Serial printer and a method of assembling the same

Abstract: A serial printer easy to assemble and capable of being assembled through an automatic assembling process. The control device (240) is disposed near and along one of the opposite sides of the chassis (101), and the electrical components and the distributed functional devices are disposed opposite to the control device. The electrical components and the distributed functional devices are connected electrically to the control device (240) by connectors (260) having elastic contact portions which maintain elastic contact with the signal terminals of the control device, the electrical components and the distributed functional devices.

Description: The present invention relates to a serial printer having a print head mounted on a carriage and moved step by step in a horizontal direction for printing, and to a method for assembling the serial printer. The distributed functional devices of a conventional serial printer including a control device, a power supply device, an operating device and an IC card connecting device are interconnected by a junction circuit device, and the electrical components including motors and sensors are connected to the distributed functional devices by leads. However, the use of the junction circuit device for interconnecting the distributed functional devices is an impediment to the reduction of cost of the serial printer. The troublesome work for connecting the electrical components to the distributed functional devices by leads requires much labor and affects adversely the efficiency of production of the serial printer. Furthermore, long leads require difficult wiring work and careful handling, and make the automatic assembling of the serial printer impossible. The document JP-A-61 206 682 describes a known serial printer having a platen disposed in a horizontal position, a carriage, and a print head mounted on the carriage and moved along the platen for printing, comprising: a chassis supporting the platen and the carriage; a control device disposed near to either the right-hand side or the left-hand side of the chassis; electrical components including driving motors, disposed with their signal terminals respectively opposite to the signal terminals of the control device; and connectors having elastic contact portions capable of being in direct contact with the signal terminals to connect the signal terminals of the control device electrically to the corresponding signal terminals of the distributed functional devices and the electrical components. In the known serial printer, however, at least two connectors and a junction device are necessary to connect the control device with the electrical components and the distributed functional devices. It is an object of the present invention to provide a serial printer easy to assemble and handle, and capable of being assembled through an automatic assembling process. It is another object of the present invention to provide an inexpensive serial printer eliminating components which are essential to the conventional serial printer, such as a junction circuit device and the like. These objects are solved by the serial printer according to claim 1 and by the method according to claim 6. The inventive serial printer having a platen disposed in a horizontal position, a carriage, and a print head mounted on the carriage and moved along the platen for printing, comprises: a chassis supporting the platen and the carriage; two side frames mounted on the chassis and rotatably supporting therebetween the platen; a control device with signal terminals disposed near and in parallel to either the right hand side or the left hand side of the chassis; electrical components, including driving motors, having signal terminals, connected with their signal terminals respectively to the signal terminals of the control device; connectors having elastic contact portions capable of being in direct contact with the signal terminals to connect the signal terminals of the control device electrically to the corresponding signal terminals of the electrical components and distributed functional devices; wherein said distributed functional devices including a power supply device, an operating device and a IC card connecting device, disposed with their signal terminals respectively opposite to corresponding signal terminals of the control device; one of the driving motors for driving a drive shaft of the platen being fixed to one of the two side frames; the control device having a side face and said signal terminals along its length, the control device being disposed outside of the selected one side frame fixed to the drive motor and disposed in parallel to the respective side of the chassis, whereby the side face of the control device being perpendicular to a bottom side of said chassis; the other electrical components and distributed functional devices being disposed at the selected side of the control device with their signals terminals opposite to corresponding signal terminals of said control device; said signal terminals of said distributed functional devices and electrical components being electrically connected to corresponding signal terminals of said control device by disposing said connectors between the corresponding signal terminals. The inventive method for assembling the above mentioned serial printer comprises: providing electrical connectors including electrical connecting members having opposite ends each presenting electrical contacts, and