JP4289036B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile machine, or a multifunction machine of these, and more particularly to an operation control technique of the image forming apparatus.
[0002]
[Prior art]
[Patent Document 1]
JP-A-5-142880
[Patent Document 2]
Japanese Patent Laid-Open No. 9-230738
[Patent Document 3]
JP-A-10-333486
[0003]
2. Description of the Related Art Conventionally, image forming apparatuses such as copying machines and printers using an electrophotographic system (electrostatic transfer system) are widely known. Some of these image forming apparatuses are configured to change the control conditions according to the type of toner.
[0004]
For example, in Patent Document 1, toner type information is stored in advance in a memory mounted on a toner cartridge, and a fixing device of an image forming apparatus to which the toner cartridge is mounted corresponds to the toner type information. A technique for selecting and setting an appropriate fixing temperature and the like is disclosed.
[0005]
[Problems to be solved by the invention]
However, none of these conventional techniques controls idling of the fixing device. That is, in the fixing device of the image forming apparatus, in order to uniformly increase the temperature of the fixing rotator before fixing, the surface temperature is increased while rotating the fixing rotator for a certain time before fixing. Further, in order to prevent overheating of the fixing rotator after fixing, the fixing rotator is rotated for a certain time after fixing. On the other hand, rotating the fixing rotator at the timing before and after fixing from the viewpoint of the lifetime of the functional parts including the fixing rotator (particularly, those that come into contact with the fixing rotator, such as cleaning means). Is disadvantageous. In particular, when the driving source of the fixing rotator and the photosensitive rotator is the same, the photosensitive rotator also rotates together with the rotation of the fixing rotator, and the functional components including the photosensitive rotator (particularly, the photosensitive rotator contacted). (For example, charging means, developing means, transfer means, cleaning means, etc.) are also disadvantageous.
[0006]
The present invention has been made in view of such technical problems, and an object of the present invention is to prevent a fixing temperature shortage during a fixing operation and an overheating of the fixing rotating body after the fixing operation, respectively. Another object of the present invention is to provide an image forming apparatus capable of extending the lifetime of functional parts such as a photosensitive rotating body.
[0007]
[Means for Solving the Problems]
That is, the present invention includes an image forming unit that forms a toner image on a recording medium, and a fixing unit that fixes the toner image formed by the image forming unit on the recording medium. The image forming unit and the fixing unit are driven by the same driving source. An image forming apparatus, When the usage history of the image forming unit is high, the usage history is prevented from rising compared to when the usage history is low. An image forming apparatus comprising a control unit that controls a pre-fixing operation and / or a post-fixing operation.
[0008]
Further, the image forming unit includes a first storage unit that stores first history information indicating a use history of the image forming unit, and the control unit is based on the first history information stored in the storage unit. The operation before fixing and / or the operation after fixing can be controlled. The control unit may be configured to update the first history information based on a usage state of the image forming unit. Further, the first storage unit stores first specification information indicating the specification of the image forming unit, and the control unit performs pre-fixing operation and / or operation based on the first specification information stored in the first storage unit. Alternatively, the post-fixing operation can be controlled.
[0009]
The present invention is also an image forming apparatus including an image forming unit that forms a toner image on a recording medium, and a fixing unit that fixes the toner image formed by the image forming unit on the recording medium. The image forming apparatus includes a control unit that controls a pre-fixing operation and / or a post-fixing operation based on the use history of the unit.
[0010]
The fixing unit includes a second storage unit that stores second history information indicating a usage history of the fixing unit, and the control unit is based on the second history information stored in the second storage unit. Thus, the operation before fixing and / or the operation after fixing can be controlled. The control unit may be configured to update the first history information based on a usage state of the image forming unit. Further, the second storage unit stores second specification information indicating the specification of the fixing unit, and the control unit performs an operation before fixing and / or based on the second specification information stored in the second storage unit. It can be configured to control the post-fixing operation. The control means may be configured to control a pre-fixing operation and / or a post-fixing operation so as to prevent an increase in the usage history when the usage history is high.
[0011]
As a specific example of the control by the control means, the control means can change the set time for the pre-fixing operation to be shorter and change the set temperature for the pre-fixing operation to be higher when the usage history is high. . In addition, when the usage history is high, the control unit can change the setting time of the post-fixing operation to be shorter and can change the pause time after the fixing of the fixing operation to be longer.
