JP2998819B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention detects a temperature inside an apparatus main body by a temperature sensor, and based on a result of comparison between the detected temperature and a predetermined set temperature, removes warm air inside the apparatus main body through an exhaust device. In particular, the present invention relates to an image forming apparatus, such as a laser printer, which discharges paper to a printer. The present invention relates to an image forming apparatus capable of changing a set temperature to be set.

[0002]

2. Description of the Related Art Generally, in an image forming apparatus such as a laser printer, a high-temperature generating section is provided in the apparatus, and the temperature in the apparatus increases with the image forming operation. An exhaust device is provided for exhausting the air.

This exhaust system has an exhaust fan,
If the exhaust fan is constantly rotated during image formation, power is consumed more than necessary, and noise is generated for a long time as the exhaust fan rotates. Therefore, conventionally, a temperature sensor for detecting the temperature inside the apparatus, a temperature inside the apparatus detected by the temperature sensor and a preset temperature (usually set to a relatively high temperature, and set to a high temperature of about 80 ° C.). Various types of image forming apparatuses have been proposed which have a comparing means for comparing the set temperature with the set temperature, and perform the rotation drive of the exhaust fan when the temperature in the apparatus becomes higher than the set temperature.

According to such an image forming apparatus, when the internal temperature of the apparatus detected by the temperature sensor becomes higher than the set temperature, the rotation driving of the exhaust fan is started.
It does not consume power unnecessarily or generate noise over a long period of time, and can reduce the temperature inside the device relatively quickly to prevent the temperature inside the device from becoming too high. .

[0005]

However, the conventional image forming apparatus has only one set temperature which is a reference for starting the driving of the exhaust fan, and the set temperature is detected by the temperature sensor. The exhaust fan is driven based only on the result of comparison with the internal temperature of the apparatus. Further, there is no attempt to detect the transport state of a sheet in a transport device that transports printing paper in the apparatus, and to start driving the exhaust fan in conjunction with the detection result.

Therefore, in the conventional image forming apparatus, the exhaust fan is driven irrespective of whether the printing apparatus is properly transporting the printing paper by the transport apparatus or whether the transport state is abnormal. Becomes Than this,
If an abnormality occurs in the transport state, the exhaust fan will not be driven to rotate unless the inside of the apparatus reaches a high temperature of about 80 ° C. Therefore, the printing paper left in the apparatus due to the transport abnormality because the inside of the apparatus is high temperature. However, there is a problem that it becomes difficult to remove from the inside of the apparatus.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and detects the state of conveyance of printing paper and, when an abnormality is detected in the conveyance of paper, lowers the temperature in the apparatus. Provided is an image forming apparatus capable of quickly lowering the temperature inside the apparatus by driving a discharge unit when a set temperature is reached, and easily removing print paper remaining in the apparatus due to a conveyance abnormality from the apparatus. With the goal.

[0008]

In order to achieve the above-mentioned object, the present invention provides a paper transporting means for transporting a printing paper along a transporting path in an apparatus main body, and a printing paper on the printing paper transported by the paper transporting means. Image forming means for forming an image, conveying state detecting means disposed in the conveying path and detecting a conveying state of the printing paper conveyed by the conveying means, and detecting a temperature in the apparatus main body. Temperature detecting means, temperature storing means for storing a first temperature set in advance and a second temperature lower than the first temperature, discharging means for discharging warm air in the apparatus main body to the outside of the apparatus main body, Comparing means for comparing the temperature detected by the temperature detecting means with the first temperature and the second temperature stored in the temperature storing means; and driving the discharging means based on the result of the comparison by the comparing means. Control means for controlling, when the conveyance state detection means detects that the conveyance of the printing paper is performed normally, the control means detects the detection via the temperature detection means by the comparison means. The drive control of the discharge unit is performed based on a comparison result between the detected temperature and the first temperature, and when the conveyance state detection unit detects that an abnormality has occurred in the conveyance state of the printing paper, the comparison unit determines The drive control of the discharge means is performed based on a comparison result between the temperature detected through the temperature detection means and the second temperature.

