JPH0657648U - Paper feeder for printer - Google Patents

Abstract

(57) [Summary] [Purpose] To prevent retransfer by ink adhering to the discharge roller without causing paper feeding failure. The printing means A includes a print head 4 and a platen 7, and the paper feeding device B includes a paper feed roller 8 provided upstream of the print means and a paper discharge roller 9 provided downstream thereof. ing. The recording paper P sent to the printing means A by the paper feed roller 8 is printed, and the front end of the printed recording paper is sent to the paper discharge roller 9. On the surface of the roller 9b of the paper discharge roller 9 which is in contact with the printing surface, the Japanese Industrial Standard (J
Abrasive grains of 30 to 150 mesh defined by (IS) are attached. Even when the roller 9b comes into contact with the printing surface of the recording paper P, the amount of ink adhering to the recording paper becomes extremely small because of point contact due to the abrasive grains, and printing defects due to retransfer are prevented. Further, since the abrasive grains having a particle size suitable for paper feeding are attached to the surface of the roller 9b, paper feeding failure does not occur.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a paper feeding device of a printer provided in an inkjet printer or the like.

[0002]

[Prior art]

 There are various types of paper feeders for printers, depending on the printer type and paper type. These paper feeding devices generally take a recording paper from a paper feeding cassette by a picking roller, and then feed the recording paper to the printing means by a pair of paper feeding rollers provided on the upstream side of the printing means. is there. The recording paper printed by the printing means is ejected by a paper ejection roller provided on the downstream side of the printing means.

The paper feed roller and the paper discharge roller are each configured by a cylindrical body having a smooth surface a as shown in FIG. 3, and one roller of each pair of rollers is driven by a driving means. It can be driven to rotate, and the other roller is elastically contacted with one roller and rotated by frictional force so that the recording paper sandwiched between the rollers can be sent out.

[0004]

[Problems to be solved by the device]

 As described above, when the recording paper is fed out by the frictional force of the cylindrical roller with a smooth surface, one of the paper ejection rollers is not connected to the printing surface of the recording paper immediately after the ink is attached to the recording paper. This results in the ink sticking to the surface of the paper ejection roller because it is in contact and therefore not fully dried. The ink adhering to the surface of the paper ejection roller re-transfers to the surface of the recording paper as the paper ejection roller makes one rotation, and the printing surface becomes dirty, which causes printing failure. As one measure against this, as shown in FIG. 4, a plurality of discharge rollers on the side contacting the printing surface are formed in a narrow columnar shape at predetermined intervals, and a tip is provided on the outer periphery of each roller. It has also been attempted to suppress contact between the roller and the ink on the printing surface as much as possible by continuously providing a large number of protrusions 29a formed at an acute angle. However, in this case, the contact area between the roller and the recording paper becomes smaller, and sufficient frictional force cannot be obtained, resulting in paper feeding failure.

Therefore, an object of the present invention is to prevent the occurrence of printing defects due to retransfer of ink without causing paper feeding defects.

[0006]

[Means for Solving the Problems]

 In order to achieve the above object, the paper feeding device of the printer in the present invention supplies the recording paper to the printing means by the paper feed roller provided on the upstream side of the printing means, and is provided on the downstream side of the printing means. In a paper feeding device of a printer that discharges recording paper printed by a printing means by a discharging roller, the surface of the discharging roller that is in contact with the printing surface of the recording paper has a range of 30 to 150 mesh specified by Japanese Industrial Standards. Abrasive grains are attached.

[0007]

[Action]

 Abrasive grains in the range of 30 to 150 mesh defined by Japanese Industrial Standards are attached to the surface of the discharge roller that contacts the printing surface of the recording paper. Since the tip part makes point contact with the ink on the print surface, the ink that has adhered to the tip part of the abrasive grains dries in a short time, and even if the paper discharge roller makes one revolution and the part with ink contacts the print surface. No retranscription occurs. Further, since the grain size of the abrasive grains is selected to be an appropriate size, a friction coefficient suitable for paper feeding can be obtained and paper feeding failure does not occur.

[0008]

【Example】

An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 shows a printing means A and a paper feeding device B of a printer to which the present invention is applied.

In the construction of the printing means A, the guide shafts 1 and 2 are laid across in the direction perpendicular to the paper surface, and the print head 4 is movably supported on the guide shaft in a direction orthogonal to the paper feeding direction. There is. The print head 4 has a carrier 3 slidably engaged with one guide shaft 1 and a receiving portion 4a slidably engaged with the other guide shaft 2 formed therein. It is movably supported by the guide shafts 1 and 2 via the carrier 3. The print head 4 employs an ink jet type in which ink droplets are ejected from a nozzle portion 5 at the tip, and ink droplets can be ejected so as to form a predetermined dot by a signal from a control circuit of a printer main body (not shown). .

Below the moving range of the print head 4, there is provided a table 6 having a flat upper surface, and the table 6 is formed substantially parallel to the center of the table so as to face the nozzle portion 5 of the print head 4. A platen 7 whose upper surface is slightly higher than the table is mounted in the groove 6a.

The paper feeding device B of the printer according to the present invention comprises a pair of paper feed rollers 8 provided upstream of the print head 4 and a pair of paper discharge rollers 9 provided downstream of the print head. It is configured. Of the pair of paper feed rollers 8a and 8b, the lower roller 8a is a drive roller and can be rotationally driven by a drive means (not shown) of the printer body, and the upper roller 8a is a driven roller and is pulled. A spring (not shown) makes elastic contact with the drive roller 8a. The outer peripheral surface of each of the rollers 8a and 8b has no friction and has a large friction coefficient.

