阅读说明：本技术 基于步进电机的感测电压的步进电机的温度估计 (Temperature estimation of a stepper motor based on sensed voltage of the stepper motor ) 是由 卞智暎 刘容皞 金亨一 于 2019-08-12 设计创作，主要内容包括：一种图像形成装置和图像形成方法被提供。该图像形成装置包括：打印引擎,用于形成图像；步进电机,用于驱动打印引擎；驱动电路,用于将恒定电流提供给步进电机,并且感测与提供给步进电机的恒定电流的量值相对应的电压；以及处理器,用于基于在步进电机的激励时段期间由驱动电路感测的电压来计算步进电机的温度,并且基于所计算的温度来控制图像形成装置的操作。(An image forming apparatus and an image forming method are provided. The image forming apparatus includes: a print engine for forming an image; a stepping motor for driving the print engine; a driving circuit for supplying a constant current to the stepping motor and sensing a voltage corresponding to a magnitude of the constant current supplied to the stepping motor; and a processor for calculating a temperature of the stepping motor based on the voltage sensed by the driving circuit during an excitation period of the stepping motor, and controlling an operation of the image forming apparatus based on the calculated temperature.)

1. An image forming apparatus includes:

a print engine for forming an image;

a stepper motor for driving the print engine;

a drive circuit to:

a constant current is supplied to the stepping motor, and

sensing a voltage corresponding to a magnitude of the constant current provided to the stepper motor; and a processor for:

calculating a temperature of the stepping motor based on the voltage sensed by the driving circuit during an excitation period of the stepping motor, and

controlling an operation of the image forming apparatus based on the calculated temperature.

2. The image forming apparatus as claimed in claim 1, wherein the excitation period is at least one of a front excitation period, a rear excitation period, and a holding period.

3. The image forming apparatus as claimed in claim 1, wherein the processor:

executing the print job requested in the normal mode based on the calculated temperature within a predetermined first temperature zone, and

executing a print job requested in a stress mode in which at least one of the number of consecutive prints and a print speed is reduced, within a second temperature zone higher than the predetermined first temperature zone, based on the calculated temperature.

4. The image forming apparatus as claimed in claim 3, wherein the processor does not execute the requested print job based on the calculated temperature being lower than the predetermined first temperature zone or higher than the second temperature zone.

5. The image forming apparatus as claimed in claim 1, wherein the processor:

determining a developing condition corresponding to the calculated temperature, and

controlling the print engine to execute a print job request based on the determined development condition.

6. The image forming apparatus as claimed in claim 1, wherein the driving circuit includes:

a driving driver for supplying a constant current to the stepping motor;

a sense resistance for sensing a magnitude of the constant current;

a filter circuit for performing low-pass filtering of the voltage of the sense resistor; and

an amplifying circuit for amplifying the output value of the filter circuit and providing the amplified output value to the processor.

7. The image forming apparatus as claimed in claim 6, wherein the voltage of the sensing resistor changes in proportion to a change in resistance of a coil in the stepping motor.

8. The image forming apparatus as claimed in claim 1, wherein the processor controls the driving circuit to supply a constant current to the stepping motor for a predetermined period of time to estimate a temperature of the stepping motor for the predetermined period of time.

9. An image forming method, the method comprising:

supplying a constant current to the stepping motor;

sensing a voltage corresponding to a magnitude of the constant current provided to the stepper motor;

calculating a temperature of the stepper motor based on a voltage sensed by a drive circuit during an excitation period of the stepper motor; and is

Based on the calculated temperature, the operation of the image forming apparatus is controlled.

10. The method of claim 9, wherein the excitation period is at least one of a pre-excitation period, a post-excitation period, and a hold period.

11. The method of claim 9, wherein the controlling comprises:

executing a print job requested in a normal mode based on the calculated temperature being within a predetermined first temperature zone; and is

Executing a print job requested in a stress mode in which at least one of the number of consecutive prints and a print speed is reduced, within a second temperature zone higher than the predetermined first temperature zone, based on the calculated temperature.

12. The method of claim 11, wherein the controlling comprises:

based on the calculated temperature being below the predetermined first temperature zone or above the second temperature zone, the requested print job is not executed.

13. The method of claim 9, wherein the controlling comprises:

determining a developing condition corresponding to the calculated temperature; and is

Controlling the image forming apparatus to execute a print job based on the determined developing condition.

14. The method of claim 9, wherein the sensing of the voltage comprises:

sensing a voltage of a sensing resistor to sense a magnitude of the constant current supplied to the stepping motor,

wherein the voltage of the sense resistance changes in proportion to a change in resistance of a coil in the stepper motor.