[0009]

According to the present invention having the above construction, the printing paper is transported to the image forming means via the paper transporting means, and an image is formed on the printing paper in the image forming means. In parallel with the image forming operation, the temperature inside the apparatus main body detected by the temperature detecting means is compared with the first temperature stored in the temperature storing means and the second temperature lower than the first temperature via the comparing means. At the same time, the transport state of the printing paper in the transport path is detected by the transport state detecting means.

When the conveyance state detecting means detects that the printing paper is being conveyed normally, the comparing means compares the first temperature with the temperature in the apparatus main body and compares the first temperature with the temperature in the apparatus main body. Based on the result, the control means drives the discharging means to discharge the warm air in the apparatus main body to the outside. On the other hand, when the conveyance state detecting means detects that an abnormality has occurred in the conveyance of the printing paper, the comparing means compares the second temperature with the temperature in the apparatus body, and based on the comparison result, the control means. Drives the discharging means to discharge the warm air in the apparatus main body to the outside.

In this way, when an abnormality occurs in the conveyance of the printing paper, the discharging means is driven when the temperature in the apparatus main body becomes low, so that the apparatus main body is cooled quickly. The printing paper remaining in the apparatus main body due to the conveyance abnormality is easily removed.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a laser printer according to an embodiment of the present invention; FIG. 1 is a side sectional view schematically showing the outline of the printer. In the printer main body 1, a paper feed unit A, an image forming unit B, an image fixing unit C, and an exhaust unit D are arranged.

The paper feeding section A includes a paper feeding cassette 2 and a half moon roller 3
And a pair of paper feed rollers 4. The printing paper P is stored in a stacked state in the paper cassette 2, and the bottom surface of the paper cassette 2 is constantly urged upward by a spring 5. Above the front end of the sheet cassette, a half-moon roller 3 that is driven to rotate by a main motor 45 described later is supported.
The printing paper P stored in the paper feeding cassette 2 is sequentially and intermittently fed to the paper feeding roller 4 one by one. Also,
A paper feed roller 4 is provided downstream of the half-moon roller 3, and the paper feed roller 4 is driven to rotate by a main motor 45 and sends the printing paper P further downstream.

A paper guide 12 is disposed downstream of the paper feed roller 4 and between the paper feed roller 4 and a registration roller 14, which will be described later. 13 are provided.
The sensor 13 detects the leading end of the print paper P sent from the paper guide guide 12, and
The detection signal of No. 3 is used as a trigger signal for driving the rotation of the registration roller 14.

A pair of registration rollers 14 disposed downstream of the sensor 13 correct the skew of the printing paper P at its rotational contact position, and move the printing paper P from the downstream paper guide guide 16 to the rollers 17. Is sent to the image forming unit B through The registration roller 14 is connected to the sensor 13
After a certain period of time has passed since the detection signal is output, the rotational drive is started via a solenoid clutch 43 described later. Further, the paper guide 16 and the roller 17 feed the printing paper P sent from the registration roller 14 to the image forming unit B. In the image forming unit B, a predetermined image is printed on the printing paper P. It is formed.

The image forming section B includes a scanner unit 21 disposed above the inside of the printer main body 1, a photosensitive drum 20 disposed in the case 15, a developing device 22, a transfer charger 18, and a static eliminator 19. Consists of The scanner unit 21 scans a laser oscillator based on image data received from an external device 49 (see FIG. 3) such as a host computer, and outputs a laser beam from the laser oscillator to a mirror M.
The transmission hole 15A formed in the case 15 after the reflection
Then, an image is exposed on the photosensitive drum 20 to form an electrostatic latent image. The photosensitive drum 20 is provided with a photosensitive material on a drum peripheral surface, and is rotated by a main motor 45. Further, the developing device 22 is for developing the electrostatic latent image formed on the photosensitive drum 20 via the scanner unit 21 as described above, and is developed by a high-voltage power supply unit 42 (see FIG. 3) described later. Controlled. The transfer charger 18 transfers the electrostatic latent image developed by the developing device 22 onto the printing paper P. The static eliminator 19 transfers the printing paper P to the photosensitive drum after the electrostatic latent image is transferred. In order to separate the printing paper P from the printing paper P, the printing paper P is neutralized. The transfer charger 18 and the charge remover 19 are both controlled via a high-voltage power supply unit 42 (see FIG. 3).

