JP3704938B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus, and more particularly, to an image forming apparatus effective for reducing noise and power consumption.
[0002]
[Prior art]
An image forming apparatus such as a printer or a copying machine includes a plurality of transport rollers disposed on a paper transport path, a motor that drives each of the transport rollers, and a motor driver that supplies a current to the motor. A conveying means is provided.
[0003]
In the image forming apparatus provided with the above-described sheet conveying unit, various techniques have been conventionally devised in order to reduce noise and power consumption generated by the sheet conveying unit.
[0004]
For example, Japanese Patent Application Laid-Open No. 6-155831 discloses a technique for reducing power consumption by switching a motor driving speed or the like depending on whether the paper is continuous paper or cut paper.
[0005]
Japanese Patent Application Laid-Open No. 9-132340 provides two high-speed and low-speed modes as motor operation modes, and switches between high-speed and low-speed modes according to the position where the paper is conveyed, thereby enabling high-speed operation. A technique for generating torque and preventing heat generation at low speed is disclosed.
[0006]
[Problems to be solved by the invention]
Certainly, according to the techniques described in the above-mentioned publications, it is possible to reduce noise generated by the sheet conveying means and power consumption.
[0007]
However, the motor provided in the paper conveying means as described above is generally susceptible to environmental changes such as temperature and humidity, and torque fluctuations may occur due to such environmental changes, which may cause paper jams.
[0008]
In order to prevent the occurrence of paper jams as described above, the conventional image forming apparatus determines the current value supplied to the motor in consideration of the worst environment. The current value thus determined is usually In this environment, it becomes over-spec and consumes more current than necessary.
[0009]
SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus effective in reducing noise and power consumption.
[0010]
[Means for Solving the Problems]
In order to achieve the above-described object, the invention of claim 1 includes a transport roller, a motor that drives the transport roller, a motor driver that supplies current to the motor, a paper transport unit that transports paper, and the paper. An image forming apparatus including a transfer unit configured to transfer an image onto a sheet conveyed by the conveyance unit; and a resistance value change detection unit configured to detect a change in a resistance value of the transfer unit. The amount of current supplied to the motor is controlled based on a change in the resistance value detected by the value change detection means.
[0011]
According to a second aspect of the present invention, in the first aspect of the invention, the paper conveying means includes a load fluctuation detecting means for detecting a load fluctuation of the motor, and the motor driver is detected by the load fluctuation detecting means. The amount of current supplied to the motor is controlled based on the load fluctuation.
According to a third aspect of the present invention, in the second aspect of the invention, the load fluctuation detecting unit includes a paper feed position detecting unit that detects a position where the paper is supplied.
According to a fourth aspect of the present invention, in the second aspect of the invention, the load fluctuation detecting means includes a paper type detecting means for detecting the type of the paper.
According to a fifth aspect of the present invention, in the second aspect of the invention, the load fluctuation detecting means includes a torque amount detecting means for detecting a torque amount required for the motor.
According to a sixth aspect of the present invention, in the first aspect of the invention, the paper conveying means includes a current value measuring means for measuring a current value flowing through the motor, and the motor driver includes the current value measuring means. The current value supplied to the motor is controlled based on the measured current value.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[0013]
First, the outline of the present invention will be described with reference to FIG. FIG. 1 is a block diagram showing a configuration of an image forming apparatus according to the first embodiment of the present invention.
[0014]
As shown in the figure, the present invention is provided with an environmental change detecting means 15 for detecting an environmental change around the motor 13, and the motor for driving the conveying roller 12 according to the environmental change detected by the environmental change detecting means 15. By controlling the amount of current supplied to 13, the above-described problem is solved.
[0015]
Hereinafter, the contents of the present invention will be described in more detail.
[0016]
(First embodiment)
As shown in FIG. 1, the image forming apparatus according to the first embodiment includes a plurality of transport rollers 12 disposed on a paper transport path, a motor 13 that drives each transport roller 12, and the motor 13. A sheet conveying means 10 comprising a motor driver 14 for supplying a current to the sheet, an image forming means 11 for forming an image on the sheet conveyed by the sheet conveying means 10, and an environmental change around the motor 13 are detected. And environmental change detection means 15.
[0017]
In the image forming apparatus configured as described above, the environment change detection unit 15 detects a temperature change and a humidity change around the motor 13 and outputs the detected result to the motor driver 14 as an environment change. The temperature change and the humidity change are detected by a thermometer and a hygrometer provided around the motor 13.
