JPH04223477A - Transfer paper for electrophotography and production thereof - Google Patents

Abstract

PURPOSE:To produce transfer paper for electrophotography ensuring a low rate of superposition during feeding and carrying and slight curl after fixing by specifying the ratio between the Bekk smoothness of the front and rear sides of transfer paper and the ratio between the ash contents of the front and rear sides. CONSTITUTION:One side of transfer paper for electrophotography having higher Bekk smoothness is used as the front side and the other side having lower Bekk smoothness as the rear side. The transfer paper having 15-70 sec Bekk smoothness on both the front and rear sides, 3-20% ash content and 60-90 g/cm<2> basis weight is allowed to satisfy inequalities 1.1<=BA/BB<=1.9 and 1<=KB/KA [where BA is the Bekk smoothness (sec) of the front side, BB is the Bekk smoothness (sec) of the rear side, KA is the ash content (%) of the front side and KB is the ash content (%) of the rear side].

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer paper used in an apparatus or printer using electrophotography, such as a copying machine or an LBP (laser beam printer).

0002

[Prior Art] Conventionally, plain paper transfer is used as a transfer material to obtain an image by transferring insulating toner to a transfer material to form an unfixed toner image, and then fixing the toner image to the transfer material. As the paper, PPC-specific paper and general high-quality paper are used.

[0003] A method for preventing double feeding of stacked transfer sheets during feeding and conveyance is disclosed in Japanese Patent Application Laid-Open No. 52-67634.
As proposed in the publication, by cutting at an angle, the "burrs" that occur during cutting are separated by slightly shifting from the edges of each stacked transfer paper, and the "burrs" are the cause. JP-A-58-95745
As proposed in Japanese Patent Publication No. 58-95746, the difference between the intralayer friction coefficient and the interlayer friction coefficient of the accumulated copy paper can be reduced by adding silica pigment or lubricant to the paper. There are known methods that prevent double feeding due to differences in frictional force between layers.

[0004] Furthermore, as a method whose main purpose is to reduce curl after fixing using a heat roller (heat curl), as proposed in Japanese Patent Application Laid-Open No. 57-81270, A method that specifies the degree of curl of a transfer paper having a moisture content after passing through a fixing heat roll, and JP-A-58
- As proposed in Japanese Patent Publication No. 176641, paper is made using twin wire to reduce the difference between the front and back sides of the paper, and as proposed in Japanese Patent Application Laid-Open No. 63-309700, paper thickness and density are , Beck smoothness, air permeability, Clark stiffness, ash content, and water content are known.

However, in recent years, electrophotographic copying machines and L
With the increase in speed and volume of BP (increase in the number of sheets operated per month) and the spread of applications such as sorters, the quality requirements for reducing the double feeding rate of transfer paper and suppressing the amount of curling have increased. It is a much larger paper, and if only due to the physical property regulations and manufacturing method of paper as mentioned above,
The required quality is not fully satisfied.

[0006]

OBJECTS OF THE INVENTION An object of the present invention is to provide an electrophotographic transfer paper that solves the above problems and a method for manufacturing the same.

That is, an object of the present invention is to provide an electrophotographic transfer paper that has a low double feeding rate during paper feeding and conveyance.

An object of the present invention is to provide an electrophotographic transfer paper that has a small amount of curl after fixing.

An object of the present invention is to provide an electrophotographic transfer paper with good transportability.

Another object of the present invention is to provide a method for producing electrophotographic transfer paper that has a low double feeding rate during paper feeding and conveyance, and a small amount of curl after fixing.

[0011]

[Structure of the Invention] The electrophotographic transfer paper of the present invention has a Beck smoothness of 15 to 70 seconds on both the front and back sides, when the side with high Beck smoothness is the front side and the side with low Beck smoothness is the back side. , more preferably 20 to 60 seconds, and the ash content is 3 to 20%, more preferably 5 to 15%,
and has a basis weight of 60 to 90 g/cm2, more preferably 6
In electrophotographic transfer paper having a weight of 3 to 83 g/cm2, the Bekk smoothness is as follows: When the Bekk smoothness on the front side is taken as BA (seconds) and the Bekk smoothness on the back side is taken as BB (seconds),
The following formula (1)

0012

[Outside]

More preferably,

[0013]

[Outside]

When the ash content on the front side is KA (%) and the ash content on the back side is KB (%), the following formula (2) is satisfied.

0014
]

[Outside]

More preferably,

[0015]

[Outside]

More preferably

[0016]

[Outside]

The above objective is achieved by satisfying the following.

[0017] Furthermore, in the method for producing an electrophotographic transfer paper of the present invention, a pulp sheet (paper web, web) made by a Fourdrinier paper machine is dried through a dryer part to produce an electrophotographic transfer paper. In this method, the above object is achieved by size press coating a size press liquid containing an inorganic filler on the wire surface side of a pulp sheet using a size press part provided in a dryer part.

