JPH02182465A - Apparatus for formation of image - Google Patents

Abstract

PURPOSE:To allow both melting type and sublimable type ink ribbon to be available by providing switching means for automatically switching the pressure contact force of a heat sensitive recording head to an image forming medium in response to the type of the image forming medium according to a command from a contact actuator. CONSTITUTION:When a melting type ink ribbon 24a is employed, i.e., when the pressurizing force of a thermal head 21 to the ink ribbon 24a may be small, a melt button 55 is closed and a print start button 57 is then closed. Thus, the thermal head 21 is brought into pressure contact with the ink ribbon 24a by a small pressurizing force. When a sublimable ink ribbon 24b is employed, i.e., when the pressurizing force of the thermal head 21 to the rink ribbon 24b must be increased, a sublimation button 56 is closed, and the print start button 57 is then closed. Thus, the thermal head 21 is brought into pressure contact with the ink ribbon 24 with a large pressurizing force.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an image forming apparatus used as, for example, a thermal transfer printer or a thermal transfer copying machine.

(Prior Art) In recent years, a color copying machine has been developed and put into practical use as a thermal transfer type image forming apparatus.

In the case of full-color copying, in such devices, the four colors (ink) of the ink ribbon (image forming medium) of yellow, magenta, cyan, and black are layered on the paper (recording medium) and the thermal head ( transfer by pressing a thermal recording head), or
Three colors of cyan are transferred in layers. Furthermore, in the case of a single color such as black, the transfer is performed in one transfer operation.

Incidentally, there are two types of ink ribbons: melting type and sublimation type.Usually, sublimation type ink ribbons are pressed against a thermal head with a pressure that is 2 to 4 times greater than that of melting type ink ribbons.

(Problem to be Solved by the Invention) However, in the past, the pressing force of the thermal head against the ink ribbon was constant regardless of the type of ink ribbon, so melting type ink ribbons were manufactured using special melting type machines or However, dye-sublimation ink ribbons can only be used with a dedicated dye-sublimation machine, making them inconvenient.

The present invention has been made in view of the above circumstances, and its object is to provide an image forming apparatus that can use either a melting type or a sublimation type ink ribbon.

[Structure of the invention]

(Means for Solving the Problems) In order to solve the above problems, the present invention provides a thermal transfer type image forming method in which a thermal recording head is brought into pressure contact with an image forming medium to melt and transfer the colorant of the image forming medium to a recording medium. The apparatus is characterized in that it includes a switching means for automatically switching the pressure contact force of the thermal recording head against the image forming medium according to the type of the image forming medium in accordance with a command from the operating section.

(Function) By automatically bringing the thermal recording head into contact with the recording medium with a pressure depending on the type of recording medium, it is possible to handle various types of recording medium with a single device.

(Example) The present invention will be described below with reference to an example shown in the drawings.

FIG. 2 shows, as an example of the image forming apparatus of the present invention, a thermal transfer type color copying machine capable of making multicolor copies.

In the figure, reference numeral 1 denotes a main body of a copying machine, and an operation panel 54 (shown in FIG. 3) is provided at the front of the upper surface of the main body 1. A document scanning section 3 for scanning and reading a document set on a II document table (transparent glass) 2 is provided at the top of the main body 1, and an image forming section 4 is provided at the bottom. Note that 5 is a document cover provided on the document table 2 so as to be openable and closable.

The document scanning section 3 includes an exposure lamp 7 whose back is surrounded by a reflector 6, a first mirror 8, a second mirror 9, and a third mirror.
, a mirror 10, a lens 11, a fourth mirror 12, a fifth mirror 13, and a photoelectric converter 14.

Further, the exposure lamp 7 and the first mirror 8 are mounted on a first carriage 15 that is movable along the lower surface of the document table 2, and the second mirror 9 and the third mirror 10 are mounted on a first carriage 15 that is movable along the lower surface of the document table 2. It is mounted on the carriage 16 of No. 2. The first carriage 15 and the second carriage 16 are moved in conjunction with each other by a drive mechanism (not shown), and are moved in the same direction at 1/2 the speed of the carriage 15 at tBl. The optical path length up to the lens 11 is kept constant.

When scanning a document, the first carriage 15 moves from left to right with the exposure lamp 7 turned on, and the second carriage 16 also moves in the same direction at 1/2 the speed. Then, the reflected light from the document plate is guided to the lens 11 via the first mirror 8, the second mirror 9, and the third mirror 10 in order, and the light that has passed through this lens 11 is guided to the fourth mirror 12 and the third mirror 10. The light is guided to the optical converter 14 via the fifth mirror 13 in sequence.

