JPH02185448A - Image recording device - Google Patents

Abstract

PURPOSE:To ensure that a higher head pressure is rapidly obtained at a recording head by providing a reversible head pressing device with a head pressing section on both ends of a reference section in order to make variable a pressing force to be brought to a platen by the recording head through a medium to be recorded on and an ink sheet. CONSTITUTION:A cam 30 is rotated and reversed by normal and reverse rotation of a motor 18 as a result of mutual engagements of a gear 30b, an idle gear 15 and a gear 17 for the motor 18. The reference position of the cam 30 is 30a, and the pressing force of a recording head 6 is selected by counter-clockwise rotation (theta1) and clockwise rotation of the cam 30. These rotations are achieved by a reversible motor 8 connected to a signal from a control section. The rotation of the cam 30 in the theta1 direction causes the pressing section 30c of the cam 30 to rotate a head arm 7. Furthermore, rotation of the cam 30 in the theta2 direction causes the pressing section 30d of the cam 30 to rotate farther, thus creating a stronger head pressing force.

Description

DETAILED DESCRIPTION OF THE INVENTION C. Industrial Application Field of the Invention The present invention relates to an image recording apparatus that records an image on a recording medium using an ink sheet containing ink.

[Prior Art] Conventionally, in a printing device that presses a print head against a platen via an ink ribbon and printing paper to perform printing, the pressure with which the print head is pressed against the platen is constant. However, in recent years, with the diversification of printing papers and ink ribbons, printing devices with a mechanism that can set the pressing force in multiple stages have come to be seen. As a means for this purpose, there is a printing device using a multistage cam. However, the conventional multi-stage cam has a configuration in which the cams are arranged in descending order of pressing force from the reference position of the print head and multi-stage cam, and the cams are rotated in the same direction by the motor until the cam position where the desired pressing force can be obtained. was common.

[Problem to be solved by the invention] However, in such a configuration, in order to obtain stronger pressing pressure, the cam must be rotated more, and the print head is brought into contact with the platen and the desired There was a problem that it took a long time to obtain pressure.

[Means for Solving the Problems] As a means for solving the above-mentioned problems, the present invention provides an image recording apparatus that records an image on a recording medium, including: a platen; and a platen for recording an image on the recording medium. a recording head that acts on an ink sheet containing ink; and a recording head that presses the platen at both ends with respect to a reference portion in order to vary the pressing force with which the recording head presses the platen via the recording medium and the ink sheet. The present invention is characterized in that it has a head suppressing means which has a head suppressing section at the top thereof and is capable of forward and reverse rotation.

[Function] According to the present invention, higher head pressure of the recording head can be quickly obtained.

[Example] FIG. 1 shows an embodiment of the present invention.

In the figure, printing paper 2 is held by platen roller 1. Further, a carriage 3 supported by a shaft 4:5 is provided so as to be slidable in the left-right direction along the platen roller 1. On this carriage 3, a print head 6 is supported by a head arm 7 and rotatably supported by a shaft 8 that stands up from the carriage 3. The print head 6 is provided with a plurality of heating elements 6a that selectively generate heat according to image information. By selectively generating heat from the heating element 6a, the ink on the ink sheet 1 is transferred to the printing paper 2, and an image is recorded. Further, the pressure arm 9 is rotatably supported by the shaft lO, and the push part 11 that pushes the head arm 7 is slidable on the cylindrical part 9a of the pressure arm 9 via the pressure spring 12. Supported. Note that the spring 19 is a head arm return spring that is applied between the head arm 7 and the shaft 20 that stands up from the carriage 3. This pressure arm 9
The other end 9b is in contact with the cam 30. This cam 30 is constructed by meshing a gear 30b fixed at the bottom of the cam 30, an idle gear 15 supported by a shaft 16, and a gear 17 of a motor 18 provided on the carriage 3. It rotates in forward and reverse directions by driving the motor 18 in forward and reverse directions. Note that 21 is a reference position sensor;
The pressure arm 9 is in the reference position (the state shown), and the cam 30
It is ON only when one end of the pressure arm 9 is in contact with the recess 30a of the pressure arm 9.

In this state, when the cam 30 is rotated clockwise or counterclockwise, the pressure arm 9 rotates along the profile of the cam 30 and presses the head arm 7 with a pressing force corresponding to the shape of the cam. After the printing pad 6 comes into contact with the printing paper 2, the pressure spring 12 is bent to obtain a predetermined pressing pressure.

The ink tray 1 is housed in an ink sheet cassette (not shown) that is removably attached to the carriage 3, and only a portion thereof is shown broken in the figure.

Therefore, in this embodiment, as described above, the reference position of the cam 30 is 30a, and the selection of the pressing force of the head 6 is controlled by the control unit (
This can be achieved by rotating the cam 30 counterclockwise (θ1 direction) and clockwise (θ2 direction) using the motor 8, which can rotate forward and backward in response to a signal from a motor (not shown). The rotation of the cam 30 in the 01 direction causes the pressing portion 30C of the cam 30 to rotate the head arm 7, and the rotation of the cam 30 in the 02 direction causes the pressing portion 30d of the cam 30 to rotate the head arm 7 more. By doing so, a stronger head pressing force can be obtained. Since the rotation angle with respect to the reference position can be set smaller by the amount of one position of the pressing force that is missing, a stronger pressing force can be quickly obtained. Note that by appropriately selecting the shape of the cam 30, a desired pressing force of the head 6 can be obtained.

As described above, according to this embodiment, by setting the pressing pressure positions on both sides of the reference position of the printing arm and the cam, the set pressing pressure can be set in a short time, which is effective in improving the printing speed. . Therefore, it can also be effectively applied to resin-based ink ribbons that have begun to be produced in recent years (the printing quality of resin-based ink ribbons improves as the pressure increases).

[Effects of the Invention] As described above, according to the present invention, a stronger head pressing force can be quickly obtained.

[Brief explanation of the drawing]

FIG. 1 is a plan view of an image recording apparatus to which an embodiment of the present invention is applied. In the figure, l...Platen roller 2...Print paper 3...
- Carriage 6...Printing pad 7...Printing pad arm 9...Pressure arm 12...Pushing pressure spring 18...Motor 30...Cam 30c/30d...Head pressing part

Claims (2)

[Claims] (1) An image recording apparatus that records an image on a recording medium, comprising: a platen; a recording head that acts on an ink sheet containing ink in order to record an image on the recording medium; and the recording head is connected to the recording medium. and head pressing means that has head pressing portions at both ends with respect to the reference portion and is capable of forward and backward rotation in order to vary the pressing force for pressing the platen through the ink sheet and the ink sheet. Image recording device. (2) The image recording apparatus according to item (1), wherein the head pressing means has a cam having a diameter larger at both ends with respect to the reference portion.