JPH05249784A - Printer - Google Patents

Abstract

PURPOSE:To provide a printer not having the occurrence of deflection and tension, even a transfer medium is carried by plural rollers provided in a carrying path. CONSTITUTION:The printer is provided with a transfer device 8 forming a recorded image on the transfer medium (p) of a prescribed length, a first roller 3 disposed on a carrying in side with interposed the transfer device 8, and carrying the transfer medium (p) to the transfer device 8, and a second roller 5 disposed on the carrying away side of the transfer device 8 and carrying away the transfer medium (p) on which an image is formed, and carrying the transfer medium (p) by the drive of the first roller 3 and the second roller 5, a distance between parts C and D for actuating the carrying of the first and second rollers 3 and 5, is set shorter than the length of the transfer medium (p), a drive interrupter cutting off driving force to the first roller 3, and a control part judging that the leading edge part in the carrying direction of the transfer medium (p) reaches the part D for actuating the carrying of the second roller 5, and controlling the drive interrupter, to cut off the driving force of the first roller 3, is provided, as a characteristic.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer device for printing a document or image information created by a computer or a word processor on a recording sheet, a copying machine for copying the document or image information, and a transfer of the document or image information. The present invention relates to a printer device that is a component of a facsimile or the like.

[0002]

2. Description of the Related Art A conventional conveying system such as a printer of this type comprises a plurality of conveying roller pairs which are simultaneously driven by a motor. For example, in an electrophotographic printer or the like, a take-out roller is arranged on the carry-in side and a fixing roller pair is arranged on the carry-out side so as to sandwich a transfer device for forming a recorded image on a sheet, and one or more motors are provided. Is connected to the roller shaft by a reduction mechanism using a pulley and a gear. Then, the take-out roller and the fixing roller pair are simultaneously driven by the motor, and the paper placed in the paper stocker is carried into the transfer device in the printer by the take-out roller. Next, a toner image as a recording image is formed on the paper by the transfer device, and then, when the paper reaches the fixing device, the toner image on the paper is melt-pressed and fixed by the fixing roller pair. Then, the sheet is carried out by the fixing roller pair.

In such a printer, if the peripheral speeds of the take-out roller and the fixing roller pair do not match, the paper will be pulled or bent due to the difference in transport speed. In particular, in an electrophotographic printer device, the transfer efficiency may change due to the bending or pulling of the paper, or the image may deteriorate due to the paper being displaced at the transfer position. In addition, when the paper is bent, the toner image, which is only attached to the paper after transfer, may come into contact with the structural member of the printer device and come off, so that the height in the paper transport path from transfer to fixing may be high. It is necessary to take a large space in the direction, which is disadvantageous for downsizing. Further, when the sheet is pulled by the take-out roller during conveyance by the pair of fixing rollers, slipping of the sheet may cause fixing failure.

For this reason, conventionally, the take-out roller and the fixing roller pair are simultaneously driven to match the outer peripheral speeds of the rollers.

However, it is very difficult to accurately match the outer peripheral speeds of the rollers due to reasons such as the limit of processing accuracy, and there is a risk of causing troubles due to pulling or the like.

[0006]

As described above, it is very difficult to accurately match the outer peripheral speeds of the respective rollers in the conventional printer apparatus using a plurality of rollers due to the limitation of processing accuracy. Due to the difference in the transport speed, there is a possibility that a defect may occur due to the bending and pulling of the paper.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a printer device that does not affect printing due to the difference in the peripheral speed of each roller, even in the printer device in which the paper is conveyed by a plurality of rollers.

[0008]

In order to achieve the above object, according to the present invention, a transfer device for printing information on a transfer medium having a predetermined length, a first roller for carrying the transfer medium into the transfer device, A printer device comprising: a second roller that carries out the transfer medium, the first roller and the second roller
The distance between the conveying action parts of the rollers is set shorter than the length of the transfer medium, and a driving force interrupting means for interrupting the driving force to the first roller is provided, and a front end portion in the conveying direction of the sheet-like transfer medium is provided. Is provided with a control means for controlling the driving force connecting / disconnecting means to determine that the driving force has been reached to the conveying action portion of the second roller to cut off the driving force of the first roller.

