JP2000238943A - Continuous paper printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the pulling of a sheet and to miniaturize a tractor motor in a device having a fixing puller for carrying sheets fed from a pair of fixing rollers by stopping the rotation of the fixing puller when the sheet is returned to the direction reverse to the sheet carrying direction in printing. SOLUTION: When a sheet 5 to be fed by a tractor 6, after an electrostatic latent image formed on the surface of a photosensitive drum 1 is developed by a processor 3 according to print signal, travels in front of a transfer device 4, the sheet 5 is pressed onto the surface of the photosensitive drum 1 by a retractor to transfer the toner image to the sheet 5. Thereafter, the sheet 5 is fed to a pair of fixing rollers 9 and 10 after solving the difference in paper feeding speed by a buffer plate 8 to fix the toner image, and then fed to a stacker 15 by a fixing puller 11. When the printing is stopped, the sheet 5 is returned to the direction reverse to the sheet carrying direction in printing. At this time, the rotation of the fixing puller 11 is stopped to solve the pulling of the sheet between the fixing puller 11 and the tractor 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous paper printing apparatus for performing printing on a long continuous paper (continuous paper).

[0002]

2. Description of the Related Art FIG. 2 is a schematic configuration diagram of a continuous paper printing apparatus using an electrophotographic system. When a print signal decomposed into dot data comes from a host device (not shown), a laser beam 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 beam escapes, so that an electrostatic latent image is formed on the surface of the photosensitive drum 1. The electrostatic latent image is developed by the developing device 3 and carried to 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 a retractor (not shown). The toner image on the surface of the photosensitive drum 1 transported before the transfer unit 4 is transferred to a sheet 5 by the transfer unit 4. The sheet 5 onto which the toner image has been transferred passes over the buffer plate 8 and then passes between a fixing roller pair including a heat roller 9 and a backup roller 10 to be fixed by heat and pressure. The fixed paper 5 is sent to the swing fin 12 by the fixing puller 11, and is sequentially sent to the stacker 15 while being alternately folded by the pendulum movement of the swing fin 12.

Next, the operation when printing is stopped will be described with reference to FIG. FIG. 3 is a time chart showing an outline of the paper feeding operation from during printing to at the end of printing, where "1" or "-1" indicates that the signal is valid. Here, the case of rotating in the same rotation direction as the sheet conveyance direction during printing is described as positive, and the case of rotating in the rotation direction opposite to the sheet conveyance direction is described as negative.

During printing, the fixing puller 11 rotates in the same direction as the direction in which the paper 5 is conveyed, and the paper feed speed a
(B / inch / s)
Seconds)). At the end of printing, when a print stop signal is received from the host device, the backup roller motor 1
4, the heat roller 9 and the backup roller 10
The state is gradually shifted from the pressed state to the opened state (the state shown in FIG. 3). When the perforation of the paper 5 is conveyed to the pressure contact between the heat roller 9 and the backup roller 10, the paper feeding operation by the tractor 6 and the heat roller 9 ends, and the pressure contact between the heat roller 9 and the backup roller 10 is released (FIG. 3-state). Next, the sheet 5 is transported in a direction opposite to the normal transport direction until the perforation of the sheet 5 comes to a position shifted by １ ／ inch from the transfer point toward the hopper 18 (the state shown in FIG. 3). The fixing puller 11 has a constant speed (b (inch / second)) during printing by the motor 17 and during returning the paper 5 by the tractor 6 after printing.
Spinning at.

[0005]

In the continuous paper printing apparatus having the above-described structure, printing is stopped when paper is perforated at the pressure contact between the heat roller and the backup roller, the heat roller and the backup roller are opened, and the transfer point is set to the transfer point. The sheet is returned to the nearest perforation. Normally, the fixing puller 11 rotates in the same direction as the paper transport direction both during printing and during the paper return operation. During printing, the paper is conveyed to the stacker without sagging by rotating at a slightly higher speed than the heat roller, but during the paper return operation, the paper feed direction (the tractor rotation direction) Since the direction is reversed, a large force is applied to the tractor, causing a problem that the tractor motor loses synchronism or the tractor motor must be a large motor.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a continuous paper printing apparatus capable of reducing the size of a tractor motor by preventing the paper from being pulled between a tractor and a fixing puller.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a tractor for transporting a long continuous paper at a constant speed, and to pressurize and heat a toner image transferred on the paper to fix the toner image on the paper. A pair of fixing rollers, a fixing puller that conveys the sheet sent out from the pair of fixing rollers, and a sheet conveyance unit that is provided so as to be able to advance and retreat with respect to a sheet conveyance path between the pair of tractors and the fixing roller. In a continuous paper printing apparatus provided with a buffer plate for absorbing a speed difference, the present invention is achieved by providing means for stopping rotation of the fixing puller when returning the paper in a direction opposite to a paper transport direction during printing. .