15. The method of claim 9, wherein the providing of the constant current comprises:

a constant current is supplied to the stepper motor for a predetermined period of time.

Background

The image forming apparatus is an apparatus for printing print data generated by a print control terminal device on a printing paper. Representative examples include a printer, a copier, a facsimile machine, a scanner, or a multifunction printer that integrates these functions.

The image forming apparatus may be equipped with a motor capable of performing various functions such as transferring printing paper, driving a print engine, and the like.

Drawings

Particular examples of the disclosure will become more apparent from the following description taken in conjunction with the accompanying drawings, in which:

fig. 1 is a schematic block diagram of an image forming apparatus according to an example;

FIG. 2 is a more detailed block diagram of an image forming apparatus according to an example;

FIG. 3 is a diagram illustrating a print engine according to an example;

fig. 4 is a view illustrating a circuit diagram of a driving circuit according to an example;

fig. 5 is a view for explaining a relationship between a temperature and a torque of a stepping motor according to an example;

fig. 6 is a view for explaining a relationship between a temperature and a coil resistance in a stepping motor according to an example;

fig. 7 is a view for explaining a relationship between torque and coil resistance of a stepping motor according to an example;

fig. 8 is a view for explaining a relationship between temperature and sensing voltage and a relationship between temperature and coil resistance according to an example;

FIG. 9 is a diagram illustrating sensed voltages during an excitation period as a function of temperature according to an example;

FIG. 10 is a flow chart of an image forming method according to an example; and

FIG. 11 illustrates a method of controlling operation according to an example.

It should be noted that throughout the drawings, the same reference numerals are used to depict the same or similar elements, features, portions, components and structures.

Detailed Description

Hereinafter, various examples of the present disclosure will be described with reference to the accompanying drawings. The examples to be described below may also be modified in various forms. In order to more clearly describe the features of the examples, detailed descriptions of matters known to those skilled in the art to which the examples belong will be omitted.

In this specification, the case where a component is "connected" to another component includes a case where a component is "directly connected" to another component and a case where a component is "connected to another component with another component interposed therebetween. In addition, the case where any component "includes" another component means that any component may further include the other component, and does not exclude the other component unless explicitly described to the contrary.

As used herein, the term "image forming job" may refer to various jobs related to an image such as formation of an image or generation/storage/transmission (e.g., printing, copying, scanning, or facsimile) of an image file, and as used herein, the term "job" may refer not only to an image forming job but also to a series of processes required to execute the image forming job.

In addition, the "image forming apparatus" refers to an apparatus for printing print data generated from a terminal such as a computer on recording paper. Examples of the image forming apparatus described above may include a copying machine, a printer, a facsimile machine, a scanner, and a multifunction printer (MFP) whose functions are complicatedly implemented by a single apparatus, and the like. An image forming apparatus may refer to any apparatus capable of performing an image forming task, such as a printer, a copier, a scanner, a facsimile machine, a multifunction printer (MFP), or a display.

As used herein, the term "print data" may refer to data that is converted into a format that can be printed at a printer. If the printer supports direct printing, the file itself may be print data.

As used herein, the term "user" may refer to a person who performs an operation related to an image forming job using an image forming apparatus or a device connected to the image forming apparatus in a wired or wireless manner. Further, as used herein, the term "administrator" may refer to a person having authority to access all functions and systems of the image forming apparatus. "manager" and "user" may refer to the same person.

Fig. 1 is a schematic block diagram of an image forming apparatus according to an example.

Referring to fig. 1, the image forming apparatus 100 may include a print engine 110, a stepping motor 120, a driving circuit 130, and a processor 140.

The print engine 110 can execute an image forming job. As an example, the print engine 110 may execute an image forming job under the control of the processor 140 or by the operation of the stepping motor 120. An example configuration of the print engine 110 will be described below with reference to fig. 3.

The stepping motor 120 may be provided in the image forming apparatus 100, and may receive pulse input and driving power to perform constant-speed driving or acceleration driving according to the pulse input. The stepping motor 120 may perform forward driving or reverse driving according to a phase sequence of pulse input. The stepper motor 120 may initiate operation of the print engine 110. For example, the stepping motor 120 may be a motor capable of performing various functions such as driving an Organic Photoconductor (OPC) drum, operating a fixer, or conveying paper.