pins for attaching the electrical connectors to the chassis, with the electrical connectors being formed by molding to create an integral unit; disposing an elongated control device, having signal terminals along its length, to one side of an longitudinal extent of the elongated platen and in a direction perpendicular to the longitudinal extent of the platen and perpendicular to the chassis; fixing the connectors to the chassis at positions near the one side of the longitudinal extent of the elongated platen by pressing the pins into holes provided in the chassis so that the electrical contacts at one end of the electrical connector members are in direct contact with corresponding signal terminals of the control device; and disposing electrical components and distributed functional devices, each having electrical terminals, so that the electrical terminals of the electrical components and distributed functional devices are in direct contact at the other end of the electrical connecting members. Thus, according to the present invention, the electrical components and the distributed functional devices are connected electrically to the control device without using any leads and junction circuit devices, so that the serial printer is easy to assemble and handle. Advantageous embodiments are mentioned in the dependent claims 2 to 5 and 7. The above and other objects, features and advantages of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings. Fig. 1 is a perspective view of a serial printer embodying the present invention; Fig. 2 is a plan view showing the internal structure of the serial printer of Fig. 1; Fig. 3 is a side elevation of an essential portion of the serial printer of Fig. 1; Fig. 4 is a plan view of the essential portion shown in Fig. 3; Fig. 5 is a perspective view of assistance in explaining a manner of assembling the essential portion shown in Fig. 3; Fig. 6 is a side elevation of another essential portion of the serial printer of Fig. 1; and Fig. 7 is a plan view of the essential portion shown in Fig. 6. Fig. 1 is a perspective view of a serial printer in a preferred embodiment according to the present invention, and Fig. 2 is a plan view showing the internal structure of the serial printer. Referring to Figs. 1 and 2, there are shown a printing unit 100, a chassis 101, side frames 102 and 103 fixed to the chassis 101, a platen 110 journaled on the side frames 102 and 103, a line-feed motor 120 fixed to the side frame 103, a driving pinion 121 fixed to the output shaft of the line-feed motor 120, an idle gear 130 engaging the driving pinion 121, a driven gear 140 engaging the idle gear 130 and fixed to the shaft of the platen 103. The line-feed motor 120 drives the platen 110 through the gear train including the driving pinion 121, the idle gear 130 and the driven gear 140 for rotation. Best shown in Fig. 2 are a carriage 150, a print head 160 mounted on the carriage 150, a spacing motor 190, a belt pulley 171, a belt pulley 172 coaxially fixed to the output shaft of the spacing motor 190, and a timing belt extended between the belt pulleys 171 and 172 and fastened to the carriage 150. The spacing motor 190 drives the carriage 150 mounted with the print head 160 through the belt pulley 172 and the timing belt 180 for lateral movement along the platen 110. A flat cable 200 is connected to the printing coil, not shown, of the print head 160 to apply driving signals to the print head 160. An operating device 210 and an IC card connecting device 220 are disposed in the front left-hand portion of the chassis 101. A power supply device 230 is disposed in the rear left-hand portion of the chassis 101. An operating panel 211 associated with the operating device 210 is provided on the front wall of a case. An IC card receiving slot 221 is formed in the front wall of the case to insert an IC card in the operating device 220. The operating device 210, the IC card connecting device 220 and the power supply device 230 are distributed functional devices. Referring to Fig. 2, a control device 240 is disposed in and in parallel to the left-hand end of the chassis 101. The electrical components including the line-feed motor 120 and the spacing motor 190, and the distributed functional devices are connected electrically to the control device 240. The control device 240, the distributed functional devices and all the electrical components are fixed to the chassis 101. Although the control device 240, the distributed functional devices and the electrical components are disposed in the left-hand section of the chassis 101 in this embodiment, those components may be disposed in the right-hand section of the chassis 104. A paper end sensor 250 for detecting the trailing end of a recording paper is soldered to the control device 240. The paper end sensor 250 is a Hall-effect element, an optical sensor or a reed switch. The power supply device 230, the line-feed motor 120, the spacing motor 190, the flat cable 200, the IC card connecting device 220 and the operating device 210 are connected to the control device 240 by connectors 260, 270, 280, 290, 300 and 310 respectively. The connectors 260, 270 and 280 are substantially the same in structure, and the connectors 290, 300 and 310 are substantially the same in structure, and hence only the structures of the connectors 270 and 300 will be described as examples. Fig. 3 is a side elevation showing the structure of the connector 270, Fig.4 is a plan view of the connector 270, and Fig. 5 is a perspective view of