JPH04316879A - Image formation device - Google Patents

Abstract

PURPOSE:To form high quality images over a long period of time regardless of the failure of life of a thermal head or the contamination of a member around the thermal head. CONSTITUTION:A finer small-diameter part 108a than a support shaft 108 is formed at one end of the support shaft 108 for a head unit 100. A notched part has a constricted part which has the same size as a hole having the same diameter as the support shaft 108 and as the diameter of a small diameter part 108a, and further communicates with the hole. This notched part is formed on a rear frame 47 and also a hole which allows passage of a screw 50 for fixing the other end of the support shaft 108 so that the other end can be released is formed on a front frame 46. Subsequently, the assembly and maintenance of this device are easy.

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 that forms an image on a recording medium using a recording head.

0002

BACKGROUND OF THE INVENTION Conventionally, an ink sheet formed by arranging ink portions of a plurality of colors is pressed onto a recording sheet on a platen roller at a recording position and selectively heated, thereby printing an image on a recording sheet. It has a recording head such as a thermal head that can move within a small range between a recording position and a non-operating position, and this head repeatedly presses and moves away from the recording sheet on the platen roller to record one sheet. 2. Description of the Related Art An image forming apparatus that forms a color image by combining images of a plurality of colors on a sheet is known.

[0003] In such an image forming apparatus, an ink sheet is pressed against and separated from a recording sheet by high pressure, and
Thermal heads, which generate heat at high temperatures and repeatedly switch current on and off at high speed, are subject to the most wear and tear among other devices, and have a high probability of failure. Furthermore, when the image forming apparatus is used frequently, the thermal head reaches the end of its life earliest. Therefore, in order to repair or replace the thermal head, the thermal head or the head unit that holds the thermal head is often attached and detached from the support frame of the image forming apparatus.

An example of such an image forming apparatus will be explained below using FIG. 15.

A head unit 400 holding a thermal head 401 is rotatably provided around a rotation shaft 402 . The head unit 400 and an arm mechanism 404 that rotates around a head drive shaft 403 are connected via a link mechanism 405. This link mechanism 405 is coupled to both the head unit 400 and the arm mechanism 404 by press fitting. The rotating shaft 402 and the head driving shaft 40
3 is incorporated into a support frame (not shown).

When the head unit 400 is removed from this image forming apparatus, the press-fit connection of the link mechanism 405 must be removed, and it must be press-fit again during assembly.
02 is incorporated into the support frame, it is very difficult to attach and detach the head unit 400.

[0007] In other general image forming apparatuses as well, the thermal head is integrally incorporated into the support frame of the apparatus through various members, and it is extremely difficult to attach and detach it after it has been shipped to the market. The lifespan of the thermal head often extends to the lifespan of the image forming apparatus itself. Even if it is possible to attach and detach the thermal head, it is very time-consuming because it requires removing many screws, E-rings, etc.

Further, jams and paper jams often occur near the thermal head and platen roller, which are the heart of the image forming apparatus. When the platen roller is made of rubber, the coefficient of friction decreases due to dirt such as paper powder and dust, so frequent maintenance and cleaning are required. However, the space near the thermal head and platen roller is extremely small, and it takes a lot of time to disassemble, repair, and clean it.

[0009] As a means to eliminate such drawbacks, for example, Japanese Patent Publication No. 56-19838 and Japanese Patent Application Laid-Open No. 58-134
There is also a method of using a holding mechanism for a thermal head or a head unit in an image forming apparatus, which is disclosed in Japanese Utility Model Publication No. 763, Japanese Utility Model Publication No. 62-35839, Japanese Utility Model Publication No. 63-3822, and the like. To give an overview of the devices described in these publications, firstly, in the device of Japanese Patent Publication No. 56-19838, the thermal head is urged in the direction of contacting the recording sheet, and the thermal head is pressed against the recording sheet against this urging force. At least in the standby state, the thermal head is brought into contact with the recording sheet by a mechanism for separating the thermal head from the recording sheet. Japanese Patent Application Publication No. 5
In the device disclosed in Japanese Patent No. 8-134763, the shaft mounting portion of the head unit is formed in a concave shape and is rotatably and detachably attached to a rotatable upper cover. Jitsukai 62-35
In the device disclosed in Japanese Patent No. 839, the thermal head is urged in the direction of contacting the platen roller, and the thermal head is separated by an eccentric cam against this urging force. In the apparatus disclosed in Japanese Utility Model Publication No. 63-3822, a link mechanism is used to press the thermal head against the platen roller.

