JPH04120576A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent a failure in fixing caused by the damage of a heating roller and the soiling of a copy by arranging a temp. control element at the position of the heating roller corresponding to a separation void part or a nonimage part. CONSTITUTION:A thermister 28 as the temp. control element is arranged at the position of one end part side of the heating roller 1 corresponding to the separation void part Pa formed in a width direction where the transfer sheet P passes. Then, a separating device forms the separation void part Pa on one end side in the width direction where the transfer sheet P passes, the thermister 28 arranged at the position of one end part of the heating roller 1 corresponding to the separation void part Pa detects the temp. of the heating roller 1, and the temp. of the image passing part Pb of the transfer sheet P is controlled. Therefore, the surface of the heating roller 1 corresponding to the image part Pb of the transfer sheet P is prevented from being damaged by the contact of the thermister 28. Thus, the failure in the fixing caused by the damage of the heating roller is prevented, and the soiling of the copy is prevented, as well.

Description

Detailed Description of the Invention The present invention relates to an image forming apparatus such as a copying machine, a printer, or a fax machine, and particularly to an end face reference having a fixing device in which a temperature control element is disposed in contact with a heating roller within the image paper passing width. The present invention relates to an image forming apparatus of this type.

The most important thing about the temperature controller 1 of the fixing device in this type of edge-based image forming apparatus is to accurately control the temperature of the image passing section of the transfer paper (for example, a thermistor). A temperature control element must be placed within the paper pile.

For this reason, for example, as shown in FIG. 5, a temperature control element 28 is placed in contact with the heating roller J within the paper stack.

However, in the conventional image forming apparatus described above in which the temperature control element 28 is placed in contact with the heating roller 1 within the paper stack, silicone rubber has been applied to the surface of the heating roller due to the spread of color copying in recent years. However, the contact of the temperature control element becomes a source of scratches on the heating roller, resulting in poor fixing.

■ Because the temperature control element is in contact within the paper stack, toner offset from the heating roller accumulates on the contact surface of the temperature control element, which also causes uneven application of silicone oil at the contact area, which is a contributing factor to copy stains. Become.

Problems such as this are occurring.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above-mentioned conventional problems and provide an edge-based image forming apparatus that can prevent fixing failures caused by scratches on the heating roller and prevent copy stains. do.

Procedure for solving f'' In order to achieve the above-mentioned object, the first invention of this application provides an edge-based type of image forming apparatus having a fixing device in which a temperature control element is disposed in contact with a heating roller within an image paper passing width. In the image forming apparatus, the heating roller has means for forming a separation white area or a non-image area on one end side of the transfer paper in the paper width direction, and the separation white area corresponds to the area or the non-image area. It is characterized in that a temperature control element is disposed at the position.

In a second invention, a plurality of suppression rollers and a pressure roller are rotatably disposed in contact with different positions on the surface of a heating roller, and a first fixing section is formed by the heating roller and the pressure roller. At the same time, a heating roller and a plurality of pressure rollers are used to
A fixing section is formed, and the heating roller is capable of forward and reverse rotation so that the transfer paper can be fixed at the first fixing section when rotating forward, and the transfer paper can be fixed at the second fixing section when rotating in reverse;
In an edge-based image forming apparatus having a fixing device in which a temperature control element is disposed in contact with a heating roller at the middle of the image sheet passing, there is a separated white spot or non-separated white spot on one end side in the paper passing width direction of the transfer paper. The apparatus is characterized in that it has means for forming an image area, and that a temperature control element is disposed at a position of the heating roller corresponding to the separated blank area or the non-image area.

With the configuration described above, the separation white area or non-image area is formed on one end side of the paper width direction of the transfer paper by the separation white area or non-image area forming means, and the separation white area or non-image area is It becomes possible to detect the temperature of the heating roller with a temperature control element disposed at the heating roller position corresponding to the non-image area and control the temperature of the image passing area of the transfer paper. Therefore, the surface of the heating roller corresponding to the image area of the transfer paper is not scratched due to contact with the temperature control element, and copying is not stained.

One block, one use, two out of Figure 1.2 shows a first embodiment of the invention.

In FIG. 1, 15 is a silicone oil application unit having first and second silicone oil coating coke 7.8 and a silicone oil receiver described later, which can be attached to and removed from the fixing device unit from its front side (in FIG. 1). It is designed to be installed on the In FIG. 2, reference numeral 16 denotes a press-contact leaf spring for holding the felt in place, which is attached to the surface of an L-shaped holding plate 17 for holding the coated felt. ] 8 is a coating felt disposed in contact with the surface of the second silicone oil coating roller 8; 19 is a U-shaped felt moon disposed in contact with the back surface of the felt 18; ]・
The material 19 is disposed within an inverted U-shaped holding plate 20, and the coated felt 18 is wound around and covering the holding plate 20 and the felt material 19. Then, with the winding side edge in contact with the felt material 19 in contact with the roller 8, the lower winding edge of the coated felt 18 is placed on the holding plate 2.
1 and the holding plate 20, and the lower edge of the winding and the other side edge are the holding plate 17.
and is held by a holding plate 20. The winding tip of the coated felt 18 hangs down in a curved manner from the gap between the two holding plates 17 and 21 into the silicone oil reservoir 22.

Reference numerals 23 and 24 designate blades 23 and 24, which are placed in contact with the surface of the roller 8, respectively, and the proximal end side or the holding plate! When holding the coated felt 18 according to 7.20.21, the coated felt 18 is sandwiched between the holding plate 17 and the holding plate 20, and between the holding plate 21 and the holding plate 20, and is fixed below. . The scraper blades 23, 24 are made of a thin metal plate, such as heat-resistant and resilient phosphor bronze. A silicone oil supply pipe 26 is connected inside the U-shaped felt material 19, and silicone oil is supplied from a supply section (not shown) to the felt material 19 through the pipe 26.
The silicone oil supplied to is supplied from the felt material 19 to the application felt 18. Reference numeral 27 denotes a separation roller, which may be replaced with a separation claw.

Reference numeral 28 denotes a thermistor as a temperature controller element, and as shown in FIGS. 2 and 4, the white separation formed in the paper passing width direction of the transfer paper P is arranged at a position on one end side of the heating roller 1 corresponding to part Pa. ing. The separated white area Pa is formed by, for example, a separating apparatus proposed by the present applicant and described in Japanese Patent Publication No. 54-32577.

In this first embodiment configured as described above,
The separation device forms a separation blank area Pa on one end side of the transfer paper P in the paper passing width direction. And this separated white outline is part Pa
The temperature of the heating roller 1 is detected by a thermistor 28 disposed at one end position of the heating roller 1 corresponding to , and the temperature of the image passing portion of the transfer paper P is controlled. Therefore, the surface of the heating roller 1 corresponding to the image area pb of the transfer paper P is not scratched due to the contact of the thermistor 28, and copy stains are not caused.

In the above, the separation white area formed by the separation device was explained only for the area Pa, but a non-image area can be forcibly formed in the paper width direction of the transfer paper P with an eraser or the like placed at the photoreceptor opening. , this non-image area may be used instead of the white area Pa.

Further, in the first embodiment, the silicone oil supplied from the supply pipe 26 to the felt material 19 is transferred from the felt material 19 to the contacting application felt 18, and from this application felt 18 to the contacting second silicone oil application roller 8. is supplied. Then, this applied silicone oil is applied to the upper scraper blade 23 on the application roller 8.
In addition, the amount is regulated to a very small and constant amount and is applied to the surface of the heating roller 1 via the roller 7. The excess silicone oil due to the above-mentioned regulations is sent from the tip side of the application felt 18 to the silicone oil reservoir 22 and stored therein. On the other hand, in the application, the heating roller 1
Foreign matter such as offset toner and paper powder adhering to the roller 7
These foreign substances are scraped off by a lower scraper blade 24, and the silicone oil receiver is collected in a reservoir 22.

FIG. 3 shows a second embodiment of the invention. This second embodiment has the silicone oil application unit 1-15 of the first embodiment as it is, and the fixing section in which this application unit 15 is installed consists of a first fixing section and a second fixing section. , which is different from the first embodiment.

Therefore, the same parts as in FIGS. 1 and 2 showing the first embodiment are given the same reference numerals, and the explanation thereof will be omitted. In this second embodiment as well, the separating device forms a non-image area on one end side of the transfer paper P in the paper passing direction with a separation white area Pa or an eraser on one end side of the transfer paper P in the paper passing direction, These separation white areas are connected to the heating roller 1 by a thermistor 28 disposed at one end position of the heating roller 1 corresponding to the area Pa or non-image area.
to detect the temperature of the transfer paper P and control the humidity of the image passing section of the transfer paper P, and to prevent the surface of the heating roller corresponding to the image section pb of the transfer paper P from being scratched due to contact with the thermistor 28. The effect of preventing smearing on copies is the same as in the first embodiment.

Further, the difference from the first embodiment in the supply operation of the applied silicone oil is that the applied silicone oil is regulated to a very small and constant amount on the application roller 8 by the lower scraper blade 24, while foreign substances such as offset toner are It is scraped off by the upper scraper blade 23, and both blades 23, 24 perform an action opposite to that during normal rotation.

The invention according to claim 1 has a means for forming a separated white area or a non-image area on one end side of the transfer paper in the paper width direction, and the separated white area Since the temperature control element is arranged at the position of the heating roller corresponding to the area or non-image area, the surface of the heating roller corresponding to the image area of the transfer paper is not scratched by contact with the temperature control element. , it is possible to effectively prevent fixing failures caused by scratches on the heating roller as in the past, and also to have the excellent effect of not causing copy stains.

In addition to the above-mentioned effects, the invention according to claim 2 also provides the same effects when using the second fixing section.

[Brief explanation of the drawing]

Fig. 1 is a front view showing a first embodiment of the present invention, Fig. 2 is a partial perspective view of the main parts of the same as above, Fig. 3 is a front view showing a second embodiment of the invention, and Fig. 4 is an operational view. FIG. 5 is a perspective view of a main part for explaining the operation of a conventional example. 1... Heating roller 2... Pressure roller 5... Suppression roller 28... Thermistor (temperature control element) Fig. 4 Fig. 5

Claims (1)

[Scope of Claims] 1. In an edge-based image forming apparatus having a fixing device in which a temperature control element is disposed in contact with a heating roller within the image paper width, the transfer paper is separated at one end side in the paper width direction. An image forming apparatus characterized in that the temperature control element is provided at a position of the heating roller corresponding to the separated white part or the non-image part, and has means for forming a white part or a non-image part. . 2. A plurality of pressure rollers and pressure rollers are rotatably arranged in contact with different positions on the surface of the heating roller, and the heating roller and the pressure roller form a first fixing section, and the heating roller A second fixing section is formed by a plurality of pressure rollers, and the heat roller fixes the transfer paper at the first fixing section when rotating in the normal direction, and fixes the transfer paper at the second fixing section when rotating in the reverse direction. In an edge-based image forming apparatus having a fixing device which is capable of forward and reverse rotation and in which a temperature control element is disposed in contact with a heating roller within the width of the image sheet, one end of the transfer sheet in the width direction of the sheet is placed. Image formation characterized in that it has means for forming a separated white area or a non-image area, and the temperature control element is disposed at a position of the heating roller corresponding to the separated white area or non-image area. Device.