The drive circuit 130 may generate a drive signal for the stepper motor 120 according to the drive command. The driving circuit 130 may supply a predetermined constant current to the stepping motor 120. As an example, the driving circuit 130 may receive a driving command (e.g., current amount value information and speed information), supply a constant current corresponding to the received current amount value information to the stepping motor 120, and supply a pulse driving signal corresponding to the speed information to the stepping motor 120.

The driving circuit 130 may sense a voltage corresponding to the magnitude of the constant current supplied to the stepping motor 120. As an example, the driving circuit 130 may include a driving driver for sensing the magnitude of the constant current supplied to the stepping motor 120 by using a sensing resistance, and sense a voltage corresponding to the magnitude of the constant current supplied to the stepping motor 120 (for example, a voltage value of the sensing resistance, hereinafter referred to as a sensing voltage) by using a sensing voltage. The drive driver may receive feedback of the magnitude of the constant current provided to the stepper motor 120 based on the voltage value of the sense resistor.

The voltage magnitude of the sense resistor may be proportional to the temperature of the stepper motor 120, and the temperature of the stepper motor 120 may be estimated based on the voltage magnitude of the sense resistor. An example of the correlation between the voltage of the sense resistance and the temperature of the stepping motor 120 will be described with reference to fig. 8.

The driving circuit 130 may perform signal processing and output the sensed voltage. As an example, the driving circuit 130 may perform low-pass filtering on the sensed voltage and amplify the low-pass filtered voltage value to output the amplified voltage value to the processor 140. An example configuration and operation of the drive circuit 130 will be described with reference to fig. 4.

The processor 140 may control each constituent element of the image forming apparatus 100. Based on the received print command, the processor 140 may control the operation of the print engine 110 so that print data corresponding to the received print command may be printed, and may transmit a driving command for the stepping motor 120 to start the operation of the print engine 110 to the driving circuit 130. For example, the processor 140 may provide a current reference value (Vref) (hereinafter, a control value of the constant current) to the driving circuit 130 as a driving command so that a predetermined constant current may be provided to the stepping motor 120. The constant current control value may be represented in the form of a Pulse Width Modulation (PWM) signal.

The processor 140 may receive magnitude information of the sensing voltage sensed by the driving circuit 130. The processor 140 may calculate the temperature of the stepper motor 120 based on the magnitude of the voltage delivered through an analog-to-digital converter (ADC) port (or terminal).

In order to periodically estimate the temperature of the stepping motor 120, the processor 140 may control the driving circuit 130 such that a constant current may be supplied to the stepping motor 120 for a predetermined period of time even if the stepping motor 120 is not driven.

The processor 140 may control the operation of the image forming apparatus based on the calculated temperature of the stepping motor 120. The processor 140 may determine whether the calculated temperature of the stepping motor is within a normal range, and if the temperature is not within the normal range, a limited printing operation may be performed or a printing operation may not be performed.

For example, if the calculated temperature is within a predetermined first temperature zone, the processor 140 may execute the print job requested in the normal mode. Further, if the calculated temperature is within a second temperature range that is higher than the predetermined first temperature range, the processor 140 may perform the job requested in the stress mode.

In an example, if the calculated temperature is not within the predetermined first temperature zone and not within the second temperature zone, in other words, the calculated temperature is lower than the predetermined first temperature zone or higher than the second temperature zone, the processor 140 may not execute the requested print job. The predetermined first temperature zone may be between 0 ℃ and 60 ℃ and the second temperature zone may be between 60 ℃ and 80 ℃. Of course, these temperature zones are exemplary, and the disclosure is not limited thereto.

The stress mode may be a mode for limiting the function of the image forming apparatus 100 and executing a print job. Whether to enter the stress mode may be determined based on the temperature of the stepper motor 120 or by the size of the print job of the user. For example, when the temperature of the stepping motor 120 is low and the size of the print job of the user is 100 pages or more, the processor 140 may determine the operation mode of the image forming apparatus 100 as the stress mode.

As described above, when entering the stress mode, the processor 140 may reduce the printing speed of the image forming apparatus 100. For example, in an image forming apparatus capable of printing 14 pages per minute (ppm), the processor 140 may execute a print job at a print speed of 14ppm at a normal temperature and at a print speed of 7ppm lower than 14ppm in the stress mode. The printing speed in the stress mode may be set by the function of the image forming apparatus and based on the application environment.

When entering the stress mode, the processor 140 may modify the reference range for the number of consecutive prints. As an example, at a relatively high temperature, the image quality may be deteriorated due to a smaller number of consecutive prints than the number of consecutive prints at a normal temperature.