assistance in explaining a manner of assembling the connector 270. The connector 270 comprises a base 271 formed of a nonconductive material, elastic connecting members 272 formed of spring plates, and pins 273 projecting from the lower surface of the base 271. The base 271, the connecting members 272 and the pins 273 are assembled in an integral unit by molding. The connector 270 can be fastened to the chassis 101 simply by pressing the pins 273 into holes 101a formed in the chassis 101. When the connector 270, the line-feed motor 120 and the control device 240 are set in place, the contact portions 272a of the connecting members 272 extending on one side of the connector 270 tend to press themselves against the signal terminals 122 of the line-feed motor 120 as indicated by an arrow A, and the contact portions 272b of the connecting members 272 extending on the other side of the connector 270 tend to press themselves against the signal terminals 241 of the control device 240 as indicated by an arrow B. The connector 270 may be formed integrally with the chassis 101 by molding. Referring to Fig. 6 and 7, the connector 300 comprises a base 301 formed of a nonconductive material and provided with a socket 301a for receiving the IC card connecting device 220, and elastic, conductive connecting pins 302. The elastic contact portions 302a of the contact pins 302 extending on one side of the base 301 project into the socket 301a, and the projecting contact portions 302b of the contact pins 302 extending on the other side of the base 301 project from the base 301. The connector 300 is formed in an integral member by molding. In attaching the connector 300 to the control device 240, the projecting contact portions 302b are inserted in connecting holes 242 formed in the control device 240 and are soldered to conductors provided in the connecting holes 242. The contact portions 302a of the connecting pins 302 are bent elastically in a direction indicated by an arrow C, so that the signal terminals 221 of the IC card connecting device 220 are in firm contact with the connecting pins 302 when the IC card connecting device 330 is inserted in the socket 301a. Procedure for assembling the serial printer thus constructed will be described hereinafter. First, the connectors 260, 270 and 280 are fastened to the chassis 101 in the aforesaid manner. Then, the power supply device 230, the line-feed motor 120 and the spacing motor 190 are fastened to the chassis with their connecting terminals (for example, the signal terminals 122 of the line-feed motor 120) pressed against the corresponding elastic contact portions (for example, the elastic contact portions 272a of the connector 270) of the contact members of the connectors 260, 270 and 280 respectively. After soldering the connectors 290, 300 and 310, and the paper end sensor 250 to the control device 240, the control device 240 is fixed to the chassis 101 at the predetermined position with the signal terminals 241 a thereof pressed against the corresponding elastic contact portions (for example, the elastic contact portions 272b of the connector 270) of the connecting members of the connectors 260, 270 and 280. Thus, the power supply device 230, the line-feed motor 120 and the spacing motor 190 are connected electrically to the control device 240. Subsequently, the flat cable 200, the operating device 210 and the IC card connecting device 220 are inserted in the sockets of the connectors 290, 300 and 210 respectively with their signal terminals pressed against the elastic contact pins of the corresponding connectors. Thus, the flat cable 200, the operating device 210 and the IC card connecting device 220 are connected electrically to the control device 220. Then, the operating device 210 and the IC card connecting device 220 are fastened to the chassis 101. Although this embodiment employs the connectors fixed to the control device 240 to connect the flat cable 200, the operating device 210 and the IC card connecting device 220 to the control device 240, and the connectors fixed to the chassis 101 to connect the power supply device 230, the line-feed motor 120 and the spacing motor 190 to the control device 240, means for connecting those components to the control device 240 need not be limited thereto; the flat cable 200, the operating device 210 and the IC card connecting device 220 may be connected by connectors fixed to the chassis 101, and the power supply device 230, the line-feed motor 120 and the spacing motor 190 may be connected to the control device 240 by connectors fixed to the control device 240, or the flat cable 200, the operating device 210, the IC card connecting device 220, the power supply device 230, the line-feed motor 120 and the spacing motor 190 may be connected to the control device 240 by either the connectors fixed to the control device 240 or the connectors fixed to the chassis 101. Furthermore, although the control device 240 is disposed near and in parallel horizontally to one of the shorter sides of the chassis 101 in this embodiment, the control device 240 may be disposed longitudinally near one of the shorter sides of the chassis 101 and the distributed functional devices and the electrical components may be arranged accordingly. Although the invention has been described in its preferred form with a certain degree of particularity, it is to be understood that many variations and changes are possible in the invention without departing from the scope thereof as described in the appended claims.