As a result, a predetermined image is formed on the printing paper P sent from the paper guide guide 16 by the rollers 17 in accordance with the image data when the printing paper P passes through the image forming section B. The sheet is conveyed to the image fixing section C from a conveyance guide 23 disposed downstream of the static eliminator 19.

The image fixing section C is composed mainly of a heat roller 25 disposed in a case 24. A heater 26 is provided inside the heat roller 25, and the rotational drive of the heat roller 25 is controlled by a main motor 45, while the heating control of the heater 26 is performed via an AC driver circuit 46 described later. In addition, a driven roller 50 is disposed in contact with the heat roller 25, and the printing paper P is heated by the rollers 25 and 50 and is fed toward the pair of discharge rollers 51 while an image is fixed. Here, the heater 26 is turned on simultaneously with the start of the image forming operation by the image forming unit B, and the heat roller 25 is heated.

A discharge guide 27 is disposed downstream of the discharge roller 51, and a discharge roller 28 rotated by a main motor 45 is supported at a downstream end of the discharge guide 27. As a result, the printing paper P discharged from the image fixing unit C is discharged from the discharge guide 27 via the discharge rollers 28 onto the discharge tray 29 formed on the upper surface of the printer body 1 and stacked. .

Further, a paper sensor 30 is disposed near a connecting portion between the image fixing section C and the paper discharge guide 27. The paper sensor 30 is connected to a timer T described later.
(See FIG. 3) to constitute a conveyance state detecting device for detecting the conveyance state of the printing paper P, and the first state set by the timer T after the registration roller 14 starts rotating. If the paper sensor 30 does not detect the passage of the printing paper P even after the predetermined time elapses, or if the paper sensor 3
The paper sensor 30 does not detect that there is no paper (that the printing paper P has passed through the paper sensor 30) even if the second predetermined time set in the timer T has elapsed since 0 has detected the passage of the printing paper P. In this case, it is determined that an abnormality has occurred in the conveyance of the printing paper P.

Further, an exhaust fan F rotated by a fan motor 31 is mounted at an upper position between the image forming section B and the image fixing section C. As shown in FIG. This is mainly for discharging the warm air in the printer main body 1 heated by the heat generated from the heat roller 25 of the image fixing section C to the outside. Further, a temperature sensor 41 is disposed above the image fixing section C, and the temperature sensor 41 detects a temperature in the printer main body 1.

Thus, when the paper sensor 30 detects that the printing paper P is normally conveyed, the first temperature (80) stored in the temperature memory 52 (see FIG. 3) described later. C.) and the temperature inside the printer main body 1 detected by the temperature sensor 41, and the detected temperature is stored in the first memory 52 of the temperature memory 52.
When the temperature becomes higher than the temperature, the exhaust fan F is driven to rotate, and the warm air in the printer main body 1 is discharged to the outside. Then, the printer unit 1 is cooled down to a temperature lower than 80 ° C., thereby protecting the scanner unit 21 and the like.

On the other hand, if the sheet sensor 30 detects that an abnormality has occurred in the conveyance of the printing sheet P, the second temperature lower than the first temperature stored in the temperature memory 52 (about 40 ° C.). Is set) and the temperature inside the printer main body 1 detected by the temperature sensor 41,
When the detected temperature becomes higher than the second temperature in the temperature memory 52, the exhaust fan F is driven to rotate, and the warm air in the printer main body 1 is discharged to the outside. And
Cooling is rapidly performed until the temperature inside the printer main body 1 becomes lower than 40 ° C.

