JPH01218857A - Image forming apparatus - Google Patents

Abstract

PURPOSE:To well form an image without generating wrinkles in an ink film, by a method wherein a thermal head is arranged in the opening part of an ink film cartridge so as to be inclined with respect to the line vertically crossing the line connecting the centers of winding cores. CONSTITUTION:A thermal head 60 is arranged in an inclined state crossing the line (b) vertically crossing the line (a), which connects the centers of the winding cores 57, 58 of an ink film cartridge 53, at an angle theta(theta=about 25 deg.) and a platen roller 65 is brought into contact with the inclined upper surface thereof in a rotatable manner. Since the thermal head 60 is obliquely arranged, the platen roller 55 and the thermal head 60 can be received in the opening part 54 of the ink film cartridge 53 in a state applying no unreasonable force to an ink film 56 and an image can be well formed without generating wrinkles in the ink film 56.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an improvement in a thermal transfer type image forming apparatus that can be applied to, for example, a thermal transfer type copying device, a thermal transfer type printer, and the like.

(Prior Art) In recent years, thermal transfer type image forming apparatuses have been developed and put into practical use, which melt and transfer ink from an ink film onto a recording medium such as paper via a thermal head to form a desired image.

Conventionally, as shown in FIG. 11, in this type of device, an ink film a is wound into a core, and the ink film a is assembled into a case d together with c to form a cartridge, so that the ink film a can be easily handled, and the tip The width W of the ink film cartridge e is made as small as possible by having a flat thermal head g provided with a heat generating part f interposed in the central opening of the ink film cartridge e. Note that 1 is a platen roller i provided facing the heat generating part f of the thermal head g;
The recording medium j is pressed against the ink film a so that the ink film a is densely packed, and the molten ink on the ink film a is transferred to the recording medium j.

(Problems to be Solved by the Invention) However, such a conventional configuration has the following problems.

a) The cost is high because a special flat thermal head with a heat generating part at the tip is used.

b) Direction of bending to the thermal head (arrow 1”l in Figure 11)
Since a force is applied (in the JF direction), the thermal head needs to be supported firmly and in a narrow place, which makes it difficult to find a way to support it.

C) Since the tip of the thermal head faces the platen roller, the thermal head lacks flexibility, and uneven contact occurs between the thermal head and the platen roller, making it impossible to form a good image.

The present invention has been made based on the above circumstances, and an object of the present invention is to house a pair of cores around which both ends of an ink film are wound in a case having an opening in the center, and to store the ink film in the opening. Although it uses an ink film cartridge with the middle part exposed, it is inexpensive and easy to support the thermal head.
Moreover, it is an object of the present invention to provide an image forming apparatus capable of forming good images without uneven contact or wrinkles of the ink film.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention includes a case in which a pair of cores around which both ends of an ink film are wound are housed in a case having an opening in the center. an ink film cartridge having a middle part of the ink film exposed in the opening; a thermal head having a heat generating part on a surface that melts the ink on the ink film;
The ink film is arranged so as to face the heat generating part of the thermal head and is wrapped around the recording medium, which is superimposed on the ink film, and includes a platen roller that transfers the molten ink on the ink film to the recording medium. .

(Function) That is, by having the above configuration, the present invention uses a thermal head having a heat generating part on the surface instead of the tip, so a commonly used thermal head can be used, and costs can be reduced.

In addition, since the platen roller and the thermal head face each other, the force in the direction of movement of the recording medium is along the surface of the thermal head, so there is no undue force on the thermal head and the normal support method is sufficient. Flexibility occurs and uneven contact with the platen roller is eliminated, making it possible to form a good image. In addition, because the thermal head is arranged diagonally to a line that intersects perpendicularly to the line connecting the centers of the cores of the ink film cartridge, the platen roller and thermal head can be placed at the opening of the ink film cartridge without applying excessive force to the ink film. It is possible to form a good image without causing wrinkles on the ink film.

(Embodiment) Hereinafter, one embodiment of the present invention will be described with reference to FIGS. 1 to 10.

FIG. 2 shows the external appearance of the image forming apparatus 1 of the present invention.
1 is a main body of an image forming apparatus 1, and an operation section 3 is formed on the front surface of the main body 2 of the apparatus.

Further, an original placing table 4 on which a document is placed is provided at the front of the upper surface of the apparatus main body 2, and a document holding body 5 is superimposed on this original placing table 4. . Also,
A paper insertion/ejection opening 6 is provided at the rear of the top surface of the apparatus main body 2 for inserting and removing paper P as a recording medium.

