JPH01152079A - Image forming device - Google Patents

Abstract

PURPOSE:To minimize the deterioration of image quality and shorten image forming time by providing a control means to transfer the coloring agent of a transfer material to a transfer medium using a printing means following the backward and forward movement of the transfer medium. CONSTITUTION:When an ink ribbon 53 stored in a ribbon cassette 52 is judged as for full color use by a control part 111, first a light source 9 lights and an original is exposed and scanned, and then a platen roller 20 and an ink ribbon 5 are driven. At the same time, a thermosensitive head 19 is actuated in accordance with image information which is output from an image sensor 14 and an image is formed on paper using the first ink. After this, when the original is scanned under light exposure, pulse motors 38, 95 are reversed to scan the copy under light exposure in reverse direction, and the paper and ink ribbon 53 are transported in reverse direction. Subsequently, an image is formed using ink of the second color. At that time, the paper is held by holding members 71, 72 so that no positional shift occurs.

Description

Detailed Description of the Invention [Objective of the Invention] (Industrial Application Field) The present invention is directed to, for example, exposing and scanning a document using a scanning device to generate an electrical signal corresponding to the document image, and transmitting this electrical signal to a printing device. The present invention relates to a portable image forming apparatus that prints images using a portable image forming apparatus.

(Prior Art) As is well known, in this type of image forming apparatus, when full-color printing is performed, an image is first formed using the first ink while moving the paper in one direction, and this image is When the forming operation is completed, transport the paper in the opposite direction and
It is returned to the printing start position, and in this state, an image is formed using the second ink. When this image formation is completed, the paper is conveyed in the opposite direction to the printing start position in the same manner as described above, and image formation is performed using the third ink.

(Problems to be Solved by the Invention) As described above, in conventional full-color printing, the paper is transported in the opposite direction to the printing start position every time the -color printing operation is completed, so the number of transports is large. , misalignment of paper occurs, resulting in misalignment of images of each color and deterioration of image quality.

Furthermore, since the paper is conveyed many times, it takes time to form an image.

This invention solves the problems that occur when an image is formed by moving a transfer material back and forth, and its purpose is to create an image that has less deterioration in image quality and can shorten the image forming time. The present invention aims to provide a forming device.

[Structure of the Invention (Means for Solving Problems)] The present invention provides a scanning means for exposing and scanning a document placed on a document table, and a converter for converting light emitted by the scanning means into an electrical signal. a movable transfer material in which a plurality of colorants are sequentially arranged; a conveying means for conveying the transferred material in both directions; a printing device that transfers the colorant of the transfer material according to an output signal of the conversion device; and a control device that causes the printing device to transfer the colorant of the transfer material to the transfer material as the transfer material moves in both directions. It is composed of.

(Function) This invention controls the conveyance means and the printing means by the control means, and forms an image as the transfer material moves in both directions, thereby reducing the number of times the transfer material moves and printing on the transfer material. In addition to suppressing the shift in image quality and preventing deterioration of image quality, the time required for image formation is also shortened.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIGS. 2 and 3 schematically show an image forming apparatus, such as a scanner printer apparatus, according to the present invention.

That is, on the front side of the upper surface of the image forming apparatus main body (hereinafter referred to as the apparatus main body) 1, there is a document table (transparent glass) 2 that supports a document.
However, it is slanted so that the front side is lower.

This document table 2 is provided with a fixed scale 2a that serves as a reference for setting the document, and furthermore, a document cover 3 that can be opened and closed is provided near the document table 2.

Furthermore, a printing section 4 is provided on the back side of the apparatus main body 1. This printing section 4 is covered by a cover 5 that is rotatably provided with respect to the main body 1 of the apparatus. An insertion opening 5a for inserting paper as a transfer material is provided in the cover 5 near the center of rotation of the document cover 3. Furthermore, the apparatus main body 1 located at one end in the longitudinal direction of the cover 5 is provided with a print key 6 for instructing the start of printing, and an operator 7 for releasing the locked state of the thermal head when performing multicolor printing, which will be described later. It is being Further, the apparatus main body 1 located at the other longitudinal end of the cover 5 is provided with a density setting section 8 for setting, for example, print density.