However, even if such means are used, it is difficult to remove the thermal head from the apparatus in order to repair or replace the thermal head or to repair or replace parts around the thermal head such as the platen roller. After removing exterior parts such as the front cover and top cover to expose the print unit, which includes the head unit, paper feed unit, paper ejection unit, paper guide, etc., remove the connectors and harnesses connected to this print unit. The print unit must be removed from the support frame, and the head moving means for moving the entire head unit including the thermal head and the connectors must be removed. Therefore, even if the above-mentioned method is used, it still takes a lot of effort and man-hours, and since the parts to be disassembled extend to parts that are not directly related to the head unit, there is a risk of making mistakes in assembly or wiring when reassembling the head unit. There is.

An object of the present invention is to provide a system that is easy to assemble and maintain, and can form a large number of good images over a long period of time, regardless of the failure and lifespan of the thermal head or the dirt on the parts surrounding the thermal head. An object of the present invention is to provide an image forming apparatus.

0012

[Means for Solving the Problems] Accordingly, an image forming apparatus according to the present invention includes a support frame, a support frame supported by the support frame, movable between a recording position and a non-operating position, and a recording medium at the recording position. The recording head is provided with a recording head that forms an image on the recording head, and a head moving means that moves the recording head, the head moving means is separated from the recording head when the recording head is in a non-operating position, and the recording head is moved. It is characterized in that it is attached to the support frame so that it can be attached to and detached from it independently.

[0013]

[Operation] When the recording head is in the non-operating position, the head moving means is separated from the recording head, and the recording head can be attached to and detached from the support frame independently.

[0014]

Embodiment A first embodiment of an image forming apparatus according to the present invention will be described below with reference to FIGS. 1 to 11.

As shown in FIG. 1A, the housing 1 of the image forming apparatus of this embodiment is provided with an operation panel 1a and a front door 1b attached to be openable and closable on the front side. The housing 1 includes a paper feed cassette section 200 for stacking recording sheets before image formation, and a paper ejection tray 300 installed above the cassette section 200 for stacking recording sheets on which image formation has been completed. hold possible. As shown in FIG. 1B, a platen roller is connected to the inside of the front door 1b so that the platen roller can be manually rotated outside the apparatus when a recording sheet is jammed inside the apparatus. Platen knob 1
c is provided.

The general structure of the image forming apparatus of this embodiment having such an appearance will be explained with reference to FIG. First, the platen roller is indicated by the reference numeral 2 in the figure. This platen roller 2 is rotatably provided at a recording position where an image is formed on a recording sheet. This platen roller 2 is
The printing section 8 is constituted by the first and second pinch rollers 4 and 6, which are biased against each other by biasing means (not shown). A head unit 100 having a thermal head 102 serving as a recording head is installed on the side facing the print section 8 . This head unit 100 is driven by a head unit lifting arm 104, and this driving causes the thermal head 102 to
is moved between a non-operating position and the recording position. This head unit elevating arm 104 constitutes a part of a head unit elevating mechanism which is a head moving means. Between the print section 8 and the head unit 100,
An ink sheet cartridge 10 is attached. In this ink sheet cartridge 10, an ink sheet 12 is wound, in which three ink parts of different colors are arranged at equal intervals. The thermal head 102 selectively generates heat on the recording sheet via the ink sheet 12 to form an image.