For example, when the reference value of the number of consecutive prints at the normal temperature is 100, the number of prints in the second temperature zone may be changed to 50. However, such a diagram is exemplary, and may be modified by the function and arrangement environment of the image forming apparatus.

According to an example, it is illustrated and described that the image forming apparatus has only one stress mode, but when implemented, the temperature range may be specifically divided so that the image forming apparatus may have a plurality of stress modes.

The processor 140 may determine a developing condition corresponding to the calculated temperature and control the print engine 110 such that a print job requested based on the determined developing condition may be executed. As an example, the developing operation may be affected by the internal temperature in the image forming apparatus 100. The temperature of the stepping motor 120 may be the same as the temperature of the image forming apparatus 100 before a print job in which the stepping motor generates heat, or when a predetermined period of time elapses after the print job is executed. Accordingly, the processor 140 may determine a developing condition corresponding to the calculated temperature and control the print engine 110 based on the developing condition. According to an example, it is described that only the developing condition is variable, but when implemented, other conditions in a series of processes of the printing operation, such as a fixing condition, a charging condition, and the like, may be determined based on the calculated temperature.

Referring to fig. 1, it is described that the stepping motor 120 and the driving circuit 130 are separated, but when implemented, the stepping motor 120 may be included in the driving circuit 130.

Although only a simple configuration of the image forming apparatus has been described, various configurations may be additionally provided upon implementation. An example of an additional configuration will be described below with reference to fig. 2.

Fig. 2 is a more detailed block diagram of an image forming apparatus according to an example.

Referring to fig. 2, the image forming apparatus 100 may include a print engine 110, a stepping motor 120, a driving circuit 130, a processor 140, a communication device 150, a display 160, an input device 170, and a memory 180.

The print engine 110, the stepping motor 120, and the driving circuit 130 have already been described with reference to fig. 1, and thus repetitive descriptions will be omitted. The processor 140 has also been described with reference to fig. 1, and therefore a repetitive description of fig. 1 will be omitted, and a description will be made of a configuration added to fig. 2.

The communication device 150 may be connected to a print control terminal device (not shown), and may receive print data from the print control terminal device. The communication device 150 may be formed to connect the image forming apparatus 100 to an external device, and is connected to a terminal device not only through a Local Area Network (LAN) or an internet network but also through a Universal Serial Bus (USB) port or a wireless communication (e.g., WiFi 802.11a/b/g/n, NFC, and bluetooth) port. The print control terminal device may be a general Personal Computer (PC), a notebook, or a mobile device such as a smartphone, or the like.

The communication 150 may receive print data from the print control terminal device. When the image forming apparatus 100 has the scan function, the communication device 150 may transmit the generated scan data to a print control terminal device or an external server (not shown).

The display 160 may display various information provided by the image forming apparatus 100. The display 160 may display an operation state of the image forming apparatus 100 or display a user interface window for selecting functions and options selectable by a user.

The display 160 may display an operation state of the image forming apparatus 100. For example, when the image forming apparatus 100 operates in the stress mode, the display 160 may display that the image forming apparatus operates at a low printing speed due to a high temperature of the image forming apparatus 100, or that the printing operation cannot be performed when the temperature of the stepping motor 120 is outside the first temperature zone and the second temperature zone.

The input device 170 may include a plurality of function keys for a user to set or select various functions supported by the image forming apparatus 100. The input device 170 may be implemented as a mouse, a keyboard, etc. or a touch screen for simultaneously performing the function of the display 160. The user can input various driving commands for the image forming apparatus 100.

The memory 180 may store print data. As an example, the memory 180 may store print data received from the communication device 150. The memory 180 may be implemented not only as a storage medium in the image forming apparatus 100 but also as an external storage medium, a removable disk including a USB memory, or a web server via a network, or the like.

The memory 180 may store lookup data, such as a lookup table, for controlling the stepper motor 120. The lookup table may be an acceleration table including pulse period information for each driving speed of the stepping motor 120, may be a speed (or acceleration) table corresponding to a plurality of load voltages (Vload), a lookup table for torque values corresponding to a plurality of load voltages (Vload), a lookup table for constant current control values (Vref values or control voltage values) corresponding to a plurality of load voltages (Vload), or the like. The accelerometer may be a table having pulse period information for each driving speed of the stepping motor 120.

The memory 180 may store information on a temperature range for entering the stress mode, operation information of the image forming apparatus 100 in the stress mode, or information on a developing condition for each sensed temperature, and the like.