4 and 5 show the document cover 3 removed from the main body 1 of the apparatus. The document placed on the document table 2 is processed by an optical system consisting of a light source 9 made of, for example, a light emitting diode, and mirrors 10, 11, and 12 arranged on the back side of the document table 2 along the lower surface of the document table 2. Exposure scanning is performed by reciprocating in the directions of arrows A and B. In this case, mirrors 11 and 12 are connected to one of mirrors 10 to maintain the optical path length.
It moves at a speed of /2. The driving means for these optical systems will be described later.

The light reflected from the original by the light irradiation from the light source 9 is guided to the lens block 13 via the mirrors 10, 11, and 12. The light focused by this lens block 13 is transmitted to an image sensor 1 consisting of, for example, a CCD line sensor.
4 and photoelectrically converted. This image sensor 1
4 and the lens block 13 is a filter device F.
L is provided, and this filter device FL can be moved in and out of the optical path. Details of this filter will be described later.

The output signal of the image sensor 14 is transmitted to the printed wiring board 1
The information is supplied to the printing unit 4 via a control unit provided in the controller 5, which will be described later. These lens blocks 13
, the image sensor 14 and the printed wiring board 15 are shielded from light by a light shielding member 16 provided inside the main body 1 of the apparatus.

FIG. 6 shows said mirror 10.11.12. Here, the mirror 12 that ultimately guides the reflected light from the original to the lens block 13 is cut off on the bottom side of the apparatus main body 1 within a range that does not affect image formation. Therefore, the document table 2, the light source 9, and the mirrors 10, 11, and 12 can be arranged to be inclined according to the inclination of the cut of the mirror 12, which contributes to making the main body 1 of the apparatus thinner.

On the other hand, in FIG.
There is a paper conveyance path 1 in communication with the insertion opening 5a.
7, and the cover 5 is provided with a paper discharge port 18 communicating with the conveyance path 17. Further, a thermal head 19 is provided along the moving direction of the optical system in the middle of the conveyance path 17. A plurality of heating resistive elements (not shown) are arranged along the longitudinal direction of the thermal head 19, and a platen roller 20 is brought into pressure contact with the thermal head 19. This platen roller 20 is driven by a drive device, which will be described later, during printing operation.
It is adapted to be rotated in the direction of the arrow shown in the figure in response to the movement of the optical system. Therefore, the paper (for example, thermal paper) inserted into the conveyance path 17 from the insertion opening 5a is pressed against the thermal head 19 by the platen roller 20 during the printing operation and is moved in the direction of arrow C in the figure. By supplying a print signal from the signal processing section to the head 19, an image corresponding to the original image set on the original platen 2 is printed on the paper P. The paper on which the image has been formed in this manner is discharged from the discharge port 18 as the platen roller 20 rotates.

Further, at the inner bottom of the apparatus main body 1 on the side of the printing section 4, there is provided a housing section 22 in which a battery 21 as a power source is housed.

FIG. 1 shows the optical system and a drive device for the platen roller 20. As shown in FIG.

The light source 9 and the mirror 10 are arranged on the first carriage 31a, and the mirror 11.12 is arranged on the second carriage 31b. These first and second carriages 31a and 31b are guided by guide rails 32a132b and are movable in parallel.

An endless belt 33 is disposed near and along the guide rail 32a, and the first carriage 31a is fixed to an intermediate portion of the endless belt 33. Further, both ends of the endless belt 33 are wrapped around pulleys 34 and 35, and the pulley 34 is rotated by a pulse motor 38 via gears 3B and 37.

On the other hand, pulleys 39.40 are rotatably provided on the guide rail 32a side of the first and second carriages 31a and 31b, and a wire 4 is provided between these pulleys 39.40.
1 is being passed. One end of this wire 41 is connected to the fixed part 4
2, and the other end is fixed to the fixing part 42 via a coil spring 43. Therefore, when the pulse motor 38 is rotated, the belt 33 rotates, the first carriage 31a moves, and the second carriage 31b also moves accordingly. At this time, since the pulleys 39 and 40 serve as movable pulleys, the second carriage 31b moves in the same direction at half the speed of the first carriage 31a. Note that the moving directions of the first and second carriages 31a and 31b are controlled by switching the rotational direction of the pulse motor 38.

