JP2000238366A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily perform the mounting and positioning to a support frame, in a recording apparatus using an ink ribbon, by attaching a resin bracket having a complicated shape to a thermal head to use members projected toward upper and lateral parts. SOLUTION: Resin brackets 43 are attached to both end portions of a thermal head 40 and the projected members arranged to the upper and lateral parts of the brackets are used to attach the brackets to the mounting parts of a support frame. Brackets 42 are held to an operation position by providing projected parts 44 to the upper engaging members 43 engaged with the upper part of the frame and mounting upper engaging members 45 and side engaging members successively and engaging pawl members. The attaching and detaching work of the thermal head can be easily performed by using two engaging members.

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 such as a facsimile machine, and more particularly, to a device such as a recording device or a reading device, and a roller arranged in a fixed positional relationship with the device. And an image forming apparatus having the same.

[0002]

2. Description of the Related Art In an image forming apparatus such as a facsimile apparatus, devices such as a thermal head as a recording device and an image sensor as a reading device are arranged in combination with a platen roller as an urging means opposed thereto. That is the general configuration. The device includes:
A large number of elements are arranged in a line, and a sheet is passed between the device and a platen roller to read an image of a document or record an image on the sheet. When performing recording or reading using the device, it is necessary to position both members so that the elements formed in one row are aligned with the axis of the roller. Uses means such as forming a U-shaped groove in a support member or the like movably attached to the device and engaging a roller shaft with the U-shaped groove.
Further, in order to support the device at a position where the device is urged toward the platen roller, an attachment member such as a bracket and a pressing unit using a spring are provided in combination with the device holding frame, and the attachment member is provided as the attachment member. Uses a member formed by bending an iron plate or the like.

[0003]

However, when the bracket is formed of a bent member made of an iron plate, there is a problem that the degree of freedom in designing parts is low and the shape of the bracket is limited. Further, for example, in a case where the device is configured to be supported by a swing frame that enables opening and closing of a paper transport path with respect to a platen roller, an operation of attaching and detaching a device to and from the swing frame can be easily performed. There is a disadvantage that there is no. Therefore, at present, it is desired to improve the structure of the support member of the device in order to position the device in an operating state and to improve workability during assembly.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problem of the conventional support means of a device. By using a plastic mounting member and arbitrarily forming the shape thereof, it is easy to attach / detach to / from the holding member. It is an object of the present invention to provide a mechanism that can be performed and can perform the holding action of the device well.

[0005]

According to the present invention, a device such as a thermal head and an opposing member such as a platen roller are arranged in close contact with each other, and the device is supported on a frame so as to be separated from the opposing member. The present invention relates to an image forming apparatus configured to be accessible. The invention according to claim 1 of the present invention is characterized in that a resin mounting member is used to support the device on a frame. Therefore, a mounting member having a complicated shape can be integrally formed, and the degree of freedom of design can be increased.

The invention according to claim 2 is characterized in that the resin-made mounting member is formed integrally with an elastic claw member for mounting to a frame. And an elastic part can be provided in a mounting part, without increasing the number of parts. The invention according to claim 3 is characterized in that the attachment member is
It is characterized in that a pin member for positioning with respect to the opposing member is provided integrally. Therefore, it is possible to provide positioning pins at arbitrary positions without increasing the number of members to be combined with the thermal head.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One example of an image forming apparatus according to the present invention will be described using a facsimile machine according to the illustrated example. FIG. 1 shows the entire configuration of the facsimile apparatus 1. An operation unit 3 is arranged on the front side of the apparatus main body 2 and numeric keys and function buttons are provided at the top of the apparatus main body 2. In addition to the functions, a function such as telephone call and copy creation can be selected at any time. A paper cassette 11 is provided at the lower part of the apparatus main body.
A paper feed unit 10 is disposed, a printing unit 20 is disposed in an intermediate portion of the apparatus main body, and a document handling mechanism is disposed above the print unit 20. An upper frame 3 is provided above the printing unit 20.
0 is arranged to be openable and closable, an outer cover 32 is mounted on the upper surface of the upper frame 30, and the outer cover 32 is opened and closed together with the upper frame to form an opening in the upper portion, and the ink ribbon 21 is replaced and the internal mechanism is inspected. For example, the upper frame is opened so that the opening provided can be used.

A document reading section is disposed below the operation section 3, and is disposed so as to protrude from the upper portion of the apparatus main body, and a document is inserted from a detachably provided document tray 4. Further, a transport roller device 6 for transporting the document toward the reading unit via the document transport path 5 is provided, and a platen roller 7 and a reading device 8 are provided downstream of the transport roller device 6. A reading unit is provided so as to face the document, and the read document is discharged through the discharge port 9. The reading device 8 is constituted by a device using a photoelectric conversion element such as a CCD, irradiates an image of a document conveyed at a predetermined speed with light, receives reflected light thereof, and converts a light signal into an electric signal. Output, and the image signal can be transmitted through a telephone line using a facsimile function. Also, when the copy mode is selected, it is also possible to transmit the read information of the original to the thermal head of the printing unit and use it to create a recording sheet.