The memory 180 may store temperature information of the stepping motor 120 corresponding to a voltage value sensed by the ADC port. As an example, the memory 180 may store formula information for calculating temperature information.

Based on the print data received from the communication device 150, the processor 140 may determine the operation mode of the image forming apparatus 100 according to the size of the received print data (e.g., the number of copies) and the temperature of the stepping motor 120.

The processor 140 may control the print engine 110 so that print data received according to the determined operation mode may be printed. When the determined operation mode is the stress mode, the processor 140 may control the display 160 to display a message informing that the printing speed is limited.

When the calculated temperature is outside the first temperature zone and the second temperature zone, the processor 140 may control the display 160 to display a message notifying that the printing operation cannot be performed, or control the communication device 150 so that information corresponding to the message may be transmitted to the print control terminal device from which the print data is received.

When the temperature at the stepping motor 120 reaches a temperature at which a print job can be performed after the print data is received, the processor 140 may control the print engine 110 to print the previously unprinted print data.

As described above, the image forming apparatus 100 can determine the temperature of the stepping motor based on the voltage value of the sense resistor. Therefore, even without a temperature sensor, the print job can be stably executed. In addition, since the image forming apparatus 100 executes a print job by changing the developing condition with the determined temperature, it is possible to output a high-quality image even if the temperature changes. Further, the image forming apparatus 100 may not need to enter the stress mode in a low temperature environment, and motor step-out due to a decrease in torque of the motor caused by a high temperature environment and a continuous print job may be prevented in advance. Therefore, the printing function can be improved without additional cost.

Referring to fig. 1 and 2, it has been described that a single driving circuit controls a single stepping motor, but when implemented, a single driving circuit may control a plurality of stepping motors as well as a stepping motor in parallel with a brushless direct current (BLDC) motor or a DC motor.

With reference to fig. 1 and 2, the stepper motor 120 has been described as being separate from the print engine or drive circuit, but in implementations the stepper motor may be included in the print engine or drive circuit.

In the above examples, it has been described that the temperature of the stepping motor is determined based on the voltage value of the sense resistance. However, in implementation, the temperature of the stepping motor may be used as the internal temperature of the image forming apparatus 100. As an example, the temperature of the stepping motor may be the same as the internal temperature of the image forming apparatus when a predetermined time elapses before the print job is executed or after the print job is executed. The temperature of the stepping motor at this time can be used as the temperature in the image forming apparatus.

Fig. 3 is a diagram illustrating a print engine according to an example.

Referring to fig. 3, the print engine 110 may include a photosensitive drum 111, a charger 112, an exposure device 113, a developing device 114, a transfer device 115, and a fixing device 118. The print engine 110 may further include a supply device (not shown) that supplies the recording medium P.

In an example, an electrostatic latent image may be formed on the photosensitive drum 111. The photosensitive drum 111 may be referred to as an image forming medium, a photosensitive drum, a photosensitive belt, or the like, depending on the form of the photosensitive drum 111.

For convenience of explanation, a configuration of the print engine 110 corresponding to only one color will be described and illustrated. However, in an implementation, the print engine 110 may further include a plurality of photosensitive drums 111 corresponding to a plurality of colors, a plurality of chargers 112, a plurality of exposure devices 113, a plurality of developing devices 114, and an intermediate transfer belt (not shown).

The charger 112 can charge the surface of the photosensitive drum 111 to a uniform potential. The charger 112 may be implemented in the form of a corona charger, a charging roller, a charging brush, or the like.

The exposure device 113 can form an electrostatic latent image on the surface of the photosensitive drum 111 by changing the surface potential of the photosensitive drum 111 according to image information to be printed. For example, the exposure device 113 may form an electrostatic latent image by irradiating light modulated according to image information to be printed to the photosensitive drum 111. This type of exposure apparatus 113 may be referred to as a light scanning apparatus or the like. In an example, a Light Emitting Diode (LED) may be used as a light source of the exposure apparatus 113.

The developing device 114 may include a developer therein, and supply the developer to the electrostatic latent image to develop the electrostatic latent image into a visible image. The developing device 114 may include a developing roller 117 that supplies developer to the electrostatic latent image. For example, the developer may be supplied from the developing roller 117 to the electrostatic latent image formed in the photosensitive drum 111 by a developing electric field formed between the developing roller 117 and the photosensitive drum 111.

The visible image formed in the photosensitive drum 111 may be transferred to the recording medium P by a transfer device 115 or an intermediate transfer belt (not shown). The transfer device 115 can transfer the visible image to the recording medium P by using, for example, an electrostatic transfer method. The visible image can be attached to the recording medium P by electrostatic attraction.