Further, the power of the pulse motor 38 is transmitted through a bevel gear 44.4.
5. It is transmitted to the platen roller 20 via gears 46 and 47. Therefore, this platen roller 20
, are rotated with the movement of the second carriage 31a131b.

Next, a case where this image forming apparatus is used to print on plain paper will be described. In this case, the thermal head 19
A ribbon cassette is attached to the cassette.

That is, as shown in FIG. 8, when the operator 7 is pressed while the cover 5 is open, the locking member 51 locking one end of the thermal head 19 locks the thermal head 19.
be freed from. The other end of the thermal head 19 is rotatably held, and when the locking member 51 is released, it can be rotated in the direction of the arrow shown in FIG. In this state, as shown in FIG.
is attached from one end of the thermal head 19, and when the ribbon cassette 52 and the thermal head 19 are integrally rotated in the direction of arrow E in the figure, the thermal head 19 is locked again by the locking member 51, and as shown in FIGS. As shown in FIG. 12, a ribbon cassette 52 is attached to the thermal head 19.

FIG. 13 shows the ribbon cassette 52. This ribbon cassette 52 has bobbins 52a and 5 at both ends.
An ink ribbon 53 wound around 2b is housed.

This ink ribbon 53 is black or a monochrome ink consisting of one specific color, or a size slightly larger than the maximum paper size for printing, for example, ink (not shown) consisting of yellow, magenta, cyan, and black is sequentially applied. There is a full-color one with an array. The type of ink ribbon stored in the ribbon cassette 52 can be determined by, for example, providing a plurality of protrusions on one side of the ribbon cassette 52 indicating code information corresponding to the type of ink ribbon, and providing these protrusions on the side of the main body 1 of the apparatus. For example, this can be carried out by using a well-known method of detection using a cassette detection sensor (described later) consisting of a microswitch.

Further, inside the ribbon cassette 52, a thermal head 19 is provided.
A housing portion 52c is provided, into which the housing portion 52c is inserted.
c has protrusions 52d and 52 that are fitted into the thermal head 19.
e is provided.

FIG. 14 shows a state in which the ribbon cassette 52 is attached to the thermal head 19.

Here, the thermal head 19 is composed of a head housing 19a1, a head base body 19b, and the like.

The ribbon cassette 5 is provided on the outer surface of the head housing 19a.
Grooves 19c and 19d are provided to fit into protrusions 52d152e provided in the second housing portion 52c. Also,
Head base 1 provided with a plurality of heating resistance elements (not shown)
9b is attached at its lateral end to the head housing 19a via, for example, an elastic member 19e. A protrusion 19f is provided at the other end in the lateral direction of the head base body 19b, and the protrusion 19f is loosely engaged with a recess 19g provided in the head housing 19a. Therefore, the head base body 19b is engaged with the head housing 19a so as to be able to rotate slightly.

Further, a housing portion 19h is provided in the central portion of the head housing 19a in the lateral direction, and the housing portion 19h includes:
As shown in FIG. 15, coil springs 19i are housed at both ends of the head base 19b in the longitudinal direction and at the center thereof, spaced apart from each other at equal intervals. Therefore, when the platen roller 20 comes into contact with each part of the head base body 19b, each part of the head base body 19b is brought into contact with the platen roller 20 with uniform pressure by the coil spring 19i.

FIG. 16 shows the configuration of the platen roller 20. As described above, this platen roller 20 can come into contact with and separate from the heat-sensitive platen 19. That is, in the standby state before printing and in the printing state, the platen roller 20 is in contact with the thermal head 19 as shown in FIG. 16, and when performing full color printing,
- When printing with color ink is completed and the next ink is moved to the printing start position, it is separated from the thermal head 19 as shown in FIG. 17.