[0009]

According to the present invention configured as described above, the first
Even if the transfer medium is carried in to the transfer device by the second roller and is carried out by driving the second roller, the control means determines that the front end portion of the transfer medium in the carrying direction has reached the carrying action of the second roller. Since the driving force connecting / disconnecting means is controlled based on the judgment, the driving forces of the first roller and the second roller do not act on the transfer medium at the same time, or even if they act at the same time, it is possible to shorten the time. ..

[0010]

Embodiments of the present invention will be described below.

FIG. 1 is a schematic diagram showing the construction of an electrophotographic printer apparatus according to an embodiment of the present invention, FIG. 2 is a schematic construction diagram showing the construction of a paper transport mechanism according to the embodiment of the present invention, and FIG.
Is also a schematic configuration diagram showing a driving force transmission and mode switching mechanism according to the embodiment of the present invention, FIG. 4 is a schematic configuration diagram showing a drive control unit according to the embodiment of the present invention, and FIG. 6 is a timing chart showing a drive / non-drive mode switching timing according to an example.

The printer device 1 includes a printing device 2 capable of printing characters and images, a take-out roller 3 as a first roller included in a take-out means, and a fixing roller pair as a second roller. The fixing device 7 having the number 5 is provided.

The printing device 2 includes a photosensitive drum 9 and a transfer roller 1 as a transfer device 8 for forming an information image such as characters and images on a printing paper P as a sheet-shaped transfer medium having a predetermined length.
1, an optical line head 13, a developing roller 15
And a developing device 19 having a rubber blade 17, a charge eliminating lamp 21, a memory charge eliminating brush 23, and a charging charger 25.

The take-out roller 3 is arranged on the carry-in side of the transfer device 8, and takes out one print paper p from the top of the print paper group P stocked in the paper stocker 33 and carries the print paper p into the transfer device 8. It is a thing.

The fixing device 7 is arranged on the unloading side of the transfer device 8 and is provided with a fixing roller 27 as a fixing roller pair 5 and a pressure contact roller 29 to fix the toner image transferred onto the printing paper p. A paper carry-out roller 31 is provided behind the fixing device 7.

Therefore, the printing paper p is conveyed toward the printing device 2 by driving the take-out roller 3 and is sent to the nip portion between the photosensitive drum 9 and the transfer roller 11. The photosensitive drum 9 is rotationally driven at a constant speed in the direction of arrow A in the figure to form a toner image on the surface of the printing paper p.

The formation of the toner image will be described.
On the surface of the photosensitive drum 9, a photoconductor layer such as an organic photoconductor that causes a photoconductive phenomenon when irradiated with light is formed. The surface of the photosensitive drum 9 is uniformly charged by a charging charger 25 that applies a high voltage to a thin wire and causes corona discharge. The charging charger 25 in this embodiment charges the surface of the organic photoconductor negatively with a minus charger. The optical line head 13 irradiates the surface of the photosensitive drum 9 with light so as to correspond to printed characters and images. Each light emitting element of the optical line head 13 blinks according to the printed character / image information, and irradiates the charged surface of the photosensitive drum 9 with light. Carriers are generated in the photosensitive layer in the portion irradiated with light, and the charges charged on the surface are removed through the earth line grounded to the conductive portion of the photosensitive drum 9, and the surface potential is almost 0V.
And a positive surface potential difference occurs between the charged surface and the surface. An electrostatic latent image is formed on the surface of the photosensitive drum 9 by this electrostatic action.

