JPH06130752A - Image forming device - Google Patents

Abstract

PURPOSE:To provide the image forming device where the length of feeding interval of a feeding means is set according to the rise and fall of temperature of a fixing means. CONSTITUTION:In the image forming device provided with a feeding means 54 feeding a multiple number of recording materials 52 in sequence with specified intervals in between, an image forming means 1 forming an image on fed recording material 52 and a fixing means 40 heating the recording material 52 to fix a formed image on the recording material 52, a detection means 46 to record the temperature of the fixing means 40 and a control means to set the feeding interval of the feeding means 54 to be short when the recorded result is higher than the specified temperature and setting the feeding interval to be longer when the recorded result is lower than the specified temperature are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus applied to a printer, a copying machine, a facsimile or the like.

[0002]

2. Description of the Related Art FIG. 6 shows a schematic configuration of a conventional printer. In the figure, reference numerals 100 and 101 denote multi-manual paper feed trays and paper feed cassettes as a feeding means, and have paper feed rollers 102 and 103. The multi-manual paper feed tray 100 has a thickness of 127 g / m ² or a thickness of 157 as a recording material.
A cardboard 104 of g / m ² or the like is used.

On the other hand, the paper feed cassette 101 has a thickness of 64 to
Plain paper 105 of 80 g / m ² is used as a recording material.

The thick paper 104 or the plain paper 105 is passed through the conveyance guide 106 and the photosensitive drum 1 as an image forming means.
The image is conveyed toward 07 and an image by toner is recorded. After that, the recording material is conveyed to the fixing means 108 by the conveying means 111, and the heating roller 10 of the fixing means 108 is conveyed.
9. The image is fixed by the pressure roller 110 and discharged to the outside of the apparatus.

As described above, the supply means is separately provided corresponding to the thickness of the recording material for the following reason. That is, cardboard 1
04 has a larger heat capacity than plain paper 105,
In order to sequentially supply 04 with continuous fixing, the next fixing operation cannot be performed without waiting for the temperature rise of the fixing unit 108 which is lowered by the fixing operation.

For this reason, the supply interval by the paper feed roller 102 is set longer than that of the paper feed roller 103, and the plain paper 10
It is configured to supply separately from No. 5.

[0007]

However, in the above-mentioned conventional example, when the plain paper 105 is put in the multi-manual paper feed tray 100 and supplied (when recording materials having the same thickness but different sizes are continuously copied). However, the workability is poor if only one of the supply means is used), and the passage time from the supply to the end of fixing is unnecessarily long. As a result, the efficiency of the image forming work is reduced.

SUMMARY OF THE INVENTION The present invention is intended to solve the above problems, and an object of the present invention is to provide an image forming apparatus capable of setting the length of the supply interval of the supply unit in correspondence with the temperature of the fixing unit. .

[0009]

In order to achieve the above object, the present invention comprises a supply means for sequentially supplying a plurality of recording materials at predetermined intervals, and an image forming means for forming an image on the supplied recording materials. In an image forming apparatus having a fixing means for heating the recording material to fix the formed image on the recording material, a detecting means for measuring the temperature of the fixing means, and a case where the measurement result is higher than a predetermined temperature And a control means for setting the supply interval of the supply means to be short, and for setting the supply interval of the supply means to be long when the measurement result is lower than a predetermined temperature.

[0010]

The detecting means measures the temperature of the fixing means. When the measurement result is higher than the predetermined temperature, the recording material supply interval becomes short, and when the measurement result is lower than the predetermined temperature, the recording material supply interval becomes shorter. Becomes longer. That is, if the recording material that is sequentially supplied becomes thin, the time interval between each fixing operation after the supply is short, and if the recording material is thick, the time interval after each fixing operation becomes long.

[0011]

【Example】

(First Embodiment) Next, the image forming apparatus according to the present invention will be described in more detail with reference to the drawings. In the embodiment shown in FIG. 1, the present invention is embodied in an electrophotographic copying machine. In this embodiment, the image forming means is the electrophotographic photosensitive drum 1, and the photosensitive drum 1 is surrounded by a primary charger 2, an exposing means 4 such as a laser beam exposing device, and a developing device 6.
Etc. are provided. Since those configurations and operations are well known to those skilled in the art, further description will be omitted.

The image formed on the photosensitive drum 1 is a multi-manual sheet feeding unit 20a or a cassette sheet feeding unit 2.
Under the action of the transfer discharger 8, the image is transferred to the recording material fed from 0b through the transport path 50. The recording material that has completed the transfer is conveyed to the fixing means 40 by the endless belt 32 of the conveying means 30, and the toner image is fixed on the recording material.

