FRONT-LOADING PAPER FEED FOR A PRINTER

Abstract: A printer comprises a casing (1) having a substantially cuboidal shape with an operation panel (2) formed on the front face thereof. At least a printing head portion, a printing medium attaching portion and a control circuit for controll­ ing the printing operation of the printing head portion are stored in the casing. At least the printing medium-attaching portion is supported in the casing through a moving mechanism so that the printing medium-attaching portion can be freely drawn out forward from the front face of the casing, thereby permitting easier setting and dismounting of the printing medium.

Description: The present invention relates to printers, such as thermal printers or electrosensitive printers, for producing a hard copy of image data such as that generated by television sets, video tape recorders or personal computers, and in particular the invention relates to the insertion of supplies of printing medium, such as paper, in such printers. In some types of conventional thermal printer, a lid provided on the upper face of a casing of the printer is arranged so that it can be opened for inserting a roll of heat-sensitive recording paper used as the printing medium or for checking the remaining quantity of such a roll. When the quantity of heat-sensitive recording paper remaining on the roll becomes small, the lid is opened, the roll of heat-sensitive recording paper is taken out, and a new roll of heat-sensitive recording paper is placed therein. Checking or maintenance of the printer components can also be performed with the top lid open. In a printer having a structure in which a top lid is opened and closed in the above-mentioned manner, articles must not be placed on the printer and the space on and immediately above the printer should be kept permanently clear. Thus, this type of printer is not preferable from the viewpoint of the effective utilization of space. Furthermore, such a printer is not suitable for rack-mounting in close vertical proximity to other equipment. If an operation panel is also arranged on the upper face of the casing the printer must be located at a relatively low level, for example on a desk, so that the panel can easily be seen, thereby restricting the range of possible locations of the printer. Also, in many types of conventional printer, the printing paper approaches a platen from below and is in sliding contact with the front face of the platen where printing is effected. Then, the printing paper is delivered upwardly to emerge from an upper portion of the printer. Because of this structure, other devices cannot be positioned directly above the upper portion of the printer, and there again arises the problem of inefficient utilization of space. In another type of conventional printer a door through which a supply of printing paper may be introduced is arranged on the front face of the printer. To facilitate the operation of introducing the supply of printing paper, the printing paper is mounted forward of the platen and the platen is disposed vertically within the printer. Accordingly, the height of the printer must be relatively large, and therefore a large vertical space is required for mounting the printer. Moreover, in conventional printers using rolls of continuous printing paper, since the space between the platen and the printing head is normally narrow, the operation of introducing a fresh roll and advancing the paper roll to a predetermined position, which involves passing it between the platen and printing head, can be very difficult. US-A-3,346,872 discloses a printer in which the printing mechanism is housed in an enclosure and is supported movably by a frame so that the printing mechanism can be withdrawn forwardly of a front face of the enclosure. The printing mechanism includes printing medium mounting means, for holding a supply of printing medium such as a roll of paper, and a printing portion including a plurality of units operable to print on paper drawn from the supply. When the frame is withdrawn, the printing portion can be moved upwardly, to permit threading of a leading edge of such printing paper, such movement being constrained in a rather complex manner by J-shaped slots in which are slidably fitted respective pairs of pins fastened to the sides of the frame. With the printing portion raised, to enable a fresh supply of printing paper to be introduced the printing medium mounting means must then be moved upwardly with respect to the frame. Thus two separate successive movement operations are required to gain access to the printing medium mounting means in order to insert a new supply of the printing medium. Hence the prior art printer concerned is not convenient to maintain or use. According to the present invention there is provided a printer housed in a casing that is substantially cuboidal in its external form and including a printing unit supported movably within the casing so that the unit can be withdrawn forwardly of a front face of the casing, the said printing unit including printing medium mounting means, for holding a supply of a printing medium when the printer is in use, a printing head portion including a printing head operable to print on printing medium drawn from the said supply, and control circuitry for controlling such operation of the printing head, and the said printing head portion being mounted to permit upward movement thereof from its normal operating position, when the printing unit is so withdrawn, to facilitate