JP2016139046A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus that accurately predicts the temperature inside the apparatus.SOLUTION: An image forming apparatus comprises: first acquisition means that acquires ambient temperature; holding means that holds a temperature prediction parameter for a temperature prediction target member; prediction means that obtains the convergence temperature of the target member when the current operation state continues, and predicts the temperature of the target member on the basis of the convergence temperature, the ambient temperature, and the temperature prediction parameter; and control means that controls the operation state on the basis of the predicted temperature of the target member.SELECTED DRAWING: Figure 9

Description

  The present invention relates to a technology for predicting an in-machine temperature of an image forming apparatus and a control technology based on the predicted temperature.

  As a method for predicting the temperature in the image forming apparatus (hereinafter referred to as “in-machine temperature”), there is a method in which temperature change data is measured in advance for each of various image forming conditions and the in-machine temperature is predicted based on this temperature change data. Further, Patent Document 1 sets a threshold value according to the environmental temperature, and when the predicted amount of change in the machine temperature exceeds the threshold value, control for suppressing the temperature rise in the machine, such as intermittent operation (hereinafter, temperature rise suppression). Control).

Japanese Patent No. 4781217

  However, an error occurs in the prediction of the in-machine temperature. Therefore, the threshold value for switching to the temperature rise suppression control needs to be reduced in consideration of the prediction error. However, if the prediction error is small, the temperature increase suppression control is switched more quickly than necessary due to a small threshold. Further, when the environmental temperature changes from a low state to a high state during image formation, the predicted temperature tends to be higher than the actual temperature. As a result, the temperature rise suppression control is switched more quickly than necessary.

  The present invention provides an image forming apparatus that accurately predicts an in-machine temperature.

  According to an aspect of the present invention, the image forming apparatus includes: a first acquisition unit that acquires an environmental temperature; a holding unit that holds a temperature prediction parameter for a temperature prediction target member; and the current operation state when the current operation state continues. Control for obtaining the convergence temperature of the target member, predicting the temperature of the target member based on the convergence temperature, the environmental temperature, and the temperature prediction parameter, and controlling the operation state based on the predicted temperature of the target member And means.

  According to the present invention, the in-machine temperature can be accurately predicted.

1 is a configuration diagram of an image forming apparatus according to an embodiment. 1 is a diagram illustrating a control configuration of an image forming apparatus according to an embodiment. The figure which shows the example of the actual measurement temperature of the full load detection flag at the time of performing image formation continuously. The figure which shows the example of the actual temperature of the full load detection flag when image formation is done with various image formation modes The figure which shows the temperature prediction parameter by one Embodiment. The figure which shows the actual measurement temperature and prediction temperature of the target member by one Embodiment. The figure which shows the actual measurement temperature and prediction temperature of the target member by one Embodiment. Explanatory drawing of the temperature prediction parameter by one Embodiment. The flowchart of the temperature prediction control by one Embodiment. The flowchart of the temperature rising suppression control by one Embodiment. The figure which shows the actual temperature and estimated temperature of a full load detection flag by one Embodiment. The figure which shows the estimated temperature when environmental temperature changes.

  Hereinafter, exemplary embodiments of the present invention will be described with reference to the drawings. In addition, the following embodiment is an illustration and does not limit this invention to the content of embodiment. In the following drawings, components that are not necessary for the description of the embodiments are omitted from the drawings.

<First embodiment>
FIG. 1 is a configuration diagram of an image forming apparatus 100 according to the present embodiment. The image forming apparatus 100 includes a process cartridge 200 that can be attached to and detached from the main body of the image forming apparatus 100. The process cartridge 200 includes a photoconductor 201 that is an image carrier, a developing container 205 that contains a developer, a charging roller 202, a developing roller 203, and a cleaning blade 204. The paper feed cassette 110 is detachable from the main body of the image forming apparatus 100 and can accommodate a plurality of sheets S.

  At the time of image formation, the sheet feeding roller 111 rotates, and the sheet S stacked on the sheet feeding cassette 110 is fed toward the conveying roller pair 109. The conveyance roller pair 109 conveys the sheet S toward the nip region 207 between the photosensitive member 201 and the transfer roller 206. On the other hand, in the process cartridge 200, the charging roller 202 charges the surface of the photoreceptor 201 to a uniform potential. The exposure unit 108 irradiates the photoconductor 201 with light according to the image data to expose the photoconductor 201, thereby forming an electrostatic latent image on the photoconductor 201. The developing roller 203 develops the electrostatic latent image on the photoconductor 201 with the developer in the developing container 205 and visualizes it as a developer image. The transfer roller 206 transfers the developer image on the photoreceptor 201 to the sheet S. The developer that is not transferred to the sheet S and remains on the surface of the photoreceptor 201 is removed by a cleaning blade 204 that is a cleaning member.