Next, a control system of the laser printer configured as described above will be described with reference to FIG. FIG.
FIG. 1 shows a block diagram of a control system in a laser printer, which is configured with a control device (hereinafter, referred to as a CPU) 40 as a core. The CPU 40 executes various calculations and processes, and has a known ROM and RAM. The ROM stores various programs necessary for controlling the printer, such as a rotation control program for the fan motor F, a jam processing program when the conveyance of the printing paper P is abnormal, and a print control program. RAM is CPU
Various types of data calculated by 40 are temporarily stored.

The CPU 40 is connected to a low-voltage power supply unit 47 from an AC power supply via a power switch S.
The unit 40 receives a voltage from the low-voltage power supply unit 47 and executes a predetermined operation. In addition, the low-voltage power supply unit 4
7, the motor driver 44 and the AC driver circuit 46
Is supplied with voltage.

The CPU 40 includes a paper sensor 30, a scanner unit 21, a fan motor 31, and a sensor 13.
Is connected. The paper sensor 30 measures the first time set by the timer T (measured after the registration roller 14 starts rotating) and the second time (measured after the paper sensor 30 detects the passage of the printing paper P). ), The CPU 40 determines whether or not the printing paper P is normally conveyed based on the detection result. Note that the first and second times are stored as data in the ROM, and the CPU 40
Is set to

When the printing paper P is normally conveyed,
The CPU 40 detects the temperature in the printer main body 1 detected by the temperature sensor 41 and the first temperature stored in the temperature memory 52.
Compare with temperature (80 ° C). As a result of the comparison, when the temperature detected by the temperature sensor 41 is higher than the first temperature, the fan motor 31 is driven to rotate to discharge the warm air in the printer main body 1 to the outside via the exhaust fan F. When the temperature detected by the temperature sensor 41 is lower than the first temperature, the rotation of the fan motor 31 is stopped.

When an abnormality occurs in the conveyance of the printing paper P, the CPU 40 detects the temperature in the printer main body 1 detected by the temperature sensor 41 and the second temperature stored in the temperature memory 52 (which is lower than the first temperature). Lower 40 ° C.). As a result of the comparison, when the temperature detected by the temperature sensor 41 is higher than the second temperature, the rotation of the fan motor 31 is performed and the printer main body 1 is driven via the exhaust fan F.
While the internal warm air is discharged to the outside, if the temperature detected by the temperature sensor 41 is lower than the second temperature, the rotation drive of the fan motor 31 is stopped. The temperature memory 52 for storing the first and second temperatures is connected to the CPU 40.

Further, the CPU 40 controls the scanner unit 21 based on image data and the like received from an external device 49 such as a host computer via the video controller 48, and irradiates a laser beam onto the photosensitive drum 20 from a laser oscillator. Thus, an electrostatic latent image is formed on the drum 20.
The paper sensor 13 outputs a detection signal to the CPU 40 when detecting the leading end of the printing paper P. The CPU 40 receives the detection signal, measures a predetermined time by a timer T, and then registers the registration roller via the solenoid clutch 43. 1
4 is rotationally driven.

The CPU 40 includes a high-voltage power supply unit 42
, Developing device 22, transfer charger 18 and static eliminator 19
To form an image on the printing paper P based on the electrostatic latent image formed on the photosensitive drum 20 as described above. Further, the CPU 40 controls the rotation of the main motor 45 by controlling the motor driver 44 to which the voltage is supplied from the low-voltage power supply unit 47. The rotation of the roller 4, the photosensitive drum 20, the paper discharge roller 28, and the heat roller 25 is controlled. Also, CP
U40 is a voltage A supplied from the low-voltage power supply unit 47.
The heating control of the heater 26 provided inside the heat roller 25 is performed via the C driver 46.

Next, the operation of the laser printer configured as described above will be described with reference to FIGS. FIG. 4 is a flowchart showing a rotation control program for the fan motor F, and FIG. 5 is a flowchart showing a jam processing program when the conveyance of the printing paper P is abnormal.