[0012]
Such an invention is particularly effective when the image forming unit and the fixing unit are driven by the same drive source.
[0013]
Here, the operation from the stop state or the rest state to the state where the toner image can be fixed on the recording medium is meant. The post-fixing operation refers to an operation from a state where a toner image can be fixed on a recording medium to a stop state or a rest state. Further, the fixing operation refers to an operation in a state where a toner image can be fixed on a recording medium. In the fixing operation, a pause operation is performed after the actual fixing operation.
[0014]
The (first and second) history information includes the number of rotations of the process cartridge, the number of rotations of the photosensitive rotator, the amount of wear of the photosensitive rotator, the number of rotations of the developing rotator, the remaining amount of developer, the number of images formed, Cumulative energization time of the fixing unit, cumulative lighting number of the lamp (heating means) of the fixing unit, rotation speed of the fixing rotator, cumulative image density, developer charge amount, oil amount of the fixing unit, remaining cleaning blade amount of the fixing unit, etc. It is possible to detect from a single or a plurality of.
[0015]
Also, (first and second) specification information includes process cartridge setting life, fixing unit setting life, developer characteristics (melting point characteristics, charging characteristics, etc.), fixing unit control temperature, photosensitive member setting life, Photoreceptor film pressure, image formation speed, fixing unit lamp wattage, operating power supply voltage, fixing unit (fixing rotating body) temperature rise rate, ROS or LED beam diameter, ROS or LED beam intensity, fixing unit specifications, process cartridge Specifications, fixing rotator (heat roll) specifications (tube film thickness, material, thickness, elastic layer thickness, outer diameter, etc.), nip pressure of fixing rotator pair, fixing rotator (pressure roll) specifications (hardness, tube thickness) , Outer diameter, etc.), fixing rotating body (fixing belt) specifications (material, thickness, etc.), installation environment, recording medium type (thick paper, thin paper, OHP film, envelope, etc.), recording medium size (paper width, etc.) ) It can be detected from a single or multiple such.
[0016]
Control targets in the pre-fixing operation include the rotation timing, rotation speed, rotation time, surface set temperature, applied voltage value, applied voltage polarity, applied voltage timing, applied voltage switching timing, applied voltage off, and the fixing rotating body of the fixing unit. The timing, the recording medium conveyance timing, the rotational speed of the rotational drive source, the rotational time of the rotational drive source, the rotational timing of the rotational drive source, etc. can be single or plural.
[0017]
Control targets in the post-fixing operation include the rotation timing, rotation speed, rotation time, surface set temperature, applied voltage value, applied voltage polarity, applied voltage timing, applied voltage switching timing, applied voltage off, and the fixing rotating body of the fixing unit. The timing, the rotational speed of the rotational drive source, the rotational time of the rotational drive source, the rotational timing of the rotational drive source, etc. may be single or plural.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0019]
FIG. 1 is a schematic cross-sectional view illustrating the configuration of a printer (image forming apparatus) 1 according to this embodiment. First, the basic configuration of the image forming apparatus 1 will be described. The image forming apparatus 1 includes an image forming unit, a paper transport unit, and a fixing unit 40.
[0020]
The image forming unit includes a process cartridge 10, an exposure device 20, and a transfer roll 14. The process cartridge 10 includes a photosensitive drum 11 as a photosensitive rotator, a charging roll 12 as charging means for uniformly charging the surface of the photosensitive drum 11, and an electrostatic latent image electrostatically written by an exposure device 20. Are integrally provided with a developing device 13 as developing means for developing the toner with toner, a cleaning blade 15 as cleaning means for removing residual toner after transfer from the surface of the photosensitive drum 11 and the like. The paper transport unit includes sheet trays 30a to 30c, pickup rolls 31a to c, retard rolls 32a to c, a resist roll pair 33, a discharge roll pair 34, and the like that accommodate different types of recording media. . The fixing unit 40 includes a heating roll 41 and a pressure roll 42 each having a heater inside at least one of them.
[0021]
Here, as shown in FIG. 2, the process cartridge 10 is integrally configured and is detachable from the printer main body. Further, as shown in FIG. 3, the fixing unit 40 is also integrally formed and is detachable from the printer body. These process cartridges 10 and the fixing unit 40 are replaced with new process cartridges 10 and the fixing unit 40 when their lifetimes are reached.