The developing device 19 visualizes the electrostatic latent image with a developer such as toner. Particle size 8 to 10 μm in the developing device 19
Negative bias is applied to the developing roller 15 including the non-magnetic toner and made of conductive rubber.
By sliding the surface with the rubber blade 17, a charged toner layer having a uniform thickness is formed on the surface of the developing roller 15.
The toner negatively charged on the surface of the developing roller 15 comes into contact with the electrostatic latent image on the photosensitive drum 9, and thus adheres only to a portion irradiated with light. This developing method is called a one-component non-magnetic developing method.

The electrostatic latent image, that is, the toner image visualized by the developing device 19 is transferred onto the printing paper p by the transfer roller 11.

On the surface of the photosensitive drum 9 after the toner image has been transferred, if the transfer efficiency of the transfer roller 11 is 100%, there is no residual toner. After the surface potential is made uniform by the lamp 21 and the memory charge-eliminating brush 23 that is positively biased, it is charged by the charging charger 25. The optical line head 13 blinks according to the character / image information to form an electrostatic latent image, but the slight transfer residual image toner remaining in the exposed portion is attracted to the potential difference between the developing roller 15 and the developing device 19 and is transferred to the developing device 19. Be recovered. At the same time, toner adheres to the exposed area.

On the other hand, the printing paper p on which the toner image is transferred
Is sent to the fixing device 7. Pressure contact roller 2 inside fixing device 7
9 rotates in contact with a fixing roller (heat roller) 27. The printing paper p is the fixing roller 27 and the pressure contact roller 29.
Since the toner is conveyed in between, the toner on the surface of the printing paper p is melted and pressed to fix the toner image as a permanent character / image.

The printing paper p that has passed through the fixing device 7 is ejected from the rear portion of the printing device 2 by the paper unloading roller 31.

The above is a series of printing processes in the printer device 1 according to the embodiment of the present invention.

On the other hand, in the embodiment of the present invention, the distance between the feeding action portions of the take-out roller 3 which is the first roller and the fixing roller pair 5 which is the second roller is set shorter than the length of the printing paper p. ing. That is, as shown in FIG. 2, the take-out roller 3 and the fixing roller pair 5 are the paper length R of the printing paper p carried by the distance L between the respective carrying action parts C and D (the paper in this embodiment). The size is such that the transfer device 8 is sandwiched at a distance shorter than A4). Note that the transport action portion C is the point where the take-out roller 3 contacts the printing paper p, and the transport action portion D is the point where the fixing roller 27 and the pressure contact roller 29 contact. However, the transport action portions C and D may be captured with a certain width in consideration of the formation of a nip.

Next, in the embodiment of the present invention, a driving force interrupting device for interrupting the driving force applied to the take-out roller 3 as the first roller is provided. This will be described with reference to the transmission mechanism of FIG. 3 for driving the take-out roller 3 and the fixing roller 27.

The transmission mechanism uses a motor 35 as a drive source, and includes a first timing pulley 37 attached to the output shaft of the motor 35, a second timing pulley 39, and a third timing pulley 41. In addition, a fourth timing pulley 43 and a fifth timing pulley 45 are provided. First timing pulley 37 and second
The first timing belt 47 is looped between the third timing pulley 41 and the fourth timing pulley 43, and the second timing belt 49 is looped between the third timing pulley 41 and the fourth timing pulley 43. A third timing belt 51 is wound around the third timing pulley 41 and the fifth timing pulley 45.

The fourth timing pulley 43 is coaxially provided with a first gear 53, and a second gear 57 is meshed with the first gear 53 via a first idle gear 55 so as to interlock. Has been done. The second gear 57 is provided coaxially with the take-out roller 3.

Further, a third gear 59 is coaxially provided on the fifth timing pulley 45.
9 is interlocked with a fourth gear 63 meshed with the second idle gear 61. The fourth gear 63 is provided coaxially with the fixing roller 27.

Therefore, the driving force of the motor 35 is the first timing pulley 37, the first timing belt 47, and the second timing pulley 47.
Is transmitted to the third timing pulley 41 through the timing pulley 39 of FIG.
On the one hand, it is decelerated and transmitted to the first gear 53 via the second timing belt 49 and the fourth timing pulley 43 on the one hand. Then, the take-out roller 3 is rotationally driven via the first idle gear 55 and the second gear 57.