  The sheet S on which the developer image has been transferred is conveyed to the fixing unit 103. The fixing unit 103 heats and pressurizes the sheet S to fix the developer image on the sheet S. The sheet S on which the image is fixed is conveyed toward the paper discharge roller pair 106 and is discharged by the paper discharge roller pair 106 to a paper discharge tray 105 that is a discharge unit of the image forming apparatus 100. When images are formed on both sides of the sheet S, the paper discharge roller pair 106 is reversely controlled before the sheet S is discharged. As a result, the sheet S is conveyed toward the duplex conveyance path 112 and further conveyed toward the conveyance roller pair 109 by the refeed roller pair 107. The full load detection flag 104 presses the rear end of the sheet S stacked on the paper discharge tray 105 and prevents the sheet S from blocking the discharge port of the paper discharge roller pair 106.

  FIG. 2 is a diagram illustrating a control configuration of the image forming apparatus 100. The control unit 300 includes a CPU 301, ROM 302, RAM 313, and NVRAM 303. The control unit 300 also functions as a prediction unit that predicts the in-machine temperature by a method described later. Further, the operation of the image forming apparatus is controlled by the predicted in-machine temperature. The CPU 301 performs various arithmetic processes necessary for controlling the image forming apparatus 100. The ROM 302 is a holding unit that stores and holds fixed information, and stores information such as programs and parameters necessary for the calculation of the CPU 301. The RAM 313 is a holding unit that holds information to be temporarily stored when the CPU 301 performs arithmetic processing. The NVRAM 303 is a non-volatile memory in which information is not lost even when power supply is stopped, and is a holding unit that holds the predicted temperature T in the machine calculated by the CPU 301 and the like.

  The fixing thermistor 103b, the environment thermistor 307, the external device 314, the photo interrupter 311 and the like are connected to the control unit 300 via the input interface 308. The fixing thermistor 103 b is an acquisition unit that detects and acquires the temperature of the fixing unit 103. The environmental thermistor 307 is an acquisition unit that is mounted on the electric substrate of the image forming apparatus and detects and acquires the environmental temperature Te where the image forming apparatus 100 is installed. The photo interrupter 311 transmits and receives infrared light. The infrared light transmitted and received by the photo interrupter 311 is provided so as to be shielded by the full load detection flag 104 when a certain amount of sheets S are stacked on the paper discharge tray 105 in FIG. When the photo interrupter 311 detects the blocking of infrared light, the photo interrupter 311 notifies the control unit 300 of a signal indicating that the sheet S on the paper discharge tray 105 has reached a predetermined value. For example, when the photo interrupter 311 detects light shielding, the control unit 300 stops the main body operation. The external device 314 outputs image data to be printed to the image forming apparatus.

  An output signal from the control unit 300 is output via an output interface 309 to the heater 103a of the fixing unit 103, the exposure unit 108, the drive motor 304, the fan 305 that cools the components of the image forming apparatus 100, and the display unit 306 as a user interface. Sent to. The heater 103 a is a heat source for the fixing unit 103 to fix the developer image, and is used for temperature control of the fixing unit 103. The drive motor 304 is a power source such as a paper feed roller 111, a transport roller pair 109, a photoconductor 201, a roller pair of the fixing unit 103, a paper discharge roller pair 106, and a paper refeed roller pair 107. A display unit 306 displays the state of the image forming apparatus and the like to the user.

  FIG. 3 shows measured temperatures of the full load detection flag 104 and the developing container 205 when image formation is continuously performed from a state in which the in-machine temperature in the image forming apparatus 100 is substantially equal to the environmental temperature Te. 3 represents the temperature of the full load detection flag 104, and line b represents the temperature of the developing container 205. These temperatures were obtained by attaching a thermocouple to the full load detection flag 104 and the developing container 205. Note that image formation was performed in normal speed and duplex printing mode with thin paper set in the paper feed cassette 110. When there was no thin paper in the paper cassette 110, the thin paper was set in the paper cassette 110 in about 1 minute and image formation was resumed, and the image formation was completed at time t1. Thereafter, the image forming apparatus 100 is set to a standby state, that is, a state waiting for an input signal for image formation.