In the figure, on the right side of the ink sheet cartridge 10 are the paper feed cassette section 200 and the paper output tray 300.
is installed. The ink sheet cartridge 1
0 and the paper feed cassette section 200 constitute a paper cassette 160 having an integral structure, as will be described later. Above the paper feed cassette section 200, recording sheets before image formation are conveyed from the paper supply cassette section 200 to the upstream side, that is, the printing section 8, and recording sheets after image formation are further conveyed from the printing section 8. Upstream side, that is, the paper output tray 30
A paper feed/discharge roller 14 that conveys the paper to the paper is disposed. This paper discharge paper feed roller 14 selectively transports only the topmost recording sheet stacked in the paper feed cassette section 200 . Below the paper feed cassette section 200, there is a tongue 15 that lifts the recording sheets stacked therein and brings them into contact with the paper feed/discharge roller 14 to assist in transporting the recording sheets to the upstream side.
0 is set. Note that reference numeral 16 in the figure indicates a cooling fan that cools the thermal head 102.

Next, the detailed configuration of the device in FIG. 2 is as follows.
This will be explained using FIGS. 3 and 4.

As shown in FIG. 3, the platen roller 2
A first paper guide 18 is attached to the housing 1 on the downstream side of the first pinch roller 4 so as to guide recording sheets from the paper feed cassette 200 therebetween. Above the first paper guide 18, that is, on the downstream side of the platen roller 2 and the second pinch roller 6,
A second paper guide 20 is attached to the housing 1 to guide the recording sheet from between these to the paper discharge tray section 300. A registration sensor 22 is installed above the second paper guide 20 to detect the recording sheet being conveyed and to start printing. The registration sensor 22 also has the function of detecting whether a recording sheet on which image formation has been completed is conveyed to the paper discharge tray 300. An ink sheet sensor 24 is fixed to the housing 1 above the ink sheet cartridge 10 for detecting the beginning of the ink sheet 12 wound inside the cartridge.

As shown in FIG. 4, the paper feed and discharge roller 1
Above 4, there is a paper ejection pinch unit that rotatably holds a paper ejection roller 202 that assists in conveying the recording sheet to the downstream side, and brings this roller into contact with and separates from the paper ejection paper feed roller 14. 200 is attached. A push-out arm 250 is provided on the downstream side of the paper ejection pinch unit 200 for pushing forward the recording sheet conveyed to the paper ejection tray 300 so that it can be easily taken out of the housing 1.

The general operation of the first embodiment of the image forming apparatus constructed in this manner will be described below.

As shown in FIG. 4, the topmost one of the recording sheets stacked in the paper feed cassette 200 is lifted by the tongue 150 which is linked to the movement of the head unit 100. The tongue 150 brings the recording sheet into contact with the paper feed/discharge roller 14 . In this state, the paper feed/discharge roller 14 is rotated, and the recording sheet is conveyed to the print section 8 located at the recording position. The recording sheet that has been conveyed is shown in Figure 3.
As shown in FIG. 2, the ink sheet passes between the first paper guide 18 and the end of the ink sheet cartridge 10 and reaches the print section 8, and stops when the leading edge is bitten by several millimeters (print start position). Here, the ink sheet 12 is slightly wound up to perform cueing. Next, the head unit 100 is moved from the non-operating position to the recording position by driving the arm 104 for raising and lowering the head unit, and presses the recording sheet against the platen roller 2 via the ink sheet 12. In this state, the platen roller 2 rotates and image formation for the first color is started.

After the first color image formation is completed, the head unit 100 is returned to the non-operating position, and the platen roller 2
rotates in the opposite direction to return the recording sheet to the printing start position. Simultaneously with this operation, the next color on the ink sheet 12 is located. By repeating this operation three times, a three-color image is formed on the recording sheet.

After image formation, the head unit 100 returns to the non-operating position and the ink sheet 12 is slightly rolled to remove slack. In this state, the platen roller 2 rotates, and the recording sheet on which image formation has been completed is moved to the first paper guide 18.
and the second paper guide 20, and the paper feed/discharge roller 1
It is transported to around 4. At this point, the paper ejection pinch unit 200 contacts the paper feed and ejection rollers 14 and pinches the recording sheet between them. Then, the paper feed and discharge rollers 14 rotate, and the recording sheet on which the image has been formed is conveyed to the paper discharge tray 300. Thereafter, the push-out arm 250, which operates in conjunction with the head unit 100, pushes the recording sheet conveyed to the paper discharge tray 300 forward, making it easier to take out the recording sheet from the housing 1.

