JPH09134091A - Fixing device for continuous paper printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent reduction in an effective printing speed and to reduce the size of an opening/closing mechanism and the cost by executing the opening/ closing operations of a heating roll and a backup roll, after transient stopping at a position just before the heating roll and a paper come into contact with each other. SOLUTION: When a printing start command is issued from a host device 16, a motor 15 is driven clockwise. When a sensor 27 for detecting the position just before the heating roll 9 and the paper come into contact with each other is turned on, a middle position is obtained and the driving of the motor 15 is transiently stopped. Then, the motor 15 is driven clockwise again and when the sensor 27 for detecting the contact state of the heating roll 9 with the paper 5 is turned on, the motor 15 is stopped. After that, the feeding of the paper is started to start, a printing operation. When printing is stopped, a printing stop command is issued from the host device and the motor 15 is driven counterclockwise. When the middle position as the position just before the heating roll 9 and the paper 5 come into contact with each other is obtained, the sensor 27 is turned on to transiently stop the driving of the motor 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device suitable for a continuous paper printing device using an electrophotographic method.

[0002]

2. Description of the Related Art FIG. 4 is an example of a diagram showing the principle of a continuous paper printing apparatus using an electrophotographic system. The outline of the principle will be described below. When a print signal decomposed into dot data comes from the host device 16, the laser light scans the surface of the photosensitive drum 1. The surface of the photosensitive drum 1 is uniformly charged by the charger 2, and the charge of the portion irradiated with the laser light escapes to form an electrostatic latent image on the surface of the photosensitive drum 1. The electrostatic latent image is developed by the developing device 3 and carried to the front of the transfer device 4. The paper 5 sent by the tractor 6 travels in front of the transfer device 4 at a constant speed, and is pressed against the surface of the photosensitive drum 1 by the retractor 7.
The toner image on the surface of the photosensitive drum 1 carried to the transfer device 4 is transferred to the sheet 5 by the transfer device 4. The sheet 5 on which the toner image is transferred passes through the buffer 8 and then the heat roll 9
It is fixed by heat and pressure by passing through between the backup roller 10 and the backup roll 10. The fixed paper 5 is sequentially sent to the stacker 12 by the puller 11. The buffer 8 absorbs the paper feed speed difference between the tractor 6 and the heat roll 9.

The fixing device of the continuous paper printing apparatus has an opening / closing mechanism 17 for bringing the heat roll 9 and the paper 5 into contact with each other at the time of printing and making the heat roll 9 and the paper 5 out of contact with each other at the time of non-printing. One embodiment of the opening / closing mechanism 17 will be described with reference to FIGS. 5, 6, and 7. 5 shows a state where the heat roll 9 and the paper 5 are separated from each other, and FIG. 6 shows a state where the heat roll 9 and the paper 5 are in contact with each other. The heat roll 9 and the paper 5 are brought into contact with each other by moving the backup roll 10 up and down. A pressure arm 20 is connected to the backup roll 10, and the pressure arm 20 moves up and down by rotating an eccentric cam 22. Also, by moving the pressure arm 20,
The spring 21 is pressed to apply pressure between the heat roll 9 and the backup roll 10. By rotating the motor 15, the gear 23, the gear 24
The cam 22 rotates through it. Backup roll 10
The open / closed state of is detected by the sensor 26. The sensor 26 is a transmissive optical sensor, and when the heat roll 9 and the paper 5 come into contact with each other, the sensor 26 is blocked by the sense plate 25, and the sensor 26 is turned on (“1” level).
Becomes

Next, the paper feeding operation from the start of printing to the stop of printing will be described with reference to the time chart of FIG. Heat roll 9 and backup roll 1 when not printing
0 is open and sensor 26 is off. When the print data is prepared, a print start command is issued from the upper level device 16, the motor 15 is driven clockwise for a certain period of time, and the heat roll 9 and the backup roll 10 are closed at a position where the cam 22 rotates about 180 degrees. Heat roll 9
When the sheet 5 comes into contact with the sheet 5, the sensor 26 is turned on. The motor 13 and the motor 14 are driven, the tractor 6 and the heat roll 9 are accelerated at the same time, and the paper is fed at a constant speed.
When printing is stopped, a print stop command is issued from the host device 16, the motors 13 and 14 are stopped, and the tractor 6 and heat roll 9 are stopped. The motor 15 is driven clockwise about 180 degrees to open the heat roll 9 and the backup roll 10. When the heat roll 9 and the paper 5 are separated from each other, the sensor 26 is turned off, the motor 15 is stopped, and printing is stopped.

