JP2000159368A - Paper separating mechanism of printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably separate and convey paper by making it possible to adjust frictional forces between a pickup roller and the paper and between the paper and a separating pad during separation of the paper. SOLUTION: A paper separating mechanism for a printer, having a pickup roller 3 whereby only one paper abutting against it can be separated from stacked paper and conveyed and a pressure plate 2 having a separating pad 1 buried in its portion against which the pickup roller 3 is pressed, is so formed that its longitudinal dimension b' in a direction perpendicular to the paper feed direction of the separating pad 1 is shorter than the corresponding longitudinal dimension a' of the pickup roller 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper separating mechanism for a printer, and more particularly to a paper separating mechanism for a printer, which separates the sheets one by one from a plurality of stacked sheets by a pickup roller and conveys the sheets to a recording unit of the printer. The present invention relates to a paper separating mechanism.

[0002]

2. Description of the Related Art Generally, a thermal transfer printer, an output device such as a computer, a word processor, a facsimile, etc., is used.
Various printers such as page printers are used.

In order to perform desired recording in such a printer, a plurality of sheets are stacked and stored in a paper storage section such as a paper feed cassette or a paper feed tray provided in the printer body. The sheet stored in the sheet storage unit is separated and conveyed one by one by rotating the pickup roller in contact with the pickup roller. The sheet conveyed by the pickup roller is taken over by various rollers to a recording unit of the printer, conveyed, and used for recording.

FIG. 2 is an explanatory view showing a positional relationship between a pressure plate formed in a paper storage portion of a paper feed cassette and a pickup roller in a paper separation mechanism of a conventional printer.

[0005] The leading end pieces of the paper storage section, in which the sheets to be used for recording are stacked and stored in the paper feeding direction, are brought into contact with the uppermost sheet in order from the uppermost sheet to thereby store the sheets one by one. A guide slope for separating and guiding the sheet in the sheet feeding direction is formed. A pressure plate 12 with which the pickup roller 13 is pressed against the sheet in the sheet feeding direction for reliable sheet separation is formed integrally with the guide slope. ing. As shown in FIG. 2, a plurality of flat rectangular separation pads 11 made of a material having a high coefficient of friction are embedded in the pressure plate 12 such that the surfaces thereof are flush with the pressure plate 12. I have.

The pickup roller 13 has a shaft extending in a direction perpendicular to the sheet feeding direction (hereinafter, this direction is referred to as a width direction), and is arranged so as to be able to press against the separation pad and to be rotatable via a sheet. ing. This pickup roller 1
Special rubber is used as the material of No. 3.

Further, the separation pad 11 is provided with a material such as cork or special rubber having a high friction coefficient so as to prevent the paper to be stopped in the paper storage unit from being transported along with the uppermost paper to be transported. Conventionally, the width dimension of the separation pad 11 (indicated by a in the figure) is, as shown in FIG. 2, the width dimension of the pickup roller 13 (in the figure, b).

The paper separating mechanism of the printer constructed as described above rotates the pickup roller 13 in the paper feeding direction by contacting the pickup roller 13 with the leading end of the uppermost paper stored in the paper storage section. And act to separate only the uppermost sheet from the lower sheet. That is, when a plurality of the sheets are stacked,
The rotational force of the pickup roller 13 acts only on the uppermost stacked sheet to separate the uppermost sheet from the lowermost sheet, and the lower stacked sheets are respectively stacked. And the frictional force acting between the separation pad and the lower surface of the lower-level sheet and the separation pad, the sheet stops at the sheet storage portion.

[0009]

In the paper separating mechanism of the conventional printer constructed as described above, the pickup roller 13 does not come into pressure contact with the upper surface of the pressure plate 12 at the time of separating the paper, but through the paper. It comes into pressure contact only with the separation pad 11 made of cork or the like. Therefore, the separation pad 1 can be used for a long time.
1 is worn by the contact width of the pickup roller 13,
Pressure contact between the separation pad 11 and the pickup roller 13 is not properly performed, and a problem such as so-called double feed may occur.

Furthermore, as the number of sheets used for recording has become diversified in recent years, it is necessary for the sheet separating mechanism of the printer to more strictly adjust the frictional force on the sheet used for recording.

The present invention has been made in view of these points, and enables adjustment of the frictional force between the pickup roller and the paper and the paper and the separation pad when the paper is separated, thereby stably separating and transporting the paper. It is an object of the present invention to provide a paper separating mechanism of a printer capable of performing the above operation.

[0012]

According to a first aspect of the present invention, there is provided a sheet separating mechanism for a printer, wherein only one sheet abutted is separated and conveyed from a stacked sheet. A pickup roller, and a pressure plate in which a separation pad is embedded in a portion where the pickup roller is in pressure contact, wherein a length dimension of the separation pad in a direction perpendicular to a sheet feeding direction is The pickup roller is formed to be shorter than the length of the pickup roller.

According to the present invention, the pickup roller is brought into pressure contact with the separation pad projecting from the pressure plate in the entire width direction of the upper surface of the separation pad.

According to a second aspect of the present invention, there is provided a paper separating mechanism for a printer, wherein the separation pad of the paper separating mechanism for the printer according to the first aspect is formed of an elastic foam material, and protrudes from the upper surface of the pressure plate by a predetermined amount. It is characterized by being arranged.

According to the present invention, the pressing force is changed by utilizing the elastic force and the friction coefficient of the elastic foam material, and the frictional force is adjusted in relation to the sheet positioned on the pressure plate when the sheet is separated. It is.