Next, the ink sheet cartridge 10 and the paper feed cassette section 200 will be explained in detail with reference to FIGS. 5 and 6.

As shown in FIG. 5, the ink sheet cartridge 10 and the paper feed cassette section 200 constitute a paper cassette 160 having an integral structure. On one side of the ink sheet cartridge 10, as shown in FIG. 6A, an attachment/detachment sensor 25 is installed to detect attachment/detachment of the paper cassette 160 to/from the housing 1. This attachment/detachment sensor 25 also has a function of detecting the type of recording sheet (for example, OHP sheet, sticker paper, standard paper, etc.) in the paper feed cassette section 200. This attachment/detachment sensor 25 has protrusions 25a and 25b. These protrusions 25a and 25b correspond to the three discrimination holes 10c formed on one side of the ink sheet cartridge 10, respectively, as shown in FIG. 6(B). These protrusions 25a, 2
5b is pushed into the discrimination hole 10c when the paper cassette 160 is installed in the housing 1.
It is determined whether the paper cassette 160 is attached. These discrimination holes 10c make it possible to discriminate the type of recording sheet in the paper feed cassette 200. Also, as shown in FIG. 6(C),
The ink sheet cartridge 10 includes a paper cassette 1.
Positioning holes 10a and 10b are formed for positioning the housing 1 when the housing 1 is mounted thereon.

Paper cassette 160 configured in this way
When the ink sheet cartridge 10 is inserted into the housing 1, pins (not shown) protruding from the housing 1 fit into the positioning holes 10a, 10b of the ink sheet cartridge 10, and the front side position is determined, and the torque limiter (not shown) and the ink sheet cartridge The winding core No. 10 is loosely engaged and positioned. At the same time, the protrusion 25a of the sensor 25 is pushed in to detect that the paper cassette 160 has been inserted into the housing 1, and the other two protrusions 25b are inserted into the discrimination hole 1.
0c, the protrusions in the part with the hole are not pushed in, but the protrusions in the part with the hole are pushed in, and depending on the position and number of the protrusions pushed in, the paper feed cassette 20
The type of recording sheet within 0 is determined.

Next, the detailed configuration of the head unit 100 will be explained using FIGS. 7A and 7B.

First, as shown in FIG. 7B, the head unit 100 is rotatably supported by the print unit about a support shaft 108. As shown in FIG. This head unit 100 rotatably holds the thermal head 102 by a head holding mechanism 110. This thermal head 102 is urged by a head pressing mechanism 112 so as to press it against the platen roller 2. This head pressing mechanism 112 includes a shaft 114.
A link mechanism 116 is rotatably provided. This link mechanism 116 moves the head unit 100 up and down in conjunction with the movement of the head unit lifting arm 104, and also presses the thermal head 102 against the platen roller 2 via the head pressing mechanism 112. At this time, the hook portion of the arm 104 for raising and lowering the head unit engages with both ends of the shaft 114 of the link mechanism 116, thereby raising and lowering the entire head unit 100. In addition,
(A) Reference numeral 118 in the figure indicates a pinch roller that causes the ink sheet 12 to align with the platen roller 2. Further, at one end of the support shaft 108, specifically at the end on the rear frame side which will be described later, there is a small diameter portion 108 which is thinner than the support shaft 108.
a is formed. For convenience, a portion outside the small diameter portion 108a is designated by the reference numeral 108b as a large diameter portion. On the other hand, the other end of the support shaft 108, specifically, the end on the front frame side, which will be described later, is threaded so that a screw 50, which will be described later, can be screwed into the end.

Next, details of the head unit elevating mechanism which is the head moving means in this embodiment will be explained with reference to FIG.

