Two-way paper pickup system

A two-way paper pickup system in which both a feed tray and a feed cassette can be used, and a printer adopting the same. The paper pickup system includes a feed tray on which paper or a feed cassette is placed, a first pickup assembly that moves the paper placed on the feed tray, a resistance plate that allows the moved paper to be separately transferred, and a second pickup assembly that is moved to a paper exit of the feed cassette so as to move paper included in the feed cassette when the feed cassette is placed on the feed tray. When the feed cassette is inserted into the printer, the first pickup assembly is moved on the feed cassette while being rotated.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority of Korean Patent Application No. 2004-4979, filed on Jan. 27, 2004, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present general inventive concept relates to a two-way paper pickup system and a printer adopting the same, and more particularly, to a two-way paper pickup system in which both a feed tray and a paper cassette are available, and a printer adopting the same.

2. Description of the Related Art

In general, since most inkjet printers are manufactured as low-cost popular types, only a paper tray is adopted as a paper feed mechanism to minimize manufacture costs.FIGS. 1 and 2illustrate a conventional inkjet printer and a conventional paper feed mechanism adopted by the conventional inkjet printer, respectively. Referring toFIG. 2, the conventional paper feed mechanism includes a feed tray110in which paper S is placed, a pickup roller121that moves the paper S placed on the feed tray110, a pickup roller supporter123that delivers a driving force to the pickup roller121and pressurizes the pickup roller121onto the paper S, a resistance plate140that allows sheets of the paper S transferred by the pickup roller121to be supplied to a feed roller130one by one; and the feed roller130that supplies the paper S to a printing unit (not shown).

A process of supplying the paper S using the conventional paper feed mechanism will now be described with reference toFIGS. 1 and 2. First, the pickup roller supporter123and the pickup roller121, fixed by an end of the pickup roller supporter123, press the paper S on the feed tray110with their own weight. In this case, when the pickup roller supporter123delivers a driving force to the pickup roller121, the delivered driving force rotates the pickup roller121to transfer the paper S toward the resistance plate140. A plurality of projections145are formed on the resistance plate140to separately supply the paper S to the feed roller130. When the paper S is stopped by the projections145, only a sheet of the paper S directly contacting the pickup roller121is transferred to the feed roller130. This method is referred to as a paper separation method using a resistance plate.

There is a growing need to develop popular-type printers adopting a paper feed mechanism, such as that shown inFIG. 2, that can use both nonstandard sized paper of various types and sizes and standard sized paper, e.g., A4, B5, or letter sized paper. Accordingly, in a tray-type feed mechanism adopted by a conventional inkjet printer, a paper pickup system that picks up and supplies sheets of paper S one by one has the pickup roller121installed at one side of the feed tray110as shown inFIG. 3B. That is, as shown inFIGS. 3A and 3B, which are a plan view of and a rear view of the paper pickup system, respectively, the pickup roller121is installed at one side of the feed tray110rather than at a center thereof, and a paper guide115is installed at the opposite side of the feed tray110so that the paper S does not sway from one side to another. In particular, the paper guide115is installed such that the paper guide115can slide on the feed tray110along the width direction. Therefore, the location of the paper guide115can be adjusted to a size of the paper S.

A reason for locating the pickup roller121to one side of the feed tray110is to allow paper having various sizes to be transferred toward the resistance plate140. If the pickup roller121is installed at a center of the feed tray110, it is impossible to move very small sized paper. In general, a minimum width of paper that can be fed in an inkjet printer is about 3 inch.

However, in a case where paper with various types or sizes are fed by only one feed tray, such as the feed tray110, the performance of feeding paper is lower than when using a feed cassette dedicated to specific sized paper, e.g., A4 sized paper. Further, it is more difficult to feed special type paper, such as overhead transparency paper (OHP), label paper, and photo paper, only using one feed tray. In particular, the performance of feeding paper deteriorates when using low-quality paper to which a large amount of paper powder (paper dust) adheres. In this case, the pickup roller121becomes stained with the paper powder, thus considerably lowering the performance of feeding paper.