FIG. 18 shows a moving device for the platen roller 20. As shown in FIG. The platen roller 20 and the gears 46 and 47 that drive the platen roller 20 are connected to a U-shaped holder 61.
It is rotatably installed. A shaft 62 is attached to the mutually opposing distal ends of the holding body 61, and is rotatable about the shaft 62 as a fulcrum. This holding body 6
1 is provided with a spring 63 that biases the platen roller 20 toward the thermal head 19 , and the other longitudinal end is provided with a holder 61 that resists the biasing force of the spring 63 to bias the platen roller 20 toward the thermal head 19 . A solenoid plunger 64 is provided which is spaced apart from the solenoid plunger 64 .

FIG. 19 shows another embodiment of the mobile device,
The same parts as in FIG. 18 are given the same reference numerals. In the embodiment described above, the holding body 61 was driven by the solenoid plunger 64, but in this embodiment, a protrusion 65 is provided at the other longitudinal end of the holding body 61, and a cam 66 is brought into contact with this protrusion 65.

This cam 66 is connected to a motor 68 via a reduction gear mechanism 67.
It is designed to be driven by With this configuration as well, the platen roller 20 can be moved in the same manner as in the above embodiment.

On the other hand, as shown in FIGS. 16 and 17, plate-shaped pressing members 71 and 72 are provided near the platen roller 20 to regulate the movement of the paper P in conjunction with the movement of the platen roller 20. There is.

FIG. 20 shows the structure of the holding members 71 and 72. The presser members 71, 72 are arranged along the platen roller 20, and moving devices for the presser members 71, 72 are provided at both ends of the presser members 71, 72, respectively. In the same figure, only the moving device provided at one end side of the presser members 71 and 72 is shown.
．． A similar moving device is provided on the other end side of 72 as well.

The proximal end of the pressing member 71.72 is connected to the support 73.74.
It is rotatably supported at the tip of the

At the tips of these supports 73, 74, presser members 71, 7
Contact portions 75 and 76 are provided on the tip end side of the platen roller 20, with which the presser member comes into contact when the presser member is spaced apart from the platen roller 20. Further, the base end portion of the support body 73.74 is fixed to a rotation shaft 77.78 rotatably provided near the platen roller 20, and a lever 79.80 is attached to the rotation shaft 77.78. The proximal end is fixed. therefore,
These levers 79, 80 and supports 73, 74 are operable as a unit. Further, the supports 73 and 74 are constantly urged by a spring (not shown) in a direction in which the tips thereof are separated from each other, and the tips of the levers 79 and 80 are able to come into contact with the shaft 20a of the platen roller 20. There is. Furthermore, springs 81.82 are stretched between the intermediate portions of the levers 79.80 and the tip portions of the holding members 71.72, respectively.
The presser members 71, 72 are always urged in the direction of the abutting members 75, 76 by these springs 81, 82.

In the above configuration, in the standby state before printing and in the printing state, the platen roller 20 is in contact with the thermal head 19, as shown in FIG. 16. In this state, the shaft 20a of the platen roller 20 is moved above the rotation shaft 77.78, so the support 73.7
4 are moved in a direction in which their tips are separated from each other, and the tips of the presser members 71 and 72 are separated from the platen roller 20.

In the above state, when a sheet of paper is inserted from the insertion section 5a shown in FIG. 2, the leading end of the sheet of paper P passes through the lower surface side of the presser member 71 and is set between the platen roller 20 and the ink ribbon 53.

On the other hand, in the full-color printing operation, when the negative color printing operation is completed, the platen roller 20 is separated from the thermal head 19, as shown in FIG. 17, and the levers 79 and 80 are pushed down by the shaft 20a of the platen roller 20.

Therefore, the tips of the supports 73 and 74 are rotated in a direction toward each other, and the tips of the presser members 71 and 72 are brought into contact with the surface of the platen roller 20, thereby holding the paper P. At this time, the presser members 71, 72 and the supports 73, 74
The paper P is held by the biasing force of springs 81 and 82.