On the other hand, the driving force of the motor 35 is the third
From the timing pulley 41 to the third timing belt 5
The third gear 5 through the first and second timing pulleys 45
It is decelerated to 9 and transmitted. And the second idle gear 6
The fixing roller 27 is rotationally driven via the first and fourth gears 63.

Incidentally, the developing roller 15 and the paper carry-out roller 3
1 may be configured to be driven by the motor 35 via another transmission mechanism, or may be configured to be driven by another motor.

On the other hand, the first idle gear 55 is rotatably supported by an intermediate portion of a lever 65 rotatably supported by the shaft portion of the first gear 53, and the other end of the lever 65 is rotatably supported. The tension spring 67 and the solenoid 69 are vertically connected. When the lever 65 moves upward by a certain amount, the lever 65 comes into contact with the stopper 71, so that an excessive rise of the lever 65 is restricted.

These first idle gear 55 and lever 6
5, the tension spring 67, the solenoid 69, and the stopper 71 constitute a driving force interrupting device that interrupts the driving force of the take-out roller 3 which is the first roller in this embodiment. Therefore, when the solenoid 69 is not excited, the lever 65
Is pulled upward by the tension spring 67 and stops at the position regulated by the stopper 71. In this state, the first idle gear 55 and the second gear 57 are not meshed with each other, and the driving force is not transmitted to the second gear 57 (non-driving mode). When the solenoid 69 is excited, the lever 65 is pulled downward, the first idle gear 55 and the second gear 57 mesh with each other, and the driving force is transmitted to the take-out roller 3 (driving mode).

In this way, the take-out roller 3 (see FIGS. 1 and 2) can be provided with the driving mode and the non-driving mode.

Further, the drive force connecting / disconnecting device 73 has a control unit 75.
Is controlled by the second end of the printing paper p in the transport direction.
It is determined that the conveyance action portion D (see FIG. 2) of the fixing roller pair 5 as the first roller has been reached, and the driving force of the take-out roller 3 that is the first roller is interrupted. Specifically, the motor 35 and the solenoid 69 are driven / excited by the controller 75 of the printer device shown in FIG. Control unit 75 is CP
U, ROM, RAM and I / O, and in this embodiment the control unit 75 also serves as the control unit for the printer printing process. Then, after the print sheet p reaches the conveying action section D of the fixing roller pair 5 and the fixing roller 27 and the pressure contact roller 29 start to convey the print sheet p, the control section 75 takes out the take-out roller 3
Stop driving.

The judgment that the print sheet p has reached the conveying action portion D of the fixing roller pair 5 is made by determining the conveying speed of the print sheet p and the distance between the ejecting roller 3 and the conveying action portions C and D of the fixing roller pair 5. It is done according to the time determined from.

Then, a signal is sent from the control section 75 to the motor controller 77 to control the motor drive circuit 79 to drive the motor 35. Further, the solenoid 69 is excited by controlling the solenoid drive circuit 81 from the controller 75.

Next, specific control timing will be described with reference to FIG.

FIG. 5 is a timing chart showing time on the horizontal axis and input of digital signals to the motor controller 77, the solenoid drive circuit 81, and the transfer device 8 on the vertical axis.

First, the motor 35 is driven. And
At the same time or with a slight delay, the solenoid 69 is turned on, the take-out roller 3 starts to be driven, and the conveyance of the printing paper p is started. At the same time, the fixing roller 27 also starts to drive. In this state, the print sheet p is conveyed only by the take-out roller 3. The printing paper p is the photosensitive drum 9 of the transfer device 8.
Then, when passing through the transfer roller 11, the formation of characters and images starts. When the print paper p plunges into the fixing roller pair 5, the solenoid 69 is turned off and the drive of the take-out roller 3 is released, the print paper p is conveyed only by the fixing roller pair 5, and the take-out roller 3 follows the paper. When the printing paper p passes through the transfer device 8, the formation of characters and images is completed, and when the paper unloading is completed, the motor 35 is stopped.

