JPH0613230B2 - Printer - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a printer such as a printer or a typewriter, and more particularly to a printer provided with a novel paper feed / paper discharge drive mechanism.

[Prior art]

Printers such as printers and typewriters have a structure that supplies paper below the platen and discharges paper above the platen. Generally, the structure is such that it can be easily attached and detached. For this reason, the paper feeding device has two driving parts, that is, a paper feeding roller and a paper discharging roller. In the conventional device, (1) the same driving source in the paper feeding device is used for both paper feeding and paper discharging. The method used is (2) the same drive source in the printing apparatus is used for both paper feeding and paper ejection, and (3) different drive sources are used for paper feeding and paper ejection. However, if paper feed and paper ejection are driven by the same drive source as in (1) and (2), one of them will rotate when it is not necessary, and in the method of using another drive source in (3), If there are two separate drive sources in the device, the number of parts increases, which is a drawback. Therefore, it is considered most desirable to have a paper feed drive source in the paper feed device and supply the paper discharge drive source from within the printing device. In particular, since the paper discharge roller is close to the platen and is required to rotate synchronously with the platen, it is adopted to use the rotation of the platen as its drive source. Therefore, in the paper feeding device, the gear attached to the platen shaft of the printing device and the gear of the paper feeding device are connected to drive the paper ejection roller from the driving method and the condition that the paper feeding device is detachable from the printing device. The structure is adopted. However, in this method, since the gear on the platen side and the gear on the automatic paper feeder side are detachably meshed with each other, the teeth of both gears collide with each other at the time of mounting, damaging the teeth, and Repeatedly attaching and detaching causes abnormal wear of the teeth, which prevents the rotation from being transmitted smoothly due to the damage and wear, causing speed fluctuations and rotation of the platen by a predetermined amount on the rotated side, that is, the discharge roller side. A fluctuation in the amount of rotation with respect to occurs. This disturbs the synchronization between the feeding of the platen and the conveyance of the automatic sheet feeder, and the sheet is conveyed abnormally or sags, which adversely affects the recorded image.

Therefore, as disclosed in Japanese Patent Application Laid-Open No. 58-90972, a structure has been proposed in which a driving force is transmitted from a gear integrally provided on a platen to a discharge roller via a gear and a transmission belt. However, in such a configuration, since the drive transmission mechanism is added to the side of the platen in addition to the width of the platen, the width of the entire apparatus becomes large. Alternatively, even if you try to keep the overall width of the device small, the drive transmission mechanism fills the space beside the platen, so the platen width must be reduced accordingly, and the maximum width of the paper that can be transported and the printing The width of the area is kept small.

〔Purpose〕

In order to solve the above-described problems, the present invention includes a transmission rotary body that is in rolling contact with the first transport rotary body (platen) itself, so that the effective width of the platen is not impaired by the drive force transmission mechanism. It is an object of the present invention to provide a printing device that avoids an increase in the size of the entire device, or can convey a paper having a larger width and can secure a large width of a printing region even when the size of the device is the same.

[Summary]

The present invention conveys a sheet by rotating while contacting the outer peripheral surface of the sheet, and a first conveying rotating body (platen) having a width corresponding to the width of the conveyed sheet, and the first conveying rotation. Recording means for recording on a sheet conveyed to the body, a second conveying rotary body for conveying the sheet conveyed by the first conveying rotary body, and a sheet on the outer peripheral surface of the first conveying rotary body. The first conveyance rotator is arranged in a position that directly contacts the contact area and does not hinder the conveyance of the sheet, and is rotated by receiving a drive transmission from the first conveyance rotator due to a frictional force to rotate the first conveyance rotator. And a transmission rotator for transmitting to the second transport rotator.