First, in FIG. 4, when the power of the laser printer is turned on via the power switch S, the CPU 40
Starts the execution of the flowchart after performing the initial setting. In step (hereinafter abbreviated as S) 1, image data and the like are received from the external device 49 via the video controller circuit board 48, and whether a print start signal exists in the data from the video controller circuit board 48. Judge whether or not. If there is a print start signal (S1: YES), the flow shifts to S2, while if there is no print start signal (S1: NO), the process waits until a print start signal is input.

In S2, the heating of the heater 26 provided inside the heat roller 25 is started to increase the temperature of the heat roller 25. When the temperature of the heat roller 25 reaches a state in which the image can be fixed, the half-moon roller 3 and the paper feed roller 4 of the paper feed unit C are rotated via the main motor 45 to start the conveyance of the printing paper P, The scanner unit 21 is scanned based on the image data received from the controller circuit board 48 to form an electrostatic latent image on the photosensitive drum 20.
The transfer charger 18 and the neutralizer 19 are driven to start printing an image on the printing paper P (S3).

Thereafter, in S4, the temperature inside the printer body 1 is detected by the temperature sensor 41, and the detected temperature inside the printer body 1 is compared with the first temperature stored in the temperature memory 52. It is determined whether the detected temperature is equal to or higher than the first temperature. If it is determined that the temperature is equal to or higher than the first temperature (S4: YES), the fan motor 31 is rotated to exhaust the warm air in the printer main body 1 to the outside via the exhaust fan F (S5), and then the process proceeds to S7. On the other hand, when the temperature detected by the temperature sensor 41 is lower than the first temperature (S4: NO), the rotation of the fan motor 31 is stopped (S6), and the process proceeds to S7.

In step S7, the transport state of the printing paper P is detected by the paper sensor 30, and it is determined whether the transport state is normally performed. If the printing paper P is normally conveyed (S7: YES), it is determined in S8 whether the printing operation is completed. If the image data to be printed remains (S8: NO), the processing from S4 is repeated to continue printing. If the printing is to be ended (S8: YES), the process returns to S1 to start printing new image data. On the other hand, in S7, as described above, the paper sensor 30 does not detect the passage of the printing paper P even if the first predetermined time set in the timer T has elapsed from the start of rotation of the registration roller 14 as described above. Or
An abnormality occurs in the conveyance of the printing paper P such that the paper sensor 30 does not detect the absence of the paper even after the second predetermined time set in the timer T has elapsed since the paper sensor 30 detects the passage of the printing paper P. In this case (S7: NO), after the jam processing of the printing paper P, which will be described later, is executed in S9, S1 is executed.
Return to

Next, a jam process for handling a jam caused by an abnormal conveyance of the printing paper P will be described with reference to FIG. First, when an abnormality occurs in the conveyance of the printing paper P,
In S11, the heater 26 in the heat roller 25 is turned off. Subsequently, in S12, the rotation of the main motor 45 is stopped, and the scanning of the laser oscillator by the scanner unit 21 is also stopped (S13). Further, the high voltage power supply unit 42 is also turned off (S14).

In the following S15, the temperature inside the printer main body 1 is detected by the temperature sensor 41, and the detected temperature is compared with the second temperature stored in the temperature memory 52, and the detected temperature becomes higher than the second temperature. Determine if it has become. When the temperature is equal to or higher than the second temperature (S15: YES), the fan motor 31 is rotated to exhaust the warm air in the printer body 1 to the outside via the exhaust fan F (S1).
6), proceed to S18. On the other hand, when the temperature detected by the temperature sensor 41 is lower than the second temperature (S15: N
O), after the rotation of the fan motor 31 is stopped (S1).
7) The process proceeds to S18.

In S18, it is determined whether or not the jammed print sheet P has been removed by the sheet sensor 30. If the jammed paper has not been removed (S18:
(NO), the process returns to S15 to perform the rotation control of the fan motor 31 again. If the jammed paper has been removed (S18: YES), the rotation of the fan motor 31 is stopped (S19), and the jam processing is thereafter terminated.