Similarly to the paper feeding roller 8, the pair of paper discharging rollers 9 has a lower roller 9a as a driving roller, which is rotationally driven by a driving means similarly to the paper feeding roller 8 and an upper roller 9b serves as a driven roller. Has become. The driven roller 9b is elastically contacted with the drive roller 9a by a tension spring (not shown). When the drive rollers 8a and 9a of the paper feed roller 8 and the paper discharge roller 9 are driven to rotate, the driven rollers 8b and 9b elastically contacting the drive rollers 8a and 9a are rotatable by frictional force. When the recording paper P is fed between the rollers, the recording paper can be delivered by the frictional force between the surface of each roller and the paper surface.

As shown in FIG. 1, abrasive grains 9c are attached to the surface of the driven roller 9b of the paper discharge roller 9 which is in contact with the printing surface of the recording paper P. In this embodiment, the abrasive grains 9c are those of # 80 (80 mesh) defined by Japanese Industrial Standards (hereinafter referred to as "JIS"). The size of the abrasive grains 9c adhered to the surface of the driven roller 9b is appropriately selected in consideration of the roller diameter and other factors, but is generally within the range of JIS JIS # 30 to # 150. It is preferable to select the range of # 60 to # 100. Further, as the material of the abrasive grains, white fused alumina (WA), brown fused aluminum (A), single crystal alumina, etc., which are defined by JIS, may be appropriately selected.

As shown in FIG. 1, the driven roller 9b of the paper discharge roller 9 is provided with a shaft hole 9d at the center of the columnar body, and a support shaft (not shown) inserted through the shaft hole is provided. Free rotation is possible. The abrasive grains 9c can be easily attached to the outer peripheral surface of the driven roller 9b with an adhesive or the like. The outer peripheral surface of the driven roller 9b is made uneven by the adhered abrasive grains 9c, and it makes point contact with the printing surface of the recording paper P during paper feeding, and only a small amount of the printed ink adheres. Instead, it functions to prevent transfer and at the same time obtains a coefficient of friction suitable for paper feeding, which enables proper paper feeding.

A picking roller 10 is provided on the upstream side of the paper feed roller 8 (on the right side in FIG. 2), and the recording paper P stored in the paper feed cassette 11 can be taken out. The front portion (left side in FIG. 2) of the paper feed cassette 11 is biased upward by a compression spring (not shown), and the picking roller 10 elastically contacts the upper surface of the recording paper P to generate a frictional force due to the rotation of the picking roller. The recording paper P can be sent out to the paper feed roller 8. A paper guide 12 is provided on the downstream side (the left side in FIG. 2) of the paper discharge roller 9 and can guide the recording paper P sent from the paper discharge roller 9.

Next, the operation will be described.

First, in response to a print start signal from the printer body, the picking roller 10 rotates to take out the recording paper P, and the front end portion thereof is sent to the paper feed roller 8. Then, the recording paper P is sent out to the gap between the print head 4 and the platen 7 by the paper feed roller 8 and stopped at a predetermined position. Next, the print head 4 moves laterally with respect to the recording paper P fed into the gap between the facing surfaces of the print head 4 and the platen 7, and the printing operation is started. During printing, dots are formed by the ink droplets ejected from the nozzle portion 5 of the print head 4, and it takes a certain amount of time for the printed ink to dry. Therefore, the printing surface reaches the paper discharge roller 9 before the ink on the printing surface is completely dried, and the outer peripheral surface of the driven roller 9b comes into contact with the printing surface. However, since the abrasive grains 9c adhere to the surface of the driven roller 9b and the abrasive grains 9c make point contact with the printing surface, the amount of ink adhered to the roller surface is extremely small. The retransfer to the recording paper surface by the line 9b is not performed. In this way, the recording paper P printed one after another is sent out onto the paper guide 12 by the paper discharge roller 9, and is ejected after being projected into the paper guide 12.

In this embodiment, the case where the invention is applied to the ink jet printer is described, but the present invention is also applicable to the impact printer. Also, although the platen is of a fixed type, it can also be applied to a rotary type.

Further, in the present embodiment, the abrasive particles are adhered only to the driven roller of the paper discharge roller, but the abrasive particles are also adhered to the drive roller of the paper discharge roller and the paper feed roller to cause frictional force. May be increased to increase the paper feed accuracy.

[0020]

[Effect of device]

 As described above, according to the present invention, since the mesh of the predetermined mesh is adhered to the surface of the paper discharge roller which is in contact with the printing surface of the recording paper, the paper discharge roller comes into contact with the printing surface just printed. However, it becomes a point contact, and the ink in the state before it is completely dried adheres to the discharge roller only very slightly. Therefore, the printing surface is not stained due to the retransfer of the ink. Furthermore, by attaching abrasive particles of a particle size suitable for paper feeding, there is an effect that paper feeding defects do not occur.

[Brief description of drawings]

FIG. 1 is a perspective view of a discharge roller according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a paper feeding device and a printing unit according to an embodiment of the present invention.

FIG. 3 is a perspective view showing an example of a paper discharge roller in a conventional technique.

FIG. 4 is a perspective view showing a paper discharge roller that has been tried to be adopted in the related art.

[Explanation of symbols]

 A printing means B paper feed device 8a, 8b paper feed roller 9a, 9b paper discharge roller 9c abrasive grain

Claims (1)

[Scope of utility model registration request] 1. A recording sheet supplied to the printing means by a paper feed roller provided on the upstream side of the printing means, and printed by the printing means by a paper discharge roller provided on the downstream side of the printing means. In a paper feeding device of a printer for discharging paper, abrasive grains in the range of 30 to 150 mesh defined by Japanese Industrial Standards are attached to the surface of the paper discharging roller which is in contact with the printing surface of the recording paper. And the paper feeder of the printer.