FIG. 21 shows a drive section for the ink ribbon 53. A gear 9 is attached to the bobbin 52b of the ribbon cassette 52.
1 is provided, and gears 92 and 93 are sequentially meshed with this gear 91. These gears 91 to 93 are housed, for example, in the ribbon cassette 52. When the ribbon cassette 52 is attached to the thermal head 19, the gear 93
is meshed with a gear 94 provided within the device main body 1.

This gear 94 is rotated by a pulse motor 95, and the ink ribbon 53 is driven by this pulse motor 95.

Further, the apparatus main body 1 is provided with a cassette detection sensor 96 composed of, for example, a double-current microswitch, and this cassette detection sensor 96 indicates the type of ink ribbon provided on the outer surface of the ribbon cassette 52.
Code information consisting of a plurality of protrusions can be read.

Furthermore, the apparatus main body 1 is provided with a ribbon detection sensor 97 that detects the type of ink in the middle of the conveyance path of the ink ribbon 53. This ribbon detection sensor 97 is composed of, for example, a well-known photocoupler, and as shown in FIG. In addition, code information BC consisting of a barcode is detected.

FIG. 23 shows the filter device FL used when performing full color printing.

In this filter device FL, for example, filters Fa, Fb, and Fc of a plurality of colors corresponding to the colors of ink of the ink ribbon 53 are arranged in the vertical direction in a frame 100. The arrangement order of these filters F a to F c matches the arrangement order of ink on the ink ribbon 53 . Also,
The frame 100 is movably held by springs 103 and 104, and is further provided with an engaging portion 100a. This engaging portion 100a has an eccentric cam 10.
2 are brought into contact with each other, and this cam 102 is rotated by a motor 101. Therefore, when performing full color printing, this motor 101 causes the cam 102 to
By rotating the filters F a to F c, the filters F a to F c are sequentially inserted into the optical path of the image sensor 14 in correspondence with the ink colors of the ink ribbon 53, and the original is exposed and scanned for each color of the filters F a to F c. . Therefore, this filter F
A document image is photoelectrically converted by the image sensor 14 for each transmitted light of a-Fc.

Note that the filter driving means is not limited to the above-mentioned configuration, but may also include, for example, a solenoid whose movement position can be set in multiple stages.
It is also possible to use a plunger.

FIG. 24 shows the configuration of the control system.

The control unit 111 controls the entire image forming apparatus, and the print key 6, for example, the density setting unit 8 made of a variable resistor, is connected to the control unit 111, and the light source is connected via the drive circuit 112. 9 is connected. Further, the image sensor 14 is connected to the control unit 111 via an amplifier 113, and the head drive circuit 1
The thermal head 19 is connected via 14.

Furthermore, the pulse motors 3g and 95.101 are connected to the control unit 111 via a motor drive circuit 115, and the solenoid plunger 64 is connected via a solenoid drive circuit 116.

The control unit 111 also includes a buffer memory 117 that stores several lines of image information supplied from the image sensor 14, a cassette that detects the attachment of the ink ribbon 52, and the type of the ribbon cassette. A detection sensor 96 is connected to a ribbon detection sensor 97 that detects the type of ink in a full-color ink ribbon.

In the above configuration, the printing operation will be explained with reference to FIGS. 25 and 26.

First, the image forming operation when thermal paper is used will be explained. With a document set on the document table 2, paper such as thermal paper is inserted from the insertion section 5a. In this state, when the print key 6 is operated, the control unit 111 determines whether or not there is a ribbon cassette (step STI, 2). In this case, since the cassette is not installed, the printing operation is performed immediately (step 5T3).
).

In this printing operation, as shown in FIG. 26, first, the drive circuit 1
12. The motor drive circuit 115 is controlled, the light source 9 is turned on, and the pulse motor 38 is driven in the forward direction. Then, the first and second carriages 31a and 31b are moved from the home position shown in FIG. 5, and the original set on the original platen 2 is exposed and scanned (step ST31). According to the exposure scan of the original, the original image is sequentially photoelectrically converted by the image sensor 14, and the image information output from the image sensor 14 is transmitted to the amplifier 11.
3. Stored in the buffer memory 117 via the control unit 111 (step 5T32). This buffer memory 11
The image information stored several lines at a time in 7 is sequentially read out one line at a time, and is sent to the control unit 111 and the head drive circuit 114.
is supplied to the thermal head 19 via. Further, the paper inserted into the insertion section 5a is moved by the platen roller 20, which is rotated by the pulse motor 38 in synchronization with the first and second carriages 31a and 31b, and in this moving state, the thermal head 19, an image corresponding to the original image is printed (step ST33).

