JPH0764405A - Recording device - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a recording apparatus using an intermediate transfer drum, capable of preventing vibration when the vicinity of a fixture of the intermediate transfer drum contacts a photosensitive drum. According to the recording apparatus of the present invention, a drum 32, a flexible material 33 that covers the outer periphery of the drum 32, a film 34 that covers the flexible material 33 and is fixed to the drum 32 by a fixture 35, The intermediate transfer drum 31 provided with the guides 36 provided at both ends of the drum 32 is used so that the fixed portion of the film 34 does not contact the photosensitive drum. Guide 3
The surface of 6 is covered with a soft material 37.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording apparatus of the type which forms an image on a photoconductor and transfers the image onto an intermediate transfer drum.

[0002]

2. Description of the Related Art FIG. 4 shows an example of a color recording apparatus using a single photosensitive drum and an intermediate transfer drum, and the details of its construction and operation are as follows. The feeding operation of the recording paper is started by a recording command from a control unit (not shown). The recording paper 100 is stored in the storage unit 1, taken out by the pick roller 2 that operates in response to a recording command, and conveyed to the nip portion of the registration roller 3.

On the other hand, around the photosensitive drum 4, a charger 5 is provided.
And an exposure system 6, and Y, M, C, K (yellow, magenta, cyan, black) color developing devices 7 _Y , 7 _M ,
And 7 _C, 7 _K, and a cleaner blade 8 is provided by a known electrophotographic process, Y for each drum revolution, M, C, toner images in the order of K is formed on the photosensitive drum 10.

An intermediate transfer drum 9 is opposed to the photosensitive drum 4, and the intermediate transfer drum 9 rotates while contacting the photosensitive drum 4. The Y, M, C, and K toner images formed on the photosensitive drum 4 as described above are transferred onto the intermediate transfer drum 9 each time they are formed (primary transfer). The surface of the photosensitive drum 4 after the transfer is cleaned by the cleaner 8.

When the transfer of all four colors of Y, M, C, and K onto the intermediate transfer drum 9 is completed, the registration roller 3 rotates, and the recording paper 100 is placed between the intermediate transfer drum 9 and the transfer roller 10 opposite thereto. send. Here, the transfer roller 10 is pressed against the intermediate transfer drum 9 via the recording paper 100, and the color images are collectively transferred to the recording paper 100 (secondary transfer).

When the transfer onto the recording paper 100 is completed, the transfer roller 10 is separated from the intermediate transfer drum 9. Also,
The cleaner blade 11 is separated from the intermediate transfer drum 9. The recording paper 100 is finally sent to the fixing device 12, and the color toner image is fixed on the recording paper 100 by the heat and pressure of the fixing roller 13 and the pressure roller 14. By repeating this operation, color recording is performed one after another.

A conventional intermediate transfer drum 21 used in such a recording apparatus is shown in FIG. 5 (FIG. 5A is a schematic perspective view and FIG. 5B is a detailed side view). The intermediate transfer drum 21 has a structure in which a film 24 is fixed to a surface of a drum 22 around which a flexible material 23 is wound by a fixture 25 in order to secure sufficient contact with the photosensitive drum in the longitudinal direction.

At this time, the radius of the surface of the intermediate transfer drum 21 rapidly changes in the vicinity of the fixture 25 as shown by the dotted line in FIG. In order to prevent the vibration generated by this, conventionally, a guide 26 is attached to the side surface of the drum 22, and the guide 26 is brought into contact with a portion outside the printing region at both ends of the photosensitive drum in the vicinity of the fixture 25. The radius of the surface of the drum 22 is made constant. This intermediate transfer drum is shown in Japanese Patent Application No. 5-62378 already proposed by the present applicant.

[0009]

However, since the soft material 23 sinks due to the contact of the drums with each other, the guide 26 may be protruded at the time of contact and vibration may occur.
To prevent this, it is possible to lower the guide setting position in anticipation of the amount of subsidence, but the mechanical characteristics of the intermediate transfer drum surface and guide surface are different, so the rotational behavior of the drum changes before and after contact with the guide. However, vibration cannot be suppressed.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a recording apparatus capable of preventing vibration when the vicinity of a fixing member of an intermediate transfer drum contacts a photosensitive drum.

[0011]

In order to achieve the above object, according to the present invention, a drum, a flexible member covering the outer periphery of the drum, and a fixing member provided over the flexible member and fixed to the drum. In an electrophotographic recording apparatus using an intermediate transfer drum provided with a film and guides provided at both ends of the drum so that a fixed portion of the film does not contact the photosensitive drum, a surface of the guide is made of a soft material. The structure (first structure) is characterized by being covered.

Further, the softening material on the guide surface of the recording apparatus of the first construction is covered with one or more layers of film (second construction).

Further, the guide of the recording apparatus having the above-mentioned first configuration or the second configuration has a spring constant such that the amount of depression of the drum surface is constant when the guide contacts the photosensitive drum and when the guide does not contact the photosensitive drum. The configuration (third configuration) is characterized by being supported by a biasing means.