operative replacement of such printing medium; characterised in that the said upward movement is pivotal movement about a pivot axis which is fixed in relation to the printing medium mounting means, and in that a spring is arranged in engagement with the said printing head portion to bring about the said upward movement automatically, when the printing unit is so withdrawn, thereby to provide access to the said printing medium mounting means from above so as to permit insertion of such a supply, there being a printer operation panel provided at the said front face of the printer. Such a printer can be designed to be of low height and to have generally compact structure such that the space above the printer can be freely utilised, for example to permit mounting of related equipment directly on the top face of the printer. The simple pivotal mounting of the printing head portion facilitates the use of a spring to provide for reliable automatic opening on withdrawal of the printing unit, thereby rendering significantly more convenient the operation of replacing such printing medium. Reference will now be made, by way of example, to the accompanying drawings in which: Figure 1 shows a perspective view of a printer embodying the present invention, with a printing unit thereof shown in a withdrawn position; Figure 2 shows a view corresponding to that of Figure 1 but with the printing unit in its normal operating position; Figure 3 shows a perspective view of the printing unit of the printer of Figure 1; and Figure 4 is a schematic side elevational view for illustrating movement of the printing unit of the Figure 1 printer between the normal operating position and the withdrawn position. The printer shown in Figures 1 and 2 includes a casing 1 in which a control circuit for controlling a printing portion, a paper feed mechanism and the like, and a power source portion are contained. An operation panel 2 is arranged on a front face of the casing 1, and operation switches and display means are arranged on the operation panel 2. The casing 1 has a substantially cuboidal shape, but concave-convex, inclined and curved parts may be formed on the side and front faces of the casing for decorative and/or functional purposes. A printing head portion and printing medium mounting means are also contained in the casing 1. Ordinarily, the printing head portion and printing medium mounting means are contained in the casing 1 at the side of the operation panel 2, as illustrated in Figure 2. However, when a supply of printing medium is to be replaced, as shown in Figure 1 the printing head portion and printing medium mounting means are withdrawn forwardly of the front face of the printer. The printing head portion and the printing medium mounting means form part of a printing unit of the printer supported by a draw-out frame 3 having a shape similar to that of a drawer of a desk or the like, which is attached to a guide rail formed on the casing 1 so that the frame 3 can be moved forward and backward. A heat-sensitive recording paper roll 4 (providing the supply of printing medium) is held by the printing medium mounting means in the draw-out frame 3. A platen 5 is arranged between the roll 4 and a front plate 3a of the draw-out frame 3. At an inner part of the draw-out frame 3, a cover-like arm 7 forming a part of the printing head portion is rotatably attached to the frame by a supporting shaft 6. A thermal (printing) head 8 which forms another part of the printing head portion is fixed relative to the arm 7 at a position adjacent to the lower side of the free end thereof. In the state shown in Figure 1, the arm 7 is in the open position. When the draw-out frame 3 is pushed into the casing 1, the arm 7 is restored to the closed position, and as shown in Figure 2, the printing head portion and printing medium-attaching portion are housed in the casing 1. When the arm 7 is in the closed position, a heat-generating element (not shown) of the thermal head 8 is pressed against the platen 5 by spring means (not shown). Heat-sensitive recording paper 4a drawn from the heat-sensitive recording paper roll 4 is guided in the forward direction within the casing 1 between the platen 5 and the thermal head 8. Accordingly, the heat-generating element of the thermal head 8 is brought into pressure contact with the heat-sensitive recording paper 4a on the platen 5. When the heat-generating element is actuated according to the information to be printed, heat is selectively generated in the heat-generating element to heat the heat-sensitive recording paper 4a, whereby printing is performed. The heat-generating element of the thermal head 8 and the feed mechanism for the heat-sensitive recording paper are electrically connected to the control circuit and power source portion in the casing 1 through cables (not shown). The heat-generating element of the thermal head 8 consists of 100 to 200 resistors arranged in a line. In the control circuit, for example, an image signal is divided into 16 or 32 stages according to the densities of respective parts of the image, and the application of an electric current to the respective resistors is controlled according to the density levels, whereby an image consisting of parts differing in density is formed. A structure may be adopted in which a colour print is formed by a colour image signal. A printing signal as described above is formed, for example, from an image signal output by a television set, and if the printer is connected to the television set, a