A paper feeding unit 10 arranged at a lower portion of the apparatus main body
In, the paper accommodated in the paper cassette 11 is
The paper is fed one by one by a paper feed roller 15, conveyed while being sharply curved through a curved path 16, and fed to the printing unit 20. Then, the ink is conveyed together with the ink ribbon 21 between the thermal head 40 as a device for producing recording paper and the platen roller 25, and the ink of the ink ribbon is melted by the heat of the thermal head and transferred to paper to form recording paper. Then, the ink ribbon is separated from the ink ribbon and discharged to the discharge path 18 via the discharge roller device 17. The discharge path is formed on the cover 12 of the paper feed cassette 11, and deposits recording paper between the lower plate and the cover of the main body. The leading end of the recording paper is supported by a support member 13, and a pressing member 19 is disposed above the support member so that even when a large number of recording papers are discharged, the recording paper is disturbed in a stacked state. Not to be.

The ink ribbon 21 used in the printing unit 20 includes:
In the course of moving from the feeding roll 22 to the take-up roll 23, the heating element is superposed on the paper and passes between the thermal head 40 and the platen roller 25 to generate heat based on the information applied to the thermal head, thereby causing the ink ribbon to move. Transfer ink to paper to create recording paper. In order to move the ink ribbon 21 together with the paper, the drive mechanism provided on the take-up roll 23 is used to drive the ink ribbon 21 at the same speed as the paper feed speed. Also, when the recording paper is formed through the printing unit, the paper may adhere to the ink ribbon.Therefore, by rapidly bending and guiding the ink ribbon via the peeling edge 33 downstream of the printing unit, The recording paper is separated from the ink ribbon, and the recording paper is sent out toward the discharge roller device 17.

An upper frame 3 provided with a thermal head holder 32 is provided above the portion where the ink ribbon is arranged.
0 is arranged and provided so as to be swingable via a support shaft 31.
An outer cover 32 is provided on the upper frame 30.
The outer cover 32 and the upper frame are opened via a support shaft, and when the ink ribbon 21 is replaced in the printing unit, the upper part of the printing unit is fixed. A large opening is formed in the work.

The structure of the thermal head supporting portion disposed on the upper frame 30 is as shown in FIG. 2. The head holding unit 35 is integrally connected. The thermal head holder 3
5 is upwardly formed in a substantially U-shaped groove, the thermal head 40 is disposed above the groove, and is pressed toward the platen roller 25 by using a biasing member 41 such as a spring, so that the paper 5 A predetermined nip pressure can be applied to the ink ribbon.

On the upstream and downstream sides of the thermal head holding section 35, there are disposed projections projecting downward, respectively, and the downstream projection is provided with a peeling edge 33 for peeling the paper from the ink ribbon. Is formed as The side plate member 38 of the frame on the side of the peeling edge 33 has an engagement hole 3.
9 and the upper plate member 36 is provided with a locking hole 37,
The bracket 42 provided on the thermal head 40 is supported using the engagement hole 39 and the engagement hole 37.

As shown in FIG. 3, the thermal head 40 is integrally provided with resin brackets 42 at both end portions thereof, each being fixed with a screw. The bracket 4
2 is provided with an end plate 42a bent so as to cover the end of the thermal head, and the end plate 42a is provided with positioning pins 47 protruding from both ends of the thermal head. Also, at the top of the bracket,
An upper engaging member 43 is provided so as to protrude toward an upper portion of the thermal head, and a side locking member 45 is provided on a side portion. The thermal head holding member is formed by using the side engaging member and the upper locking member. The thermal head 40 is held and fixed to the portion 35. In the upper engagement member 43, projections 44 are provided so as to protrude on both sides of the distal end thereof (both sides in the length direction of the thermal head).
In, the claw members 46, 46 are provided such that the hook portions of the claws are located outside.

As described above, when the thermal head 40 having the brackets 42, 42 integrally provided at both ends is mounted on the thermal head holding portion 35 of the upper frame 30, the thermal head 40 is mounted as shown in FIG. I do. First, the bracket 32 is inserted into the engagement hole 37 provided in the upper plate member 36.
The upper engaging member 43 is inserted, and the protrusion 44 of the side engaging member 43 is locked on both sides of the engaging hole. The engaging hole 37 allows the upper engaging member 43 to be inserted. A wide portion and a narrow portion for locking the protrusion 44 are provided, and the position for holding the thermal head is set to the narrow portion.
Then, the side locking member 45 of the bracket is inserted into the locking hole 39 of the side plate member 38, and the claw members 46 provided on both sides of the upper locking member 45 are engaged with both side portions of the locking hole 39. By stopping, the thermal head is held. Then, a spring of an urging member disposed above the thermal head 40 is pressed toward the platen roller.