As shown in FIG. 8, the head unit elevating arm 104 is fixed onto a head drive shaft 106. As shown in FIG. This head drive shaft 106 is rotatably supported between a front frame 46 and a rear frame 47. These front frame 46 and rear frame 47 constitute a support frame. On the outside of the rear frame 47, a drive gear 32 consisting of a spur gear 28 and a worm wheel 30 is connected to the head drive shaft 10.
6 is fixed on top. The worm wheel 30 is connected to a worm shaft 36 of a motor 34 supported by a drive frame 48.
It meshes with the.

The general operation of the head unit elevating mechanism constructed in this manner will be described below.

When the image forming operation is started, the motor 34
is rotated. As shown in FIG. 8, the driving force of the motor 34 is transmitted to the worm wheel 30 and spur gear 28 of the drive gear 32 attached to the head drive shaft 106 via the worm shaft 36, so that the head drive shaft 106 The arm 104 for lifting and lowering the head unit is rotated.
drive. This head unit lifting arm 104
engages with the link mechanism 116 of the head unit 100 to drive the entire head unit 100.

Next, using (A) to (E) in FIG.
The moving operation of the head unit 100 between the non-operating position and the recording position, that is, the raising and lowering operation will be schematically explained.

First, during image formation standby and when the power is turned off, the link mechanism 116 of the head unit 100 and the head unit lifting arm 104 are separated from each other, as shown in (A). That is, when the thermal head 102, which is a recording head, is in the non-operating position, the head unit elevating arm 104, which is a part of the head moving means, is separated from the head unit 100 that holds the thermal head 102. Therefore, when the head unit 100 is taken out from the housing 1, there is no need to remove the head unit 100 from the head unit elevating mechanism, so the head unit 100 can be easily attached and detached.

(B) shows the arm 1 for lifting and lowering the head unit.
04 is shown in contact with the link mechanism 116. From here, the actual lifting and lowering of the head unit 100 begins.

(C) is the arm 1 for lifting and lowering the head unit.
The hook part of 04 is the shaft 114 of the link mechanism 116
The shaft 114 is shown pushing up the head unit 100 while sliding on the hook portion of the arm 104 for lifting and lowering the head unit.

(D) shows a state in which the head unit 100 is in contact with the platen roller 2. In this state, the elevating and lowering operations of the head unit 100 are completed, and then the pressing operation is about to begin.

In (E), the head unit lifting arm 104 further rotates from the state in (D), and the link mechanism 116
shows a pressing state in which the head unit 100 rotates relative to the head unit 100 and presses the head unit 100 against the platen roller 2.

By repeating these operations (A) to (E) three times, three-color images are formed on one recording sheet, thereby forming a color image. After image formation, the state returns to the state shown in (A) again, and the head unit elevating arm 104 and the link mechanism 116 are in a separated state.

Next, a mechanism for attaching and detaching the head unit 100 in this embodiment will be explained using FIGS. 10 and 11.

As shown in FIGS. 10A, 10C, and 10E, the rear frame 47 is formed with a notch 47a that is partially constricted, and the width of the constricted portion is as follows. It has the same diameter as the small diameter portion 108a shown in FIG. 10B. The diameter of the hole portion of the notch 47a is the same as that of the support shaft 108 and the large diameter portion 108b. On the other hand, as shown in FIG. 11, the front frame 46 has a hole formed therein to support the other end of the support shaft 108 of the head unit 100.

[0043] The head unit 100 is attached to the housing 1.
When installing the support shaft 108 inside, first insert the small diameter portion 108a of the support shaft 108 into the notch 47a of the rear frame 47, as shown in FIGS. 10(C) and 10(D). At this time, the end of the support shaft 108 on the front frame 46 side is not fitted into the front frame 46. (C) in Figure 10
From the state shown in FIG.
Match the center of 8. After that, the support shaft 108 is moved along the axis toward the front frame 46, and as shown in FIG.
As shown in (E) and (F), the large diameter portion 108b and the hole portion of the notch 47a are fitted together, and the support shaft 1
The other end of 08 is fitted into the hole of the front frame 46. In this state, the other end of the support shaft 108 is drawn in from the outside of the front frame 46 with a screw 50 as shown in FIG. 11, and the head unit 100 is fixed. To remove it, conversely, remove the screw 50, slide the support shaft 108, and after the small diameter portion 108a intersects the rear frame 47, lift the head unit 100 and remove it.