Even when the take-out roller 3 and the fixing roller pair 5 are present in the conveying path due to such a conveying action, the printing paper p is conveyed only by either one of them, and depending on the limit of processing accuracy, etc. Even if there is a difference in peripheral speed between the take-out roller 3 and the fixing roller pair 5, the printing paper p is not pulled or bent. Therefore, the transfer efficiency of the transfer device 8 does not change and the characters and images do not deteriorate. Further, it is not necessary to take a large space in the height direction in consideration of the bending of the printing paper p in the paper conveyance path from transfer to fixing, which is convenient for downsizing. Further, the fixing roller pair 5 does not cause the paper to slip due to the pulling of the printing paper p, so that the fixing failure can be prevented.

Actually, the drive of the take-out roller 3 is cut off slightly after the timing when the print paper p enters the fixing roller pair 5, but in this case, the take-out roller 3 and the fixing roller pair are used. Simultaneous driving of the printing paper p by No. 5 is extremely short time. Therefore, compared to the case where the peripheral speed difference between the take-out roller and the fixing roller pair is accumulated for a long time during the paper conveyance as in the conventional case, there is almost no effect. Therefore, the printing paper p is not pulled or bent.

The present invention is not limited to the above embodiment. For example, when it is determined that the front end of the printing paper p in the carrying direction has reached the carrying action portion D of the fixing roller pair 5, a photoelectric sensor is provided immediately before the fixing device 7, and the front end of the printing paper p is detected by this sensor. It is also possible to take into consideration the distance between the sensor and the transport acting portion D of the fixing roller pair 5 by detecting the value of.

Further, in the above embodiment, the printer device using the electrophotographic system has been described, but the same applies to printer devices using other printing processes, that is, printer devices using the electrostatic recording system, the inkjet system, the thermal transfer system and the like. In addition, the present invention can be applied not only to a printer device but also to a copying machine or a facsimile.

[0045]

As is apparent from the above, according to the present invention, even if there is a peripheral speed difference between the first roller and the second roller due to the limit of processing accuracy, the transfer medium is bent or pulled. Therefore, it is possible to prevent lowering of transfer efficiency, deterioration of information, and poor fixing, and it is also possible to reduce the size of the apparatus. Furthermore, since the transfer medium does not bend, clogging is less likely to occur.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an electrophotographic printer device according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a paper transport mechanism according to an embodiment of the present invention.

FIG. 3 is a schematic configuration diagram of a driving force transmission and mode switching mechanism according to an embodiment of the present invention.

FIG. 4 is a schematic configuration diagram of a drive control unit according to an embodiment of the present invention.

FIG. 5 is a timing chart of driving / driven mode switching according to the embodiment of the present invention.

[Explanation of symbols]

 1 Printer Device 2 Printing Unit 3 Ejecting Roller (First Roller) 5 Fixing Roller Pair (Second Roller) 7 Fixing Device 8 Transfer Device 27 Fixing Roller 29 Pressure Contact Roller 73 Drive Interrupting Device 75 Control Unit p Printing Paper (Transfer) Medium) C Transport action part D Transport action part

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location G03G 15/20 102 H04N 1/00 108 M 7046-5C 1/29 F 9186-5C

Claims (1)

[Claims] 1. A printer comprising a transfer device for printing information on a transfer medium having a predetermined length, a first roller for carrying the transfer medium into the transfer device, and a second roller for carrying out the transfer medium. A device for interrupting driving force, wherein the distance between the transport action parts of the first roller and the second roller is set shorter than the length of the transfer medium, and the driving force to the first roller is interrupted. And a control means for cutting off the driving force of the first roller by controlling the driving force connecting / disconnecting means by judging that the front end of the transfer medium in the conveying direction has reached the conveying action part of the second roller. A printer device provided.