JPH0238077A - Image forming device - Google Patents

Abstract

PURPOSE:To enable accurate feeding of a transfer recording material without enlarging a non-image-forming area by providing a grit roller pressed against a platen roller, clamping the transfer recording material between the grit roller and the platen roller, and driving the grit roller. CONSTITUTION:A paper is caused to butt against a register roller 12, whereby the leading end of the paper is registered. Then, the roller 12 is started rotating with an appropriate timing, and a grit roller 15 is also driven to rotate. By the rotation of the grit roller 15, a platen roller 2 and a pressure roller 18 are driven to rotate. The paper is therefore fed by the register roller 12, and is guided between the pressure roller 18 and the platen roller 2. The paper is fed by the pressure roller 18 and the platen roller 2 in the state of being wrapped around the platen roller 2, and is passed between the platen roller 2 and a thermal transfer film 4. Thereafter, the leading end of the paper is clamped between the grit roller 15 and the platen roller 2.

Description

Detailed Description of the Invention [Objective of the Invention] (Industrial Application Field) The present invention relates to a thermal transfer type image forming method in which, for example, a coloring material of a thermal transfer material is transferred to a transfer material to form an image on the transfer material. Regarding equipment.

(Prior Art) Thermal transfer type image forming apparatuses are small, inexpensive, generate less noise, and can use plain paper as the transfer material. It has also been put into practical use as a device.

Normally, in this type of transfer type image forming apparatus, a thermal head is brought into pressure contact with a platen through a transfer material and a transfer material.
By causing this thermal head to generate heat in accordance with image information, the colorant of the transfer material is transferred to the transfer material to form an image.

By the way, in such an image forming apparatus, as a configuration for conveying the transfer material, there is one in which the platen roller is driven and the transfer material is conveyed by the rotational force of the platen roller. Alternatively, the platen roller may simply be driven to rotate, the material to be transferred is held between a grid roller and a pressure roller, and the material to be transferred is conveyed by driving the grid roller.

(Problems to be Solved by the Invention) However, when the former conveyance configuration is adopted, since the friction coefficient of the platen roller is small, the grip force on the transferred material is weakened, and misalignment is likely to occur during conveyance. Note that since the platen roller is pressed against the thermal head, it is not possible to use a platen roller with a large coefficient of friction. On the other hand, when the latter transport configuration is adopted, the transferred material can be transported accurately, but since the grip roller and pressure roller are located downstream of the platen roller in the transport direction, There is a problem in that the image forming area (margin) becomes larger accordingly.

The present invention has been made based on the above circumstances, and an object thereof is to provide a thermal transfer type image forming apparatus that can accurately convey a transfer material without increasing the size of the non-image forming area. There is a particular thing.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above problems, the present invention provides a grid roller in pressure contact with a platen roller, and a material to be transferred is sandwiched between the grid roller and the platen roller. The transfer material is conveyed by driving the grid roller.

(Function) That is, in the present invention, the distance from the thermal head to the grid roller is set short by bringing the grid roller into pressure contact with the platen roller, so that the non-image forming area becomes small. In addition, since the material to be transferred is conveyed while being held between the grid roller and the platen roller, even if the gripping force of the platen roller is weak, the material to be transferred is sufficiently held between the grid roller and the platen roller. Accurate conveyance can be performed.

(Embodiment of the Invention) An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic sectional view of an image forming apparatus, and this image forming apparatus has an image forming section having the following configuration.

That is, the platen roller is located approximately in the center of the apparatus main body 1. A thermal head 3 serving as a recording head is arranged opposite to the platen roller 2 so as to be able to approach and separate from it. The thermal head 3 is formed in a line tod shape on a surface facing the platen roller 2, and has a heating element that generates heat in accordance with image information. Further, a thermal transfer film 4 as a transfer material is interposed between the thermal head 3 and the platen roller 2. This thermal transfer film 4 has a pair of winding cores 5 at both ends thereof.
, 6, and is stretched by a pair of guide rollers 7.8 provided with the thermal head 3 as a boundary. This thermal transfer film 4 is
The winding cores 5 and 6 are rotated by a drive means (not shown) so that they are wound and run in the direction of the arrow in the figure. Further, a paper feed cassette 9 for accommodating stacked sheets of paper as a transfer material is provided on the lower side of the apparatus main body 1 in a manner that is removably attachable to the apparatus main body 1 . Also, near the top in this diagram of the paper feed cassette 9, there are
A paper feed roller 10 is provided that rotates and sequentially takes out sheets of paper from the topmost sheet in the paper feed cassette.