The fixing device 118 may fix the visible image on the recording medium P by applying heat or pressure to the visible image on the recording medium P. The print job can be completed through this series of processes.

The developer can be used each time an image forming job is executed, and is exhausted when used over a predetermined time. In this case, the unit for storing the developer (for example, the developing device 114 itself) may need to be replaced. A component or a constituent element that can be replaced by a user of the image forming apparatus may be referred to as a consumable or replaceable unit (CRU). A CRU memory (e.g., a CRUM chip) may be attached to the consumable unit for appropriately managing the consumable unit.

The stepping motor 120 may rotate each constituent element of the print engine 110. In an example, a plurality of constituent elements of the print engine 110 may be simultaneously driven by a single stepping motor 120 or a plurality of motors combined with each other.

Although the configuration directly related to image formation has been described and illustrated, the print engine 110 may further include a sheet conveying device (not shown) that conveys the sheet loaded in the loading deck to the conveying machine and the fixing machine.

Fig. 4 is a view illustrating a circuit diagram of a driving circuit according to an example.

Referring to fig. 4, the driving circuit 130 may be composed of a driving driver 131, a sensing resistor 132, a filter circuit 133, and an amplifying circuit 135.

The driving driver 131 may supply a constant current to the stepping motor 120. The driving driver 131 may be supplied with a constant current control value (Vref) and a pulse value corresponding to a driving speed from the processor 140. The driving driver 131 may supply a constant current to the stepping motor 120 based on the received constant current control value (Vref) and a voltage value (Vsens) corresponding to a value of the current flowing through the stepping motor 120 based on the sensing resistor 132.

The driving driver 131 may periodically supply a constant current when the stepping motor 120 does not need to be driven and when the stepping motor 120 needs to be driven, so as to periodically estimate the temperature of the stepping motor 120.

The drive driver 131 may generate respective pulse signals for the coils (e.g., 121, 122) of the stepper motor 120 based on the received pulse values and provide the generated pulse signals to the stepper motor 120.

The sensing resistor 132 may be a resistor for sensing the magnitude of the current flowing through a single coil (e.g., 121 or 122) of the stepper motor 120.

Since the sensing resistor 132 may not output a constant value, the voltage value of the sensing resistor 132 may be smoothed by using a filter circuit 133, an example of which is described below.

The filter circuit 133 may perform low pass filtering of the voltage of the sense resistor 132. The filter circuit 133 may be an RC smoothing circuit composed of a plurality of resistors (R1 and R2) and a plurality of capacitors (C1 and C2). Referring to fig. 4, the filter circuit 133 has been implemented by connecting two RC circuits in series. However, it will be appreciated that this is merely an example and in an implementation, only a single RC smoothing circuit may be used. In another example, the filter circuit may be implemented using another smoothing circuit different from the RC smoothing circuit.

When the smoothed voltage value does not satisfy the ADC level of the processor 140, the smoothed voltage value may be amplified by using the amplifying circuit 135 that amplifies the voltage value at a predetermined ratio. When the smoothed voltage value satisfies the ADC level to be measured, the amplification circuit 135 to be described below may be omitted.

The amplification circuit 135 may amplify the output value of the filter circuit 133. The amplifying circuit 135 may be composed of an operational amplifier (op-amp) and a plurality of resistors R3 and R4.

The voltage value output by the amplification circuit 135 may be provided to the output port 136 of the amplification circuit 135 and input to the ADC port of the processor 140. In an example, the processor 140 may monitor load fluctuations in real time.

As will be described below, the voltage value of the sense resistor 132 may not have a constant value when the stepping motor is driven as shown in fig. 9, but may have a constant value during the excitation period. The processor 140 may sense the voltage value of the sense resistor 132 during the excitation period of the stepper motor 120. The excitation period may be a period during which the coil (e.g., 121 or 122) of the stepping motor 120 is supplied with a constant current but the stepping motor is not driven, and may be one of a front excitation period, a rear excitation period, and a holding period.

Hereinafter, the correlation of the temperature of the stepping motor with the voltage value of the sensing resistor 132 will be described with reference to fig. 5 to 9.

Fig. 5 is a view for explaining a relationship between a temperature and a torque of a stepping motor according to an example.

Referring to fig. 5, the torque of the stepping motor may be reduced as the temperature of the stepping motor increases.