[0022]
Next, the basic operation of the image forming apparatus 1 will be described. The exposure device 20 writes an electrostatic latent image on the surface of the photosensitive drum 11 based on an image forming command input from an image reading device (scanner) or a computer (not shown). The electrostatic latent image is developed by the developing device 13 and a toner image is formed on the surface of the photosensitive drum 11. The toner image is electrostatically transferred onto the paper (recording medium) conveyed from the sheet tray 30 by the transfer roll 14 at the same timing. The sheet is nipped and conveyed in the nip portion between the heating roll (fixing rotator) 41 and the pressure roll (fixing rotator) 42 in the fixing unit 40, and a toner image is generated by the action of heat and pressure at that time. Is established. Then, the fixed sheet is discharged out of the image forming apparatus 1 by the discharge roll pair 34. On the other hand, the toner remaining on the photosensitive drum 11 at the time of transfer is removed from the surface of the photosensitive drum 11 by the cleaning blade 15.
[0023]
Here, the fixing operation for fixing the toner image on the paper and before and after the fixing operation, the rotation and heating of the heating roll 41 and the pressure roll 42 are controlled as follows.
[0024]
FIG. 4 is a control block diagram for controlling the rotation and heating of the heating roll 41 and the pressure roll 42. This control system is configured with a control unit (control means) 50 as the center, and examples of the input unit of the control unit 50 include a storage unit 10m of the process cartridge 10 and a temperature sensor 43. Further, examples of the output unit of the control unit 50 include a storage unit 10m, a drive motor M, and halogen lamps 41h and 42h.
[0025]
Here, the storage unit 10m is configured by a semiconductor memory and is configured to be accessible by the control unit 50. The storage unit 10m stores specification information SI of the process cartridge 10 and history information HI. As the specification information SI, information such as the layer thickness of the photosensitive layer of the photosensitive drum 11 provided in the process cartridge 10 is stored. Further, as the history information HI, information such as the number of images formed by the process cartridge 10 and the number of rotation cycles of the photosensitive drum 11 is stored. The history information HI is updated by the control unit 50 every time the printer 1 is used. Moreover, the temperature sensor 43 contacts the surface of the heating roll 41, and detects the surface temperature T '.
[0026]
The drive motor (drive source) M transmits a rotational drive force to all of the photosensitive drum 11, the heating roll 41, and the pressure roll 42 via a drive transmission system including gears (not shown). ing. In this embodiment, the drive motor M is on / off controlled, but may be configured to control this rotational speed. Further, the halogen lamps 41h and 42h exist inside the heating roll 41 and the pressure roll 42, respectively, and are for heating each roll. The halogen lamps 41h and 42h are on / off controlled. Further, a bias voltage V is applied to the heating roll 41 so that the toner image on the paper does not adhere to the surface of the heating roll. That is, a bias voltage V having the same polarity as the toner constituting the toner image on the paper is applied to the surface of the heating roll 41.
Further, a bias voltage having a polarity opposite to that of the toner may be applied to the surface of the pressure roll 42. By doing so, the toner image on the paper is electrostatically attracted toward the pressure roll across the paper, so that it can be further prevented from adhering to the surface of the heating roll.
[0027]
Hereinafter, details of the control of the image forming apparatus 1 will be described as examples.
[0028]
Example 1 (Rotation Drive, Heating Control) FIG. 5 shows a fixing operation, rotation drive control before and after the fixing operation, heating control, and the surface temperature T ′ of the heating roll 41. First, basic operations will be described by dividing into preheating operation (pre-fixing operation) M1, fixing operation M2, and cool-down operation (post-fixing operation) M3.
[0029]
The preheating operation M1 is an operation from the stop state (or the rest state) of the printer 1 until the printer 1 can be fixed. During this time, the surface of the heating roll 41 reaches the set temperature T. For example, at time t0, the main power button of the printer 1 is “on”. At this time, the surface temperature T ′ of the heating roll 41 is equal to the environmental temperature T0. Then, the control unit 50 turns on the halogen lamps 41h and 42h and turns on the drive motor M to increase the temperature of the surface of the heating roll 41 while rotating the heating roll 42 and the pressure roll 43. By performing such an operation, the surface temperatures of the heating roll 42 and the pressure roll 43 can be increased uniformly. As the drive motor M is driven, the photosensitive drum 11 also rotates at the same time. Then, after the surface temperature T ′ of the heating roll 41 reaches the set temperature T, the preheating operation over a predetermined time A is terminated.
