JPH0781237A - Image forming device - Google Patents

Abstract

(57) [Summary] [Purpose] To improve the maintainability of the components such as the developer transporting means, which has a shorter life than the machine life. A developer supply means 11, an endless film-shaped developer transport means 1, a developer transfer means 4 for transferring the developer 10 supplied by the developer supply means 11 to the developer transport means 1, In an image forming apparatus equipped with a thermal head 5 which is provided on the back surface of the developer transport means 1 and selectively melt-transfers the developer 10 onto the recording paper 20 by a plurality of elements capable of selectively generating heat, The agent transporting means 1, the developer transferring means 4, and the thermal head 5 constitute an image forming unit 8 which can be attached to and detached from the body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus used for a page printer or the like, and more particularly to a plurality of elements capable of selectively generating heat of a developer uniformly attached to a film-like developer conveying means. The present invention relates to a thermal transfer type image forming apparatus which selectively melt-transfers onto a recording paper by a heating means (hereinafter abbreviated as a thermal head) arranged in parallel.

[0002]

2. Description of the Related Art In recent years, as output devices for computers and the like,
Page printers that print image data forming an orthogonal matrix in the row and column directions have been widely used. Many of these page printers have used a method generally called an electrophotographic process, which requires many steps of charging, exposing, developing, transferring, cleaning, and fixing in order to obtain an image on a recording sheet.

As a method for obtaining an image on a recording paper with a simple structure, there is a method generally called a thermal transfer method.
This is a system in which a thermal transfer sheet having a hot-melt ink layer provided on a base film is superposed on a recording paper, and the ink is transferred to the recording paper by heat from a thermal head.

Further, as a method having the advantages of the above two methods, for example, as disclosed in JP-A-58-155971, a developer is uniformly attached to an endless film, and a thermal head is used for selection. A method has been proposed in which a developer is melt-transferred onto recording paper to form an image.

The outline of the conventional image forming apparatus will be described below. However, since the electrophotographic process and the thermal transfer system are generally well known,
The description is omitted here.

In FIGS. 4 and 5, the endless film 32 is formed.
The developer conveying means 31 having a conductive material coating layer 33 formed on one side thereof is supported by a supporting roller 34 with the coating layer 33 inside, and a thermal head 35 is disposed so as to face the coating layer 33. Has been done. On the other hand, a charger 36 is provided at a position higher than the thermal head 35 so as to face the surface of the developer transport means 31 opposite to the coating layer 33 and the charger 36 and the thermal head 3.
A developing device 37 is provided in the middle of 5, and a cleaner 38 is provided below the thermal head 35. Also,
A platen roller 39 is disposed so as to face the thermal head 35 with the developer conveying means 31 sandwiched therebetween. A recording paper 40 is sandwiched between the platen roller 39 and the developer conveying means 31, and recording is performed by the platen roller 39. The paper 40 and the developer transport means 31 are configured to be pressed against the thermal head 35.

In the above structure, the developer conveying means 31 is rotated clockwise by the supporting roller 34 and is uniformly charged by the charger 36, and the coating layer 33 of the developer conveying means 31 is charged next. The developer 37 uniformly deposits the developer on the opposite surface. Next, the recording paper 40 is closely contacted and supplied onto the developer of the developer conveying means 31, and the platen roller 39 presses the recording paper 40 and the developer conveying means 31 against the thermal head 35.
In the state where the developer conveying means 31 is pressure-bonded to the thermal head 35, the heating element of the thermal head 35 is selectively heated to melt or soften the developer and transfer it onto the recording paper 40 to form an image. The recording paper 40 on which the image has been formed is discharged by the discharge roller 41, and the developer on the developer conveying means 31 that has completed the transfer is removed by the cleaner 38 to prepare for the next transfer. By repeating the above operation, continuous images are obtained.

[0008]

However, in the image forming apparatus using the electrophotographic process, detailed description of which is omitted, many steps are required to form an image, and the overall size and cost of the image forming apparatus is reduced. However, since a high voltage is used in the process of charging and transfer, its safety measures are required.

On the other hand, in an image forming apparatus using a thermal transfer system, a thermal transfer sheet having a hot-melt ink layer provided on a base film is used. However, this thermal transfer sheet cannot be used for one recording, and the cost required for recording. There is also a problem in that the heat transfer sheet remains in a state where the heat-melted ink layer in the transferred portion is removed, which is also a secret keeping aspect.