Further, as shown in FIG. 3, the image forming apparatus 1 includes a document reading section 10 that reads image information on a document placed on a document placing table 4, and a document reading section 10 that reads image information read by the document reading section 10. The image forming section 11 is configured to include an image forming section 11 that outputs a visible image onto the paper P, and a control section (not shown) that controls these.

First, the configuration of the document reading section 10 will be explained.

As shown in FIGS. 4 and 5, there is a light source 15 that illuminates the document tray, a first mirror 16 that horizontally reflects the reflected light from the document tray, and a light source 16 that reflects light from the document tray in the horizontal direction. A second mirror 17 that receives light and reflects it downward. A scanning optical system consisting of a third mirror 18 that receives the reflected light from the second mirror 17, horizontally reflects it, and guides it to a lens 19, and a reading sensor (CCD sensor) 20 that receives the reflected light transmitted through the lens 19. 21.

Further, as shown in FIGS. 4 and 6, the light source 15 and the first mirror 16 are mounted on the first carriage 22, and the second mirror 17 and the third mirror 18 are mounted on the second carriage 22.
It is installed in 3. As shown in FIG. 6, the first carriage 22 and the second carriage 23 are each slidably guided by a guide shaft 25 at one end, and guide rollers 26 and 26 attached to the other end. By placing it on the rail 27, it is supported so as to be parallel to the document mounting table 4. The first carriage 22 and the second carriage 23 are connected to a pulse motor 2 which can rotate in forward and reverse directions.
The first carriage 22 moves at a constant speed (V), and the second carriage 23 moves along the lower surface of the document table 4 at half the speed (V/2) by the carriage moving mechanism 29 using the drive source 8. It moves and scans the document while maintaining a constant optical path length.

The carriage moving mechanism 29 has the following configuration. That is, the drive pulley 3 is located at one end of the guide shaft 25 and fitted onto one shaft 28a of the motor 28.
A driven pulley 31 is disposed at the other end, and an endless belt 32 is wound around these rollers 30 and 31. A midway portion of this belt 32 is connected to the first carriage 22 via a connector 34.

Further, a driven pulley 35 is disposed at one end of the guide shaft 25 and the second carriage 23
A pulley 36 that functions as a movable pulley is attached to. A wire 3 is connected to these rollers 35 and 36 in an endless manner via a spring 37, and its intermediate portion is fixed to a connecting tool 33 and a fixture 39 on a base (not shown).
8 is being passed.

When the belt 32 is driven by the motor 28, the first carriage 22, which is connected to the belt 32 via the connecting member 33, moves forward at a constant speed (v). On the other hand, at this time, as the wire 38 whose midway portion is fixed to the connector 33 moves, the pulley 3 around which the wire 38 is wrapped
6 functions as a movable pulley, and the second carriage 23 moves forward in the same direction at half the speed (v/2) of the moving speed of the first carriage 22.

The document set on the document table 4 is optically scanned and guided to the reading sensor 20, and this optical information is photoelectrically converted and input to the image forming section 11.

Further, due to the reverse rotation driving operation of the motor 28, the first carriage 22 and the second carriage 23 move backward and return to the home position.

Next, the configuration of the image forming section 11 will be explained.

As shown in FIG. 3, a partition plate 5 is provided at the rear of the device main body 2.
A cartridge accommodating section 52 is formed, which is a space that includes a paper insertion/ejection port 6 and a paper insertion/ejection port 6, and is surrounded by a cover 51 that constitutes a part of the apparatus main body 2.
An ink film cartridge 53 is housed therein.

As shown in FIG. 7, this ink film cartridge 53 includes a pair of cores 57.5 in which both ends of an ink film 56 are wound inside a case 55 having an opening 54 in the center.
8 is accommodated, and the middle part of the ink film 56 is exposed from the opening 54.

Furthermore, a flat thermal head 60 is disposed in the center of the cartridge accommodating portion 52 so as to be interposed within the opening 54 of the ink film cartridge 53 .

As shown in FIG. 8, this thermal head 60 is supported via a mounting plate 61 screwed to the partition plate 50, and as shown in FIG. It is arranged at an angle θ (approximately θ-25°) with respect to a line that intersects perpendicularly with a line a connecting the centers of the cores 57 and 58, and the platen roller 65 is in rolling contact with the inclined upper surface thereof. ing.