SUMMARY OF THE INVENTION

The present general inventive concept provides a low-cost tray-type paper pickup system in which both a feed tray for paper with various types or sizes and a feed cassette for low-quality paper or specific sized paper can be used, thereby improving feeding quality.

The present general inventive concept also provides a printer adopting such a two-way paper pickup system.

The foregoing and/or other aspects and advantages of the present general inventive concept are achieved by providing a two-way paper pickup system of a printer that includes a feed tray on which paper or a feed cassette is placed, a first pickup assembly that moves the paper placed on the feed tray, and a resistance plate that allows the moved paper to be separately transferred, the system comprising a second pickup assembly that moves to a paper exit of the feed cassette so as to move paper included in the feed cassette when the feed cassette is placed on the feed tray.

When the feed cassette is inserted into the printer, the first pickup assembly is moved on the feed cassette while being rotated.

The foregoing and/or other aspects and advantages of the present general inventive concept may also be achieved by providing a printer that includes a two-way paper pickup system of a printer that includes a feed tray on which paper or a feed cassette is placed, a first pickup assembly that moves the paper placed on the feed tray, and a resistance plate that allows the moved paper to be separately transferred, the system comprising a second pickup assembly that moves to a paper exit of the feed cassette so as to move paper included in the feed cassette when the feed cassette is placed on the feed tray. When the feed cassette is inserted into the printer, the first pickup assembly is moved on the feed cassette while being rotated.

The paper placed on a feed tray is fed for a general print job, but when feeding of standard sized paper, such as letter sized paper, or special type paper is required, the paper placed on the feed tray is replaced with a feed cassette in which the standard sized paper or the special type paper is placed and the paper in the feed cassette is used. Therefore, it is possible to easily feed even paper that cannot be satisfactorily fed by a conventional tray-type pickup system without modifying the structure of the conventional tray-type pickup system, using the feed cassette.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 4illustrates a two-way paper pickup system adopted by a printer when a feed cassette is not in use, according to an embodiment of the present general inventive concept. Similarly to a conventional paper pickup system, the two-way paper pickup system ofFIG. 4includes a feed tray10on which paper S is placed, a first pickup assembly20that moves the paper S placed on the feed tray10, and a resistance plate40that allows sheets of the paper S delivered by the first pickup assembly20to be separately supplied one by one to a feed roller30. Thus, detailed descriptions of these elements will be omitted.

Compared to the conventional paper pickup system, the paper pickup system ofFIG. 4further includes a second pickup assembly50installed in a printer (not shown) near the resistance plate40. As shown inFIG. 4, the second pickup assembly50is manufactured such that a second pickup roller supporter53can be rotated with respect to a rotating axis51. An upper part56of the second pickup roller supporter53is provided with both a second pickup roller57that moves the paper S from a feed cassette (not shown) and a friction pad55that separates sheets of the paper S delivered by the second pickup roller57one by one. Also, the second pickup roller supporter53is bent with respect to the rotating axis51at a predetermined angle. Accordingly, upper and lower parts56and54, respectively, of the second pickup roller supporter53, are inclined toward the feed tray10or the feed cassette depending on which one is presently being used.

As shown inFIG. 4, when the paper S, rather than the feed cassette, is placed on the feed tray10, the upper part56of the second pickup assembly50is drawn back by a spring59so that the second pickup roller57does not interfere with feeding of the paper S. In this case, the second pickup roller57deviates from a path along which the paper S is fed.FIG. 4illustratively shows that the spring59is installed between the upper portion56of the second pickup assembly50and a frame (not shown) inside the printer, but the spring59may be replaced by any elastic device. Alternatively, a hinge spring may be used by coupling it to the rotating axis51, rather than the spring59, the hinge spring being connected between the upper portion56of the second pickup assembly50and the frame inside the printer.