Further, in the configuration shown in FIGS. 4 and 5, the endless developer carrying means 31 efficiently generates the dot heat of the thermal head 35 to the developer deposited on the developer carrying means 31. It is necessary to have a thickness of 20 to 30 μm or less for conduction, and the developer transport means 31 is sufficiently rubbed while being pressed by the thermal head 35 and repeatedly heated by the thermal head 35. Although heat resistance and durability are required, the service life was not sufficiently satisfied with the machine life guaranteed by the manufacturer. Further, the thermal transfer is performed on the recording paper 40 in a melted or semi-melted state by the thermal head 35.
The transfer efficiency to 0 is not 100%, but actually lower than that, and the molten or semi-molten developer remains on the developer transport means 31, and if it is used for a long time in that state, it is fixed on the developer transport means 31. However, heat transfer to the developer by the thermal head 35 is not efficiently performed, and an incomplete image is formed. Also, regarding the life of the thermal head 35, the developer transporting means 31 rubs against the thermal head 35 while rubbing the surface coating layer, and the electrode abnormality occurs due to repeated heat generation. Is not completely satisfied.

Therefore, it is necessary to clean and replace the developer conveying means 31 and the thermal head 35 during the life of the machine. However, the work is complicated and the maintenance cost is high. .

In view of the above-mentioned conventional problems, it is an object of the present invention to provide an image forming apparatus having improved maintainability of components such as a developer transporting means having a shorter life than the machine life.

[0013]

SUMMARY OF THE INVENTION The present invention is directed to a developer supplying means for supplying a developer, an endless film-like developer conveying means for uniformly adhering and conveying the developer on the surface, and a developer supplying means. Developer transfer means for transferring the developer supplied by the means to the developer transport means and uniformly adhering the developer, and selectively generating heat provided on the back surface of the developer transport means and arranged in parallel. A heating means for selectively melting and transferring the developer onto the recording paper by a plurality of possible elements, and at least the developer conveying means, the developer transferring means, and the heating means are detachable units from the main body. It is characterized by

Preferably, the unit is constructed so as to be attachable to and detachable from the developer supplying means.

[0015]

According to the present invention, the unit is not disassembled without disassembling the entire machine against the occurrence of sticking, deformation, scratches, etc. of the untransferred developer in the developer transporting means and the abnormality of the thermal head. Therefore, maintenance such as cleaning and replacement of parts can be performed, and the time required for maintenance work can be significantly reduced.

Further, if the unit is detachable from the developer supplying means, the positioning with respect to the developer supplying means, which requires a high positioning accuracy, can be performed with a high accuracy with a simple structure.

[0017]

【Example】

(Embodiment 1) An image forming apparatus according to a first embodiment of the present invention will be described below with reference to FIGS.

In FIG. 1, reference numeral 1 denotes a developer conveying means. As shown in detail in FIG. 2, one side of a 25 μm-thick endless film 2 of polyester, which is a dielectric substance, is coated with a silicone resin solution. It is configured by providing a coating layer 3 which is formed by coating with the coating layer 3 on the outside. The developer transport means 1 is supported by a developer transfer means 4, a thermal head 5, and a pair of support rollers 6 disposed inside thereof so as to be rotatable and driven along a fixed path, and these constituent elements are An image forming unit 8 is configured by being sandwiched between the front and rear side plates 7, 7. The front and rear side plates 7 are provided with locking portions 9 for locking to a unit carrying member (not shown) arranged on the main body side.

Reference numeral 11 denotes a developer supplying means for supplying the developer 10 to the developer conveying means 1, which is provided with a developer accommodating portion 12 and a developer supplying portion 13, from which the developer replenishing member is provided. At 14, the developer supply unit 13 is sequentially replenished with the developer, and at the developer supply unit 13, the developer stirring roller 15 stirs the developer 10 to frictionally charge it, and the charged developer is supplied to the developer supply roller 16 And is regulated to a constant thickness by the layer thickness regulating member 17, and the developer 10 is supplied in a thin layer state having a uniform thickness.

The developer supplying means 11 is arranged so that the developer supplying roller 16 faces the developer carrying means 1 wound around the developer transferring means 4 with a proper gap. A voltage having a polarity opposite to that of the developer 10 for charging the dielectric substance of the developer transporting means 1 is applied to the developer transferring means 4, and the charged developer transporting means 1 develops the developer by Coulomb force. The developer 10 on the supply roller 16 is attracted, and is conveyed while being uniformly attached to the coating layer 3.

