Incremental printing of symbolic information – Thermal marking apparatus or processes – Record receiver driving means
Utility Patent
1998-04-29
2001-01-02
Tran, Huan (Department: 2861)
Incremental printing of symbolic information
Thermal marking apparatus or processes
Record receiver driving means
C347S164000, C271S171000, C399S381000
Utility Patent
active
06169561
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention generally relates to image forming apparatus and methods and more particularly relates to an image forming apparatus including receiver supply tray capable of automatically accommodating receiver sheets of various sizes, and method of assembling same.
An image forming apparatus may be a thermal printer which forms a color print by successively printing with a dye donor onto individual sheets of a dye receiver (i.e., paper or transparency). The print head of such a thermal printer commonly provides a print line of thermal resistive elements that can be individually heated in order to transfer dye from the donor to the receiver.
More specifically, a typical color thermal printer includes the previously mentioned print head and a platen. A picker mechanism “picks” individual sheets of the receiver from a stack of cut sheets of the receiver and feeds the individual sheets into a nip area defined between the print head and platen. The donor is positioned between the print head and platen. The print head is then lowered, so that the donor and receiver sheet are sandwiched between the print head and platen. An image is printed on the sheet by selectively heating the elements of the print head in order to transfer a first dye to the receiver sheet. The receiver sheet is then repositioned to receive a second color of the image, and the donor is positioned to provide a second dye color. These steps are repeated until all colors of the image are printed and the completed print is ejected from the printer.
Moreover, a receiver cassette tray loaded with the stack of cut receiver sheets is removably inserted into the printer. The tray includes a spring loaded support plate (i.e., platen) supporting the stack of sheets. The support plate upwardly biases the stack of sheets into engagement with the picker mechanism, so that the picker mechanism can pick individual sheets from the stack of sheets. It is known that the stack of sheets should reside in the tray such that the marginal edges of each sheet generally aligns with the marginal edges of the other sheets in the stack of sheets. Such alignment is desirable so that each sheet is properly presented to the picker mechanism for picking. Proper presentment of each sheet to the picker mechanism in turn decreases likelihood that sheets will “jam” in the picker mechanism when the sheets engage the picker mechanism. Moreover, it is desirable that receiver supply trays be able to accommodate receiver sheets of various sizes, such as sheets that, for example, are “letter-sized” having dimensions of 8.50 inches (21.59 cms) wide by 11 inches (27.94 cms) long or “A4-sized” sheets having dimensions of 8.27 inches (21 cms) wide by 11.69 inches (29.7 cms) long. To accommodate sheets of different sizes, prior art receiver supply trays include manually adjustable sheet “restricter” members therein.
A cassette for accommodating receiver sheets is disclosed in U.S. Pat. No. 5,537,195 titled “Sheet-Accommodating Cassette With Main Container And Sub Container” issued Jul. 16, 1996 in the name of Seiji Sagara, et al. This patent discloses a sheet-accommodating cassette used in an image forming apparatus, such as a copying machine or a printer, for accommodating sheets supplied to the image-forming apparatus. The Sagara, et al. device includes a main container and a subcontainer coupled to each other to form the sheet-accommodating cassette. A rear “end-restricting member” is manually engageable with any of several engagement holes in the sub-container for restricting the rear end of the sheets. In addition, a “side-restricting member” can be manually brought into engagement with an engagement hole formed in the main container for accommodating letter size sheets. Moreover, the side-restricting member also can be brought into engagement with another engagement hole for accommodating A4 size sheets. Also, the side-restricting member can be manually brought into engagement with yet another engagement hole for accommodating B5 size sheets. Thus, to accommodate a sheet of a given length, the end and side-restricting members are manually moved, such that they engage sets of appropriate engagement holes. Therefore, the Sagara et al. device requires manual repositioning of the end and side-restricting members to accommodate sheets of various sizes. However, manually repositioning the end and side-restricting members is time consuming and therefore costly. Hence, a problem in the art is time consuming and costly manual repositioning of end-restricting and side-restricting members in a receiver sheet cassette when it is necessary to load sheets of different sizes.
Therefore, there has been a long felt need to provide an image forming apparatus including receiver supply tray capable of automatically accommodating receiver sheets of various sizes, and method of assembling same.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an image forming including receiver supply tray capable of automatically accommodating receiver sheets of various sizes, and method of assembling same.
With the above object in view, the invention resides in an image forming apparatus capable of automatically accommodating a receiver having a predetermined size, comprising a print head for printing an image on the receiver; and a receiver supply tray associated with the print head for accepting the receiver, the supply tray adapted to automatically accommodate the receiver size.
According to one aspect of the present invention, the tray includes a housing having a rear wall and two parallel sidewalls perpendicular to the rear wall. A platen is movably connected to the housing for supporting a stack of receiver sheets thereon, each receiver sheet having two lateral marginal edges, a rearwardly-facing marginal edge and a front-facing marginal edge. The tray includes a resilient first leaf spring adjacent one of the sidewalls of the housing for aligning one lateral marginal edge of the stack and further includes a side panel adjacent the other sidewall for aligning the other marginal edge of the stack. The tray also includes a resilient second leaf spring and a resilient third leaf spring parallel to the second leaf spring. Both the second and third leaf springs are disposed adjacent the rear wall of the housing for aligning the rearwardly-facing marginal edge of the stack of sheets.
If the receiver sheets which are loaded onto the platen are 8.5 inches wide by 11.0 inches long (i.e., “letter-sized”), the lateral marginal edge of the stack of sheets will rest atop and compress the first leaf spring disposed near one sidewall and will abut the side panel near the other sidewall. The rearwardly-facing marginal edge of the stack of sheets will abut a side edge of the resilient second leaf spring disposed near the rear wall. Thus, in the case of letter-sized sheets, one marginal edge thereof will compress the first leaf spring due to its relatively wider width compared to A4-sized sheets and will abut the side edge of the second leaf spring due to its relatively shorter length compared to A4-sized sheets. Of course, the other marginal edge of the sheets will abut the side panel. As another example, if the receiver sheets which are loaded onto the platen are 8.27 inches wide by 11.69 inches long (i.e., “A4-sized”), a lateral marginal edge of the stack of sheets will abut a side edge of the resilient first leaf spring disposed near one sidewall and will abut the side panel near the other sidewall. In this case, the rearwardly-facing marginal edge of the sheet will rest atop and compress the second leaf spring but abut a side edge of the third leaf spring. Thus, in the case of A4-sized sheets, one marginal edge thereof will abut the side edge of the first leaf spring due to its relatively narrower width compared to letter-sized sheets and will compress the second leaf spring but abut the side edge of the third leaf spring due to its relatively longer length compared to letter-sized sheets. That is, for the most commonly used sizes of re
Eastman Kodak Company
Stevens Walter S.
Tran Huan
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