picture received and shown by the television set can be printed by the printer. Furthermore, when the printer is connected to a video tape system or video disc system, information stored in the video tape or on the video disc can be printed by the printer. Moreover, when the printer is connected to a microcomputer, information stored therein can be printed, and information input through various information exchange systems using telephone lines also can be printed by the printer. A printing paper detector is arranged behind the rear face of the platen 5. When printing paper is present, a detection piece 31 biassed to project upwardly by a spring (not shown) is held down by the printing paper, indicating the presence of printing paper, and when the printing paper is not present or has been completely consumed, the detecting piece 31 moves upwards to indicate the absence of printing paper. A cutter 13, for cutting the printing paper 4a into pages, is arranged on the inner edge of a paper exit 34 provided in a front face plate 33 of an openable lid 32 formed integrally with the arm 7. The cutter 13 may be formed integrally with the front face plate 33 or may be attached as an individual member to the front face plate 33 by appropriate means. In the printer of Figure 1, the insertion of a supply of printing medium is performed in the following manner. The draw-out frame 3 is drawn out, whereupon the arm 7 is automatically pivoted upwards to the open position. When the arm 7 is in the open position, the heat-sensitive recording paper roll 4 is placed in the printing medium mounting means between the arm 7 and the bottom portion of the draw-out frame 3 at the position indicated by the broken line in Figure 3, and the heat-sensitive recording paper 4a is guided forwardly over the platen 5. Respective slots 12 formed on the opposed inner surfaces of the frame 3 serve to receive opposite ends of a shaft carrying the recording paper roll 4. As shown in Figure 3, when the draw-out frame 3 is withdrawn, the lid 32 is opened wide and the top face of the draw-out frame 3 is substantially in the open position. The heat-sensitive recording paper roll 4 can be inserted from above into the draw-out frame 3 through the opening between the shaft 6 and platen 5, which enhances the convenience of the operation of changing the roll 4. The arm 7 can then be turned downward to the closed position and the draw-out frame 3 pushed into the casing 1, this completing the operation of inserting the printing medium supply. The operation of withdrawing the draw-out frame 3 from the casing 1 or pushing it into the casing 1 may be performed manually, or may be carried out by a motor. In the latter case, the motor is operated by a changeover switch 9 arranged on the front plate 3a of the draw-out frame 3. The linkage mechanism for the arm 7 and the draw-out frame 3 will now be described with reference to Figs. 3 and 4. Figure 3 is a perspective view of the printing unit housed within the draw-out frame 3, the frame being shown in the open position, and Figure 4 is a side view illustrating the movement of the arm during opening and closing operations of the frame. In the draw-out frame-containing portion of the casing 1, respective left and right guide rollers 10 are arranged in an upper portion of the front face of the casing 1. These guide rollers 10 are positioned respectively on the left and right sides above the draw-out frame 3, and left and right guide faces 7G of the arm 7 are located respectively below these left and right guide rollers 10. The arm 7 is moved forward and backward together with the draw-out frame 3, and this forward-backward movement is preferably performed by the driving action of a motor. In such a case, if the casing 1 is connected to the draw-out frame 3 by a known feed mechanism comprising a rack and pinion, or they are connected by screws, the draw-out frame 3 may be moved forward and backward simply by engaging the operation switch 9 to control the motor appropriately. In the closed position, the front part 7G1 of each guide face 7G of the arm 7 is inclined to the horizontal, with the guide roller 10 abutting against the top end of the front part 7G1. The rear part 7G2 of the guide face 7G close to the supporting shaft 6 is substantially horizontal and is separated by a gap G from the lower ease of the guide roller 10. A torsion coil spring 11 is wound on the supporting shaft 6 symmetrically on the left and right sides thereof, with one end of the coil spring 11 supported on the draw-out frame and the other end supported on the arm 7, whereby the arm 7 is urged in the opening direction (upward). The spring biassing force for moving the arm 7 upward may be provided by means other than the torsion coil spring 11. Referring to Figure 4, the state where the draw-out frame 3 is contained in the casing is designated as A1. When the draw-out frame 3 is moved outward from the interior of the casing 1 by the driving mechanism, and while the supporting shaft 6 is remote from the guide roller 10, that is, during movement between positions A1 and A2, even if the draw-out frame 3 and the arm 7 are moved in the forward direction indicated by an arrow a1, the arm 7 cannot be moved upward since the upper part of the inclined portion 7G1 of the arm 7 is under pressure from the guide roller 10. However, as the arm 7 moves to the position A3 so that the supporting shaft 6 approaches the guide roller 10, the lower part of the inclined portion 7G1 is advanced to the position of the