A heating section 62 (not shown in detail) in which a group of heating elements for melting the ink on the ink film 56 are arranged in a line tod shape is formed on the inclined upper surface of the thermal head 60 at a position facing the platen roller 65. .

As shown in FIGS. 8 and 9, this platen roller 65 is attached to a cover 51 which is rotatably displaceable about a support shaft 66.
It is attached at a position corresponding to the paper insertion/ejection port 6 of the paper. The cover 51 is connected to the other end of a tension spring 67 whose one end is connected to the device main body 2 side.
When the cover 51 is closed as shown by the solid line in FIG. 8, the counterclockwise biasing force of the tension spring 67 holds the cover 51 in the closed state, and the platen roller 65 comes into pressure contact with the thermal head 60. Further, when the cover 51 is opened as shown by the two-dot chain line in FIG. 8, the cover 51 is held in the open state by the clockwise biasing force of the tension spring 67.

In addition, by opening the cover 51 as shown in FIG. 9, the platen roller 65 is moved to the ink film cartridge 5.
Since the ink film cartridge 53 is displaced to a position away from the insertion/removal path of No. 3, it becomes possible to replace the ink film cartridge 53, and
Cleaning of the heat generating portion 62 of the thermal head 60 can be easily performed.

Further, as shown in FIG. 1, the platen roller 65 moves toward the heating section 62 of the thermal head 60 at a position displaced upward (toward the insertion/ejection port side) by H from the line a connecting the centers of the cores 57 and 58 of the ink film cartridge 53. This eliminates large bending of the ink film 56 and prevents the ink film 56 from being wrinkled.

Further, the platen roller 65 and the cores 57 and 58 of the ink film cartridge 53 are driven as follows.

As shown in FIG. 10, a gear 70 is attached to one end of the platen roller 65, and gears 71, 72 are attached to one end of the core 57, 58 of the ink film cartridge 53, respectively. When the platen roller 65 is brought into pressure contact with the thermal head 60, the gear 70 meshes with a gear 73 provided on the apparatus main body 2 side.

Further, when the ink film cartridge 53 is loaded in a predetermined position, the gears 71 and 72 mesh with the gears 74 and 75 provided on the apparatus main body 2 side. In addition, the gears 73, 74, 75 are connected to the driving force transmission system 76 shown in FIG.
The driving force of the motor 28 is transmitted through the motor 28 to rotate it.

That is, the rotational force of the other drive shaft 28b of the motor 28 is applied to the bevel gears 77, 78 and the clutch 69. The rotational force of the gear 80 is sequentially transmitted to the gear 80 via the gear 79, and is further transmitted to the gear 73 of the platen roller 65 that meshes with the gear 70, and is transmitted to the winding core via the first transmission system 81. The signal is transmitted to the gear 74 that meshes with the gear 71 of the winding core 58 via the second transmission system 82, and to the gear 75 that meshes with the gear 72 of the winding core 58.

The first transmission system 81 includes a gear 83 that meshes with the gear 80 and a clutch 84 that meshes with the gear 71 .

The rotational force is transmitted to the gear 74 that rotates. Further, the second transmission system 82 includes a pulley 8 that interlocks with the gear 80.
6. Belt 87. Pulley88. Clutch 89. and a gear 90 that meshes with the gear 75, and transmits rotational force to the gear 75 that meshes with the gear 72.

Therefore, during image formation, the drive shaft 28b of the motor 28
rotates in the positive direction (in the direction of the arrow in Figure 10), this rotational force is applied to gears 77, 78, clutch 69, and gear 79.
, 80, 73, and 70 in order to the platen roller 65, and the platen roller 65 rotates in the direction of the arrow in FIG. 3 (clockwise). As a result, the paper P, which is wound around the platen roller 65 and is in close contact with the ink film 56, is transported together with the ink film 56 at a constant speed. On the other hand, at this time, the clutch 84 of the first transmission system 81 of the driving force transmission system 76 is turned off, and the clutch 89 of the second transmission system 82 is turned on, applying rotational force only to the winding core 58 and sequentially winding the ink film 56. It turns out.

Further, in synchronization with the feeding operation of the paper P, the heat generating section 62 of the thermal head 60 formed in a line tod shape along the axial direction of the platen roller 65 generates heat according to the image information, and the ink of the ink film 56 is transferred to the paper. It will be transferred to P.

Note that when the document reading section 10 scans the document, the scanning exposure system 21
The motor 28 is driven to move the first carriage 22 and the second carriage 23, but at this time the clutch 69 is in the OFF state, and rotational force is applied to the platen roller 65 and the cores 57, 58 of the ink film cartridge 53. is not communicated.