Claims: A serial printer having a platen (110) disposed in a horizontal position, a carriage (150), and a print head (160) mounted on the carriage (150) and moved along the platen (110) for printing, comprising: a chassis (101) supporting the platen (110) and the carriage (150); two side frames (102, 103) mounted on the chassis (101) and rotatably supporting therebetween the platen (110); a control device (240) with signal terminals disposed near and in parallel to either the right hand side or the left hand side of the chassis (101); electrical components, including driving motors (120, 190), having signal terminals, connected with their signal terminals respectively to the signal terminals of the control device (240); connectors (260, 270, 280, 290, 300, 310) having elastic contact portions (272) capable of being in direct contact with the signal terminals to connect the signal terminals of the control device (240) electrically to the corresponding signal terminals of the electrical components and distributed functional devices; wherein said distributed functional devices including a power supply device (230), an operating device (210) and a IC card connecting device (220), disposed with their signal terminals respectively opposite to corresponding signal terminals of the control device (240); one (120) of the driving motors for driving a drive shaft of the platen (110) being fixed to one of the two side frames (102, 103) ; the control device (240) having a side face and said signal terminals along its length, the control device (240) being disposed outside of the selected one side frame fixed to the drive motor (120) and disposed in parallel to the respective side of the chassis (101), whereby the side face of the control device (240) being perpendicular to a bottom side of said chassis (101); the other electrical components and distributed functional devices being disposed at the selected side of the control device (240) with their signals terminals opposite to corresponding signal terminals of said control device (240); said signal terminals of said distributed functional devices and electrical components being electrically connected to corresponding signal terminals of said control device (240) by disposing said connectors between the corresponding signal terminals. A serial printer according to Claim 1, wherein each of said connectors (270; 300) comprises a base (271; 301) formed of a nonconductive material, and connecting members (272; 302) having the elastic contact portions (272a, 272b; 302a) and formed of elastic plates, and the base (271; 301) and the connecting members (272; 302) are combined in an integral structure by molding. A serial printer according to Claim 2, wherein the elastic contact portions (272a, 272b) of said connectors (270) project from the opposite sides of the corresponding bases (271). A serial printer according to Claim 2, wherein the bases (271) of said connectors (270) are provided with pins (273) projecting from the respective lower surfaces thereof. A serial printer according to Claim 2, wherein the bases (301) of said connectors (300) are provided with sockets (301a) respectively for receiving the distributed functional devices, and the elastic contact portions (302a) are exposed in the sockets (301a). A method for assembling a serial printer according to claim 1, wherein: providing electrical connectors (260, 270, 280, 290, 300, 310) including electrical connecting members (272a, 272b) having opposite ends each presenting electrical contacts, and pins (273) for attaching the electrical connectors to the chassis (101), with the electrical connectors (260, 270, 280, 290, 300, 310) being formed by molding to create an integral unit; disposing an elongated control device (240), having signal terminals along its length, to one side of an longitudinal extent of the elongated platen (110) and in a direction perpendicular to the longitudinal extent of the platen (110) and perpendicular to the chassis (101); fixing the connectors (260, 270, 280, 290, 300, 310) to the chassis at positions near the one side of the longitudinal extent of the elongated platen (110) by pressing the pins (273) into holes (101a) provided in the chassis (101) so that the electrical contacts at one end of the electrical connector members (272b) are in direct contact with corresponding signal terminals (241) of the control device (240); and disposing electrical components and distributed functional devices, each having electrical terminals (122), so that the electrical terminals (122) of the electrical components and distributed functional devices are in direct contact at the other end of the electrical connecting members (272a). A method of assembling a serial printer, according to Claim 6, wherein said connectors (270) are provided with pins (273) on the lower surfaces of the bases (271) thereof, and the pins (273) are pressed in holes (101a) formed in the chassis (101) to fix the connectors (270) to the chassis (101).

Inventors: MIZUTANI MINORU OKI ELECTRIC I, SAITO TOSHIAKI TOHOKU OKI ELEC, WATANABE SHYOICHI OKI ELECTRIC, MIZUTANI, MINORU OKI ELECTRIC INDUSTRY CO., LTD., SAITO, TOSHIAKI TOHOKU OKI ELECTRIC CO., LTD., WATANABE, SHYOICHI OKI ELECTRIC INDUSTRY CO., LTD.
Applicants: OKI ELECTRIC IND CO LTD, OKI ELECTRIC INDUSTRY CO., LTD.
Application year: 1989
Main classification: B41J29
IPC codes: B41J29