JPH01200980A - Type drum system printer - Google Patents

Abstract

PURPOSE:To simplify a structure of a printed by enabling deterring of a type drum and control of a paper feed mechanism to be performed by operation of a type selection lever, by a method wherein the title type drum system printer is so constructed that a groove part is formed on a selection ratchet to a part having no type established on a type drum, and a paper feed mechanism is actuated by selecting the groove part with the type selection lever. CONSTITUTION:When a type dram 1 makes a half turn, an electric clutch is turned on to drop a selection lever 5 into a notched groove of a selection ratchet, and engagement of the selection lever 5 with a control gear 6 is released. Then, the type drum 1 makes further a half turn, and printing of remaining columns is performed during this turn. When this type drum 1 has made a half turn, a gear of an intermittent gear 4 is engaged with a gear of a control gear 6. A paper feed gear 7 is rotated following rotation of the control gear 6, and paper feed is performed. After ending this paper feed, engagement of the control gear 6 with the intermittent gear 4 is released, and the control gear 6 is rotated to be deterred to a position wherein the projection is engaged with a crest of the selection lever by resilience of an elastic member.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a small printer mounted on a calculator or the like.

[Conventional technology]

Japanese Patent Application Laid-Open No. 61-164 as a conventional type drum type printer
As described in No. 865, intermittent teeth are provided on the side of the type drum corresponding to positions where no type is placed, and each time the type drum rotates once, the intermittent teeth mesh with the paper feed gear and automatically [Problem to be solved by the invention] In such type printers, after paper is fed, it is necessary to stop the type drum at a reference position. There is,
This required the use of a stepping motor or a special stop mechanism for locking the type drum.

However, when a stepping motor is used, the type drum can be stopped at a reference position by controlling the motor, and the mechanism is simple, but the stepping motor itself is expensive, so there is the problem that the printer itself is expensive. there were. Furthermore, if a low-cost DC motor is used instead of a stepping motor, a special mechanism is required to forcibly stop the type drum at the reference position, which poses the problem of complicating the mechanism and complicating the control. there were.

The present invention was made to solve these problems, and an object of the present invention is to provide a low-cost type drum type printer that can use a low-cost DC motor and does not require a special stop mechanism. With the goal.

[Means for solving problems]

In order to achieve the above object, the present invention includes a type drum having a plurality of type characters arranged on its surface, and a locking part that engages directly or indirectly with the type drum and corresponds to each of the type characters. A type drum type printer comprising a selection ratchet, a selection lever that selects type by selectively locking the selection ratchet, and a paper feed mechanism, wherein the type drum is provided with a portion without type, and the selection ratchet is provided with a portion without type; A groove is formed corresponding to the portion without printed characters, and when the selection lever selects the groove, a paper feeding mechanism is driven to feed the paper.

[Effect]

The means described above operate as follows.

Since the paper feeding mechanism is controlled by the selection lever used to select type, the type drum can be locked in place without requiring a special mechanism to lock the type drum at the reference position.
It becomes possible to control the paper feeding mechanism.

〔Example〕

The present invention will be explained below using the drawings.

FIG. 1 is a block diagram of the main parts of a type drum type printer showing one embodiment of the present invention. FIG. 2 is an exploded perspective view further showing essential parts of the block diagram shown in FIG. 1.

In the figure, reference numeral 1 denotes a type drum having a plurality of type bodies arranged around its outer periphery, and a portion 1a where there is no type body is formed in part. In this embodiment, two sets of typefaces are provided to perform two-color printing of purple and red, and by shifting the typeface drum 1 in the digit direction every round, that is, in two rotations. It is configured to print one line. (For details, see Japanese Patent Application No. 62-269195). Reference numeral 2 designates a selection ratchet which is provided on the side surface of the type drum 1 and has a ratchet turn corresponding to the type body of the type drum 1, and a notch groove 2b which is deeper than the ratchet teeth 2a corresponds to the part without the type body. is formed. 3 is a gear body that transmits the rotational force of the motor 10 to the type drum 1 via an intermediate gear 12 to rotate the type drum 1. Reference numeral 4 denotes an intermittent gear body in which gears 4a are formed corresponding to portions of the type drum 1 where there are no type characters. These selection ratchet 2, gear body 3, and intermittent gear body 4 are arranged on the side surface of the type drum 1 so as to rotate together with the type drum 1. 5 is a selection lever driven by an electromagnetic clutch 11. Note that a locking pawl is formed at the tip of the selection lever, and the ratchet tooth 2a of the selection ratchet 2
and locks the type drum 1 at a desired position. 6 is a control gear that meshes with the intermittent gear body 4 at two places, and 7 is a paper feed gear that meshes with only one gear of the control gear 6 and is connected to the paper feed roller 8. A small roller (not shown) is pressed against the paper feed roller 8, and as the paper feed gear 7 rotates, the paper is fed by the pressure contact between the paper feed roller 8 and the small roller. Further, 9 is an ink roller that applies ink to the type bodies of the type drum 1. Here, the selection lever 5 and the control gear 6 each have a protrusion 5a on their opposing sides.
, 5a are formed, and those protrusions are the selection lever 5.
is engaged when it is in the initial position and engaged with the ratchet teeth of the selection ratchet 2 (when selecting type), and when the selection lever 5 falls into the notch groove 2b of the selection ratchet 2, the engagement is released. The position is such that Further, the control gear 6 has gear portions 5a at two opposing locations as shown in FIG.
, 5b, and a non-gear coupling portion 6d and an intermittent portion 6e are formed between the gear portions. And this both gear parts 5
b, 5c are formed so that only the first gear 6C meshes with the gears of the intermittent gear body 4, but only the first gear 6C meshes with the paper feed gear 7.The control gear 6 is connected to the second gear by an elastic member (not shown). A force that provides rotational force is applied in the direction of arrow B in the figure.