Then, when the exposure scanning of the document is completed and the printing operation by the thermal head 19 is completed (step 5T34), the paper is ejected from the apparatus main body 1, the light source 9 is turned off, and the pulse motor 38 is stopped. The first and second carriages 31a131b are stopped (step 5T35)
. Thereafter, as shown in step ST4 in FIG. 25, the pulse motor 38 is rotated in the opposite direction, and the first and second carriages 31a and 31b are returned to the home position.

Next, a printing operation using a ribbon cassette will be explained.

When performing a printing operation using a ribbon cassette, as described above, with the cover 5 open, operate the operator 7 on the main body 1 of the apparatus, open the thermal head 19, and attach the ribbon cassette 52 to the thermal head 19. Attach. Then, close the thermal head 19 again and insert the ribbon cassette 52 into the device main body 1.
to be integrated into.

In this state, when paper is inserted through the insertion slot 5a and a document is set on the document table 2, and the print key 6 is operated (step 5T1), the ribbon cassette is installed by the control unit 111 according to the output of the cassette detection sensor 96. (Step 5T)
2) The type of ribbon cassette 52 is determined (
Step 5T5). As a result, if the ink ribbon housed in the ribbon cassette 52 is a monochrome ink ribbon, the control moves to step ST3, and the original image is exposed and scanned by the same operation as in the case of using thermal paper described above. The ink on the ink ribbon 53 driven by the pulse motor 95 is heated and melted by the thermal head 19 to form an image on the paper.

Further, in step ST5, the control unit 111 controls the ink ribbon 5 accommodated in the ribbon cassette 52.
If 3 is determined to be for full color,
The following operations are performed.

First, the pulse motor 95 is operated, and the first color of the ink ribbon 53 is moved to the printing position while determining the output signal of the ribbon detection sensor 97 (step 5T6). Thereafter, the motor 101 is operated, and the filter Fa corresponding to the first ink color of the filter device PL is inserted into the optical path of the image sensor 14 (step 5T7). In this state, an operation substantially similar to the printing operation described using FIG. 26 is performed (step 5T8). That is, the light source 9 is turned on, and the original is exposed and scanned in the same manner as described above. Along with this exposure scanning, the platen roller 20 and ink ribbon 5 are driven, and the thermal head 19 is operated according to image information output from the image sensor 14.
An image is formed on the paper using the first ink.

For example, if the first ink is yellow (Y), the second
As shown in FIG. 2, printing is performed by moving yellow ink in the direction of the arrow in the figure.

When the exposure scanning of the document is completed, the control is transferred from step ST8 to step ST9, and the solenoid plunger 64 is operated while the first and second carriages 31a and 31b are stopped at the position, and the platen The roller 20 is separated from the thermal head 19. At this time,
The paper is pressed against the platen roller 20 by pressing members 71 and 72.
This is done to prevent positional deviation from occurring (step 5T9). In this state, the motor 95 is driven to send out the second ink (magenta (M)), and as shown in FIG. ). Further, the motor 101 is energized, and the filter Fb corresponding to the second ink color is inserted into the optical path of the image sensor 14 (step 5TII).

In this state, the solenoid φ plunger 64 is deenergized, and the platen roller 20 is brought into contact with the thermal head 19 (step 5T12). After this, a printing operation is performed in step 5T13.

At this time, the pulse motor 38.95 is rotated in the opposite direction to expose and scan the document in the opposite direction, and the paper and the ink ribbon 53 are transported in the opposite direction, and an image is formed using the second color ink. It will be done.