[0008]

1 and 2 show an embodiment of the present invention.
This will be described with reference to FIG. FIG. 1 is a time chart showing an outline of a paper feeding operation during printing from the end to an end showing an example of the operation of the present invention. As in FIG. 3, it is confirmed that a signal is valid at "1" or "-1". Show. In addition, the case where the sheet rotates in the same rotation direction as the sheet conveyance direction during printing is described as positive, and the case where the sheet rotates in the rotation direction opposite to the sheet conveyance direction is described as negative.

The continuous paper printing apparatus starts a print stop operation in response to a print stop command received from a host device (not shown). At the end of printing, the backup roller motor 14 is driven to shift from the state in which the backup roller 10 and the heat roller 9 are in pressure contact to the state in which the backup roller 10 is gradually opened (the state of FIG. 1). At the timing when the heat roller motor 13 starts to decelerate before the conveyance of the sheet 5 is completed, the buffer plate 8 is fixed at the buffer position during the sheet conveyance by the buffer plate motor 19 (the state of FIG. 1). When the perforation of the paper 5 is conveyed to the pressure contact between the heat roller 9 and the backup roller 10, the paper feeding operation by the tractor 6 and the heat roller 9 ends, and the pressure contact between the heat roller 9 and the backup roller 10 is released (FIG. 1-).
After that, the fixing puller 11 is rotated to eliminate the slack of the sheet on the buffer plate 8. At the stop timing of the fixing puller motor 17, the tractor motor 7 is operated in the direction opposite to the paper transport direction to transport the paper 5 to the hopper side (the state shown in FIG. 1-). The paper 5 is transferred to the hopper 1 by the rotation of the tractor 6 and the transport puller 16 not shown in the timing chart.
The conveyance of the sheet 5 is stopped when the first perforation of the sheet 5 reaches the hopper side by 搬 送 inch from the transfer point.

After the conveyance of the sheet 5 is stopped, the fixing puller motor 17 is rotated again to prevent the sheet 5 from sagging on the buffer plate 8, and the fixing puller motor 17 is rotated so that the buffer motor 19 is tensioned on the sheet 5.
, The damage of the buffer 5 to the sheet 5 can be eliminated.

[0011]

As described above, according to the present invention, by stopping the fixing puller during the paper returning operation by the tractor, the paper is not pulled between the tractor and the fixing puller, and the tractor motor is not driven. Can be reduced in size. Further, after the paper return operation is completed, the fixing puller motor is rotated again, and the excitation of the buffer is cut off while the tension is applied to the paper by the fixing puller, so that the unfixed portion of the toner on the paper is jumped up by the paper, It is possible to prevent a serious trouble such as a printing paper being rubbed by a paper guide or the like, thereby causing improper printing.

[Brief description of the drawings]

FIG. 1 is a time chart showing an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a continuous paper printing apparatus.

FIG. 3 is a time chart showing a conventional example.

[Explanation of symbols]

6 tractor, 9 heat roller, 10 backup roller, 11 fixing puller, 17 fixing puller motor,
8 ... buffer plate, 19 ... buffer motor.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2C058 AB02 AC08 AE03 GA06 GB13 GB19 2C060 CB21 CB31 3F105 AA02 AB03 BA02 BA18 DA03 DB02

Claims (3)

[Claims] A tractor for conveying a long continuous sheet at a constant speed; a pair of fixing rollers for pressing and heating a toner image transferred onto the sheet to fix the toner image on the sheet; A fixing puller that conveys the sheet fed from the roller pair, a buffer plate that is provided so as to be able to advance and retreat to a sheet conveyance path between the tractor and the fixing roller pair, and absorbs a difference in sheet conveyance speed between the tractor and the fixing roller pair. A means for stopping rotation of the fixing puller when returning the paper in a direction opposite to a paper transport direction during printing. 2. The continuous paper printing apparatus according to claim 1, further comprising means for fixing the position of the buffer plate when returning the paper in the direction opposite to the paper transport direction during printing. 3. The continuous paper printing apparatus according to claim 2, wherein the fixing of the buffer plate is released while the fixing puller is rotating.