  If the operation state continues after the start of image formation, the temperature of the full load detection flag 104 rises with time due to heat transfer from the sheet heated by the fixing unit 103. The amount of temperature increase per unit time decreases as the temperature of the full load detection flag 104 increases. Furthermore, the temperature of the full load detection flag 104 does not rise above the temperature Tzmax even if image formation is continued. When the image forming apparatus 100 shifts to the standby state at time t1, the temperature of the full load detection flag 104 decreases toward the environmental temperature Te. The temperature of the developing container 205 also increases with time after the start of image formation. The amount of temperature increase per unit time becomes smaller as the temperature of the developing container 205 increases. Further, the temperature of the developing container 205 does not rise above the temperature Tbmax even if image formation is continued. When the image forming apparatus 100 shifts to the standby state at time t1, the temperature of the developing container 205 decreases toward the environmental temperature Te. Although not shown in FIG. 3, the temperature of other members such as the cleaning blade 204 and the drive motor 304 shows the same behavior. In the following description, the temperature at which the member converges by continuing image formation, such as the above-described temperatures Tzmax and Tbmax, is referred to as an ultimate temperature.

  FIG. 4 shows measured temperatures of the full load detection flag 104 when images are continuously formed in various image forming modes. In FIG. 4, a line c indicates a temperature change at the duplex printing mode and the normal speed, and a line d indicates a temperature change at the duplex printing mode and a half speed of the normal speed. A line e indicates a temperature change at a single-sided printing mode and at a normal speed, and a line f indicates a temperature change at a single-sided printing mode and at half the normal speed. The reached temperature Tzmax of the full load detection flag 104 indicates a different value for each image forming mode. Further, the temperature rise amount per unit time of the full load detection flag 104 also shows a different value for each image forming mode. Although not shown in FIG. 4, other members such as the developing container 205, the cleaning blade 204, and the drive motor 304 exhibit the same behavior.

  As shown in FIGS. 3 and 4, the temperature of each member of the image forming apparatus 100 rises due to image formation. For example, if the user touches the full load detection flag 104 while the temperature of the full load detection flag 104 is excessively high, the user may be burned. If the temperature of the developing container 205 rises excessively, the developer held inside the developing container 205 may melt beyond the glass transition point, causing image defects. If the cleaning blade 204 rises excessively, the cleaning blade 204 may be swollen by heat and cause a cleaning failure. When the temperature of the drive motor 304 rises excessively, the element on the electric board that drives the drive motor 304 may be destroyed.

  For this reason, the image forming apparatus 100 sets the target member as a temperature increase predicted portion and predicts the temperature of the target member. In the present embodiment, the full load detection flag 104, the developing container 205, the cleaning blade 204, and the drive motor 304 are assumed to be temperature rise predicted portions. However, an element on the electric substrate mounted on the image forming apparatus can also be a predicted temperature rise. In the present embodiment, the threshold temperature Tx is set for each target member, and the image forming apparatus 100 performs the temperature rise suppression control so that the predicted temperature T of the target member does not exceed the corresponding threshold temperature Tx. Note that the temperature of the environmental thermistor 307 that measures the environmental temperature also rises due to image formation, and an error occurs between the actual environmental temperature Te and the detected temperature Tp of the environmental thermistor 307. The image forming apparatus 100 predicts this error and detects the environmental temperature Te from the detected temperature Tp of the environmental thermistor 307. An arbitrary method can be used for the error prediction method, but the description is omitted because it is not directly related to the present invention.

  Hereinafter, a method for predicting the temperature of the target member will be described. FIG. 5 shows temperature prediction parameters (hereinafter simply referred to as parameters) for predicting the temperature of the target member stored in the ROM 302. In the present embodiment, the temperature change coefficient k1 and the switching temperature increase rate Trc are used as parameters used for temperature prediction when the temperature rises. Here, the temperature change coefficient k1 is a coefficient indicating the speed of temperature rise at the time of temperature rise. The switching temperature increase rate Trc will be described later. Further, the temperature change coefficient k2 and the switching temperature Tmc are used as parameters used for temperature prediction when the temperature drops. Here, the temperature change coefficient k2 is a coefficient indicating the speed of temperature decrease at the time of temperature decrease. The switching temperature Tmc will be described later. In addition, the temperature reached by the target member is determined in the temperature prediction. For this reason, the fixing temperature coefficient Kf, the environmental temperature coefficient Ke, the reference reaching temperature Tab, the reference temperature adjustment temperature Tfb, and the reference environment temperature Teb are determined. Used as a parameter. These parameters are determined in advance by attaching a thermocouple to the target member and observing temperature changes. As described with reference to FIGS. 3 and 4, the temperature change of the target member is different for each target member, and even for the same target member, is different for each image forming mode of the image forming apparatus 100. Therefore, the parameters are acquired in advance for each combination of the image forming mode and the target member and stored in the ROM 302.