The present inventor determined that the ash content on the side with lower Bekk smoothness, that is, the wire side during paper making, usually has a lower filler content than the felt side, and therefore has a lower ash content. By making the ash content higher than that on the higher side (usually the felt side), electrophotographic copying machines and LBP
It has been found that double feeding during sheet feeding and conveyance in electrophotographic printers such as the following can be reduced, and curling after fixing can also be reduced.

Although the reason for this is not certain, FIG.
2, when the stacked transfer papers 91, 91' are fed and conveyed by the paper feed roller 92 rotating in the direction of the arrow, the paper feed roller 92 and the arrow by the pressing means such as a spring located below the paper feed roller 92 rotate in the direction of the arrow. The stacked transfer papers 91, 91' are compressed by the pressing force in the paper feed roller direction, and the transfer is performed by the frictional force between the paper feed roller 92 and the transfer paper 91 caused by the rotation of the paper feed roller 92. Paper 91 is fed, but at this time, by reducing the difference in characteristics between the front and back sides of the transfer paper as in the structure of the present invention, the lower surface of the transfer paper 91 and the upper surface of the transfer paper immediately below it are separated in the drawing. We believe that this will reduce the frictional force between the two and the double feed rate.

[0020] Similarly, curling after fixing is also thought to be reduced by reducing the difference in characteristics between the front and back sides of the transfer paper.

[0021] As will be described later, a preferred manufacturing method for manufacturing such electrophotographic transfer paper is to apply felt to the wire side surface during paper making by on-machine size press or off-machine coating. This is done by applying more filler than on the surface side.

[0022] In the present invention, the back side refers to the side with lower Beck smoothness even in the case of paper made with twin wires and has wire sides on both sides, and does not necessarily mean the wire side. Not so.

[0023] In the present invention, "paper ash" is defined by JIS
(Japanese Industrial Standard) This is a value measured according to P8128-1976.

[0024] The ash content on the front side of the paper and the ash content on the back side are:
As shown in the cross-sectional view of the paper in FIG. When divided, it is normal that the "ash content of the paper" in the upper part is taken as the ash content on the front side 51 of the paper, and the "ash content of the paper" in the lower part is taken as the ash content on the back side 52 of the paper. However, because it is difficult to accurately separate the front and back sides of the paper along the center line,
In the present invention, the front side 5 of the paper is
1 and the back side 52 of the paper were divided and samples were collected for ash content measurement, and these samples were defined as "ash content on the front side" and "ash content on the back side."

That is, to collect a sample for ash content measurement, as shown in FIG.
) from the edge of the paper to the center, apply a strong load to the paper from above the tape, make the tape and paper adhere well, and then peel off the tape 61 in the P direction more slowly than the paper 62. . At this time, the peeled off tape 61 has
The paper is adhered to the adhesive surface of the tape 61 without any gaps, and the paper remaining without being peeled off is used as the sample for measurement, as will be described later.

[0026] At this time, the paper is JIS P8111
-1976 (pretreatment of test paper), the test paper should be left at a temperature/humidity of 20° C./65% RH for 4 hours or more.

FIG. 10 shows the adhesive tape after being stretched.
The shaded area is the front or back side of the paper adhered to the adhesive tape and peeled off from the original paper.

FIG. 11 shows the paper after being pulled, and the shaded area surrounded by dotted line C is the back or front surface of the paper that remained without being pulled off.

Here, 1 to 2 g of the shaded area surrounded by the dotted line Q and remaining without being peeled off is collected and used as a sample for measuring the ash content on the back side or front side of the paper, respectively.

[0030] Bekk smoothness of paper is JIS P8119
- According to 1976, the basis weight is JIS P812
4-1976, and other items, physical property values, test methods, and measurement methods described in this specification shall also comply with JIS.

The electrophotographic transfer paper of the present invention preferably satisfies the following physical properties in terms of transportability.・Thickness: 80 to 110μ ・Air permeability: 5 to 3
0 seconds・Clark stiffness in the direction of the grain (vertical direction): 70 to 140 cm3/100・Clark stiffness in the direction perpendicular to the grain (horizontal direction): 20 to 60 cm3/100・Moisture content: 4
6.5% Next, a method for producing an electrophotographic transfer paper according to the present invention will be described.

The raw material pulp is LBK like conventional high-quality paper.
Pulp such as bleached kraft pulp such as P and NBKP is beaten to a freeness degree (C.F.S.) of 300 to 600 ml, and internal additives such as rosin size, sizing agents such as aluminum sulfate; talc, kaolin clay, etc. Fillers; paper strength enhancers such as starch and PVA; dyes, electrical resistance regulators, etc. are added as necessary to prepare a pulp suspension.