[0018]
The motor driver 14 that has received the environmental change output from the environmental change detection means 15 controls the amount of drive current supplied to the motor 13 in accordance with the received environmental change. For example, since the torque of the motor 13 decreases as the temperature decreases, the supply amount of the drive current is increased when the temperature around the motor 13 decreases, and the drive current increases when the temperature increases. Reduce supply.
[0019]
The motor 13 to which the drive current is supplied from the motor driver 14 supplies power corresponding to the amount of the supplied drive current to each transport roller 12.
[0020]
As described above, according to the first embodiment of the present invention, since an amount of current corresponding to the environment is supplied to the motor, unnecessary power consumption can be suppressed, noise can be prevented, and power consumption can be reduced. it can.
[0021]
(Second Embodiment)
FIG. 2 is a block diagram showing a configuration of an image forming apparatus according to the second embodiment of the present invention. The image forming apparatus shown in the figure detects the environmental change of the transfer unit 20 constituting the image forming unit 11 and controls the current supplied to the motor 13 according to the detected environmental change, thereby solving the above-described problem. It is a solution.
[0022]
The image forming unit 11 of the image forming apparatus according to the second embodiment includes a transfer unit 20 that transfers an image onto a sheet conveyed by the sheet conveying unit 10 and a fixing unit that fixes the image transferred by the transfer unit 20. The environmental change around the transfer means 20 is detected by the environmental change detection means 15.
[0023]
The environmental change detection means 15 outputs an environmental change detection signal to the transfer means 20, and as a result, outputs the obtained signal to the motor driver 14 as an environmental change. For example, when the transfer unit 20 is provided with a photosensitive drum and a transfer roller, a voltage is applied to the transfer roller as an environmental change detection signal, the flowing current is measured to detect the resistance value of the transfer roller, The detected change in resistance value is converted into a change in temperature and humidity. And the detection result obtained by the said conversion is output to the motor driver 14 as an environmental change. Other configurations are the same as those of the image forming apparatus according to the first embodiment described above.
[0024]
Since a general laser printer is provided with a mechanism for detecting a change in the environment of the transfer means as described above in order to maintain the transfer accuracy, the second embodiment is configured using this mechanism as it is. May be.
[0025]
As described above, according to the second embodiment of the present invention, since the environment change detection means provided in the laser printer can be used as it is, the power consumption can be reduced without providing any special detection means. An image forming apparatus can be provided.
[0026]
(Third embodiment)
FIG. 3 is a block diagram showing a configuration of an image forming apparatus according to the third embodiment of the present invention. The image forming apparatus shown in the figure solves the above-described problem by detecting a load fluctuation of the motor 13 and controlling a current supplied to the motor 13 based on the detected load fluctuation.
[0027]
As shown in FIG. 3, the image forming apparatus according to the third embodiment is provided with a load fluctuation detecting unit 30 that detects a load fluctuation of the motor 13, and the load fluctuation detecting unit 30 detects the load fluctuation detected. Is output to the motor driver 14. The motor driver 14 that has received the load fluctuation output from the load fluctuation detecting means 30 controls the amount of drive current supplied to the motor 13 in accordance with the received load fluctuation. Other configurations are the same as those of the image forming apparatus according to the first embodiment described above.
[0028]
Here, the load fluctuation detecting means 30 detects, as load fluctuations, changes in the number of driving of the conveying roller 12 depending on the paper supply position, changes in the thickness and type of the paper to be conveyed, and torque fluctuations due to speeding up and starting up the motor 13. To do. For example, when paper is supplied from the option tray of the printer, the number of driving of the transport roller 12 increases, so the supply amount of the drive current output from the motor driver 14 is increased. Further, when the printer handles a plurality of types of paper, when the thick paper is transported, the amount of current required for the motor 13 increases, so the amount of drive current supplied from the motor driver 14 is supplied. Increase. In addition, when the paper transport unit 10 is provided with two modes, a high speed mode and a low speed mode, when switching from the low speed mode to the high speed mode, the amount of current required for the motor 13 increases. Increase supply amount of output drive current. In addition, when the motor 13 is temporarily stopped due to a power saving mode of the printer or the like, when the conveyance of the sheet is resumed, a start-up current of the motor 13 is required, so that the drive current output from the motor driver 14 is reduced. Increase supply.
[0029]
As described above, according to the third embodiment of the present invention, since the drive current is supplied to the motor 13 according to the load applied to the motor 13, an increase in noise and power consumption due to an excessive current supply is prevented. can do.
[0030]
(Fourth embodiment)
FIG. 4 is a block diagram showing a configuration of an image forming apparatus according to the fourth embodiment of the present invention. The image neglect acquisition apparatus shown in the figure measures the current value flowing through the motor 13 and controls the amount of current supplied to the motor 13 based on the measured current value.