According to a third aspect of the present invention, there is provided a sheet separating mechanism for a printer, wherein the pressure plate of the sheet separating mechanism for the printer according to the first or second aspect is formed on a sheet feeding cassette detachably mounted on the printer. The paper separating mechanism of the printer according to claim 4 is characterized in that:
The pressure plate of the paper separating mechanism of the printer according to claim 1 or 2 is formed on a paper feed tray integrally formed with the printer.

In the automatic paper feeder of the printer according to the present invention, the position of the pressure plate of the paper separating mechanism is specifically shown.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory view showing the positional relationship between a pressure plate of a paper storage section such as a paper feed cassette or a paper feed tray provided in a printer main body and a pickup roller. 3 is a drawing corresponding to FIG. Hereinafter, an embodiment of a paper separating mechanism of a printer according to the present invention will be described with reference to FIG.

In the present embodiment, in order to obtain an appropriate frictional force, each of the plurality of separation pads 1 having a flat rectangular shape has its surface separated from the surface of the pressure plate 2 formed in the paper storage portion by an appropriate size. It is buried so as to protrude. The material of the separation pad 1 is an elastic foam material. As the elastic foam material, for example, urethane foam or the like can be considered. And
In the present embodiment, the width direction dimension of the separation pad 1 (indicated by a ′ in the figure) is, as shown in FIG. 1, greater than the width direction dimension of the pickup roller 3 (indicated by b ′ in the figure). Are also formed short.

In the paper separating mechanism of the printer according to this embodiment, the pickup roller 3 separates the pressure plate 2 from the pressure plate 2 through the paper stacked and stored in the paper storage unit when the paper is separated. The protruding separation pad 1 comes into pressure contact with the upper surface in the entire width direction.
Therefore, the frictional force can be adjusted according to the length of the separation pad 1 in the width direction.

When the paper is separated, the elastic foam material such as urethane foam constituting the separation pad 1 is compressed in the thickness direction by the pressing force of the pickup roller 3. Therefore, by adjusting the protrusion amount of the separation pad 1 and the material and the like according to the paper to be used, the pressure contact pressure is changed, and the frictional force is adjusted in relation to the paper positioned on the pressure plate 2 at the time of paper separation. It is possible to do. In other words, if the leading ends of a plurality of sheets are positioned on the pressure plate 2, the frictional force acting between the lower surface of the lowermost sheet and the separation pad 1 is set to an appropriate value, and By rotating the roller 3, only the uppermost sheet can be transported separately from the lower sheet.

Further, as described above, the width dimension of the separation pad 1 is made smaller than the width dimension of the pickup roller 3, so that when the pickup roller 3 is pressed against the separation pad 1 to a predetermined value, both ends in the width direction. Is in contact with the upper surface of the pressure plate 2, so that the separation pad 1 is not further compressed and bent.

As described above, the frictional force is adjusted by changing the press contact pressure by using the elastic force of the urethane foam, and the protrusion amount, width dimension, material and the like of the separation pad 1 are adjusted. This makes it possible to adjust the frictional force according to the characteristics of various types of paper used for recording,
Sheets stacked below the uppermost sheet separated and conveyed can be stopped in the sheet storage section to prevent double feed.

Another problem is that the surface of the separation pad 1 is worn by the contact width of the pickup roller 3 due to long-term use.
Can be eliminated by pressing the entire surface in the width direction.

The present invention is not limited to the above-described embodiment, but can be variously modified as needed.

For example, the paper separating mechanism of the above embodiment is
The pickup roller presses the paper stacked on the paper storage unit and the pressure plate from above, but abuts on the lowermost paper stored by stacking the pickup roller on the paper storage unit. In this case, a sheet separating mechanism configured to separate only the lowermost sheet from the sheet positioned above the lowermost sheet may be used.

Further, the pressure plate has been described as being disposed on the leading end side in the paper feeding direction of the paper storage unit. However, as long as it means a face plate against which the pickup roller of the paper storage unit comes into pressure contact for paper separation. Also, the upper surface of the sheet storage portion formed of a material having a small coefficient of friction, such as a synthetic resin such as plastic or a thin metal plate, can be considered as a pressure plate. In this case, the separation pad is formed at a portion where the pickup roller is pressed against the sheet via the sheet, and supplements the frictional force acting between the sheet and the lowest sheet stacked and stored in the sheet storage section. It becomes a separation pad.

[0028]

As described above, the paper separation mechanism of the printer according to the present invention utilizes the elastic force and friction coefficient of the separation pad to adjust the pickup roller at the time of paper separation according to the type of paper to be used. And the pressure between the paper and the separation pad and the frictional force can be adjusted, the paper can be separated and transported stably, and the surface of the separation pad can be prevented from being worn due to long-term use. It has effects such as being able to do.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a main part structure in an embodiment of a paper separating mechanism of a printer of the present invention.

FIG. 2 is an explanatory diagram showing a main structure of a paper separating mechanism of a conventional printer.

[Explanation of symbols]

 1 Separation pad 2 Pressure plate 3 Pickup roller

Claims (4)

[Claims] A plurality of pick-up rollers capable of separating and conveying only one sheet in contact with a stacked sheet; and a pressure plate having a separation pad embedded in a portion facing each of the pick-up rollers. Wherein the length of each of the separation pads in a direction perpendicular to the paper feeding direction is shorter than the length of each of the corresponding pickup rollers. Printer paper separation mechanism. 2. The printer according to claim 1, wherein the separation pad is formed of an elastic foam material, and is provided so as to protrude from the upper surface of the pressure plate by a predetermined amount. mechanism. 3. The paper separation mechanism of a printer according to claim 1, wherein the pressure plate is formed on a paper feed cassette detachably mounted on the printer. 4. The paper separating mechanism according to claim 1, wherein the pressure plate is formed on an upper surface of a paper feed tray formed integrally with the printer.