In this way, when the image forming operation using the second ink is completed, the solenoid plunger 64 is energized and the platen roller 20 is separated from the thermal head 19.
The paper is held (step 5T14). In this state,
The third ink (cyan (C)) is set at the print start position (step 5T15). Also, the motor 101 is driven, and the filter F corresponding to the third ink color is
c is inserted into the optical path of the image sensor 14 (step 5T16). In this state, the plunger 64 is deenergized and the platen roller 20 is brought into contact with the thermal head 19 (step 5T17). And step ST1g
The printing operation is performed in . At this time, the motor 38.95 is rotated in the forward direction, the original is exposed and scanned in the forward direction, and an image is formed using the third ink.

After this, an image forming operation using the fourth ink (black (BK)) is performed by the same operation as printing using the second ink, and when this is completed, all printing operations are completed. (Steps 5719-23)
. However, when printing black (BK), filter F
Since L is not necessary, the filter FL is
is extracted from the optical path (step ST21).

Note that when three colors of ink are set on the ink ribbon, all image forming operations are completed when the image forming operation using the third ink is completed.

According to the above embodiment, by cutting the portion of the mirror 12 that does not affect image formation, the light source 9 and the mirrors 10, 11, and 12 that make up the optical system can be arranged at an angle. The stand 2 can also be arranged at an angle. Therefore, the external appearance of the device main body 1 can be reduced in size.

In addition, the optical system is composed of a light source 9, mirrors 10, 11, 12, a lens block 13, and an image sensor 14,
Since a color contact sensor is not used as in the past, manufacturing costs can be reduced.

Furthermore, by arranging the thermal head 19 above the platen roller 20, a sheet of paper as a transfer material can be set from the front side into the insertion opening 5a provided on the top surface of the apparatus main body 1.

Therefore, it is easier to set the paper than in the conventional case where the paper is set from the back side of the platen roller. In addition, since the paper can be transported in a nearly straight line, there is less resistance during paper transport, which prevents paper misalignment and color misalignment, especially when printing back and forth on the paper, such as in full-color printing. Since it is possible to reduce the number of pixels, it is possible to improve image quality.

In addition, a plate-shaped pressing member 71 is provided near the platen roller 20.
．． 72 is provided, and when the platen roller 20 is separated from the thermal head 19, the paper is pressed against the platen roller 20 by the presser members 71 and 72. Therefore, compared to the conventional case where the paper is pressed against the platen roller using a roller, the space for arranging the parts can be reduced. Moreover, this pressing member 71.72
In this case, since the position where the paper is pressed against the platen roller 20 can be set near the printing area by the thermal head 19, it is possible to reduce the unprintable area compared to the case where a roller is used.

Further, when full-color printing is performed, printing is performed by reciprocating the paper and reciprocating the optical system according to the direction of movement of the paper. Therefore, compared to conventional unidirectional printing in which the paper is returned to the printing start position each time one color printing operation is completed, the number of paper movements can be halved, which prevents paper misalignment. In addition, it is possible to increase the printing speed.

Further, a plurality of springs 19i are provided inside the head housing 19a constituting the heat-sensitive heater 19 at predetermined intervals, and the head base body 19b is pressed toward the platen roller 20 by the springs 19i. Therefore, each part of the thermal head 19 in the longitudinal direction can be brought into contact with the platen roller 20 with equal pressure, so that uneven printing can be prevented. Moreover, the accommodating portion 19h for accommodating the spring 19i of the head housing 19a is arranged so that the ribbon cassette 5
Since the ribbon cassette 52 is located between the two bobbins 52a and 52b, it is possible to prevent the ribbon cassette 52 from increasing in size.

Furthermore, when performing full-color printing, the filter F of the filter device FL is
a - F c are sequentially inserted into the optical path of the image sensor 14, the optical image input through the filter F a - F c is photoelectrically converted by the image sensor 14, and this photoelectric conversion output is subjected to color image processing. It is supplied to the thermal head 19 and prints without any problem. Therefore, compared to the conventional case where a color contact sensor is used and printing is performed after color image processing, it is possible to significantly reduce costs.

Note that this invention is not limited to the above embodiments,
Of course, various modifications can be made without departing from the gist of the invention.