Next, the temperature prediction of the target member when the temperature rises will be described. A line g in FIG. 6A is a temperature rise curve of the actually measured temperature of the full load detection flag 104. Note that the image forming mode was thin paper duplex printing and normal speed. A line g1, a line g2, and a line g3 in FIG. 6A are approximate curves according to the following expression (1).
T = Ta- (Ta-T0) * e- ^{k1 * t} (1)
Here, t is the time, T is the predicted temperature of the target member, Ta is the reached temperature, T0 is the initial temperature (time t = 0), and k1 is the temperature change coefficient. In FIG. 6A, the reached temperature Ta is Tzmax, and the initial temperature T0 is the environmental temperature Te. Lines g1, g2, and g3 are approximate curves when k1 = 0.4, 0.16, and 0.08, respectively. FIG. 6A shows that an approximate curve close to the line g can be obtained by selecting an appropriate temperature change coefficient k1.

A line g4 in FIG. 6B is obtained by switching the value of the temperature speed coefficient k1 when the predicted temperature T reaches the temperature T2. Specifically, the temperature change coefficient k1 = 0.21 when the predicted temperature T is equal to or lower than T2, and the temperature change coefficient k1 = 0.1 when the predicted temperature exceeds T2. An approximate curve after time t2 when the predicted temperature reaches T2 is expressed by the following equation (2).
T = Ta− (Ta−T2) × e− ^{k1 × (t−t2)} (2)
In this embodiment, a plurality of values are used as the temperature change coefficient k, and the temperature change coefficient k1 is switched according to the value of the predicted temperature T. With this configuration, the actual temperature rise characteristic of the target member can be approximated more accurately. In the present embodiment, switching of the temperature change coefficient k1 is controlled by the switching temperature increase rate Trc. Specifically, the temperature change coefficient k1 is switched depending on whether the value of (T−T0) / (Ta−T0) is equal to or lower than the switching temperature increase rate Trc. In FIG. 6B, Trc = 0.75, and when the value of (T−T0) / (Ta−T0) is 0.75 or less, the temperature change coefficient k1 is 0.21, and (T−T0) When the value of / (Ta−T0) is larger than 0.75, the temperature change coefficient k1 is set to 0.1.

  Next, the temperature prediction of the target member when the temperature is lowered will be described. A line h in FIG. 7A is a temperature decrease curve of the actually measured temperature of the full load detection flag 104. A line h1, a line h2, and a line h3 in FIG. 7A are approximate curves according to Expression (1). Note that the initial temperature T0 in the equation (1) is Tzmax, and the reached temperature Ta is Tzs that is the reached temperature during standby. Lines h1, h2, and h3 are approximate curves when k2 = 0.03, 0.065, and 0.15, respectively. FIG. 7A shows that an approximate curve close to the line h can be obtained by selecting an appropriate temperature change coefficient k2.

  A line h4 in FIG. 7B is obtained by switching the value of the temperature change coefficient k2 when the predicted temperature T reaches the temperature T3. Specifically, when the predicted temperature T is equal to or higher than T3, the temperature change coefficient k2 is set to 0.088, and when the predicted temperature is lower than T3, the temperature change coefficient k2 is set to 0.045. In this embodiment, a plurality of values are used as the temperature change coefficient k2, and the temperature change coefficient k2 is switched according to the value of the predicted temperature T. With this configuration, the actual temperature drop characteristic of the target member can be approximated more accurately. In the present embodiment, switching of the temperature change coefficient k2 is controlled by the switching temperature Tmc. Specifically, the temperature change coefficient k2 is switched depending on whether or not the predicted temperature is equal to or higher than the value of Tzs + Tmc.