〔Example〕

An embodiment of the present invention will be described with reference to FIGS.
FIG. 1 shows a schematic cross-sectional view in which a paper feeding device is attached to a printing device. Reference numeral 1 is an exterior cover of the paper feeding device, 2 is a paper feeding cassette, which is a paper feeding cassette located in the upper stage. A sheet feeding cassette 3 is located at the lower stage. Cut sheets (sheets) 4 are stacked in the upper sheet feeding cassette 2. Reference numeral 5 denotes a paper feed roller (feeding rotary member) for feeding the cassette sheet 4 to a printing device (described later), which is in frictional contact with the upper surface of the cut sheet 4 and is fixed to the paper feed shaft 18. A paper feed roller 6 is arranged on the paper feed cassette 3 and is fixed to the paper feed shaft 19. Reference numeral 7 is a gear, 8 is a motor (driving source), the gear 7 is provided on the shaft of the motor 8, and meshes with a gear (not shown) provided on the paper feeding shaft 18,
The motor 8 is used as a drive source for the paper feed roller 5. The paper feed roller 6 is also connected to the motor 8 by a gear device (not shown) and serves as a drive source. Reference numeral 9 denotes a paper discharge roller (second transport rotary member) for transporting the cut sheet, and 10 denotes a gear, which is fixed on the paper discharge shaft 20. A paper discharge idler 11 is in contact with the paper discharge roller 9. Reference numeral 12 denotes a cylindrical friction wheel (transmission rotary member), which is in contact with a platen 14 as a first transport rotary member of the printer 13. The cut sheet 4 conveyed by the paper feed rollers 5 and 6 collides with the lower part of the platen 14 of the printing device 13, and then is sent to a predetermined position for recording by the recording means, that is, the start of printing. After the printing is completed, the cut sheet 4 passes between the paper discharge roller 9 and the paper discharge idler 11 and is discharged onto the paper discharge tray 21. In FIG. 2, a method of driving the paper discharge shaft 20 will be described in detail. Reference numeral 12 is a friction wheel, 14 is a platen, and 17 is a gear wheel.
Are in contact with each other, and the friction wheel 12 is integral with the gear 17. 1
Reference numerals 5 and 16 are swing arms, which are arranged on both side surfaces of the friction wheel 12. A fixed shaft 22 is a central shaft of the friction wheel 12 and the gear 17. The friction wheel 12 and the gear 17 are integrally rotatable on a fixed shaft 22, and these three parts are held on a paper discharge shaft 20 by rocking arms 15 and 16, and can be rocked. There is. Further, the gear 17 meshes with the gear 10 fixedly held on the paper discharge shaft 20. When the paper feeding device is mounted on the printing device, the friction wheel 12, the gear 17, the swing arm 15, 1
6. The positions of the fixed shaft 22 are set so that the fixed shaft 22 is integrally brought into frictional contact with the platen 14 by its own weight and does not hinder the passage of sheets. As another embodiment, it is possible to add a spring member to the swing member to ensure sufficient frictional contact. With the above configuration, the platen 1
When 4 rotates as indicated by the arrow, the friction wheel 12 rotates, and the paper discharge shaft 20 rotates via the gears 10 and 17.

The gear ratio of the gears 10 and 17 may be set so that the rotation of the platen 14 and the rotation of the paper discharge shaft 20 do not hinder the paper feeding. The gears 10 and 17 are wound around a round belt, a timing belt, or the like. It is also possible to replace with a hanging device.

The friction wheel 12 in the embodiment can be attached at any position in the platen width direction, and it is not necessary to provide extra parts on the platen, and the platen width can be maximized. It is used and unlimited. Therefore, when the automatic paper feeder is installed on the printer, the friction transmission mechanism is located at the rear position so as not to obstruct the paper transport path leading to the discharge of the printed paper. It is also possible to do.

〔effect〕

As described in detail above, the present invention includes the transmission rotary body that is in rolling contact with the first transport rotary body (platen) itself, thereby transmitting the rotation of the first transport rotary body to the second transport rotary body. Since the transmission rotator directly contacts the area of the outer peripheral surface of the first conveyance rotator that comes into contact with the paper, and is arranged at a position where it does not hinder the conveyance of the paper, the drive force transmission mechanism is the first conveyance rotation. Since it does not protrude laterally beyond the width of the body, it is possible to avoid increasing the size of the device. Further, even with a small machine, it is possible to convey a paper having a large width and to increase the width of the printing area, the width of the first conveying rotary member can be increased.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view in which an embodiment of the automatic paper feeder of the present invention is attached to a printer. FIG. 2 is a partial sketch of the platen sheet discharge shaft drive unit. 1 ... Paper feed device exterior cover, 2, 3 ... Paper feed cassette, 4 ...
Cut sheet, 5, 6 ... Feed roller, 7 ... Gear, 8 ... Motor, 9 ... Discharge roller, 10 ... Gear, 11 ... Discharge idler, 12 ... Friction wheel, 13 ... Printing device, 14 ... Platen,
15, 16 ... Swing arm, 17 ... Gear, 18, 19 ... Paper feeding shaft, 20 ... Paper discharging shaft, 21 ... Paper discharging tray, 22 ... Fixed shaft.

Claims (2)

[Claims] 1. A first transport rotating body having a width corresponding to the width of the transported sheet, wherein the first transport rotating body transports the sheet by rotating while contacting with the sheet on the outer peripheral surface thereof. A recording unit that performs recording on a sheet to be conveyed, a second conveyance rotator that conveys a sheet conveyed by the first conveyance rotator, and a sheet on the outer peripheral surface of the first conveyance rotator. It is arranged at a position where it directly contacts the area and does not hinder the conveyance of the sheet, and is rotated by receiving a drive transmission from the first conveyance rotator due to a frictional force to rotate the first conveyance rotator. And a transmission rotary member that transmits to the second transport rotary member. 2. A feeding rotating body for feeding a sheet to a recording means, and a drive source for driving the feeding rotating body,
The printing apparatus according to claim 1, wherein the second transport rotating body is configured to transport the sheet discharged from the printing apparatus.