[Effects of the Invention] As described in detail above, according to the present invention, the conveyance means and the printing means are controlled by the control means, and an image is formed as the transfer material moves in both directions, so that the transfer material can be moved in both directions. It is possible to provide an image forming apparatus that can reduce the number of times the material is moved, suppress displacement of the transferred material, prevent deterioration of image quality, and shorten the time required for image formation.

[Brief explanation of the drawing]

The drawings show an embodiment of an image forming apparatus according to the present invention, and FIG. 1 is a perspective view of essential parts showing an optical system and a drive device for a platen roller, and FIG. 2 is an external view of the image forming apparatus. 3 is a perspective view showing the state in which the document table cover in FIG. 2 is opened, FIG. 4 is a diagram shown to explain the relationship between the document table and the optical system, and FIG. 5 is the same as in FIG. 6 is a sectional view taken along the line I--I shown in FIG. 2, and FIG. 7 is a sectional view taken along the line Figure 8 is a perspective view of Figure 2 with the cover open, Figure 9 is a perspective view of the thermal head rotated, and Figures 10 and 11 are each with a ribbon cassette attached to the thermal head. A perspective view showing the state, FIG. 12 is a side sectional view showing the ribbon cassette attached to the thermal head, and FIG. 13 is a side sectional view showing the configuration of the ribbon cassette.
Fig. 14 is a side sectional view showing the ribbon cassette attached to the thermal head, Fig. 15 is a side sectional view showing the pressing means of the thermal head, and Figs. 16 and 17 are the relationships between the platen roller and the pressing member, respectively. Fig. 18 is a perspective view of the main parts showing the platen roller moving device, and Fig. 19 is a side view with a partial cross section showing different operating states, and Fig. 19 shows another implementation of the platen roller moving device. FIG. 20 is a perspective view of the main parts showing the structure of the presser member, FIG. 21 is a perspective view of the main parts showing the drive section of the ink ribbon, and FIG. 22 is a full-color ink ribbon. FIG. 23 is a plan view showing an example of the filter device, FIG. 24 is a configuration diagram showing the configuration of the control system, and FIGS. 25 and 26 are for explaining the printing operation. FIG. 1...Device main body, 2...Original table, 4...Printing section,
9...Light source, 10.11.12...Mirror, 14.
...Image sensor, 19...Thermal head, 19a.
...Head housing, 19b...Head base, 19i...
・Spring, 20...Platen roller, 38.95...
Pulse motor, 52... Ribbon cassette, 53...
Ink ribbon, 71.72...pressing member, FL...
Filter device, F a -F c... filter, 11
1...control unit. Applicant's Representative Patent Attorney Takehiko Suzue-A Figure 7] Figure 12 Figure 13 Figure 14 Figure 15 Figure 16 Figure 17 Figure 19 Figure 20 Figure 22 Figure 23 (b) Figure 25 = 26 Figure

Claims (5)

[Claims] (1) A scanning device that exposes and scans a document placed on a document table, a conversion device that converts the light emitted by the scanning device into an electrical signal, and a movable transfer material in which a plurality of colorants are sequentially arranged. a conveyance means for conveying the transfer material in both directions, and a transfer means provided above the conveyance means to transfer the colorant of the transfer material to the transfer material conveyed by the conveyance means in accordance with an output signal of the conversion means. 1. An image forming apparatus comprising: a printing means for transferring a colorant of a transfer material to a transfer material by the printing means as the transfer material moves in both directions. (2) The scanning means includes an exposure lamp that irradiates the original with light, a first mirror that directs the light reflected from the original in one direction of movement of the scanning means, and scans the light guided by the first mirror. 2. The image forming apparatus according to claim 1, further comprising second and third mirrors disposed orthogonally for guiding the means in the other direction of movement. (3) The image forming apparatus according to claim 1, wherein the conveyance means is comprised of a platen roller. (4) The image forming apparatus according to claim 1, wherein the control means controls the movement of the scanning means as the transfer material and the transferred material move. (5) A filter is provided between the scanning means and the converting means to separate the reflected light from the original according to the colorant of the transfer material. The image forming apparatus described in .