[0031]
As shown in FIG. 4, the image forming apparatus according to the fourth embodiment is provided with a current value measuring means 40 for measuring the value of the operating current actually flowing through the motor 13, and the current value measuring means. 40 outputs the value of the measured operating current to the motor driver 14. The motor driver 14 that has received the value of the operating current controls the amount of current supplied to the motor 13 based on the received value. For example, when the current value measured by the current value measuring unit 40 is smaller than a specified value, the supply amount of the drive current output from the motor driver 14 is increased. Other configurations are the same as those of the image forming apparatus according to the first embodiment described above.
[0032]
As described above, according to the image forming apparatus according to the fourth embodiment of the present invention, since the current that actually flows through the motor 13 is taken into consideration, the amount of the current according to the variation in the characteristics of the motor 13 and the secular change. A drive current can be supplied.
[0033]
(Example)
FIG. 5 is a block diagram showing an embodiment in which the present invention is applied to a laser printer. The printer shown in the figure includes a laser scanning unit 101, a photosensitive drum 104, a charging roller 102, a developing roller 103, a transfer roller 105, a charge removing plate 106, a conveying roller 12, a feed, which are conventionally provided in an electrophotographic printer. A motor 111, a process motor 113, a first paper feed tray 114, a second paper feed tray 115, a third paper feed tray 116, and a paper discharge tray 100 are provided as shown in FIG. Since these components are conventionally known, a detailed description of each component is omitted.
[0034]
In addition to the above configuration, the laser printer shown in FIG. 2 is provided with a resistance value measurement circuit 110 that selectively measures the resistance value of the charging roller 102, the developing roller 103, the transfer roller 105, or the charge removal plate 106. The value measuring circuit 110 detects a change in the resistance value of the charging roller 102, the developing roller 103, the transfer roller 105, or the charge removal plate 106 due to a temperature change or a humidity change as an environmental change, and outputs it to the CPU 112. The CPU 112 that has received the resistance value measured by the resistance value measurement circuit 110 outputs a control signal to the feed motor 111 and the process motor 113 in accordance with the change in the resistance value, thereby driving the motors. That is, in this laser printer, the resistance value measurement circuit 110 functions as the above-described environmental change detection means, the CPU 112 functions as a motor driver, and the process motor 113 and the feed motor 111 function as the motor 13. The second embodiment and the second embodiment are configured.
[0035]
The CPU 112 is connected to the first paper feed tray 114, the second paper feed tray 115, and the third paper feed tray 116 via signal lines, and determines the size of the paper stored in each tray. Detect. Then, the amount of current supplied to the process motor 113 and the feed motor 111 is determined based on the detected size. Further, the CPU 112 controls the amount of current supplied to the process motor 113 and the feed motor 111 in accordance with a change in tray to be used, a change in the operation mode of the feed motor 111, a startup of the motor, and the like. As a result, the laser printer shown in the figure constitutes the third embodiment of the present invention.
[0036]
Further, the CPU 112 periodically measures the current flowing through the process motor 113 and the feed motor 111, and controls the amount of current supplied to the process motor 113 and the feed motor 111 based on the measured current value. As a result, the laser printer shown in the figure constitutes the fourth embodiment of the present invention.
[0037]
FIG. 6 is a flowchart showing an example of current control processing executed by the laser printer shown in FIG. In the example shown in the figure, first, the CPU 112 determines whether or not the temperature has decreased based on the signal output from the resistance value measurement circuit 110 (step S100).
[0038]
If the temperature is decreasing (YES in step S100), the drive currents of the process motor 113 and the feed motor 111 are increased (step S105). At this time, the drive current is set to an optimum current value for the current temperature.
[0039]
If there is no temperature change (NO in step S100), it is determined whether or not the position of the selected paper feed tray is farther than the position of the paper feed tray used last time (step S101), and the position of the paper feed tray Is far (YES in step S101), the current amount is increased in accordance with the position of the paper feed tray (step S105).
[0040]
If the position of the paper feed tray is not far (NO in step S101), it is determined whether the paper to be fed is thicker than the previously fed paper (step S102), and the paper becomes thicker. If YES in step S102, the amount of current is increased in accordance with the thickness of the paper (step S105).
[0041]
If the sheet is not thick (NO in step S102), it is determined whether or not the conveyance mode has been switched to the high speed mode (step S103). If the sheet has been switched to the high speed mode (YES in step S103). Then, the drive current of the feed motor 111 is increased to an amount of current corresponding to the high speed mode (step S105).
