Electrostatic recording apparatus having a cooled and insulated waste toner container

An electrostatic recording appartus having a thermally fixing apparatus and an image forming case adapted to accomodate a unit having a toner container disposed adjacent to a thermally fixing apparatus. An open space is provided between the wall of the image forming case and the wall of the toner container. At the upper and lower portions of the open space, vent ports are preferably provided. Heat insulating material is effectively applied to the walls defining the open space.

FIELD OF THE INVENTION AND RELATED ART STATEMENT 
The present invention relates to an electrostatic recording apparatus 
including a thermally fixing means and an image forming case accomodating 
a unit having a container for toner adjacent to said thermally fixing 
means. 
BACKGROUND OF THE INVENTION 
Recently, such electrostatic recording apparatuses as an electro-photo 
copier, a laser printer and the like have been made more and more compacts 
and propagation of personal use of such electrostatic recording 
apparatuses requiers higher reliability in respect of the quality. In an 
electrostatic recording apparatus, a toner image formed on a 
photosensitive member in the course of the electrostatic photography 
process is transferred to a transfer paper which is then thermally fixed 
to bear a record. After the transfer process, the toner left on the 
photo-sensitive member is removed by means of a cleaning blade or a 
cleaning roller and recovered and stored in a waste toner container. 
In a recording apparatus of a compact type, the image forming system mainly 
consisting of a photo-sensitive member and a thermally fixing apparatus 
are disposed quite closely to each other. With regard to the material for 
the respective apparatuses, plastic molded members are frequently utilized 
in view of reduced cost, light weight and so forth. Furthermore, a 
consideration has been taken to enable the photo-sensitive member unit 
including the cleaning apparatus and the developing apparatus to be 
accomodated in one image forming case which is in turn removed from or 
attached to the recording apparatus as a unit to make it easy for a user 
to exchange the unit. It is to be noted, however, that the fixing 
temperature at the thermally fixing apparatus can not be considerably 
lowered exceptionally even if the apparatus in question has been made 
compact due to limitation in fixing characteristics or at most down to the 
range of 160.degree. C. and 170.degree. C. Naturally those units disposed 
in proximity to the fixing apparatus will be subjected to the effect by 
heat. In particular, the waste toner container for the cleaning apparatus 
has to be located rather near to the fixing apparatus in view of the 
layout, and the toner in such a waste toner container will get solidified 
in the form of cake if the temperature goes up abnormally or the so-called 
caking will be resulted. Consequently, the level detector adapted to 
detect the level of the surface of toner material in the container will 
fail in satisfactory operation. As a result, the toner packing generated 
in the container will cause the toner to overflow from the clearance 
between the toner cleaning member and the photo-sensitive member, 
resulting in poor cleaning, deterioration inside the electrostatic 
recording apparatus, damage to the driving gears and the like problems. 
OBJECT OF THE INVENTION 
An object of the present invention is to provide a recording apparatus 
which has solved the problems as above explained with respect to the 
recording apparatus according to a prior art in which the waste toner 
container is located adjacent to the thermally fixing apparatus and in 
which the waste toner container is constructed in such a way that it will 
be hardly affected by the thermally fixing apparatus. 
SUMMARY OF THE INVENTION 
In order to attain the objectives as above mentioned, the present invention 
provides a recording apparatus wherein the image forming case accomodating 
a unit having a toner container and a thermally fixing apparatus located 
adjacent to the toner container with the wall of the case there between 
are provided, the apparatus being characterized in that an open space is 
provided between the wall of the image forming case and the toner 
container wall of the unit. 
Other features and advantages of the present invention will be apparent 
from the explanation which follows with reference to the accompanying 
drawings.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
An embodiment of the present invention will now be explained by referring 
to the accompanying drawings. 
FIG. 1 illustrates the general constitution of an embodiment of the present 
invention as applied to a laser printer of a compact type. 