The thermal head 5 is arranged at a position lower than the developer transfer means 4 in the rotational direction of the developer carrying means 1, and the platen is arranged so as to face the thermal head 5 with the developer carrying means 1 interposed therebetween. A roller 18 is provided, and the platen roller 18 is pressed against the thermal head 5 side with a constant pressure. A paper feed roller 19 supplies the recording paper 20 between the platen roller 18 and the developer transport means 1.

In the above arrangement, the support roller 6 or the developer transfer means 4 rotationally drives the developer transport means 1 and the developer transfer means 4 charges the developer transport means 1 while supplying the developer. By means 11 the developer supply roller 16
The developer 10 is attached to a fixed thickness on the developer transfer means 4
When the developer 10 is supplied to a position opposite to, the developer 10 is uniformly attached to the developer carrying means 1 by the Coulomb force and is carried to the thermal head 5 in that state. In the thermal head 5, the platen roller 18 presses both the recording paper 20 and the developer transport means 1 against the thermal head 5 at a constant pressure, so that the heating elements of the thermal head 5 are selectively heated. The developer 10 uniformly adhered and conveyed on the developer conveying means 1 is selectively melted or softened and is thermally transferred onto the recording paper 20 to form an image. The developer 1 on the developing and conveying means 1 that has completed the transfer
0 is transported to the developer supply unit 11 and reused.
By repeating these series of operations, continuous images can be obtained.

Further, when an abnormality occurs in the developer transport means 1 or the thermal head 5, both of them are unitized as an image forming unit 8 and are locked to a carrying member (not shown) on the main body side. Because it is detachably attached at 9,
The main body can be taken out without disassembling, and the maintenance time can be shortened significantly.

(Embodiment 2) Next, an image forming apparatus according to a second embodiment of the present invention will be described with reference to FIG.

In FIG. 3, the same components as those of the image forming apparatus of the first embodiment shown in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted.

Reference numeral 21 denotes a carrying member provided on the developer supplying means 11 for supporting the image forming unit 8, and 22 denotes the developing material supplying means 11 so as to be locked to a carrying member (not shown) on the main body side. It is a provided locking portion.

In this embodiment, since the image forming unit 8 is detachably attached to the developer supplying means 11 which is detachable from the main body side, the image forming unit 8 alone or the developer is used. It can be attached to and detached from the main body side together with the supply means 11. When the image forming unit 8 is attachable / detachable to / from the developer supplying unit 11 as described above, the positioning with respect to the developer supplying unit 11 which requires the positioning accuracy can be performed with a simple configuration and with high accuracy.

[0028]

As described above, according to the image forming apparatus of the present invention, it is possible to prevent the durability of the developer conveying means, the sticking of the untransferred developer, and the like, and the thermal head. Therefore, it is possible to take out the unit and perform maintenance such as cleaning and replacement without disassembling the entire machine, it is possible to greatly reduce the time required for maintenance work, and parts with a short service life with respect to the machine life. The maintainability of can be improved.

Further, if the unit is detachable from the developer supplying means, the positioning with respect to the developer supplying means, which requires a high positioning accuracy, can be performed with a high accuracy with a simple structure.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a main part of an image forming apparatus according to a first embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of a developer carrying unit in the embodiment.

FIG. 3 is a schematic configuration diagram of a main part of an image forming apparatus according to a second embodiment of the present invention.

FIG. 4 is a schematic configuration diagram of a main part of a conventional image forming apparatus.

FIG. 5 is an enlarged cross-sectional view of a developer transport unit in a conventional example.

[Explanation of symbols]

 1 developer conveying means 4 developer transferring means 5 thermal head 8 image forming unit 10 developer 11 developer supplying means 20 recording paper

Claims (2)

[Claims] 1. A developer supplying means for supplying a developer, an endless film-like developer conveying means for uniformly adhering and conveying the developer on the surface, and a developer supplied by the developer supplying means. To a developer transporting means to uniformly attach the developer, and a plurality of selectively heat-generating elements arranged on the back side of the developer transporting means and arranged in parallel. An image forming apparatus comprising: a heating unit that selectively melt-transfers an agent onto a recording sheet, and at least the developer transporting unit, the developer transferring unit, and the heating unit are detachable units from the main body. . 2. The image forming apparatus according to claim 1, wherein the unit is configured to be attachable to and detachable from the developer supply unit.