  FIG. 8A shows the relationship between the fixing temperature Tf of the fixing unit 103 and the ultimate temperature Ta of the target member. Note that the image forming mode is thin paper, double-sided printing, and normal speed, all the conditions other than the fixing temperature are the same, and measurement is performed at the environmental temperature Te = Teb. As shown in FIG. 8A, the reached temperature Ta = Tab at the fixing temperature Tf = Tfb. In this embodiment, at this environmental temperature Teb, the reached temperature Tab at the fixing temperature Tfb is referred to as a reference ambient temperature Teb, a reference temperature adjustment temperature Tfb, and a reference attainment temperature Tab, respectively. The reference temperature control temperature Tfb is also referred to as a reference heat source temperature, and the reference attainment temperature Tab is also referred to as a reference convergence temperature. Further, as the fixing temperature Tf increases, the ultimate temperature Ta also increases. A line m in FIG. 8A is obtained by approximating the relationship between the fixing temperature Tf and the reached temperature Ta by a linear function. The slope of this line m is called the fixing temperature coefficient Kf. The fixing temperature coefficient Kf is a change rate of the reached temperature with respect to a change in the fixing temperature.

  FIG. 8B shows the relationship between the environmental temperature Te and the reached temperature Ta. In FIG. 8B, all the conditions other than the environmental temperature are the same, and the measurement is performed at the fixing temperature Tf = Tfb. As shown in FIG. 8B, when the environmental temperature Te increases, the ultimate temperature Ta also increases. The line n in FIG. 8B is obtained by approximating the relationship between the environmental temperature Te and the reached temperature Ta with a linear function. The slope of this line n is called the environmental temperature coefficient Ke. The environmental temperature coefficient Ke is the rate of change of the reached temperature with respect to the change of the environmental temperature.

The target temperature Ta of the target member can be calculated by the following equation (3) based on the fixing temperature coefficient Kf, the environmental temperature coefficient Ke, the reference reaching temperature Tab, the reference temperature control temperature Tfb, and the reference environment temperature Teb.
Ta = Tab + Ke (Te−Teb) + Kf (Tf−Tfb) (3)
Te is the environmental temperature at the time of calculation, and Tf is the fixing temperature at the time of calculation.

  FIG. 9 is a flowchart of temperature prediction control of the target member according to the present embodiment. The control unit 300 performs the process of FIG. 9 on each target member every predetermined time Δt. That is, the control unit 300 updates the predicted temperature T every predetermined time Δt. First, in S10, the control unit 300 reads the previous predicted temperature from the RAM 313. In S11, the controller 300 detects the environmental temperature Te and the fixing temperature Tf. Thereafter, the control unit 300 reads out a parameter corresponding to the image forming mode from the ROM 302, and obtains the reached temperature Ta according to the equation (3) in S13.

Subsequently, in S14, the control unit 300 obtains a temperature change amount ΔT from the previous temperature prediction time. For example, at the time of image formation, equation (1) using the parameter at the time of temperature rise is differentiated by time t to obtain the current temperature change per unit time, and this is multiplied by a predetermined time Δt, thereby the control unit 300. Finds the temperature change ΔT. Specifically, when the equation (1) is differentiated with respect to time,
dT / dt = k1 * (Ta-T0) * e-k1 ^{* t} (4)
Is obtained. Further, when the equation (1) is transformed,
(Ta-T0) * e- ^{k1 * t} = Ta-T (5)
Is obtained. From Expression (4) and Expression (5), Expression (6) indicating the amount of temperature change per unit time is obtained as follows.
dT / dt = k1 × (Ta−T). (6)
From equation (6), the amount of temperature change ΔT at a predetermined time Δt is
ΔT = k1 × (Ta−T) × Δt (7)
Can be obtained. During standby, the parameters at the time of temperature drop are used. The controller 300 updates the predicted temperature in S15 and stores it in the RAM 313. Specifically, the predicted temperature is updated by adding the temperature change amount ΔT obtained in S14 to the previous predicted temperature read in S10. Furthermore, the control unit 300 writes the predicted temperature stored in the RAM 313 into the NVRAM 303 every predetermined cycle. This is provided when the power is turned off.