Further, a paper feed path is formed between the paper feed roller 10 and the platen roller 2, and is made up of a pair of opposing guide plates 11.11. A pair of registration rollers 12 are provided at the end of the paper feed path on the side of the platen roller 2, and furthermore, a pair of registration rollers 12 are provided on the side of the paper conveyance direction with respect to the registration rollers 512.
2 in a press-contact state. On the other hand, in the figure of the apparatus main body 1, a paper ejection port is formed at the other upper end, and this paper ejection port is provided with a pair of paper ejection rollers 13 and a paper ejection tray 24 for receiving the ejected paper. There is. Roughly speaking, a paper ejection path is formed between the paper ejection roller 13 and the platen roller 2 and is composed of a pair of opposing guide plates 14,14. A grid roller 15 is provided in pressure contact with the platen roller 2 at the end of the paper discharge path on the platen row 52 side.

As shown in FIG. 3, during image formation, the thermal head 3 presses the paper against the platen roller 2 via the thermal transfer film 4, heats and melts the ink 16 as a colorant on the thermal transfer film 4, and transfers it onto the paper. It is designed to be transcribed. The thermal transfer film 4 has yellow, magenta, and cyan ink portions 16a, 16b, and 16c arranged side by side in a size approximately equal to that of the paper shown in area A in FIG.
Cyan and black ink portions 16a, 16b, 16
c.

16d are arranged side by side, and after each color is transferred, the paper is returned to its original position and overlapped accurately one after another.

The thermal transfer film 4 containing the black ink portion 16d is used when black is produced clearly, and the black ink portion 1
Since it does not have 6d, it is possible to create intertwining points by overlapping three colors.

Next, a configuration for controlling the above-described image forming section will be explained with reference to FIG. 2. FIG. 2 is a block diagram schematically showing the configuration of the image forming unit 649, the color converting unit 65, and the image forming unit 649. The configuration includes a memory section 66, an image forming section 67, and an overall control section 68.

Then, the green (
The values of the respective color portions of G), yellow (Y), and cyan (C) are converted into the colors magenta (M), yellow (Y), and cyan (C) of the thermal transfer film 4 by the color conversion unit 65, These color-converted values are stored in the memory section 66 for each color together with position information on the document. The image forming section 67 uses the values read out from the memory section 66 to display magenta (M), yellow (Y), cyan (C), and black (B) [black is magenta (M), yellow (Y), and cyan (C)]. AND output] of the ink is transferred onto the paper.

Note that the overall control section 68 includes one document scanning section 64 and a color conversion section 6.
5, the entire memory section 66 and image forming section 67 are controlled ull-2.

Next, the operation of the image forming apparatus configured as above will be explained. First, a document (not shown) is operated by the document scanning section 64, and the color components of the document are detected.

The color component values are color-converted by the color converter 65 as described above, and the color-converted values are stored in the memory part 66 together with the position information on the document for each color. On the other hand, the image forming section 67 is also operated by the overall control section 68. That is, the paper is transferred to the paper feed cassette 9 by the paper feed roller 10.
taken from.

The taken out paper passes through the paper feed path and is abutted against the stopped registration rollers 12, so that the leading edge of the paper is aligned. After that, at an appropriate timing, the distro roller 12 starts rotating U0, and the grid roller 15 starts rotating.
is also driven and rotated. Further, due to the rotation of the grid roller 15, the platen roller 2 and the pressure roller 18
starts rotating. At this time, the thermal head 3 is in a state separated from the platen roller 2. Therefore, the paper is conveyed by the registration rollers 12 and guided between the prefix roller 110-roller 18 and the platen roller 2. With this pre-flash 1r roller 18 and platen roller 2,
After being conveyed while being wrapped around the platen roller 2 and passing between the platen roller 2 and the thermal transfer film 4 , the leading end is held between the grid roller 15 and the platen roller 2 . At this point, the driving of the registration rollers 12 and grid rollers 15 is temporarily stopped. Accordingly, the rotation of the platen roller 2 and the pressure roller 13 is also stopped accordingly. Note that at this point, the trailing edge of the paper has passed through the registration rollers. Thereafter, at an appropriate timing, the thermal head 3 is pressed against the platen roller 2 via the thermal transfer film 4 and the paper. The thermal transfer film 4 has been wound up in advance at this point, and the first ink portion 16d is aligned between the platen roller 2 and the thermal head 3. In this state, the Kuserit roller 15 is driven and rotated again, and the platen roller 2 and pressure roller 13 are also rotated accordingly.