If the torque of the stepping motor falls below a predetermined torque required for a print job, step-out may occur, so that a normal image forming job may become difficult. Therefore, in order to prevent the step-out phenomenon, a torque margin may be secured by setting the current to be at least 30% to 50% or more greater than the necessary motor driving torque. However, the provision of an overcurrent may cause the stepping motor to generate vibration and heat.

Therefore, if the stepping motor is continuously driven, the temperature of the stepping motor may gradually increase.

However, as described above, when the stepping motor is continuously driven and the temperature of the stepping motor increases, referring to fig. 5, the torque of the stepping motor may be reduced, and thus step-out is likely to occur.

When departing from the normal operation mode, the image forming apparatus 100 may not perform printing by the stress mode, or may perform an operation such as limiting the number of consecutive prints that can be processed at one time.

However, if the temperature of the image forming apparatus is not known, it is necessary to determine whether the operation should be performed in the stress mode based on only the number of consecutive prints. However, when the image forming apparatus 100 is reset after the continuous output is performed, the counter of the number of continuous prints may also be reset, so that the image forming apparatus can perform in the normal mode even in a case where it is necessary to operate in the stress mode.

Hereinafter, a method of estimating the temperature without using a temperature sensor will be described with reference to fig. 6 to 9.

Fig. 6 is a view for explaining a relationship between a temperature and a coil resistance in the stepping motor according to the example, and fig. 7 is a view for explaining a relationship between a torque and a coil resistance of the stepping motor according to the example.

Referring to fig. 6, when the temperature of the stepping motor increases, the resistance value of the coil in the stepping motor may increase proportionally.

Referring to fig. 7, when the resistance of the coil is reduced, the torque of the stepping motor may be proportionally reduced.

Referring to fig. 6 and 7, assuming that the resistance value of the coil of the stepping motor is affected by temperature, the resistance value of the coil may be used to estimate the temperature of the stepping motor.

Considering the equation R ═ V/I, the resistance value may be calculated based on the voltage value or the current value applied to the coil. Since a constant current is supplied to the stepping motor under the control of the processor, a constant current value may be estimated, and the V value may be a voltage value of the sensor resistance. As an example, the drive driver may provide a current proportional to the constant current provided to the stepper motor to the sense resistor in order to provide an appropriate constant current to the stepper motor. The voltage value of the sensed value may be proportional to the resistance value of the coil, as shown in fig. 8 below.

Fig. 8 is a view for explaining a relationship between temperature and sensing voltage and a relationship between temperature and coil resistance according to an example.

Referring to fig. 8, the resistance value of the coil may change in proportion to the temperature of the stepping motor, and the voltage of the sensing resistor may similarly change in proportion to the temperature of the stepping motor. In other words, the temperature of the stepping motor can be estimated by directly calculating the resistance of the coil or by using a voltage value of the sensing resistance.

Assuming that the voltage of the sensing resistor is proportional to the temperature of the stepping motor, the temperature of the stepping motor can be estimated by using the voltage value of the sensing resistor. However, since a back electromotive force component flows in when the stepping motor is driven, it is difficult to measure the resistance of the coil. Therefore, the voltage of the sense resistance can be estimated when the back electromotive force component does not flow in. Example operations will be described with reference to fig. 9.

Fig. 9 is a view illustrating a sensing voltage during an excitation period according to a temperature change according to an example.

Referring to fig. 9, even when the same constant current is supplied, the sensing voltage may have different values according to the operation state of the stepping motor.

However, as described above, a relatively constant value may be obtained during the pre-excitation period. The pre-excitation period may be a region where current is applied to the stepping motor before the stepping motor is driven and rotation does not occur. Since actual motor rotation occurs in the acceleration section and the constant speed section, it is difficult to accurately calculate the motor coil resistance by sensing the voltage due to the inflow of the back electromotive force component.

Therefore, no motor rotation may occur during the front excitation period, the rear excitation period, and the holding period. The voltage of the sense resistor may be estimated in a section where the current is applied to the motor, and the temperature of the stepping motor may be estimated by using the measured voltage.

Fig. 10 is a flowchart for explaining an image forming method according to an example.

Referring to fig. 10, at operation S1010, a constant current may be supplied to the stepping motor. The constant current may be supplied to the stepper motor for a predetermined period of time to estimate the temperature not only when the motor needs to be driven but also when the motor does not need to be driven.

At operation S1020, a voltage corresponding to the magnitude of the constant current supplied to the stepping motor may be sensed. A voltage of a sensing resistor for sensing a magnitude of a constant current supplied to the stepping motor may be sensed. The resistance value of the sensing resistor may be changed in proportion to a change in the resistance value of the coil in the stepping motor.