guide roller 10. Thus, the arm 7 is made to move slightly upward by the torsion spring 11 with the supporting shaft 6 as the center of rotation. As the supporting shaft 6 is further advanced to A3, A4, the arm 7 is made to move further upward. When the supporting shaft 6 is advanced to the position A10 where the advance stroke terminates, the arm 7 is substantially released from the control of the guide roller 10 and is in a substantially vertical position as shown in Figure 4. When the insertion of the recording paper roll 4 is completed, the draw-out frame 3 is pushed back into the casing 1. Namely, as the arm 7 is moved backward in the direction opposite the direction of the arrow a1, the arm 7 is pushed down by the guide roller 10 and brought to the closed position through positions A10, A9,......A3. At the position A2, the arm 7 is substantially in the fully-closed position, and at the position A1, where the backward stroke terminates, the arm 7 is completely in the closed position. As is apparent from the foregoing description, in a printer embodying the present invention, the region in which printing takes place (comprising the platen 5 and the thermal head 8) and the printing medium mounting means, to which the printing medium roll 4 is attached, are arranged in the draw-out frame 3 which is contained and supported movably in the casing. Accordingly, when a fresh supply of printing medium is to be introduced in place of an exhausted supply, the exchanging operation can be performed while the draw-out frame 3 is drawn out from the casing and exposed externally thereof. Therefore, the space above the top face of the casing remains free for use, and other devices can be placed on the casing and the printer can be contained in a rack, with the result that a more effective utilization of space becomes possible. Furthermore, since the draw-out frame 3 in which the printing region and the printing medium mounting means are arranged is withdrawn from the front face, a printer operation panel is also advantageously disposed on the front face, and therefore the printer can be placed not only on a desk but also at a higher location such as in a cabinet with the result that the freedom of locating the printer is further increased. Also, since the platen and the printing paper roll are arranged horizontally in parallel to one other within the draw-out frame, the height of the casing can be relatively small, and a desirably compact printer can be provided. Because the printer is of small height and has a cuboidal shape, other devices with which the printer is to be used, such as television sets, video tape decks, personal computers and the like can be placed on the printer, and/or the printer and such other devices can be housed as one system in a rack and be operated using front-panel-mounted controls. Accordingly, space can be effectively utilized, versatility is increased and the appearance is improved. Since insertion of the printing paper roll is carried out when the lid located above the printing medium mounting means is wide open, the printing paper roll can be located very easily. In an embodiment of the present invention to be used for printing image data, the image can be reversed in the vertical direction and the horizontal direction by the control circuit.

Claims: A printer housed in a casing (1) that is substantially cuboidal in its external form and including a printing unit (3) supported movably within the casing so that the unit (3) can be withdrawn forwardly of a front face of the casing, the said printing unit (3) including printing medium mounting means, for holding a supply (4) of a printing medium (4a) when the printer is in use, a printing head portion including a printing head (8) operable to print on printing medium (4a) drawn from the said supply (4), and control circuitry for controlling such operation of the printing head (8), and the said printing head portion being mounted to permit upward movement thereof from its normal operating position, when the printing unit (3) is so withdrawn, to facilitate operative replacement of such printing medium; characterised in that the said upward movement is pivotal movement about a pivot axis (6) which is fixed in relation to the printing medium mounting means, and in that a spring (11) is arranged in engagement with the said printing head portion to bring about the said upward movement automatically, when the printing unit is so withdrawn, thereby to provide access to the said printing medium mounting means from above so as to permit insertion of such a supply (4), there being a printer operation panel (2) provided at the said front face of the printer. A printer as claimed in claim 1, wherein the said printing head (8) is of the thermal type and the said supply of printing medium comprises a roll of heat-sensitive recording paper, the said printing medium mounting means comprising a paper feed roller. A printer as claimed in claim 1 or 2, in operative combination with other devices at least one of which is supported on the upper surface of the printer. A printer as claimed in any preceding claim, wherein a platen (5) is supported rotatably within the printing unit (3) with its longitudinal axis extending substantially horizontally, the said supply (4) of printing medium (4a) comprising a roll mounted with its axis horizontal.

Inventors: MATSUMOTO, NORIO, OHKUMA, OSAMU, OKUDA, SHINYA, SEINO, MITUYOSHI
Applicants: FUJITSU LIMITED
Application year: 1985
Main classification: B41J15
IPC codes: B41J15