[0030]
Then, as the fixing operation M2, the control unit 50 “turns off” the drive motor M and prepares for an image formation command (fixing command). In addition, the control unit 50 temporarily turns off the halogen lamps 41h and 42h, and controls the halogen lamps 41h and 42h to “off / off” so that the surface temperature T ′ of the heating roll 41 becomes a predetermined standby temperature. To do. Here, a case where three fixing jobs J (1) to (3) are performed as the fixing job J will be described. The first fixing job J (1) is from time t2 to time t3, the second fixing job J (2) is from time t4 to time t5, and the third fixing job J (3) is from time t6 to time t7. Each is done. A pause time B is provided between the fixing jobs J (time t3 to t4, time t5 to t6). During the pause time B, the control unit 50 “turns off” the drive motor M.
[0031]
Then, as the cool-down operation M3, after the final job J (3) is completed, the main power button of the printer 1 is “off”. The controller 50 immediately “turns off” the halogen lamps 41h and 42h, while continuing to “turn on” the drive motor M for a certain time C, and then “turns off” the drive motor M. By performing such an operation, it is possible to prevent damage due to overheating of the heating roll 41, the halogen lamp 41h, and the like. As the drive motor M is driven, the photosensitive drum 11 also rotates at the same time.
[0032]
By the way, in the present embodiment, based on the specification information SI and the history information HI stored in the storage unit 10m of the process cartridge 10, the control unit 50 performs the set temperature T, the predetermined time (preheat time) A, Control is performed to change the pause time B and the predetermined time (cool-down time) C.
[0033]
FIG. 6 is a flowchart for explaining a procedure for changing the set temperature T and the predetermined time A, and FIG. 7 is a flowchart for explaining a procedure for changing the rest time B and the predetermined time C.
[0034]
First, a procedure for changing the set temperature T and the predetermined time A will be described based on the flowchart of FIG. First, the control unit 50 reads history information HI and specification information SI stored in the storage unit 10m of the process cartridge 10 (S101). Then, it is determined from the information HI.SI whether the degree of fatigue of the image forming member, here, the photosensitive drum 11 is high (S102).
[0035]
When it is determined that the degree of fatigue of the photosensitive drum 11 is high from the layer thickness information of the photosensitive layer of the photosensitive drum 11 as the specification information SI and the information on the number of formed images as the history information HI, the preheating time A is set to A1. (S111), the set temperature T is set to T1 (T112), and the preheating operation is performed (S113) until the surface temperature T ′ of the heating roll 41 reaches T1 (S114). On the other hand, when it is determined that the degree of fatigue of the photosensitive drum 11 is low, the preheating time A is set to A2 (S121), the set temperature T is set to T2 (T122), and the surface temperature T ′ of the heating roll 41 is set. Until T2 reaches T2 (S124), the preheating operation is performed (S123).
[0036]
Here, when the set value A1 of the preheat time A is compared with the set value A2, A1 and A2 are set so that the relationship of A1 <A2 is established. For this reason, when the degree of fatigue of the photoconductor drum 10 is high, the idling time of the photoconductor drum 10 in the preheating state is shortened, so that the life of the photoconductor drum 10 can be extended. Further, when the set value T1 of the set temperature T is compared with the set value T2, T1 and T2 are set so that the relationship of T1> T2 is established. For this reason, the shortening of the preheating time (A2-A1) can be compensated by the increase of the set temperature T (T1-T2), and fixing failure can be prevented. Conversely, when the degree of fatigue of the photosensitive drum 10 is low, the set temperature T in the preheat state is low (adopting the set value T2), which is preferable from the viewpoint of power saving.
[0037]
Next, a procedure for changing the pause time B and the predetermined time C will be described based on the flowchart of FIG. First, the control unit 50 reads history information HI and specification information SI stored in the storage unit 10m of the process cartridge 10 (S201). Then, it is determined from the information HI.SI whether or not the fatigue of the image forming member, here, the photosensitive drum 11 is high (S202).