At this time, inorganic fillers such as talc and kaolin clay are blended together with inorganic fillers that may be added to the paper later using a size press, coater, etc. so that the ash content of the paper is 4 to 20%. Adjust amount.

The pulp suspension prepared as described above is usually made into paper using a Fourdrinier paper machine as shown in FIG. 4, and then subjected to a drying process (dryer part) to become paper.

[0035] Alternatively, a twin-wire paper machine or other paper machine as shown in Fig. 5 may be used. In FIG. 4, the pulp suspension is jetted from a stock inlet onto a wire 10 moving in the direction of arrow R, and most of the water is dehydrated at the wire part. At this time, the filler and fine fibers added internally to the pulp suspension flow out from the formed paper web (pulp sheet) 11 along with dewatering from the wire surface, so that the paper web 11 is After working part time, dryer part, calendar part and reel part,
When made into paper, the smoothness of the wire side is generally lower than that of the felt side, which has more filler and fine fibers.

In the present invention, the filler is added to one side of the paper web by a size press on one side (usually the wire side) in the size press part provided in the dryer part, and the filler is added as necessary. In the calender part, the surface of the paper is processed to make the side with less filler content higher in smoothness than the side with more filler content, thereby obtaining a transfer paper having the structure of the present invention.

FIGS. 1 and 2 show a coater for a size press. Located in the middle of the dryer part, the dried paper web 11 moves in the direction of the arrow in FIG. is applied to the wire side of the web 11 by an applicator roll 20 rotating in the direction of the arrow.

FIG. 2 shows another size press coater, in which the size press liquid 221 stored in the size press liquid tray 230 is transferred to the distributor roll 21.
1 to the application role 201 through
Size press coating is applied to the wire side of the paper web 11.

In order to manufacture the transfer paper having the structure of the present invention, as described above, it is not necessary to limit the size press to only one side, but to size press both sides as shown in FIG.
The two types of inorganic filler concentrations of the size press liquids 222 and 223 and the coating amount of the two types of size press liquids coated using the applicator rolls 202 and 203 were made different, and the surface of the manufactured paper with the lower smoothness was A transfer paper having the structure of the present invention can be obtained by size-pressing a high concentration and a large amount of liquid.

Furthermore, as shown in Figures 6 and 7, a transfer paper having the structure of the present invention can be obtained by coating one side surface of the paper that has been made and subjected to a drying process with a coating liquid containing an inorganic filler. You can also do it. In FIG. 6, a paper 31 wound into a roll is rewound in the direction of the arrow, and a coating liquid 32 containing an inorganic filler is delivered to an application roll 35 via distributor rolls 33 and 34.
As a result, the surface of the paper 11 is coated so that the less smooth side of the coated paper has a higher ash content than the higher side, and after drying by the dry rolls 36 and 37, the calender roll part
8 and then wound onto a take-up roll 39.

FIG. 7 is a schematic diagram of the on-machine coater, in which the paper 11 made by the paper making section 41 advances in the direction of the arrow.
After drying with dry rolls 42 and 43, it passes through calender roll section 4 and is coated with application roll 45 coated with coating liquid 32 containing an inorganic filler in the same manner as described above with reference to FIG.
After drying in step 7, it is wound up on a winding roll 49.

In the case of the twin wire paper machine shown in FIG. 5, a size press part may be provided at the location A in FIG.

[0043]

[Embodiments] Next, specific embodiments of the present invention will be described.

Production example 1

[0045] A mixed pulp having a blending ratio of hardwood bleached kraft pulp (LBKP)/softwood bleached kraft pulp (NBKP) = 75/25 (by weight) was beaten to 370 ml CSF, and 6 to 60% of talc was added to 100 parts by weight of the mixed pulp. A pulp suspension with a pulp concentration of approximately 1% was prepared by adding 10 parts by weight, 0.1 parts by weight of a retention aid, 0.3 parts by weight of rosin size, and 0.8 parts by weight of aluminum sulfate. Paper is made using a Fourdrinier paper machine at a papermaking speed of 150 to 250 m/min, and size press liquids with the five compositions shown in Table 1 below are coated using a size press coating machine as shown in Figure 1.
Size press using 2 to 3 and calendering to determine the amount of pulp suspension discharged from the stock inlet, machine speed, dehydration filtration pressure in the wire section, surface temperature of dry rolls, compression pressure between calender rolls, and calender. By adjusting the surface material of the roll,
A paper with the following properties was produced.