In FIG. 1, recording paper 2 which has been supplied from a supply 
apparatus 1 of a printer body 10 in the direction designated by an arrow A 
is provided timing by means of a pair of register rollers 3 and 
transferred to the transfer portion along a photo-sensitive member drum 4. 
The photo-sensitive member drum 4 uniformly charged by a charger 5 is 
exposed to a laser beam containing image information by a laser write 
optical system 6 so that an electrostatic latent image is formed. This 
latent image will be developed by the a developing apparatus 7 by the 
toner to become a toner image, such that the toner image will be 
transferred to the recording paper 2 by a transfer charger 8. After 
transfer, the recording paper 2 will be fixed by means of a thermal roller 
fixing apparatus 9 and discharged to a paper discharge part 11 in the 
direction designated by an arrow B. On the other hand, the toner which has 
been left on the photo-sensitive member drum 4 after transfer of the image 
is then removed by a cleaning blade 12 of a cleaning apparatus 20, and the 
photo-sensitive member drum 4 is discharged by a discharge brush 13. The 
waste toner which has been removed by the cleaning blade 12 is recovered 
by a waste toner container 15 by way of a paddle wheel 14. 
According to the present apparatus, as illustrated in much detail in FIG. 
2, the cleaning apparatus 20 including the cleaning blade 12, the paddle 
wheel 14, and the waste toner container 15 constitutes the photo-sensitive 
member unit together with the photo-sensitive member drum 4, and it is 
accomodated in an image forming case 21. 
The waste toner container 15 is located next to ther thermal roller fixing 
apparatus 9. 
It is noted from the apparatus according to the present embodiment that 
there is provided an open space 31 between a wall 20a of the waste toner 
container 15 at the side of the thermal roller fixing apparatus 9 and a 
wall 21a of the image forming case 21 at the side thermal roller fixing 
apparatus 9. Below and above the open space 31 there are provided vent 
ports 30, so that air is caused to flow in from the opening in the bottom 
plate of the recording apparatus through the lower vent port 30 and flow 
upwardly from the upper vent port 30. Furthermore, heat insulation 
materials 21b and 20b are applied respectively to the wall 21a of the 
image forming case 21 facing the open space 31 and to the wall 20a of the 
waste toner container 15 at the side of the thermal roller fixing 
apparatus 9. The walls 20a and 21a are at opposite sides of the open space 
31. 
Since the present recording apparatus is constituted as above described, 
the heat generated at a fixing roller 9-1 of the thermal roller fixing 
apparatus 9 is effectively shielded from transfer to the waste toner by 
the air flowing through the open space 31 and the heat insulating 
materials 21b, 20b applied respectively to the walls 20a, 21a of the open 
space 31 at the opposite sides. Furthermore, since the waste toner in the 
waste toner container 15 is inhibited from being in direct contact the 
wall 20a of the waste toner container 15, but instead is in direct contact 
with the heat insulating material 20b, heat will hardly be conducted. For 
the heat insulating material 20b, foam material of plastic or the like may 
be preferably employed. 
FIG. 3 illustrates the manner of detaching or attaching the photo-sensitive 
member unit consisting of the cleaning apparatus 20 and the 
photo-sensitive member drum 4. In FIG. 3, the heat insulating material 21b 
applied to the wall 21a of the image forming case 21 and the vent port 30 
provided at the bottom of the open space 31 can be clearly seen. 
As explained above, according to the present invention, the heat generated 
in the fixing apparatus may be comparatively easily prevented from being 
conducted to the toner contained in the waste toner container of the 
cleaning apparatus in particular. Accordingly such problems as caking of 
the toner caused by the toner being overheated in the waste toner 
container and resultant failure in detecting the level of the toner in the 
container, as well as poor cleaning and so forth, may be solved. 
Experiments have shown that application of the present invention has 
enabled the temperature in the waste toner container to be reduced on the 
order of 10.degree. C.