[0038]
When it is determined that the degree of fatigue of the photosensitive drum 11 is high from the layer thickness information of the photosensitive layer of the photosensitive drum 11 as the specification information SI and the information on the number of formed images as the history information HI, the cool-down time C is set. C1 is set (S211), pause time B is set to B1 (T212), and the preheating operation is performed (S213) until the surface temperature T ′ of the heating roll 41 is lowered to some extent (S214). On the other hand, when determining that the degree of fatigue of the photosensitive drum 11 is low, the cool-down time C is set to C2 (S221), the rest time B is set to B2 (T222), and the surface temperature T of the heating roll 41 is set. Until 'falls to some extent (S224), the preheating operation is performed (S223).
[0039]
Here, when the set value C1 and the set value C2 of the cool-down time C are compared, C1 and C2 are set so that the relationship of C1 <C2 is established. For this reason, when the degree of fatigue of the photosensitive drum 10 is high, the idling time of the photosensitive drum 10 in the cool-down state is shortened, so that the life of the photosensitive drum 10 can be extended. Further, when the set value B1 and the set value B2 of the pause time B are compared, B1 and B2 are set so that the relationship of B1> B2 is established. For this reason, the shortening of the cool-down time (C2-C1) can be supplemented by the increase in the pause time B (B1-B2), and overheating can be prevented. Conversely, when the degree of fatigue of the photosensitive drum 10 is low, the downtime B is low (adopting the set value B2), which is preferable from the viewpoint of productivity.
[0040]
Modified example 1 (change of 3 steps or more)
In this embodiment, the set temperature T, the predetermined time (preheat time) A, the pause time B, and the predetermined time (cool down time) C are alternatively selected and changed. You may change into a stage (3 steps or more).
[0041]
FIG. 8 is a graph for explaining a case where the preheating time A is changed to a maximum of four stages. In the graph, the horizontal axis represents the number of formed images [K-pv], and the vertical axis represents the initial film thickness [μm] of the photosensitive drum 11. For example, when the initial photosensitive film thickness of the photosensitive drum 11 is 25 μm, the control unit 50 initially sets the preheating time A to 3000 [msec] (see (1)), and the cumulative number of images formed increases. At the same time, 1650 [msec] (see (2)) → 1200 [msec] (see (3)) → 800 [msec] (see (4)) can be reduced.
[0042]
Modification 2 (continuous change)
FIG. 9 is a graph for explaining the relationship between the cumulative number of image formations and the remaining film thickness of the photosensitive drum 11. In this graph, the horizontal axis represents the cumulative number of image formation [K-pv], and the vertical axis represents the remaining film thickness [μm] of the photosensitive drum 11. As is apparent from this graph, the remaining film thickness [μm] of the photosensitive drum 11 decreases (continuously) as the cumulative image forming number [K-pv] increases. In this embodiment, the set temperature T, the predetermined time (preheat time) A, the pause time B, and the predetermined time (cool down time) C are selected and changed alternatively. You may change continuously, paying attention to this relationship.
[0043]
FIG. 10 is a graph for explaining the relationship between the remaining film thickness of the photosensitive drum 11 and the preheat time A that is set. In this graph, the horizontal axis represents the remaining film thickness [μm] of the photosensitive drum 11, and the vertical axis represents the preheat time A to be set. The plurality of line graphs in the figure are obtained by changing the settings according to the parameters of the type (material, film thickness) charger and cleaning blade of the photoconductor.
Based on such a graph, the control unit 50 can continuously set the preheating time A according to the remaining film thickness of the photosensitive drum 11.
[0044]
Modification 3 (Other)
In this embodiment, the control is performed based on the information stored in the storage unit 10m of the process cartridge 10. However, the control unit 50 is not limited thereto, and the control unit 50 stores information (history) stored in the storage unit 40m of the fixing unit 40. Control can also be performed based on information HI and specification information SI) (see parentheses in FIG. 4). Furthermore, the control part 50 can also control based on the information memorize | stored in both these memory | storage parts 10m and 40m (refer the parenthesis of FIG. 4).
[0045]
In this embodiment, only the information on the cumulative number of formed images is used as the history information HI. However, other history information HI may be used or may be used together with other history information HI. For example, the control unit 50 can determine the degree of fatigue of the image forming member by combining the image forming size and the recording medium type in addition to the cumulative image forming number.