As described in detail above, the laser printer according to the present embodiment detects whether the printing paper P is normally conveyed in the printer main body 1 by cooperation of the paper sensor 31 and the timer T, and performs printing. When the paper P is normally conveyed, the fan motor 31 is detected based on a comparison between the temperature inside the printer main body 1 detected by the temperature sensor 41 and the relatively high first temperature stored in the temperature memory 52.
When the conveyance of the printing paper P has an abnormality, the temperature in the printer main body 1 detected by the temperature sensor 41 and the first temperature lower than the first temperature stored in the temperature memory 52 are determined. Since the rotation of the fan motor 31 is performed based on the comparison with the second temperature, when the conveyance of the printing paper P has an abnormality, the rotation of the fan motor 31 is performed based on the relatively low second temperature. As a result, the warm air in the printer main body 1 can be quickly discharged to the outside.

As a result, the inside of the printer main body 1 is quickly cooled, and the printing paper P jammed in the image fixing section C or the like can be removed very easily. It should be noted that the present invention is not limited to the above-described embodiment, and it is needless to say that various improvements and modifications can be made without departing from the spirit of the present invention.

[0041]

As described above, according to the present invention, when the transport state of the printing paper is detected and an abnormality is detected in the transport of the paper, the discharging means is activated when the temperature in the apparatus reaches a lower set temperature. By driving the image forming apparatus, it is possible to provide an image forming apparatus capable of quickly lowering the temperature inside the apparatus and easily removing the printing paper remaining in the apparatus due to a conveyance abnormality from the apparatus, and the effect provided by the apparatus is great. .

[Brief description of the drawings]

FIG. 1 is a side sectional view schematically showing an outline of a laser printer.

FIG. 2 is an explanatory diagram illustrating a state in which warm air inside the printer body is exhausted to the outside by an exhaust fan.

FIG. 3 is a block diagram of a control system in the laser printer.

FIG. 4 is a flowchart showing a fan motor rotation control program.

FIG. 5 is a flowchart of a jam processing program in a case where printing paper conveyance is abnormal.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Printer main body 2 Paper feed cassette 3 Half moon roller 4 Paper feed roller 12, 16 Paper guide guide 14 Registration roller 18 Transfer charger 19 Static eliminator 20 Photoconductor drum 21 Scanner unit 22 Developing device 23 Transport guide 27 Paper discharge guide guide 30 Paper Sensor 31 Fan motor 40 CPU 41 Temperature sensor 52 Temperature memory A Paper feeder A B Image forming unit C Image fixing unit D Exhaust unit F Exhaust fan

──────────────────────────────────────────────────の Continuation of front page (51) Int.Cl. ⁷ identification code FI G03G 21/00 520 B41J 29/00 P (58) Field surveyed (Int.Cl. ⁷ , DB name) G03G 21/00 500- 540 G03G 15/00 510-534 G03G 15/20 G03G 13/20 B41J 29/377

Claims (1)

(57) [Claims] An image forming unit configured to form an image on the printing sheet conveyed by the sheet conveying unit; a sheet conveying unit configured to convey the printing sheet along a conveying path in the apparatus main body; A transport state detecting means disposed to detect a transport state of the printing paper transported by the transport means, a temperature detecting means for detecting a temperature in the apparatus main body, a first preset temperature and a preset first temperature. Temperature storage means for storing a second temperature lower than the first temperature; discharge means for discharging warm air in the apparatus main body to the outside of the apparatus main body; and temperature detected by the temperature detection means and the temperature storage means. Comparing means for comparing the stored first temperature and second temperature with each other; and control means for controlling the driving of the discharge means based on a result of the comparison by the comparing means. The transport state detection if that transport of the printing paper is normally performed is detected by means, said comparing means is by detecting through the temperature detecting means is temperature and the first
The drive control of the discharge unit is performed based on the comparison result with the temperature, and when the conveyance state detection unit detects that an abnormality has occurred in the conveyance state of the printing paper, the comparison unit detects the abnormality through the temperature detection unit. An image forming apparatus configured to perform drive control of the discharge unit based on a comparison result between the temperature detected and the second temperature.