[0005]

In the conventional fixing device, the distance between the heat roll 9 and the backup roll 10 is always sufficient to prevent yellowing of the paper 5 due to the heat of the heat roll 9 during non-printing. There was a gap. Conventionally, when opening and closing the backup roll 10, the backup roll 1
The cam 22 that drives 0 is rotated about 180 degrees.
In one example of the conventional continuous paper printing apparatus, the time T for rotating the cam 22 by 180 degrees is, for example, about 0.6 seconds, and it takes 0.6 seconds each to start printing and stop printing. . When performing intermittent printing in which printing and stopping are frequently repeated, there is a problem that the effective printing speed is significantly reduced. In order to prevent the reduction of the effective printing speed and to increase the speed of the opening / closing mechanism 17, an expensive and large AC motor or gear has been used.

The present invention has been made in order to solve such a conventional problem, and it is possible to prevent the effective printing speed from decreasing during intermittent printing, and to reduce the size and cost of the opening / closing mechanism 17. It is a thing.

[0007]

The above object is to provide the following means (1) and (2) so that when the backup roll is opened and closed when printing is started and when printing is stopped, the paper is temporarily stopped at a position just before the heat roll comes into contact with the paper. , The heat roll and the backup roll are opened and closed.

(1) A means for detecting the position just before the heat roll and the paper contact each other.

(2) A means for temporarily stopping the backup roll at a position just before the heat roll and the paper contact each other.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a fixing device 1 according to the present invention.
It is a block diagram which shows an Example. In FIG. 1, 16 is a host device, 31 is a CPU, and 32 is an I / F circuit. The printing operation is started by sending a print start command from the higher-level device 16 to the CPU 31, and a print stop command is sent by the CPU.
It ends by being sent to 31. CPU31 is I /
The motor 13, the motor 14, the motor 15, etc. are driven through the F circuit 32, and the state of the device is recognized by the sensor 26, the sensor 27, etc. The motor 13 is a motor that drives the tractor 6, the motor 14 is a motor that drives the heat roll 9, and the motor 15 is a motor that drives the opening / closing mechanism 17. The sensor 26 is a sensor that detects a state where the heat roll 9 and the paper 5 are in contact with each other, and the sensor 27 is a sensor that detects a position immediately before the heat roll 9 and the paper 5 are in contact with each other.

FIG. 2 shows an embodiment of the present invention regarding the opening / closing operation of the backup roll 10 from the start of printing to the stop of printing.
Will be described with reference to the time chart of FIG. In FIG. 3, the (A) OPEN position shows a state in which the heat roll 9, the sheet 5 and the backup roll 10 are separated from each other. (B) M
The IDDLE position indicates a state immediately before the backup roll 10 operates and the heat roll 9 and the paper 5 are in contact with each other. (C)
The CLOSE position indicates a state in which the backup roll 10, the heat roll 9, and the paper 5 are in contact with each other.

In the above embodiment, the drive amount for moving from the OPEN position to the MIDDLE position is the cam 22.
Rotate 165 degrees to close from MIDDLE position
It is 15 degrees to the position. Driving time is M from the OPEN position
It takes 1.1 seconds from the IDDLE position to 0.1 seconds from the MIDDLE position to the CLOSE position. In the conventional example, each opening / closing operation required 0.6 seconds, but in the present invention, each opening / closing operation may require 1.2 seconds.
It is possible to reduce the size and cost of the heat roll opening / closing mechanism.