  FIG. 10 is a flowchart of the temperature rise suppression control according to this embodiment. The control unit 300 repeats the process of FIG. 10 every predetermined time Δt. The control unit 300 determines whether or not the temperature increase suppression flag is 0 in S20. A temperature increase suppression flag of 1 indicates that the temperature increase suppression operation is being performed, and a temperature increase suppression flag of 0 indicates that the operation is in a normal operation, that is, the temperature increase suppression operation is not being performed. Note that the value of the temperature rise suppression flag is stored in the RAM 313, for example. When the temperature increase suppression flag is 0, that is, during normal operation, the control unit 300 determines in S21 whether the predicted temperatures T of all target members are less than the corresponding threshold value Tx. The value of the threshold Tx is different for each target member. Further, the predicted temperature T of the target member is stored in the RAM 313. If the predicted temperatures T of all the target members are less than the corresponding threshold value Tx, the control unit 300 performs normal image formation in S22.

  On the other hand, if there is a target member whose predicted temperature T is greater than or equal to the threshold value Tx in S21, the controller 300 sets the temperature increase suppression flag to 1 in S24, and performs the temperature increase suppression operation in S25. The temperature rise suppression operation refers to an operation that suppresses a temperature rise more than a normal image forming operation. For example, the control unit 300 interrupts the image forming operation and places the image forming apparatus in a standby state. That is, the control unit 300 sets the state of the image forming apparatus to a normal state in which normal image formation is performed and a standby state in which image formation is not performed according to the predicted temperature of the target member. Further, the rotation speed of the drive motor 304 can be controlled to reduce the throughput of the image forming apparatus 100. That is, the control unit 300 can control the interval between successive sheets when forming an image on a sheet according to the predicted temperature of the target member. Further, as the temperature rise suppression operation, the cooling strength of a cooling member such as a fan may be increased. That is, the control unit 300 controls the cooling strength of the cooling member with respect to the target member according to the predicted temperature of the target member. If the cooling member is a fan, this corresponds to changing the rotational speed of the fan relative to the target member in accordance with the predicted temperature of the target member.

  If the temperature increase suppression flag is 1 in S20, that is, if the temperature increase suppression operation is being performed, the control unit 300 determines whether the predicted temperature T of any target member is greater than the value obtained by subtracting the value R from the threshold Tx. Determine. The value R is also different for each target member and is stored in the ROM 302 in advance. When the predicted temperature T of any of the target members is greater than the value (Tx−R), the control unit 300 continues the temperature increase suppression operation by the processes of S24 and S25. On the other hand, when the predicted temperatures of all the target members are equal to or lower than the value (Tx-R), control unit 300 sets the temperature increase suppression flag to 0 in S26 and ends the temperature increase suppression operation. Thereafter, the control unit 300 performs the processing from S20.

  Lines r and p in FIG. 11 are measured temperatures of the full load detection flag 104 when image formation is performed in a state where the environmental temperature Te is 25 degrees Celsius and 33 degrees Celsius, respectively. Note that the image forming mode was thin paper duplex printing and normal speed. A broken line s and a broken line q are the predicted temperatures of the full load detection flag 104 by the process of FIG. The broken line s is when the environmental temperature Te is 25 degrees Celsius, and the broken line q is when the environmental temperature Te is 33 degrees Celsius. The broken line s and the broken line q substantially coincide with the line r and the line p indicating the actually measured temperature, respectively. Therefore, in the present embodiment, it is not necessary to give a large margin considering the prediction error to the threshold value Tx for determining the switching to the temperature increase suppression operation. That is, it is not necessary to make the threshold value Tx smaller than necessary. Therefore, it is possible to prevent switching to the temperature rise suppression control more quickly than necessary, and to increase the number of image formations until the temperature rise suppression control is reached. Further, even in a situation where the environmental temperature Te is different, the measured temperature and the predicted temperature T are almost the same. Therefore, it is not necessary to acquire a temperature rise curve of the actually measured temperature at various environmental temperatures Te, and the in-machine temperature can be accurately predicted by a simple method.

  FIG. 12 shows the predicted temperature when the environmental temperature Te changes. In FIG. 12, the line x is the environmental temperature Te, the environmental temperature Te until time t3 is 25 degrees Celsius, and the environmental temperature Te after time t4 is 33 degrees Celsius. Further, the line y is the predicted temperature T of the developing container 205 by the processing of FIG. 9, and the line z is the predicted temperature T of the developing container 205 by the conventional temperature rising prediction method. In the conventional temperature rise prediction method, the predicted temperature T is calculated from the sum of the temperature rise amount of the target member with respect to the environmental temperature Te and the environmental temperature Te. For this reason, at the predicted temperature T according to the conventional method, the predicted temperature T also changes rapidly in the same manner as the environmental temperature Te at times t3 to t4 when the environmental temperature Te changes rapidly. On the other hand, according to the process of FIG. 9, the predicted temperature T does not change abruptly at times t3 to t4, and rises gently from time t3. The actually measured temperature of the developing container 205 was gradually increased from the time t3 as in the case of the line y. That is, according to the temperature prediction according to the present embodiment, even if the environmental temperature Te varies, an error from the actual temperature can be reduced.