The photoelectric converter 14 photoelectrically converts the light reflected from the document tray to separate the image on the document tray into color signals of cyan, green, and yellow (or red, green, and blue) light. For example, it is mainly composed of a CCD type line image sensor.

In this case, the pixels of the document correspond to three elements (C, G, Y) of the CCD sensor. The photoelectric converter 14
The output is output to an A/D converter (not shown).

Further, the image forming section 4 has the following configuration.

That is, a platen drum 20 is provided approximately at the center of the image forming section 4 . This platen drum 20
The periphery of the recording head 21 is made of an elastic material such as rubber, and functions as a platen roller of a thermal recording head (hereinafter referred to as a thermal head) 21.

The platen drum 20 has a collar 22 that holds the leading edge of the paper P as a recording medium, and by rotating clockwise, the platen drum 20 wraps the paper P and prevents the paper P from shifting during overlapping printing. That's what I do.

Also, pressure rollers 23 are provided around the platen drum 20 at predetermined intervals to prevent the paper P from floating up from the platen drum 20. The circumference of the platen drum 20 is slightly longer than the longitudinal length of the maximum paper size.

The thermal head 21 is disposed diagonally below and to the left of the platen roller 20 . An ink ribbon 24 as an image forming medium is interposed between the platen drum 20 and the thermal head 21.

The cores 25 and 26 of the ink ribbon 24 are connected to a drive shaft of a motor (not shown) via a driving force transmission means (not shown), and are rotated as required.

On the other hand, a paper feed roller 3 is located at the lower part of the copying machine main body 1.
0 is provided, and the sheets P stored in the paper feed cassette 31 are taken out one by one. Paper feed roller 3
The sheet P taken out at 0 is sent to a pair of registration rollers 33 by a conveyance means 32 consisting of a feed roller and a separation roller, and its leading edge is aligned. Then, as the registration roller pair 33 rotates, it is further fed to the guide body pair 3.
4 and is conveyed toward the platen drum 20,
Its tip is held by a gripper 22. Then,
As the platen drum 20 rotates in the 81 direction, the platen drum 20 is wound around the platen drum 20, and the press is maintained without lifting along the rollers 23, and is accurately fed.

During image formation, the platen drum 20 is rotated and printing is performed by the thermal head 21. Then, each time one color is printed, the platen drum 20 rotates once and the next color is superimposed and transferred.

The paper P, on which the image has been formed in this way, is peeled off from the platen drum 20 and has a number of paper ejection guides 45, a pair of transport rollers 46, a pair of paper ejection guide plates 47, and a pair of transport rollers 4.
The paper is discharged onto a paper discharge tray 50 via a paper conveyance path 49 formed by a paper sheet 8 or the like.

That is, when the paper is ejected, the trailing edge of the paper P is in the paper transport path 4.
Rotate the platen drum 20 clockwise until it faces the base end of the platen drum 9.
is rotated counterclockwise, and the rear end of the paper P is separated from the platen drum 20 by a separating claw (not shown) and guided to a pair of paper discharge guide plates 45. Finally, the leading edge of the paper P is released from the gripper 22, is transported through four paper transport paths, and is ejected onto the paper ejection tray 50.

By the way, as shown in FIG. 1, the thermal head 21 is attached to a holder 35, and one end of the holder 35 is rotatably supported by a support shaft 36. Also,
A heat radiator 37 is integrally formed in the holder 35.

Furthermore, a rotating plate 38 is attached to the support shaft 36 of the holder 35, and a coil spring 39 is interposed between the rotating plate 38 and the holder 35. The full head 21 is pressed toward the platen drum 20 by the coil spring 39.

Furthermore, a switching means 40 is connected to the rotating plate 38 for switching the biasing force of the coil spring 39 depending on the type of ink ribbon used.

This switching means 40 is composed of a camshaft 41 rotated by a drive motor (not shown) and a pressure cam 43 attached to this camshaft 41, and this pressure cam 4 has cam portions A and B.

C' is shown in white and is in contact with the rotating plate 38.

Furthermore, as shown in FIGS. 4 and 5, first and second disks (actuators) 51.52 are attached to one end of the camshaft 41, and the disks 51.52
A photo ink converter 53 is provided near the.

This photo ink converter 53 is provided with first and second sensor portions 53a53b.

The first and second discs 51 and 52 have first and second protrusions 51a and 51b, respectively.

52a and 52b are provided protrudingly at a predetermined interval in the rotational direction, and these first and second protrusions 51a.

51b, 52a, 52b are the photo interrupters 53
first and second sensor portions 53a.

53b.