When not printing, the heat roll 9 and the backup roll 10 are open. When the print data is prepared,
A print start command is issued from the host device 16, and the motor 15 is driven clockwise (CW) by about 165 degrees. When the sensor 27, which detects the position immediately before the heat roll 9 and the paper 5 come into contact with each other, is turned on, (B) the MIDDLE position is reached, and the driving of the motor 15 is temporarily stopped. Motor 15
Is driven again about 15 degrees in the clockwise direction (CW), the sensor 26 for detecting the contact state between the heat roll 9 and the sheet 5 is turned on, and the motor 15 is stopped. After that, the paper feeding is started and the printing operation is performed. Upper device 16 when printing is stopped
A print stop command is issued by this to drive the motor 15 about 15 degrees in the counterclockwise direction (CCW). Heat roll 9
When the sheet reaches the MIDDLE position, which is the position immediately before the sheet 5 comes into contact with the sheet 5, the sensor 27 is turned on and the driving of the motor 15 is temporarily stopped. The CPU 31 starts the restart monitoring timer of x seconds by the print stop command.
When a print start command is issued again from the higher-level device 16 after y seconds, which is a time shorter than x seconds, the motor 15 is driven clockwise (CW) about 15 degrees, and the state in which the heat roll 9 and the paper 5 are in contact with each other is maintained. The sensor 26 for detection is turned on, the drive of the motor 15 is stopped, and the printing operation is restarted. When the print stop command is issued from the upper device 16, the motor 15 is driven in the counterclockwise direction (CCW) by about 15 degrees, and the position immediately before the contact between the heat roll 9 and the paper 5 is MIDD.
When the LE position is reached, the sensor 27 is turned on and the driving of the motor 15 is temporarily stopped. The CPU 31 starts the restart monitoring timer of x seconds by the print stop command. When the print start command is not issued from the host device 16 even after x seconds have passed, the motor 15 is driven counterclockwise (CCW) by about 165 degrees, and the heat roll 9, the paper 5, and the backup roll 10 are opened. A certain OPE
When the N position is reached, the driving of the motor 15 is stopped and the printing is stopped.

In the above-described embodiment of the present invention, the sensor 27 is used as a means for detecting the position immediately before the heat roll 9 and the paper 5 come into contact with each other. However, as another example, a stepping motor is used to provide a certain number of steps. Can be replaced with an open loop control that operates.

[0015]

According to the present invention, after the backup roll is temporarily stopped at the position just before the heat roll and the paper contact each other,
Since the opening / closing operation of the heat roll and the backup roll is performed, it is possible to prevent the effective printing speed from decreasing without increasing the size and complexity of the heat roll opening / closing mechanism.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of a fixing device of a continuous paper printing device according to the present invention.

FIG. 2 is a time chart of the fixing device in FIG.

FIG. 3 is a state explanatory view showing a positional relationship between a heat roll, a sheet, and a backup roll of the fixing device of FIG.

FIG. 4 is a schematic configuration diagram showing the principle of a continuous paper printing device.

FIG. 5 is a configuration diagram showing an example of an opening / closing mechanism of a conventional fixing device.

FIG. 6 is a configuration diagram showing an example of an opening / closing mechanism of a conventional fixing device.

FIG. 7 is a configuration diagram showing an example of an opening / closing mechanism of a conventional fixing device.

FIG. 8 is a time chart of a conventional fixing device.

[Explanation of symbols]

5 ... Paper, 9 ... Heat roll, 10 ... Backup roll, 17 ... Opening / closing mechanism

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kiyomi Tsuchiya 1060 Takeda, Hitachinaka City, Ibaraki Prefecture Hitachi Koki Co., Ltd.

Claims (2)

[Claims] 1. A toner image is fixed by pressurizing and heating a sheet with a heat roll and a backup roll, the heat roll and the backup roll are opened during non-printing, and the heat roll and the backup during printing. In a fixing device of a continuous paper printing apparatus having an opening / closing device that closes a roll and allows the heat roll and the paper to come into contact with each other, during the opening / closing, after a temporary stop at a position immediately before the heat roll and the paper come into contact with each other, A fixing device for a continuous paper printing device, wherein a heat roll and the backup roll are opened and closed. 2. The fixing device of the continuous paper printing apparatus according to claim 1, wherein when printing is stopped, when printing is resumed within a fixed time after being temporarily stopped at the immediately preceding position, the heat roll and the backup are provided. Close the roll to print,
A fixing device for a continuous paper printing apparatus, wherein the heat roll and the backup roll are opened when printing is not restarted after a lapse of a certain time.