At operation S1030, a temperature of the stepping motor may be calculated based on a voltage value sensed by the driving circuit during an excitation period of the stepping motor. The excitation period may be any one of a front excitation period, a rear excitation period, and a holding period.

At operation S1040, the operation of the image forming apparatus may be controlled based on the calculated temperature. When the calculated temperature is within a predetermined first temperature zone, the requested print job may be executed in a normal mode, and when the calculated temperature is within a second temperature zone higher than the predetermined first temperature zone, the requested print job may be executed in a stress mode in which at least one of the number of consecutive prints and the print speed is reduced. If the calculated temperature is below a predetermined first temperature zone or above a second temperature zone, the requested print job may not be executed.

Developing conditions corresponding to the calculated temperature may be determined, and a print job may be executed based on the determined developing conditions.

FIG. 11 illustrates a method of controlling operation according to an example.

Referring to fig. 11, based on the received print command, as described in fig. 10, a voltage value of the sensing resistor may be measured at operation S1105, and a temperature may be calculated based on the measured voltage value at operation S1110.

If the calculated temperature is lower than the predetermined first temperature at operation S1115-Y, the number of consecutive prints may be checked at operation S1120. The first temperature may be 60 ℃, but the present disclosure is not limited thereto.

When the number of consecutive prints is less than the predetermined number at operation S1120-Y, the mode may be determined as the normal mode at operation S1125, and the print job may be executed in the normal mode at operation S1130. The predetermined number of consecutive prints may be 100, but the present disclosure is not limited thereto. In the normal mode, the print job can be normally executed until a predetermined number of continuous prints (e.g., number of pages: 100) is reached.

If there is a subsequent print job during the print job at operation S1135-N, the process may return to the determination operation, and if there is no subsequent print job at operation S1135-Y, the process may be terminated.

If the calculated temperature is not lower than the predetermined first temperature at operation S1115-N, it may be confirmed whether the calculated temperature is lower than the predetermined second temperature at operation S1140. The predetermined second temperature may be 80 ℃, but the present disclosure is not limited thereto.

If the calculated temperature is lower than the predetermined second temperature or if there are more print job requests than the preset number at operation S1140-Y, the image forming apparatus may enter the first stress mode at operation S1145.

When entering the first stress mode, after performing as many print jobs as the number of continuous prints available in the first stress mode (e.g., 5) at operation S1150, the driving of the motor may be stopped for a predetermined period of time (e.g., 10 seconds) at operation S1155.

When the predetermined period of time elapses at operation S1160, it may be checked whether the print job needs to be continued at operation S1165, and if there are still print jobs, the image forming apparatus may return to the operation for estimating the temperature of the stepping motor.

When the calculated temperature is not lower than the predetermined second temperature at operation S1140-N, the image forming apparatus may enter the second stress mode at operation S1170. When entering the second stress mode, the image forming apparatus may be in the standby mode for a predetermined time (e.g., 10 seconds) without a print job at operations S1155 and S1160, and return to the operation for estimating the temperature of the stepping motor again.

As described above, the image forming apparatus using the methods of fig. 10 and 11 can sense the temperature of the stepping motor (temperature in the image forming apparatus) based on the voltage value of the sensing resistor. Therefore, the image forming apparatus can perform a print job more stably than an image forming apparatus without a temperature sensor. In addition, since the image forming apparatus 100 changes the developing condition and executes the print job according to the sensed temperature, it is possible to output a high-quality image even if the temperature changes. In addition, it is not necessary to enter an unnecessary stress mode in a low-temperature environment, and motor step-out due to a decrease in torque of the motor caused by a high-temperature environment and a continuous print job can be prevented in advance. Therefore, the printing function can be enhanced without additional cost.

The image forming method described above may be implemented as a program and provided to an image forming apparatus. A program including the image forming method may be stored in a non-transitory computer readable medium.

The non-transitory computer-readable recording medium may refer to a medium that stores data and can be read by a device. The aforementioned various applications or programs may be stored in a non-transitory computer readable medium, for example, a Compact Disc (CD), a Digital Versatile Disc (DVD), a hard disk, a blu-ray disc, a Universal Serial Bus (USB), a memory card, a Read Only Memory (ROM), and the like, and may be provided.

Although examples have been shown and described, it will be appreciated by those skilled in the art that changes may be made in these examples without departing from the principles and spirit of the disclosure. Accordingly, the scope of the invention should not be construed as limited to the described examples, but rather by the appended claims and their equivalents.