The photo ink pad 53 is a melting button 55 which will be described later.
is turned on, and the first sensor part 53a is turned on.
When detecting the first projection 51a of the disk 51 (at this time, the second sensor portion 53b detects the first projection 51a of the second disk 52).
(the protrusion 52a is not detected) is adapted to stop the operation of the drive motor. At this time, the rotating plate 38 is pressurized by the cam portion A of the pressure cam 41.

Further, when the sublimation button 56 is turned on, the second sensor part 53b of the photo interrupter 53 detects the first part of the second disk 52.
The operation of the drive motor is also stopped when the protrusion 52a of the first disk 51 is detected (at this time, the first protrusion 51a of the first disk 51 is not detected by the first sensor portion 51a). It has become. At this time, cam portion B of the pressure cam 41
The rotating plate 38 is pressurized by this.

Furthermore, when the first and second projections 51a, 51b of the first and second disks 51.52 are simultaneously detected by the first and second sensor sections 53a, 53b of the photointerrupter 53, The drive motor has stopped operating. At this time, the rotating plate 38 is pressed by the cam portion C of the pressure cam 41, and the thermal head 35 is separated from the ink ribbon 24.

On the other hand, FIG. 3 shows the operating section 54.
4 is provided with a print start button 57, a number of sheets setting button 58, a melting button 55 and a sublimation button 56, and these melting button 55 and sublimation button 56
The photointerrupter 53 is connected to via a control circuit.

When the ink ribbon is, for example, a melting type ink ribbon 24a, that is, when the pressing force of the thermal head 21 against the ink ribbon 24a may be small, the melting button of the operating section 54 shown in FIG. 55 and then turn on the print start button 57. As a result, a drive motor (not shown) is activated, and the pressure cam 43 is rotated via the camshaft 41, and the first and second discs 51 and 52 are rotated.

This rotation causes the first protrusion 51a of the first disc 51 to
When this is detected by the first sensor portion 53a of the photo-interconnected 53, the operation of the drive motor is stopped and the rotary plate 38 is pressed by the cam portion A of the pressure cam 43. As a result, the coil spring 39 is slightly compressed, and the thermal head 2 is moved against the ink ribbon 24a.
1 will be pressed together with a small pressure.

In addition, a sublimation type ink ribbon 24b is used as an ink ribbon.
In other words, if it is necessary to increase the pressure force of the thermal head 21 on the ink ribbon 24, turn on the sublimation button 56 of the operation section 54 shown in FIG. As a result, a drive motor (not shown) is activated, and the pressure cam 43 is rotated via the camshaft 41.
The first and second disks 51.52 are rotated.

This rotation causes the first protrusion 52a of the second disc 52 to
When detected by the second sensor portion 53b of the photointerrupter 53, the operation of the drive motor is stopped, and the rotary plate 38 is pressed by the cam portion B of the pressure cam 43. As a result, the coil spring 39 is greatly compressed and the pressing force increases, and the thermal head 21 comes into pressure contact with the ink ribbon 24 with a large pressing force.

As described above, the pressure force of the thermal head 21 against the ink ribbon is applied to the ink ribbon 24a.

The ink ribbon 24 can be switched depending on the type of ink ribbon 24b.
It is possible to obtain a pressing force suitable for the types of a and 24b.

Therefore, the various ink ribbons 24a and 2 can be
4b can be used.

Further, by simply turning on the melting button 55 or the sublimation button 56 of the operation section 54, the ink ribbon 24a is automatically turned on.
, 24b can be obtained, which is convenient.

[Effects of the Invention] As explained above, according to the present invention, the pressure force of the thermal recording head against the image forming medium is changed according to the type of the image forming medium, so that the pressure force suitable for the type of the image forming medium can be applied. Obtainable.

Therefore, it is possible to use various image forming media with one or more devices.

Further, the setting of the pressing force of the thermal recording head against the image forming medium can be automated, which is extremely convenient.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention; FIG. 1 is a block diagram showing a thermal head switching means, FIG. 2 is a block diagram showing a color copying machine, and FIG. 3 is a part of an operating section. A plan view, FIG. 4 is a side view showing a detector that detects rotation of the cam,
FIG. 5 is a perspective view thereof, and FIGS. 6 and 7 are explanatory views showing the switching operation of the pressure contact force of the thermal head. 21... Thermal head (thermal recording head) 24...
- Ink ribbon (image forming medium), 40... switching means, P... paper (recorded object) 54... operating section. Applicant's Representative Patent Attorney Takehiko Suzue

Claims (1)

[Claims] In a thermal transfer type image forming apparatus in which a thermal recording head is brought into pressure contact with an image forming medium to melt and transfer the colorant of the image forming medium to a recording medium, the pressing force of the thermal recording head against the image forming medium is controlled by a control unit. An image forming apparatus comprising a switching means that automatically switches depending on the type of image forming medium according to a command.