[0046]
Example 2
(Control of Bias Voltage V) In this embodiment, the preheating time A, the set temperature T, and the bias voltage V applied to the heating roll 41 are controlled based on the developer information as the specification information SI stored in the storage unit 10m. (See FIG. 4).
[0047]
That is, first, the control unit 50 reads the history information HI and the specification information SI stored in the storage unit 10m of the process cartridge 10. The developer is specified from the specification information SI, and first, it is determined whether or not the melting point of the developer is high. When the melting point is relatively low, the preheating time A is set shorter and the set temperature T is set lower. On the other hand, when the melting point is relatively high, the preheating time A is set longer and the set temperature T is set higher. Similarly, the developer is specified from the specification information SI, and secondly, it is determined whether the developer has high charging characteristics. When the charging property of the developer is relatively high, the bias voltage V applied to the heating roll 41 is set lower. On the other hand, when the charging characteristics of the developer are relatively low, the bias voltage V applied to the heating roll 41 is set higher. The bias voltage applied to the pressure roll 42 may be similarly controlled.
[0048]
FIG. 11 is a graph illustrating the relationship between the charging characteristics of the developer and the bias voltage V. In this graph, the horizontal axis represents developer tribo [μq / g] as the charging characteristics of the developer, and the vertical axis represents bias voltage [V] applied to the heating roll 41. For example, when the developer development tribo is 4 [μq / g], the bias voltage V is 500 [V], and when the developer development tribo is 7 [μq / g], the bias voltage V is 400 [V].
[0049]
By performing such control, damage to the heating roll 41 and the like due to application of the bias voltage V is suppressed, and the life of the fixing unit 40 is extended.
[0050]
【The invention's effect】
As described above in detail, according to the present invention, the lifetime of the functional components such as the fixing rotator and the photosensitive rotator can be prevented while preventing the fixing temperature from being insufficient during the fixing operation and overheating of the fixing rotator after the fixing operation. Can be provided.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view illustrating the configuration of a printer.
FIG. 2 is a perspective view of a process cartridge.
FIG. 3 is a perspective view of a fixing unit.
FIG. 4 is a control block diagram illustrating a control system of the printer.
FIG. 5 is a timing chart for explaining the operation of the control system of the printer.
FIG. 6 is a flowchart illustrating a control procedure of the printer control system.
FIG. 7 is another flowchart for explaining the control procedure of the control system of the printer.
FIG. 8 is a graph for explaining a case where the preheat time A is changed to a maximum of four stages.
FIG. 9 is a graph for explaining the relationship between the cumulative number of formed images and the remaining film thickness of the photosensitive drum 11;
FIG. 10 is a graph illustrating the relationship between the remaining film thickness of the photosensitive drum 11 and the preheat time A that is set.
FIG. 11 is a graph for explaining the relationship between developer charging characteristics and bias voltage V;
[Explanation of symbols]
SI ... specification information, HI ... history information, M ... drive motor (drive source), 50 ... control unit (control means), 40 ... fixing unit, 40m ... storage unit, 41 ... heating roll (fixing rotator), 42 ... Pressure roll (fixing rotator), 41h, 42h ... halogen lamp, 43 ... temperature sensor, 10 ... process cartridge, 10m ... storage unit, 11 ... photosensitive drum (photosensitive rotator)

Claims (3)

An image forming section for forming a toner image on a recording medium, and a fixing unit for fixing the toner image formed by the image forming unit onto the recording medium, driving said image forming portion and the fixing portion are the same An image forming apparatus driven by a source ,
An image forming apparatus comprising: a control unit that controls a pre-fixing operation and / or a post-fixing operation so as to prevent an increase in usage history when the usage history of the image forming unit is high compared to when the usage history is low. . When the usage history of the image forming unit is high, the control unit changes the setting time for the pre-fixing operation to be shorter and the set temperature for the pre-fixing operation to be higher than when the usage history is low. the image forming apparatus according to claim 1, characterized in that. When the usage history of the image forming unit is high, the control unit changes the setting time of the post-fixing operation to be shorter than the case where the usage history is low, and further reduces the pause time after fixing of the fixing operation. The image forming apparatus according to claim 1 , wherein the image forming apparatus is changed long.

Images