A method of feeding the paper S from the feed tray10is similar to the conventional method described supra. More specifically, when a first pickup roller21of the first pickup assembly20is rotated while being in contact with the paper S, the paper S is transferred toward the resistance plate40. The first pickup roller21is installed to be rotatable while being fixed to an end of a first pickup roller supporter23. The other end of the first pickup roller supporter23is also installed to be rotatable while being fixed to the frame inside the printer. Therefore, the first pickup roller21contacts the paper S due to the weight of the first pickup roller supporter23. Also, the first pickup roller supporter23delivers a driving force to the first pickup roller21. A plurality of projections45are formed on the resistance plate40. Feeding of the paper S is controlled by the projections45such that only one sheet of the paper S, i.e., the top most sheet, which contacts the first pickup roller21is transferred to the ink cartridge60via the feed roller30.

FIG. 5illustrates a two-way paper pickup system adopted by a printer (not shown) while a feed cassette is in use, according to an embodiment of the present general inventive concept. When a user desires to use a cassette-type paper pickup system that enables feeding of special paper or standard sized paper, a feed cassette70in which paper S is placed is positioned on a feed tray10. The feed cassette70slides on the feed tray10and then is inserted into the printer. As shown inFIG. 5, when the feed cassette70, rather than paper, is placed on the feed tray10, a first pickup assembly20is rotated while being pushed upward by the feed cassette70and moved along an upper side of the feed cassette70. In this case, the first pick assembly20does not operate to transfer paper.

A projection75is formed at a portion of a front lower part of the feed cassette70. While the feed cassette70slides on the feed tray10, a lower part54of a second pickup roller supporter53is pushed back and rotated by the projection75. One or more projections75may be used. An aperture (not shown) must be formed in a portion of a resistance plate40that faces the projection75so that the projection75can pass through the resistance plate40and push back the lower part54of the second pickup roller supporter53. When the second pickup roller supporter53is rotated due to the projection75, a second pickup roller57, which is installed to be rotatable while being fixed with an upper part56of the second pickup roller supporter53, is moved to a paper exit77of the feed cassette70. At the paper exit, the second pickup roller57is coupled to a driving unit (not shown) where it is provided with a driving force.

A method of feeding paper using the feed cassette70according to an embodiment of the present general inventive concept will now be described. As is well known in the prior art, an aperture77is formed in a front upper part of the feed cassette70widthwise. The aperture77acts as a paper exit through which paper is fed to the printer. Also, in the feed cassette70, a tray78on which paper S is placed and a pressure device79that pushes the paper S placed on the tray78upward to the paper exit77are installed. Thus, the second pickup roller57can contact the paper S at the paper exit77of the feed cassette70. When the printer operates, the second pickup roller57is rotated to drag the paper upward and out of the feed cassette70. The dragged paper is inserted between the second pickup roller57and a friction pad55formed of rubber. Since a surface friction coefficient μRof the second pickup roller57is greater than a surface friction coefficient μPof the friction pad55, only the top most sheet of the paper is selected and transferred to the feed roller30. Then, printing is performed on the transferred paper using the ink cartridge60. As described above, it is possible to more effectively and separately feed paper using a friction pad than when using a resistance plate with projections.

If a user desires to feed paper using the feed tray10, the feed cassette70can be removed from the feed tray10and then paper is put on the feed tray10in place of the feed cassette70. Then, the second pickup roller57returns to its original position due to a restoring force of a spring59, and the first pickup roller21becomes in contact with the paper again due to its own weight as shown inFIG. 4.

As described above, a paper pickup system according to the various embodiments of the present general inventive concept allow a user to use a feed tray when performing a print job regardless of the size and type of paper, and to use a feed cassette dedicated to specific sized paper alternatively. Accordingly, it is possible to improve the performance of feeding paper since both the feed tray and the feed cassette can be used, without remarkably increasing manufacture costs, as compared to a conventional feed mechanism that uses only a feed tray based on a paper separation method using a resistance plate.