As described above, according to this embodiment, the mechanism for raising and lowering the head unit is normally separated from the head unit during image formation, and the head unit can be attached and detached independently by removing one member. Since the configuration allows the thermal head to be replaced and attached/detached easily in the market. Furthermore, by removing the paper cassette and head unit at the same time, a large space can be secured near the platen roller, making it easy to repair and clean the area around the platen roller.

Next, an image forming apparatus according to a second embodiment of the present invention will be explained with reference to FIGS. 12(A) and 12(B). Note that the same members as those in the first embodiment are indicated by the same reference numerals, and explanations thereof will be omitted. The third and fourth embodiments will be described in the same manner below.

As shown in FIG. 12, the image forming apparatus of the second embodiment uses a fixed coil spring 52 in place of the screw 50 in the attachment/detachment mechanism of the head unit 100 of the first embodiment. A support shaft 108 is inserted into the fixed coil spring 52 between the end of the head unit 100 on the rear frame 47 side and the rear frame 47 . The configuration is such that the head unit 100 is urged toward the front frame 46 side, the head unit 100 is fixed to the front frame 46 and the rear frame 47, and the head unit 100 is attached to the housing 1. The configuration other than this is the same as that of the first embodiment.

When installing the head unit 100 in the image forming apparatus of the second embodiment configured as described above, first, as shown in FIG. The small diameter portion 108a of the shaft 108 is inserted into the notch of the rear frame 47, and is slid along the axis of the support shaft 108 toward the front frame 47. Then, as shown in FIG. 12(B), with the shaft and frame fitted together, the fixed coil spring 52 is released from being held down, and the head unit 100 is fixed. To remove it, conversely, press the fixed coil spring 52 to contract it, slide the support shaft 108, and after the small diameter portion 108a intersects the rear frame 47, lift the head unit 100 and remove it.

Next, an image forming apparatus according to a third embodiment will be explained using FIGS. 13(A) and 13(B). The image forming apparatus of the third embodiment uses a fixed leaf spring 54 in place of the fixed coil spring 52 in the attachment/detachment mechanism of the head unit 100 of the second embodiment. The base end of the fixed plate spring 54 is fixed to the outside of the rear frame 47, as shown in the figure. The other end of this fixed leaf spring 54 is attached to the support shaft 10.
8 on the rear frame 17 side to the front frame 48
It is biased towards the side. The other configurations are the same as in the first embodiment.

When the head unit 100 is attached to the housing of the image forming apparatus of the third embodiment configured as described above, as shown in FIG. The small diameter portion 108a of the support shaft 108 is inserted into the notch of the rear frame 47, and is slid along the axis of the support shaft 108 toward the front frame 47. Then, as shown in FIG. 13(B), with the shaft and frame fitted together, the fixing leaf spring 54 is released from being held down, and the head unit 100 is fixed. This other effect is due to the second
This is almost the same as the example.

Next, the image forming apparatus of the fourth embodiment is shown in FIG.
4 will be used for explanation. The head unit 100 is fixed by a magnet without using the fixing spring in the second and third embodiments.
The configuration is such that it is fixed.

The fixed magnet 56 is fixed to the end of the support shaft 108 of the head unit 100 on the front frame 46 side. This fixing magnet 56 is attracted to the front frame 46 and fixes the support shaft 108 to the front frame 46 when the head unit 100 is attached to the front frame 46 and the rear frame 47. The other configurations are the same as in the first embodiment.