In addition, by driving the winding cores 5 and 6 in synchronization with this, the thermal transfer film 4 is wound and travels. On the other hand, the thermal head 3 causes a line-toad-shaped heating element to generate heat based on the information read from the memory section 66, thereby transferring the yellow ink on the thermal transfer film 4 to the paper.

In this way, the first ink portion 16d of the thermal transfer ribbon 4
When the transfer is completed, the thermal head 3 is returned to the state away from the platen roller 2. Also, grid roller 1
5 once stops, then rotates in the opposite direction, conveys the paper in the opposite direction, returns to the position before the transfer, and stops. The winding core 5.6 is driven, the thermal transfer film 4 runs, and the second ink section 1
6d is aligned between the thermal head 3 and the platen roller 2. Thereafter, the above-mentioned operation and the opposite operation are repeated for each color, and the ink portions 16a, 1 of the thermal transfer film 4 are printed on the paper.
Inks 6b, 16c, and 16d are transferred. When the ink of the last ink portion 16d is transferred to the paper, the paper is conveyed through the paper ejection path to the paper ejection roller 13 while being held between the grid roller 15 and the platen row 52, and the paper is ejected by the paper ejection roller 13. It is discharged onto the tray 24.

Next, the grid roller 15 and platen roller 2 will be explained. The grid roller 15 is formed by, for example, spraying or adhering a large number of fine particles onto its surface, or by sandblasting. Therefore, its surface is #9! It has a high coefficient of friction and has sufficient grip when holding paper.

On the other hand, the surface of the platen roller 2 has a very small coefficient of friction and has a surface that has almost no gripping force when it clamps a sheet of paper.

Therefore, when the paper is conveyed by the grid roller 15 and the platen roller 2, almost no frictional force acts between the paper and the platen roller 52, and the grid roller 15
The rfJ frictional force acts sufficiently only between the paper and the paper. In other words, the only force acting on the paper in the conveying direction is the tension caused by the grid roller 15, and there is no shift in conveyance caused by the frictional force between the paper and the platen roller as in the conventional paper.

Note that the grid roller 15 is connected to a drive source (not shown) and is directly driven. Further, the grid roller needs to have a surface friction coefficient large enough to have sufficient gripping force when holding paper.

Furthermore, it is desirable that the grip roller 15 is located not far from the thermal head 3 (printing position by the thermal head).

In this embodiment, since the grid roller 15 is brought into pressure contact with the platen roller 2, the thermal head 3 and the grip row 515 are in a relatively close positional relationship. Therefore, the width of the non-image forming portion (margin) can also be small.

[Effects of the Invention] As explained above, according to the present invention, it is possible to provide a thermal transfer type image forming AI that does not increase the size of the non-image forming area and is capable of accurately transporting the non-transfer material. .

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an embodiment of the present invention, Fig. 2 is a block diagram of the same example without showing the 1lII111Il configuration, Fig. 3 is a perspective view showing the transfer operation state of the same example, and Fig. 4 is a thermal transfer FIG. 3 is a plan view showing a ribbon coated with ink. Fig. 1 2...Platen roller, 3...Thermal head (recording head), 4...Thermal transfer film (transfer material), 1
5...Grid roller

Claims (1)

[Claims] A platen roller, a recording head disposed opposite to the platen roller with a transfer material movable therebetween, and a transfer target provided in pressure contact with the platen roller and passed between the platen roller and the transfer material. An image forming apparatus comprising: a grid roller that pinches and conveys the material between the platen rollers.