[0042]
If not switched to the high speed mode (NO in step S103), it is determined whether or not the motor is started (step S104). If the motor is started (YES in step S104). Then, the drive currents of the process motor 113 and the feed motor 111 are increased by an amount necessary for starting up the motor (step S105).
[0043]
If the motor is not started up (NO in step S104), the process returns to step S100 again to determine whether or not the temperature has dropped.
[0044]
The laser printer shown in FIG. 5 controls the amount of current supplied to the motor by repeating the series of steps described above.
[0045]
In the process shown in FIG. 6 described above, only the case where the current is increased has been described. However, a process for decreasing the current due to a temperature rise or the like may be added to the process.
[0046]
【The invention's effect】
As described above, according to the present invention, an image forming apparatus effective for reducing noise and power consumption can be provided.
[0047]
In addition, according to the first embodiment of the present invention, since an amount of current corresponding to the environment is supplied to the motor, unnecessary power consumption can be suppressed, and noise can be prevented and power consumption can be reduced.
[0048]
Further, according to the second embodiment of the present invention, since the environment change detection means provided in the laser printer can be used as it is, an image in which power consumption is reduced without providing a special detection means. A forming apparatus can be provided.
[0049]
In addition, according to the third embodiment of the present invention, since a drive current is supplied to the motor 13 according to the load applied to the motor 13, it is possible to prevent an increase in noise and power consumption due to an excessive current supply. Can do.
[0050]
Further, according to the image forming apparatus of the fourth embodiment of the present invention, since the current actually flowing through the motor 13 is taken into consideration, the amount of drive current corresponding to the variation in the characteristics of the motor 13 and the secular change. Can be supplied.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a configuration of an image forming apparatus according to a first embodiment of the present invention.
FIG. 2 is a block diagram illustrating a configuration of an image forming apparatus according to a second embodiment of the present invention.
FIG. 3 is a block diagram illustrating a configuration of an image forming apparatus according to a third embodiment of the present invention.
FIG. 4 is a block diagram illustrating a configuration of an image forming apparatus according to a fourth embodiment of the present invention.
FIG. 5 is a block diagram showing an embodiment when the present invention is applied to a laser printer.
6 is a flowchart showing an example of a current control process executed by the laser printer shown in FIG. 5. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Paper conveyance means, 11 ... Image formation means, 12 ... Conveyance roller, 13 ... Motor, 14 ... Motor driver, 15 ... Environmental change detection means, 20 ... Transfer means, 21 ... Fixing means, 30 ... Load fluctuation detection means, DESCRIPTION OF SYMBOLS 40 ... Current value measuring means, 100 ... Paper discharge tray, 101 ... Laser scanning unit, 102 ... Charging roller, 103 ... Developing roller, 104 ... Photosensitive drum, 105 ... Transfer roller, 106 ... Static elimination plate, 107 ... Heat roller, 108 DESCRIPTION OF SYMBOLS ... Pressure roller, 110 ... Resistance value measurement circuit, 111 ... Feed motor, 112 ... CPU, 113 ... Process motor, 114 ... First paper feed tray, 115 ... Second paper feed tray, 116 ... Third paper feed tray

Claims (6)

A transport roller, a motor that drives the transport roller, a motor driver that supplies current to the motor, a paper transport unit that transports paper, and a transfer unit that transfers an image to the paper transported by the paper transport unit In an image forming apparatus comprising:
Comprising a resistance value change detecting means for detecting a change in resistance value of the transfer means,
The motor driver is
An image forming apparatus, wherein an amount of current supplied to the motor is controlled based on a change in resistance value detected by the resistance value change detecting unit. The paper conveying means is
A load fluctuation detecting means for detecting a load fluctuation of the motor;
The motor driver is
The image forming apparatus according to claim 1, wherein an amount of current supplied to the motor is controlled based on a load fluctuation detected by the load fluctuation detecting unit. The load fluctuation detecting means includes
The image forming apparatus according to claim 2, further comprising a paper feed position detecting unit that detects a position where the paper is supplied. The load fluctuation detecting means includes
The image forming apparatus according to claim 2, further comprising a sheet type detecting unit configured to detect the sheet type. The load fluctuation detecting means includes
The image forming apparatus according to claim 2, further comprising a torque amount detection unit configured to detect a torque amount required for the motor. The paper conveying means is
Comprising a current value measuring means for measuring a current value flowing through the motor;
The motor driver is
The image forming apparatus according to claim 1, wherein a current value supplied to the motor is controlled based on a current value measured by the current value measuring unit.

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