The operation will be explained below using FIGS. 3(a) to 3(i).

FIG. 3(a) shows the initial position. At this time, the control gear 6 is locked by its protrusion 6a engaging with the protrusion 5a of the selection lever 5. Then, printing for half a digit is performed while the type drum 1 rotates half a rotation. When the type drum 1 rotates half a rotation, an electromagnetic clutch (not shown) is turned on and the selection lever 5 falls into the notch groove 2b of the selection ratchet 2. At this time, as mentioned above, the notch groove 2b is deeper than the ratchet teeth 2a, so the selection lever 5 and the control gear 6 are disengaged, and the control gear 6 is rotated to the right by the action of an elastic member (not shown). , stop. Then, during the subsequent half rotation of the type drum 1, printing is not performed because the printing portion is in a different color, and when the type drum 1 has made a half rotation, that is, one rotation from the initial position, the gear 4a of the intermittent gear body 4 and the control gear 6 meshes and rotates. At this time, as described above, since the intermittent gear portion 6b of the control gear 6 is formed at a position where it does not mesh with the paper feed gear 7, the paper feed gear 7 does not rotate, and the intermittent portion 6e of the control gear 6 intermittents during this time. It rotates to a position facing the gear body 4. Since the intermittent portion 6e has a concave surface having the same diameter as the intermittent portion 4b of the intermittent gear body 4, it does not rotate even under the biasing force of the elastic member. At this time, the type drum 1 is also shifted in the digit direction by the action of the shift cam. (For details of the shift mechanism, see Japanese Patent Application No. 62-269.
195). The remaining digits are then printed while the type drum 1 rotates half a rotation. When the type drum 1 makes a half rotation, the gear 4a of the intermittent gear body 4 and the gear 6b of the control gear 6 mesh with each other, and as the control gear 6 rotates, the paper feed gear 7 rotates to feed the paper. When the control gear 6 and the intermittent gear 4 are disengaged, the control gear 6 is rotated and locked by the action of an unillustrated elastic member to a position where its protrusion 6a engages with the ridge 5a of the selection lever 5. Then, the type drum 1 further rotates by half a rotation and returns to the initial position.

By repeating the above operations, the required number of lines are printed. Incidentally, in the above embodiment, a printer was described in which the type drum 1 rotates twice to print one line and feed the paper, but the present invention is not limited to the above embodiment. It is also suitable for use in a printer that prints one line and feeds paper by rotating once.

〔effect〕

As described above, according to the present invention, the paper feeding mechanism is controlled by the function of the selection lever used to select the type, so that the type can be easily moved even though a special mechanism for locking the type drum at the reference position is required. It becomes possible to lock the drum and control the paper feeding mechanism, making it possible to provide a type drum type printer with a simple configuration and high accuracy.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the main parts of a type drum type printer showing an embodiment of the present invention, FIG. 2 is an exploded perspective view of a part of FIG. 1, and FIGS. FIG. 6 is an explanatory diagram for explaining the operational relationship between the rotation of the drum and the paper feeding mechanism. 1... Type drum 2... Selection ratchet 4... Intermittent gear body 5... Selection lever 6... Control gear 7... Paper feed gear Patent applicant Masaru Kataoka Representative of Alps Electric Co., Ltd. Thick part lI21 Rin 6 Figure multi 3 z Stem 3 eyes

Claims (2)

[Claims] (1) A type drum with a plurality of type characters arranged on its surface, a selection ratchet that engages directly or indirectly with the type drum and has a locking part corresponding to each of the type characters, and selectively engages the selection ratchet. In a type drum type printer equipped with a selection lever that selects type by stopping the type, and a paper feeding mechanism, a portion of the type drum that is not used for printing is provided on the type drum, and the selection ratchet is arranged to correspond to the portion that is not used for printing. A type drum type printer, characterized in that a groove is formed in the printer, and when the selection lever selects the groove, the paper feeding mechanism is driven and paper is fed. (2) The type drum type printer according to claim (1), wherein the groove portion formed in the selection ratchet is deeper than the locking portion.