In addition, by repeating such image forming operations,
The ink film 56 is now wound around one of the cores 58, but if it is desired to rewind it to the core 57 side, the drive shaft 28b of the motor 28 is rotated in the opposite direction and the drive force transmission system is rotated. The clutch 84 of the first transmission system 81 of 76 is turned on.

By turning off the clutch 89 of the second transmission system 82, only the winding core 57 is rotated and the ink film 56 is rewound.

In addition, when forming a multicolor image by using an ink film 56 having a plurality of color inks, when recording of one color is completed, the platen roller 65 is reversely operated to return the paper P, and the paper P is The paper P is made to face the ink of a different color, and in this state, the paper P is fed +li degrees to transfer the ink of a different color. By repeating this process, multicolor images are formed.

Furthermore, in the image forming apparatus configured in this way,
Part I winding core 57, 5 in which both ends of the ink film 56 are wound in a case 55 having an opening 54 in the center
Although it is of the type that uses an ink film cartridge 53 that houses an ink film 56 and exposes the middle part of an ink film 56 in an opening 54, it is generally used because it uses a thermal head 60 that has a heat generating part 62 on the surface instead of the tip. It is possible to use a thermal head that is similar to the conventional one, thereby reducing costs. Furthermore, since the surfaces of the platen roller 65 and the thermal head 60 face each other, the force in the advancing direction of the paper P is along the surface of the thermal head 60, so that no unreasonable force is applied to the thermal head 60, and the normal supporting method is sufficient. The thermal head 60 becomes flexible and there is no uneven contact between the thermal head 60 and the platen roller 65, making it possible to form a good image. In addition, since the thermal head 60 is arranged diagonally with respect to a line that intersects perpendicularly to a line a connecting the centers of the cores 57 and 58 of the ink film cartridge 53,
Insert the ink film 5 into the opening 54 of the ink film cartridge 53 by inserting the platen roller 65 and the thermal head 60 into the opening 54 of the ink film cartridge 53.
The ink film 56 can be housed in a state where no force is applied to the ink film 56, and a good image can be formed without causing wrinkles on the ink film 56.

It goes without saying that the present invention is not limited to the above-mentioned embodiment, and can be modified in various ways without departing from the gist.

[Effects of the Invention] As explained above, according to the present invention, a pair of cores around which both ends of an ink film are wound are housed in a case having an opening in the center, and the ink film is inserted into the opening. Although it is a type that uses an ink film cartridge with the middle part exposed, it is inexpensive and easy to support the thermal head, and moreover, it can form good images without uneven contact or wrinkles of the ink film. This has the advantage that it is possible to provide an image forming apparatus with

[Brief explanation of the drawing]

1 to 10 show an embodiment of the present invention, in which FIG. 1 is a schematic configuration diagram of the main parts, FIG. 2 is an external perspective view of the image forming apparatus of the present invention, and FIG. Similarly, FIG. 4 is a schematic longitudinal sectional side view, FIG. 4 is a schematic configuration diagram of the image forming section, FIG. 5 is a partially cutaway external perspective view of the image forming apparatus, and FIG. 6 is a perspective view of the carriage moving mechanism of the scanning optical system. , Fig. 7 is a sectional view of the ink film cartridge, Fig. 8 is a drawing showing the mounting state of the platen roller and thermal head, and Fig. 9 is a sectional view of the ink film cartridge.
The figure shows the insertion and removal status of the ink film cartridge.
FIG. 10 is a schematic perspective view showing a drive system for the platen roller and the winding core, and FIG. 11 is a diagram showing a conventional example. 53... Ink film cartridge, 54... Opening, 55... Case, 56... Ink film,
57... Winding core, 58... Winding core, 60... Thermal head, 62... Heat generating section, 65... Platen roller, P... Recording medium (paper). Applicant's agent Patent attorney Takehiko Suzue Figure 2 Figure 9

Claims (1)

[Claims] An ink film cartridge comprising a pair of cores having both ends of an ink film wound therein housed in a case having an opening in the center, and a middle part of the ink film exposed in the opening; and a thermal head disposed obliquely to a line perpendicular to a line connecting the centers of the winding cores and having a heat generating part on one surface for melting the ink on the ink film, and a heat generating part of the thermal head. 1. An image forming apparatus comprising: a platen roller which is arranged to face and bring a wound recording medium into close contact with an ink film to transfer molten ink on the ink film to the recording medium.