The fixing means 40 has a heating roller 42a and a pressure roller 42b, and fuses the toner image onto the recording material.
The conveying speed of the endless belt 32 is slightly higher than the conveying speed of the heating and pressure roller pairs 42a and 42b of the fixing means 40, and the recording material forms a loop to prevent the occurrence of wrinkles during fixing. .

Further, the conveying speed of the endless belt 32 is usually matched with the peripheral speed of the photosensitive drum 1 to prevent the expansion and contraction of the image when the image is transferred onto the recording material. . The residual developer is removed from the photoconductor drum 1 after the transfer by the cleaner 10, and the next image forming process is performed.

The multi-manual paper feeding means 20a is loaded with thick paper 52 having a thickness of 127 g / m ² , and the cassette paper feeding means 20b is loaded with plain paper 53 having a thickness of about 64 to 80 g / m ^2. It

The multi-manual sheet feeding means 20a has a feeding roller 54 as a feeding means, and the cassette sheet feeding means 20b has a feeding roller 55 as a feeding means.

On the other hand, the fixing means 40 is provided with a temperature sensor 46 as a detecting means for measuring the temperature. FIG. 2 is a block diagram showing the main circuit configuration of the present invention. The temperature sensor 46 is specifically a thermal expansion type, a thermocouple, a counter type,
A thermistor type, a heat radiation type or the like is used and is connected to the CPU 56 as a control means.

The feeding rollers 54 and 55 are driven by separate motors 57 and 58, and the motors 57 and 58 are CPUs.
It is connected to 56. Then, the feeding rollers 54 and 55 feed the recording material by intermittent rotation.

The rotation of the feeding roller 54 for the thick paper 52 is controlled according to the measurement result of the temperature sensor 46. That is,
When the measurement result is higher than the predetermined temperature, the stop time of the feeding roller 54 is short, that is, the feeding interval is set to be short.
On the other hand, when the measurement result is lower than the predetermined temperature, the feeding roller 54 is stopped for a long time, that is, the feeding interval is set to be long.

Here, the throughput and supply interval of the multi-manual sheet feeding means 20a and the cassette sheet feeding means 20b will be described. In this configuration, when the process speed (paper transportation speed) is 100 mm / s and the paper size is A4 (the length in the transportation direction is 210 mm), the throughput from the cassette paper feeding unit 20b is 20 cpm. In this case, the supply interval is 100 × 60 / 20−210 = 90 mm
The plain paper 53 (64 g / m ² paper or the like) has a sufficient fixing interval.

However, the thick paper 52 (127 g / m ² , 15
7 g / m ² paper or the like), the fixing means 4
Due to lack of 0 capacity, multi-purpose paper feeder 20a
Then, the throughput is 10 cp so that it corresponds to the thick paper 52.
It is set to m.

The paper feeding interval at this time is 100 × 60/10.
Since −210 = 390 mm, the capability of the fixing unit 40 can be sufficiently restored even during continuous operation, and the thick paper 52 can be fixed. In addition, plain paper 53
In the case of adding, if the supply is performed at the same intervals as described above, it takes a long time to form an image.

In order to minimize this, the fixing means 40
Further, a temperature sensor 46 is provided to feed back the temperature drop of the fixing unit 40 to the throughput. FIG. 3A shows the relationship between the fixing temperature and the supply time during the continuous image forming operation.

In the figure, the vertical axis represents the fixing temperature and the horizontal axis represents the time. The dashed-dotted line represents the use of plain paper in the cassette sheet feeding means 20b, and the broken solid line represents the thick multi-sheet manual feeding means 20a. When in use. In case of the multi-purpose manual paper feeding means 20a, the initial throughput is 10 cp
Since the paper is fed at an interval of m, that is, once every 6 seconds, the fixing temperature is schematically shown by the solid line in the figure.

That is, as shown in FIG. 3B, the minimum temperature in one cycle is set to min. Assuming that t, during temperature measurement (step), min. If t is higher than a certain set temperature t ₁ (step) (min.t> t ₁ ), it is possible to advance the next sheet feeding interval (step), assuming that the fixing unit 40 has a sufficient capacity, and the throughput is increased. It is possible to raise.

A method of controlling so that the throughput is fast at the initial stage may be considered, but in this case, there is a problem that fixing failure occurs in the first several sheets in an uncontrollable (unstable) state. , The above is more stable.