・Basic weight: 64 to 68 g/m2・Thickness: 8
5 to 95 μ ・Air permeability: 9 to 28 seconds ・Clark stiffness in the grain direction: 75 to 100 cm3/
100 ・Clark stiffness in the direction perpendicular to the grain: 25 to 40 cm
3/100 ・Moisture: 4.8 to 5.5%

[0047]

【table】

Production example 2

In Production Example 1, the wire surface of the paper with a basis weight of approximately 52 g/m 2 was made using the size press solution (■), and was coated with approximately 15 g/m 2 of kaolin clay together with starch and other additives using a coater. Coated paper was produced.

Production example 3

[0051]

[Outside]

[0052]

【table】

Production example 4

[0054] In Production Example 3, using the size press liquid (1), the wire side of the paper with a basis weight of about 51 g/m2 was coated with about 16 g/m2 of talc together with starch and other additives using a coater. , produced coated paper.

Examples

The transfer papers manufactured in Production Examples 1 to 4 were cut into A4 size sheets using a rotary cutter, and 5,000 sheets of each sheet were cut into NP-1 sheets equipped with a paper feed roller, a heat roller, and a fixing device.
8582RF modified machine (manufactured by Canon Inc., copy speed A4 80 sheets/min), two 25 bin sorters (Canon sorter 25I modified machine and 25II modified machine are connected,
A total of 50 bin sorters were used. (Regulated number of A4 sheets per bin: 50 sheets) was connected and a conveyance test was conducted. The physical properties of the paper (ash content, smoothness) and the transport test results (multiple feeding, curl height after fixing, transportability, loadability on the sorting turbine) are shown in Tables 3 and 4 below.

[0057]

【table】

[0058]

【table】

*1, *2, *3 and *4 in Tables 3 and 4 are as follows.

*1 After the fixed paper is ejected, the leading and trailing edges of the paper bulge due to curling, and the sorting turbine has 20 to 30
I could only load one sheet.

*2 After the fixed paper is ejected, the leading and trailing edges of the paper are slightly raised due to curling, and the sorting turbine receives 35 to 45
I could only load one sheet.

*3 The stiffness of the paper was low, and jams (paper retention) occurred at a frequency of about 0.8% during paper feeding, electrostatic separation, fixing and ejection, and in the sorter.

*4 Similar to *3, jam occurred at a frequency of approximately 1.2%.

[0064]

Effects of the Invention Since the electrophotographic transfer paper of the present invention has the above-described structure, it has the following effects. ■Low double feed rate during paper feeding and transport. ■The amount of curl of the transfer paper after fixing is small. ■Good transportability.

Furthermore, since the method for producing an electrophotographic transfer paper of the present invention has the above-described structure, it is possible to produce an electrophotographic transfer paper that has a low double feeding rate during paper feeding and conveyance and a small amount of curl after fixing. can do.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a size press coater for size-pressing the surface of a paper web used in the manufacturing method of the present invention.

FIG. 2 is an explanatory diagram of a size press coater for size pressing the surface of a paper web used in the manufacturing method of the present invention.

FIG. 3 is an explanatory diagram of a size press coater for size pressing the front and back surfaces of the paper web used in the manufacturing method of the present invention.

FIG. 4 is an explanatory diagram of a Fourdrinier paper machine used in the manufacturing method of the present invention.

FIG. 5 is an explanatory diagram of a twin paper machine used in the manufacturing method of the present invention.

FIG. 6 is a schematic diagram of an off-machine coater to which the manufacturing method of the present invention is applied.

FIG. 7 is a schematic diagram of an off-machine coater to which the manufacturing method of the present invention is applied.

FIG. 8 is a cross-sectional view of the paper.

FIG. 9 is an explanatory diagram of a method for collecting the front and back sides of paper.

FIG. 10 is an explanatory diagram of a method for collecting the front and back sides of paper.

FIG. 11 is an explanatory diagram of a method for collecting the front and back sides of paper.

FIG. 12 is a schematic diagram showing a paper feeding state.

Claims (2)

[Claims] Claim 1: When the surface with high Beck smoothness is the front surface and the surface with low Beck smoothness is the back surface, the Beck smoothness is 15 to 70 seconds on both the front and back surfaces, and the ash content is 3 to 20%. For electrophotographic transfer paper with a basis weight of 60 to 90 g/cm2, the Beck smoothness on the front side is taken as BA (seconds), and the Beck smoothness on the back side is taken as BB (seconds). When the following formula (1) [outside] is satisfied, and the ash content is the ash content on the surface side, KA (%),
When the ash content on the back side is KB (%), the following formula (2)
An electrophotographic transfer paper that satisfies the following. 2. A method for producing electrophotographic transfer paper by drying a pulp sheet made by a Fourdrinier paper machine through a dryer part, in which the wires of the pulp sheet are A method for producing an electrophotographic transfer paper, which comprises size press coating the surface side with a size press liquid containing an inorganic filler.