A bracket 42 attached to both side ends of the thermal head 40 uses a resin material together with a main body portion for attaching the end plate 42a, the upper engaging member 43 and the side engaging member 45 to the thermal head. And can be integrally molded. Therefore, when a relatively elastic plastic is used, the claw member 46 of the side locking member is used.
In a state in which the brackets are integrally formed, the claw member can also be made elastic. If no hard plastic is used, the constituent members of the bracket can be made elastic.

Also, when the bracket is removed from the thermal head holding portion, the claw member 4 of the side locking member 45 is also required.
By simply applying a function of slightly pressing and pressing the side 6 from the side, the claw member can be removed from the engaging portion and the thermal head can be removed. Furthermore, since the upper engaging member 43 attached to the engaging hole provided in the upper plate member of the thermal head holding portion can also be provided with a slight twisting action, the protrusion can be removed from the engaging hole. The work of removing the thermal head mounted via the bracket can also be easily performed.

FIG. 4 shows a state in which the thermal head is mounted on the thermal head holding section 35 of the upper frame 30 and is combined with a platen roller to constitute a printing mechanism. As shown in FIG. 4, a thermal head 40 as a printing device is supported by a side plate 28 fixed to a main body frame of the apparatus via a bearing member 27, and includes a platen roller 25 provided on a shaft 26. Provided corresponding to the thermal head. The platen roller 2
The positioning of the thermal head 40 combined with the bracket 5 is performed in a state where the positioning pins 47 protruding from the ends of the brackets 42 on both sides are engaged with the guide grooves 29 provided in the side plate 28 holding the platen roller. Is done.

When the thermal head 40 is mounted on the platen roller 25, as shown in FIG. 5, the positioning pin 47 enters the guide groove 29 of the side plate from the upper side, and the lower circular arc surface of the groove is formed. Is set so that the positioning pin is accurately positioned. Then, by positioning the thermal head, the center line of the platen roller 25 and the heating element row 40 of the thermal head are aligned.
In a state where a coincides with a, it is pressed by the spring. In other words, as shown in FIG. 5, a large opening is formed in the upper part as shown in the drawing, and an arc surface having the same diameter as the positioning pin is formed in the lower part of the side plate holding the platen roller. When the printer is closed, it is possible to automatically perform the positioning operation of the thermal head, and nip the paper with the platen roller to print.
It is possible to accurately perform the operation of creating the recording paper.

In the above-described embodiment of the present invention, the configuration of the thermal head as a printing device has been described. However, the shape of the brackets disposed at both ends of the device can be changed without using screws or the like. The present invention can be applied to an apparatus provided with an arbitrary upper plate member or upper locking member for locking and holding the thermal head holding section. Further, in the shape and structure of the bracket, it is possible to slightly change the shape according to the shape of the thermal head holding portion or the like for holding the thermal head, and each component within a range that provides the same operation and effect as described above. It is possible to change the detailed structure of the member. Further, in the above-described embodiment, the thermal head as a printing device has been described as an example, but the bracket of the present invention can also be used for a reading device, for example, a contact type reading sensor. .

[0021]

The apparatus according to the present invention is constructed as described above, and uses a resin-made mounting member to support the device on the swing frame. Therefore, the mounting member having a complicated shape is integrated. And the degree of freedom of design can be increased. In addition, since the resin-made attachment member integrally forms the elastic claw member for attachment to the swing frame, the attachment part can be provided with an elastic portion without increasing the number of parts. Further, since the mounting member integrally includes a pin member for positioning with respect to the platen roller, the positioning pin can be provided at an arbitrary position without increasing the number of members to be combined with the thermal head. .

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating a configuration of an image forming apparatus.

FIG. 2 is an explanatory diagram of a support structure of a thermal head on an upper frame.

FIG. 3 is a perspective view of a thermal head.

FIG. 4 is a front view of a printing unit.

FIG. 5 is an explanatory diagram of a combination state of a thermal head and a platen roller.

[Explanation of symbols]

1 facsimile machine, 4 document tray, 7
Platen roller, 8 reading unit, 10 paper feeding unit,
11 paper cassette, 20 printing unit, 21
Ink ribbon, 22 feeding roll, 23 take-up roll, 25 platen roller, 26 axis,
29 guide groove, 30 upper frame, 35 thermal head holding part, 36 upper plate member, 37
Engagement hole, 38 side plate member, 39 locking hole, 40
Thermal head, 41 Spring, 42
Bracket, 43 upper engaging member, 44 protrusion,
45 side locking member, 46 claw member, 47 positioning pin.

Claims (3)

[Claims] 1. An image forming apparatus in which a device such as a thermal head and an opposing member such as a platen roller are arranged in close contact with each other, and the device is supported by a frame so that the device can be separated from and contacted with the opposing member. The image forming apparatus according to claim 1, wherein a resin mounting member is used to support the device on a frame. 2. The image forming apparatus according to claim 1, wherein the resin-made attachment member integrally forms an elastic claw member for attachment to a frame. 3. The image forming apparatus according to claim 1, wherein the attachment member integrally includes a pin member for positioning with respect to an opposing member.