[0014]

Since the surface of the guide is covered with the soft material, the impact when the guide contacts both ends of the photosensitive drum in the vicinity of the fixing tool is softened. Therefore, it is possible to prevent the occurrence of vibration, which has been a problem in the past, and to prevent the fluctuation of the drum drive source load.

Further, in the case of the second structure, since the surface of the soft material of the guide, which is weak against friction due to contact, is covered with the film, the durability is improved. If the film has a plurality of layers, the apparent spring constant on the drum contact surface can be the same or close to the drum surface and the guide surface, and the drum rotation can be stabilized. This effect is the third
When the urging means is also used in the above configuration, it becomes more remarkable.

[0016]

Embodiments of the present invention will be described below with reference to FIGS.

FIG. 1 shows a first embodiment.

FIG. 1 is a side view showing the structure of the intermediate transfer drum 31 of this embodiment. The intermediate transfer drum 31 covers the surface of a flexible material 33 covering the outer periphery of the drum 32 with a film 34, and fixes the film 34 to a fixture. In addition to being fixed by the guide 35, guides 36 are attached to the side surface of the drum 32 so as to come into contact with the portions outside the printing area at both ends of the photosensitive drum in the vicinity of the fixture 35.

The surface of the guide 36 is covered with a soft material 37. This softens the impact at the time of the collision between the guide and the photosensitive drum in the vicinity of the fixture 35, which has been a problem in the past, and prevents the occurrence of vibration. It has become possible.

The shape of the guide 36 is arcuate at the portion where the photosensitive drum does not contact the transfer drum, and the amount of sinking of the flexible member 37 is at other portions at the transitional portions A and B where the guide and the photosensitive drum are in contact with each other. If it is set to be the same as, it is more effective because the distance between the two drums can be made constant during rotation of the photosensitive drum over the entire circumference of the intermediate transfer drum.

FIG. 2 shows a second embodiment.

FIG. 2 is a side view showing the structure of the intermediate transfer drum 41 of the present embodiment. In the intermediate transfer drum 41, the surface of the flexible member 37 that covers the surface of the guide 36 similar to the previous example is further covered with the film 42. It is configured.

In the case of this example, since the soft material 37, which is weak against friction due to contact, is covered with the film 42 like the outer circumference of the drum 32, the durability of the intermediate transfer drum can be improved in addition to the effect similar to the previous example. The effect that it can be improved is also obtained. Also, the contact spring constant on the guide side can be easily changed by changing the thickness of the film or the number of film layers.

FIG. 3 shows a third embodiment.

FIG. 3 is a side view showing the structure of the intermediate transfer drum 51 of this embodiment. The intermediate transfer drum 51 includes a guide 36 which is covered with a flexible material 37 and a film 42 and is supported by the drum 32 so as to be vertically movable. , And is supported by a spring (biasing means) 52. The spring 52 is mounted in an elongated hole 53 provided in the guide 36, and one end of the spring 52 is locked by a pin 54 projecting from the side surface of the drum 32 to urge the guide 36 upward.

With this structure, it is possible to set the contact spring constant on the guide side more easily.

[0027]

As described above, according to the present invention, it is possible to suppress the load fluctuation of the drive motors of the photosensitive drum and the intermediate transfer drum to eliminate the vibration, and in particular, the color misregistration and the print unevenness in the color recording apparatus. Can be improved.

[Brief description of drawings]

FIG. 1 is a side view showing a structure of an intermediate transfer drum according to a first embodiment of the present invention.

FIG. 2 is a side view showing the structure of the intermediate transfer drum of the second embodiment of the present invention.

FIG. 3 is a side view showing a structure of an intermediate transfer drum of a third embodiment of the present invention.

FIG. 4 is a side view showing an outline of a color recording apparatus using an intermediate transfer drum.

FIG. 5 is a structural explanatory view of a conventional intermediate transfer drum.
FIG. 5A is a perspective view showing the outline, and FIG. 5B is a side view showing the details.

[Explanation of symbols]

 31, 41, 51 Intermediate transfer drum 32 Drums 33, 37 Flexible material 34, 42 Film 35 Fixing tool 36 Guide 52 Spring (biasing means)

Claims (3)

[Claims] 1. A drum (32), a flexible member (33) covering the outer periphery of the drum (32), and a fixing member (35) provided over the flexible member (33) to attach the drum (32) to the drum (32). Film to be fixed (34)
A guide (36) provided at both ends of the drum (32) so that the fixed portion of the film (34) does not come into contact with the photosensitive drum, and an electrophotographic system using an intermediate transfer drum (31) In the recording device, the surface of the guide (36) is covered with a soft material (37). 2. A flexible member (3) for a recording apparatus according to claim 1.
A recording device characterized in that the surface of 7) is covered with one or more films (34). 3. The guide (36) of the recording apparatus according to claim 1 or 2, the guide (3) for the photosensitive drum.
A recording apparatus characterized by being supported by an urging means (52) having a spring constant such that the amount of depression of the drum (32) is constant during contact and non-contact of 6).