, etc., and the increase in motor torque due to the initial pressure welding, from the motor torque at the current pressure welding, the fusing nip width can be calculated. The increase in motor torque due to the change in is calculated. As a result, the image forming apparatus 1 periodically and continuously acquires information regarding the motor torque at the time of separation in addition to information regarding the motor torque at the time of pressure contact, and compares the motor torque at the time of pressure contact and the time of separation. , it is possible to analyze the causes of changes in motor torque. Therefore, the image forming apparatus 1 can accurately determine the amount of increase in motor torque due to a change in the fixing nip width.

(Modification 3)
In the embodiment described above, the control temperature of the heater 851 is controlled each time the amount of change from the reference value of the motor torque is confirmed, but the control temperature is controlled only in a predetermined case. may be done.

For example, the control unit 10 according to the third modification executes the regularly and continuously acquired data stored in the storage unit 20 after executing the process of step S105 shown in FIG. 7 and before executing the process of step S106. Check the historical information about the motor torque. Then, the control unit 10 confirms, based on the history information regarding the motor torque, that the current value of the motor torque is not an abnormal value caused by, for example, an abnormal state of the own device that suddenly occurs, and then performs step S106. Proceed to processing. Thereby, the image forming apparatus 1 can avoid erroneously controlling the control temperature based on the abnormal value of the motor torque, and can stably maintain the quality of the image formed on the paper.

Further, the control unit 10 can also generate data expressing the accumulation of durable loads of the upper pressure roller 81 and/or the lower pressure roller 82 based on the motor torque history information. Furthermore, the control unit 10 can also generate data representing changes in motor torque before and after replacing the upper pressure roller 81 and/or the lower pressure roller 82, based on the motor torque history information.

(Modification 4)
Modification 3 has been described using an example in which the control temperature of the heater 851 is controlled after checking the history information regarding the motor torque; however, the control temperature may also be controlled based on other conditions. good.

For example, the control unit 10 according to the fourth modification sets the amount of change in motor torque to a predetermined threshold (hereinafter referred to as "first threshold") after executing the process of step S105 shown in FIG. 7 and before executing the process of step S106. ) or more. The first threshold value may be set to a value that corresponds to an amount of change in motor torque that does not cause the image quality to change beyond an acceptable range. If the control unit 10 determines that the amount of change is greater than or equal to the first threshold, it proceeds to step S106, and if it determines that the amount of change is less than the first threshold, it executes the process shown in FIG. finish. Thereby, the image forming apparatus 1 can control the control temperature as needed, instead of controlling the control temperature every time the amount of change from the reference value of the motor torque is confirmed, and can optimize the processing.

Moreover, although the case where the first threshold value is set has been described as an example, other threshold values may be further set according to other purposes. For example, after determining that the amount of change is greater than or equal to the first threshold, the control unit 10 determines that the amount of change is greater than or equal to a second threshold, which is set larger than the first threshold, before executing the process of step S106. It may be further determined whether or not there is. If it is determined that the amount of change is greater than or equal to the first threshold and less than the second threshold, the control unit 10 proceeds to step S106. On the other hand, if the control unit 10 determines that the amount of change is equal to or greater than the second threshold, the image forming apparatus 1 is provided with a predetermined notification urging replacement of the upper pressure roller 81 and/or the lower pressure roller 82. This may be done by the notification department. The predetermined notification may be performed, for example, by using the operation panel 40 as a notification section and displaying a predetermined screen on the operation panel 40. Alternatively, the image forming apparatus 1 may further include a sound output section such as a speaker that outputs sound, a light emitting section such as a lamp that emits light, etc. at an arbitrary position as a notification section. This may be done by causing the output unit to output a predetermined sound or by causing the light emitting unit to emit a predetermined light. However, the mode of predetermined notification is not limited to the example described above. As a result, if the upper pressure roller 81 and/or the lower pressure roller 82 deteriorate to the extent that the quality of the image formed on the paper cannot be maintained even if the control temperature is controlled, the image forming apparatus 1 It can encourage prompt replacement and improve user convenience.

Note that, after replacing the upper pressure roller 81 and/or the lower pressure roller 82, the user may input via the operation panel 40 that the upper pressure roller 81 and/or the lower pressure roller 82 have been replaced. When the control unit 10 receives a user operation to input the fact that replacement has been performed via the operation panel 40, the control unit 10 uses information regarding the motor torque detected immediately after receiving the operation as a new standard for the motor torque. It may also be acquired as information regarding the value (step S101).

In addition, in the embodiment described above, in the fixing unit 80, the heating roller 85 including the heater 851 inside and the fixing belt 86 are provided on the upper pressure roller 81 side. The configuration is not limited to the example described above. For example, a heater may be provided inside the upper pressure roller 81, and the heating roller 85 and fixing belt 86 may be omitted. Alternatively, instead of the upper belt fixing method in which the fixing belt 86 is provided on the upper pressure roller 81 side, the fixing unit 80 may employ a lower belt fixing method in which the fixing belt is provided on the lower pressure roller 82 side, or an upper pressure roller The image forming apparatus may be configured to implement an upper and lower belt fixing method in which fixing belts are provided on both the 81 side and the lower pressure roller 82 side, respectively.