  As described above, the image forming apparatus obtains the convergence temperature of the target member when the current operation state continues, and predicts the temperature of the target member based on the convergence temperature, the environmental temperature, and the temperature prediction parameter held. . The operating state is an image forming state or a standby state, and the image forming state is an image forming state that differs depending on the image forming mode. Specifically, the image forming mode is defined by the type of sheet to be printed, the image forming speed, and double-sided printing or single-sided printing. With this configuration, the in-machine temperature can be accurately predicted. Therefore, it is possible to suppress switching to the temperature increase suppression control earlier than necessary.

[Other Embodiments]
The present invention supplies a program that realizes one or more functions of the above-described embodiments to a system or apparatus via a network or a storage medium, and one or more processors in a computer of the system or apparatus read and execute the program This process can be realized. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

  307: Environmental thermistor, 313: RAM, 300: Control unit

Claims (12)

First acquisition means for acquiring an environmental temperature;
Holding means for holding a temperature prediction parameter for a temperature prediction target member;
A prediction means for obtaining a convergence temperature of the target member when the current operation state continues, and predicting a temperature of the target member based on the convergence temperature, the environmental temperature, and the temperature prediction parameter;
Control means for controlling the operating state based on the predicted temperature of the target member;
An image forming apparatus comprising: A second acquisition means for acquiring the temperature of the heat source;
The image forming apparatus according to claim 1, wherein the control unit obtains the convergence temperature based on a temperature of the heat source, the environmental temperature, and the temperature prediction parameter.   The image forming apparatus according to claim 2, wherein the heat source is a heat source for fixing a developer image. The temperature prediction parameter includes a first change rate that is a change rate of a convergence temperature due to a change in temperature of the heat source, a second change rate that is a change rate of the convergence temperature due to a change in the environmental temperature, and a reference environmental temperature. A reference convergence temperature that is a convergence temperature for a set of a reference environment temperature and a reference heat source temperature that is a reference heat source temperature, and
The control means, based on the first rate of change, the second rate of change, and the reference convergence temperature, for the set of the environmental temperature acquired by the first acquisition unit and the temperature of the heat source acquired by the second acquisition unit The image forming apparatus according to claim 2, wherein a convergence temperature is obtained. The temperature prediction parameter includes a temperature change coefficient indicating a speed of temperature change of the target member,
The said control means calculates | requires the temperature change amount of the said target member in the predetermined time based on the said temperature change coefficient, and predicts the temperature of the said target member with the said temperature change amount. 2. The image forming apparatus according to item 1. The temperature prediction parameter includes a plurality of temperature change coefficients for the target member,
The image forming apparatus according to claim 5, wherein the control unit switches a temperature change coefficient used for predicting a temperature of the target member according to a predicted temperature of the target member.   The target member is held by a member of a discharge portion of a sheet on which an image is formed, a power source for conveying the sheet, a developer container for holding a developer, a cleaning member for the developer, and the image forming apparatus. The image forming apparatus according to claim 1, further comprising at least one element on an electric substrate. A cooling means for cooling the target member;
The image forming apparatus according to claim 1, wherein the control unit controls the strength of cooling by the cooling unit in accordance with a predicted temperature of the target member. The cooling means is a fan;
The image forming apparatus according to claim 8, wherein the control unit controls a rotation speed of the fan according to a predicted temperature of the target member.   The control unit sets the image forming apparatus to a normal state in which normal image formation is performed or a standby state in which image formation is not performed according to the predicted temperature of the target member. 10. The image forming apparatus according to any one of 9 above.   The said control means controls the space | interval of the continuous sheet | seat at the time of forming an image in a sheet | seat according to the estimated temperature of the said object member, The Claim 1 characterized by the above-mentioned. Image forming apparatus.   The image forming apparatus according to claim 1, wherein the holding unit holds a temperature prediction parameter of the target member with respect to each operation state of the image forming apparatus.

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