Note that each fixed spring 5 of the second to fourth embodiments
2 and 54 and the fixed magnet 56 have sufficient strength to prevent the head unit 100 from coming off the front frame 46 and rear frame 47 and falling due to vibrations and shocks that the image forming apparatus receives normally or temporarily. Furthermore, in all of the four embodiments described above, a bottom plate (not shown) for attaching and detaching the head unit is provided at the bottom of the apparatus, and by removing this bottom plate, the head unit can be directly accessed. Further, in the above embodiment, the ink sheet is of a plurality of colors, but it may be of a single color.

The present invention is not limited to the above-mentioned embodiments, and many embodiments and modifications are possible.

[0054]

Effects of the Invention According to the present invention, it is possible to form a large number of good images for a long period of time, regardless of the malfunction or life of the thermal head or the dirt on the parts around the thermal head, and the assembly and maintenance are easy. A simple image forming apparatus can be provided.

[Brief explanation of drawings]

FIG. 1 includes (A) and (B), where (A) is a perspective view showing the appearance of an image forming apparatus according to a first embodiment of the present invention, and (B) is a perspective view of the apparatus shown in (A). FIG. 3 is a perspective view showing the front door in an open state.

FIG. 2 is a side view showing a schematic configuration of the device in FIG. 1;

3 is an enlarged side view showing the configuration around the ink sheet cartridge of the apparatus shown in FIG. 2. FIG.

FIG. 4 is an enlarged side view showing the configuration around a paper feed cassette section and a paper discharge tray section of the apparatus shown in FIG. 2;

FIG. 5 is a side view of the paper cassette of the device in FIG. 2;

FIG. 6 is a diagram including (A), (B), and (C) showing the ink sheet cartridge of the paper cassette in FIG. 5, where (A) is a top view thereof and (B) is a front view thereof. ,(
C) is a rear view.

FIG. 7 includes (A) and (B), where (A) is a front view showing the head unit, and (B) is a side view of (a).

8 is a bottom view showing a head unit elevating mechanism for elevating and lowering the head unit of the apparatus in FIG. 2. FIG.

[Figure 9] Figure 9 shows (A), (B), (C), (D), (E
), and is a side view of the head unit and the arm for lifting and lowering the head unit for explaining the lifting and lowering operation of the head unit.

[Figure 10] Figure 10 shows (A), (B), (C), (D),
It is a diagram including (E) and (F), showing a state in which the support shaft of the head unit and the rear frame are fitted, and (A) and (F).
C) and (E) are front views thereof, and (B), (D), and (F) are side views corresponding to (A), (C), and (E), respectively.

FIG. 11 is a front view showing a state in which the head unit of the apparatus shown in FIG. 2 is installed between a front frame and a rear frame.

FIG. 12 includes (A) and (B) and shows a head unit attachment/detachment mechanism in the image forming apparatus of the second embodiment, and (A) shows the head unit between the front frame and the rear frame. A top view showing the installed state;
(B) is a top view showing a state in which the head unit is attached.

FIG. 13 includes (A) and (B) and shows the attachment/detachment mechanism of the head unit in the image forming apparatus of the third embodiment, and (A) shows the attachment/detachment mechanism of the head unit between the front frame and the rear frame. A front view showing the installed state,
(B) is a front view showing a state in which the head unit is attached.

FIG. 14 is a top view showing a head unit attachment/detachment mechanism in the image forming apparatus of the fourth embodiment.

FIG. 15 is a side view showing the configuration of a conventional image forming apparatus.

[Explanation of symbols]

34...Motor, 46...Front frame, 47...Rear frame, 47a...Notch, 100...Head unit,
102...Thermal head, 104...Arm for lifting and lowering the head unit, 106...Head drive shaft, 108...Support shaft, 114...Shaft.

Claims (1)

[Claims] Claims: 1. A support frame, a recording head detachably supported by the support frame, movable between a recording position and a non-operating position, and forming an image on a recording medium in the recording position; In an image forming apparatus comprising a head moving means for moving the head, the head moving means is separated from the recording head when the recording head is in a non-operating position, and the recording head is independently attached to and detached from the support frame. An image forming apparatus characterized by: