JPS6117152A - Heat roll fixing toner - Google Patents

Abstract

PURPOSE:To prevent drum filming at the time of removing a toner remaining on the photosensitive drum with a cleaning brush, and further, to prevent the toner from causing offset trouble on the heat roll at the time of fixing by incorporating a colorant, an epoxy resin, polypropylene, and a hydrophobic silica. CONSTITUTION:The toner contains a hydrophobic silica low in friction coefft. in addition to a colorant, such as carbon black, and a base resin made of an epoxy resin, thus preventing drum filming. The use of polypropylene permits the toner to be prevented from causing offset trouble on the heat roll at the time of fixing.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to improvements in toner for hot roll fixing. especially,
Improvement of a toner for heat roll fixing that ensures that the toner is fixed on the paper surface without drum filming (offset of the toner onto the photosensitive drum) and without offset of the toner onto the heat roll. Regarding.

[Conventional technology]

A thermal roll fixing type printer is generally configured as shown in Figure 3.In Figure 0, l is a photosensitive drum, on whose surface a charge is applied to correspond to a desired image. be done. Reference numeral 2 denotes a toner supply device, which causes toner 3 to adhere only to the above-mentioned charges. Reference numeral 4 denotes a toner transfer roller which presses the print paper 5 against the photosensitive drum 1 and transfers the toner 3 adhering to the above-mentioned charges onto the print paper 5. 6.6° is a heating roll that presses and heats the print paper 5 on which the toner 3 is attached, melts the toner 3 and fixes it on top of the print paper 5. It is difficult to transfer the entire amount of toner 3 attached to the charge applied to the photosensitive drum l onto the printing paper 5, and it is unavoidable that some toner 3 remains on the photosensitive drum l. Therefore, a cleaning brush 7 is provided to remove the remaining toner 3.

In order to make it possible to repeatedly print clear images using such a thermal roll fixing printer, (a) the toner 3 attached to the printing paper 5 is transferred onto the thermal roll 6; The entire amount is printed on the printing paper 5 without any residue.
(b) The toner 3 fixed on the print paper 5 has good fixing properties and does not peel off or the like. (c) The toner 3 remaining on the photosensitive drum l is completely removed by the cleaning brush 7, that is, the toner remaining on the photosensitive drum 1 without being removed by the cleaning brush 7 is removed from the photosensitive drum l.
It is necessary that so-called drum filming, which is melting and adhesion on the surface, does not occur.

[Problem that the invention seeks to solve]

Toner for heat roll fixing is a mixture of a coloring material such as a car pump brush and a base resin for fixing. Conventionally, styrene resin or epoxy resin has been used as the base resin for fixing. Each.

It has the following drawbacks.

(a) When using styrene-based resin as the base resin, toner productivity is low due to the poor crushability of styrene-based resin, and when it is melted during fixing, it emits a bad odor, which is undesirable for hygiene. be.

(b) When using epoxy resin as the base resin, there are no disadvantages mentioned above (it has good crushability and does not emit a bad odor during fixing), but the toner tends to be offset on the heated roll during fixing, and the drum Filming is likely to occur, so
□The disadvantage is that the image becomes gradually unclear when repeated printing is performed.

It is known that adding a wax such as polypropylene to the epoxy resin can prevent the toner from being offset to the natural roll during fixing, but there is no known method for preventing the occurrence of drum filming.

[Means for solving problems]

The present invention eliminates the above-mentioned drawbacks, eliminates drum filming when the toner remaining on the photosensitive drum is removed using a cleaning brush, and prevents toner from being offset on the heat roll during fixing. The purpose of the present invention is to provide a heat roll fixing toner that enables continuous and repeated printing of clear images using a heat roll fixing type printer without the need for colorants and epoxy resins. This is done with a hot roll fixing toner containing polypropylene and hydrophobic silica.

The preferable content of hydrophobic silica for toner overlay is 0.01 to 0.3%, and the preferable weight ratio of polypropylene to the toner weight is 1 to 10%.

(Function) The toner for hot roll fixing according to the present invention contains hydrophobic silica with a small coefficient of friction in addition to a colorant such as carbon black and a base resin made of an epoxy resin, so drum filming is prevented. Furthermore, since it contains polypropylene, the toner will not be offset on the hot roll during fixing.

Each of the above effects will be explained in more detail.

(a) Effect of hydrophobic silica Hydrophobic silica was added to epoxy resin to create trial toners containing hydrophobic silica in various weight ratios and using epoxy resin as a base resin. In this case, since the occurrence of drum filming is being considered, it is not necessarily necessary to add a colorant (such as carbon black) whose content is usually several percent. Heat roll fixing printer (Fuji Renso FB
? As a result of investigating the relationship between the weight ratio of hydrophobic silica contained in the toner and drum filming resistance using a 15D fixing device that can be modified from a flash fixing device to a heated roll fixing device, the hydrophobic 0.0 silica! The epoxy resin toner containing % by weight has excellent resistance to drum filming, and drum filming, where the toner adheres to the photosensitive drum, is not observed even when the same pattern is repeatedly printed approximately 30,000 times. There wasn't. Also, when the content of hydrophobic silica was 0.3% by weight or more, a so-called fogging phenomenon was observed. Since it is known that this fogging phenomenon is caused by an insufficient amount of charge on the toner, the relationship between the weight ratio of hydrophobic silica and the amount of charge was investigated, and the graph shown in FIG. 1 was obtained.

As is clear from the figure, the charge amount, which is 20 gC/g when no hydrophobic silica is contained, is reduced to about 5#LC/g (25%) by containing hydrophobic silica at a weight ratio of 0.3.

Since the minimum charge amount of the toner required to prevent the fogging phenomenon is recognized as 5 p-C/g, the preferred content weight ratio of hydrophobic silica is 0.01 to 0.3% by weight.
It was decided.

(b) Effect of polypropylene Polypropylene was added to epoxy resin to create trial toners containing polypropylene in various weight ratios and using epoxy resin as a base resin. In this case, (a) the entire amount of toner adhering to the print paper is fixed on the print paper and no offset to the heat roll occurs (offset non-occurrence); and (b) the toner is fixed on the print paper. We are considering ensuring that the toner is bonded to the print paper and that problems such as peeling do not occur (fixability).
No addition of colorants (carbon black, etc.) is required.

The non-occurrence of offset was determined based on the offset temperature. The offset temperature is the temperature below which the toner will not be offset onto the heated roll.

Further, the fixability was determined based on the fixing temperature. The fixing temperature is a temperature at which peeling does not occur when fixing is performed at a certain temperature or higher.

The offset temperature and fixing temperature were measured using the apparatus shown in FIG. 4 according to the following procedure. The device shown in FIG. 4 is a test device constructed to approximate as much as possible the toner fixing process performed by a hot roll, and consists of a pair of hot plates 8.8' and the fitting of this hot plate 8.8'. It consists of a Teflon film 9 provided on one side, and the printed paper 5 with toner 3 attached is sandwiched between this Teflon film 9 and the other hot plate 8' to suppress and heat it.

The procedure for offset temperature measurement is as follows: (a) Using a sonic sieve, place 0 on the printed paper.
．． 2 g of toner is evenly distributed over a circular area with a diameter of 80 II m.

(b) Using the testing apparatus shown in FIG. 4, the toner was pressed onto the print paper at various temperatures for 20 seconds to fix the toner, and then the Teflon film was peeled off from the print paper.

(c) Some amount of toner adheres to the Teflon film (
The offset temperature is the lowest value in the temperature range in which fusion occurs.

The procedure for measuring the fixing temperature is as follows: (a) Using a sonic sieve, 0.
01 g of toner is evenly spread over a circular area with a diameter of 8 hm.

(b) Using the test apparatus shown in FIG. 4, the toner was pressed onto the print paper at various temperatures for 20 seconds to fix it, and then the Teflon film was peeled off from the print paper.

(c) Paste an adhesive tape on the fixed toner by applying a specific pressure and immediately peel it off, and set the fixing temperature at the lowest temperature range in which the fixed toner does not adhere to the adhesive tape and peel off. .

Using the above method, we investigated the relationship between the polypropylene content weight ratio, offset temperature, and fixing temperature, and graphs A (relationship between polypropylene content weight ratio and offset temperature) and B (polypropylene content weight ratio) and B (relationship between polypropylene content weight ratio and offset temperature) are shown in Figure 2. The relationship between the content weight ratio and fixing temperature) was obtained. As is clear from graph B, the fixing temperature is generally constant at about 125°C regardless of changes in the weight ratio of polypropylene, but in graph A
As is clearer, the offset temperature increases rapidly as the amount of polypropylene increases, and when the weight ratio of polypropylene is 4% by weight or more, the difference between the offset temperature and the fixing temperature becomes 100° C. or more.

By the way, the offset temperature indicates the temperature at which no offset occurs to the heat roll when fusing is performed below this temperature, and the fixing temperature indicates that fusing is ensured when fusing is performed at this temperature or above. Since it indicates temperature, if fixing is done at a temperature between these two temperatures, it means that good fixing will be done without offset to the heat roll. The wider the above temperature range), the smaller the possibility of offset occurrence, and the better the certainty of fixing.

From this point of view, a toner containing 1% by weight or more of polypropylene is considered to have both sufficient offset resistance and fixing properties.

C. Fogging occurs as the weight ratio of polypropylene increases, so we repeated experiments by varying the weight ratio of polypropylene to investigate the relationship between fog and the weight ratio of polypropylene. It was confirmed that if the weight ratio was 10% by weight or less, no fog that could be recognized in practice would occur.

Combining the above results, it was determined that the preferred weight ratio of polypropylene is 1-10% by weight.

〔Example〕

The heat roll fixing toner according to the embodiment of the present invention will be described in more detail below.

Toners whose composition ratios are shown in the table below were manufactured.

1 degree j 11” Epoxy resin (Epiron 9055 manufactured by Dainippon Ink Chemical Industries) 8!1
1.9 Carbon black (Black Pearls L manufactured by Capot) 3 Nigrosine dye (Oil black BY manufactured by Orient Chemical Co., Ltd.) 3 Polypropylene (Viscol TS-200 manufactured by Sanyo Chemical Industries) 4 Hydrophobic silica (Tulcoj1!Tullanox500
) 0.1 First, the above composition excluding the hydrophobic silica was heated to 1 at 100°C.
After kneading for an hour, it is crushed using a coarse crusher, a medium crusher, and a fine crusher sequentially, and then classified to have a particle size of 5 to 20 #L.
11 powders were obtained. A toner was completed by mixing hydrophobic silica with this.

This toner and carrier iron powder (EFV 25 manufactured by Nippon Iron Powder)
0), and adjusted the toner content ratio to 5% by weight.
A printing test was conducted using a fi715D fixing device (which can be modified from a flash fixing device to a hot roll fixing device) and changing the hot roll temperature in the range of 150 to teo°C. The reason for selecting this temperature range is that, as is clear from the graph shown in Figure 2, this temperature range corresponds to approximately the center temperature range of the 100 to 115°C temperature range between the offset temperature and the fixing temperature. It is.

As a result, even when the same pattern is continuously and repeatedly printed approximately 30,000 times, there is no visible drum filming or offset to the heated roll, and extremely clear prints are possible. It became clear.

〔Effect of the invention〕

As explained above, according to the present invention, the crushability is good, the productivity is excellent, and the fixing process is odorless and hygienic.
In addition, drum filming does not occur when the toner remaining on the photosensitive drum is removed using a cleaning brush, and the toner does not offset to the heat roll during fixing, making it possible for printers using heat roll fixing methods to remove toner remaining on the photosensitive drum. It is possible to provide a hot roll fixing toner that allows continuous and repeated printing of sharp images using a hot roll fixing toner.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the relationship between the weight ratio of hydrophobic silica and the amount of charge, and FIG. 2 is a graph showing the relationship between the weight ratio of polypropylene and offset temperature and fixing temperature. FIG. 3 is a schematic diagram of a thermal roll fixing type printer. FIG. 4 shows a device for measuring offset temperature and fixing temperature. 101 Photosensitive drum, 2... Toner supply device, 3... Toner, 4... Toner transfer roller, 51 Print paper, 6.6°... Heat roll, 7... Cleaning brush, 8 .8° ・1
Hot plate, 91・Teflon film・Figure 1

Claims (3)

[Claims] (1) A toner for hot roll fixing containing a colorant, an epoxy resin, polypropylene, and hydrophobic silica. (2) The content weight ratio of the hydrophobic silica is 0.01 to 0.
3% of the toner for hot roll fixing according to claim 1. (3) The toner for hot roll fixing according to claim 1 or 2, wherein the content weight ratio of the polypropylene is 1 to 10%.