Further, in the above-described embodiment, the image forming apparatus 1 has been described as one apparatus, but the image forming apparatus 1 may include, for example, an information processing apparatus that executes various judgment processes and an apparatus that executes image forming processing. , may be configured separately and connected via a bus.

Furthermore, the processing according to the embodiment described above may include steps other than the steps described above, or may not include some of the steps described above. Furthermore, the order of steps is not limited to the embodiments described above. Further, each step may be combined with other steps and executed as a single step, may be included and executed in other steps, may be divided into multiple steps and executed, or may be executed in combination with other steps. may be performed simultaneously with the step.

Furthermore, the means and methods for performing various processes in the image forming apparatus 1 according to the embodiment described above can be realized by either a dedicated hardware circuit or a programmed computer. The above-mentioned program may be provided, for example, on a computer-readable recording medium such as a CD-ROM (Compact Disc Read Only Memory), or may be provided online via a network such as the Internet. In this case, the program recorded on the computer-readable recording medium is usually transferred to and stored in a storage unit such as a hard disk. Further, the above-described program may be provided as a standalone application software, or may be incorporated into the software as a function of the image forming apparatus 1.

1 image forming device,
10 control unit,
20 storage section,
30 Communications Department,
40 operation panel,
50 paper feed section,
60 conveyance section,
70 image forming section,
80 fixing section,
81 Upper pressure roller (pressure member),
82 Lower pressure roller (pressure member),
83 Drive motor,
84 Torque sensor (detection part),
85 heating roller,
851 Heater (heating member),
86 Fixing belt,
87 Temperature sensor.

Claims (9)

an image forming unit that forms an image on paper;
a fixing unit that has a heating member and a pressure member and heats and presses the paper on which the image is formed by the image forming unit to fix the image on the paper;
a detection unit that detects the torque of a drive motor that drives the pressure member;
a control unit that acquires information regarding the torque detected by the detection unit and controls the heating member based on the amount of change in the torque from a reference value;
has
The control unit acquires information regarding the torque detected in an initial state of the pressure member as information regarding the reference value, and when the current value of the torque has increased by a predetermined amount compared to the reference value. , an image forming apparatus that controls the heating member to reduce the amount of heating to the paper per unit time. an image forming unit that forms an image on paper;
a fixing unit that has a heating member and a pressure member and heats and presses the paper on which the image is formed by the image forming unit to fix the image on the paper;
a detection unit that detects the torque of a drive motor that drives the pressure member;
a control unit that acquires information regarding the torque detected by the detection unit and controls the heating member based on the amount of change in the torque from a reference value;
has
The control unit periodically acquires information regarding the torque and stores it in a storage unit, compares the reference value and the current value of the torque based on the information stored in the storage unit, and compares the reference value and the current value of the torque. forming an image, calculating an amount of change, and controlling the heating member to reduce the amount of heating to the paper per unit time when the current value of the torque increases by a predetermined amount compared to the reference value; Device. The image forming apparatus according to claim 1 , wherein the control unit controls a control temperature of the heating member as the control of the heating member. The image forming apparatus according to any one of claims 1 to 3 , wherein the control unit controls a lighting rate of the heating member as the control of the heating member. The pressure member can be changed into a pressed state and a separated state,
The image forming apparatus according to any one of claims 1 to 4 , wherein the control unit acquires information regarding the torque detected when the pressure member is pressed. The control unit further acquires information regarding the torque detected when the pressure member is separated, and includes the torque detected when the pressure member is pressed and the torque detected when the pressure member is separated. 6. The image forming apparatus according to claim 5 , wherein the cause of the change in the torque is analyzed based on the torque. The image forming apparatus according to claim 1 , wherein the control section controls the heating member for each type and basis weight of the paper. Fixing, which has an image forming section that forms an image on paper, a heating member, and a pressure member, and heats and presses the paper on which the image is formed by the image forming section to fix the image on the paper. a detection unit that detects the torque of a drive motor that drives the pressure member;
A control program for an image forming apparatus, comprising:
an acquisition step of acquiring information regarding the torque detected by the detection unit;
a control step of controlling the heating member based on the amount of change in the torque from a reference value,
In the acquisition step, information regarding the torque detected in an initial state of the pressure member is acquired as information regarding the reference value;
In the control step, when the current value of the torque increases by a predetermined amount compared to the reference value, the computer executes a process of controlling the heating member so as to reduce the amount of heating to the paper per unit time. Control program for execution. Fixing, which has an image forming section that forms an image on paper, a heating member, and a pressure member, and heats and presses the paper on which the image is formed by the image forming section to fix the image on the paper. a detection unit that detects the torque of a drive motor that drives the pressure member;
A control program for an image forming apparatus, comprising:
an acquisition step of acquiring information regarding the torque detected by the detection unit;
a control step of controlling the heating member based on the amount of change in the torque from a reference value,
In the acquisition step, information regarding the torque is periodically acquired and stored in a storage unit,
In the control step, the reference value and the current value of the torque are compared based on the information stored in the storage unit, the amount of change is calculated, and the current value is compared with the reference value of the torque. a control program for causing a computer to execute a process of controlling the heating member so as to reduce the amount of heating to the paper per unit time when the amount of heat applied to the paper increases by a predetermined amount;