Another control method is shown in FIG.
A temperature t ₂ lower than the control set temperature t ₁ is set. Therefore, as shown in FIG. 4 (B), in addition to the above control method (steps to), min. If t <t ₂ (step), the feeding interval is lengthened (step).

That is, the minimum temperature mi during each image formation
n. t is always t ₁ <min. This is set so that t <t ₂ . As a result, the capability of the fixing unit during continuous image formation can be stably exerted, and the throughput is not unnecessarily reduced.

(Second Embodiment) FIG. 5 shows another embodiment of the image forming apparatus according to the present invention. In this embodiment, a laser beam printer for electrophotographic multicolor copying is shown. The full-color laser beam printer of this embodiment is provided with four image forming means Pa, Pb, Pc, and Pd, and each image forming means is a dedicated electrophotographic image forming medium, that is, the photosensitive drums 1a, 1b, and 1c and 1d.

Around the photosensitive drums 1a to 1d, dedicated image forming process means, for example, charging portions 2a and 2 are provided.
b, 2c, 2d and laser beam exposure means 4a, 4
b, 4c, 4d and developing units 6a, 6b, 6c, 6d,
The transfer portions 8a, 8b, 8c, 8d and the cleaning portion 10
a, 10b, 10c, 10d, etc. are provided.

The photoconductor drums 1a, 1b, 1c, 1d are driven by a drive motor (not shown), and the image forming means P is provided below the photoconductor drums 1a, 1b, 1c, 1d.
A transfer material conveying device 30 provided with a moving body that rotates in the direction of the arrow in a manner penetrating a, Pb, Pc, and Pd, that is, an endless belt 32 is arranged.

The transfer material (recording material) P is supplied by the supplying means 70, 7.
The sheet is fed to the transfer material conveying device 30 by the first feeding roller. The transfer material P is the image forming means Pa, Pb, P.
It is configured to be conveyed in the arrow direction through the transfer portions 8a, 8b, 8c, 8d of c and Pd.

In such a structure, first, a visible image of yellow toner is formed by the first image forming means Pa,
The yellow toner image is transferred to the transfer material P conveyed by the transfer material conveying device 30 at the transfer portion, that is, at the transfer position 8a.

On the other hand, while the yellow image is being transferred onto the transfer material 9, an image with magenta toner is obtained by the second image forming means Pb. Then, the transfer material P that has been transferred by the first image forming means Pa is the second image forming means Pb.
When it is carried into the transfer position 8b, the magenta toner image is transferred to a predetermined position on the transfer material P.

Hereinafter, third and fourth image forming means Pc, Pd
Image formation is performed for cyan and black colors at
The toner images of four colors are superposed on the transfer material P.
When such a transfer process is completed, the transfer material P is fixed by the fixing means 40, and a multicolor (full color) image is obtained on the transfer material P.

After the transfer, the residual toner is removed from the photosensitive drums at the cleaning portions 10a, 10b, 10c and 10d to prepare for the subsequent latent image formation.

As described above, the transfer material P, which has been transferred, is conveyed to the fixing means 40 to fix the transferred image, but the transfer speed of the endless belt 32 of the transfer material transfer device 30 is set to the fixing speed.
The transfer rate of the pair of rollers 42a, 42b is made slightly faster than that of the pair of transfer rollers 42a, 42b to prevent wrinkling of the transfer material P during fixing.

Further, the conveying speed of the endless belt 32 is made to coincide with the peripheral speed of the respective photosensitive drums 1a, 1b, 1c, 1d, so that the expansion and contraction of the image when the visible image is transferred to the transfer material occurs. To prevent.

Even in such a full-color image forming apparatus, the system for monitoring the fixing temperature of the fixing means 40 by the temperature detecting sensor 46 and feeding it back to the feeding roller 72 is the same as that of the above-mentioned embodiment. Same as the example.

However, in the case of polymerizing and fixing a plurality of toners as in this embodiment, the fixing means 40 is loaded with several times the load of the above-mentioned single color, and especially in the case of thick paper,
Since the put must be further delayed from 10 cpm (1/2 of plain paper) in the previous embodiment to about 5 cpm (¼ of plain paper), the effect of the present invention is further enhanced.

[0041]

Since the present invention is configured as described above, the detecting means measures the temperature of the fixing means, and when the measurement result is higher than the predetermined temperature, the recording material supply interval becomes short,
When the measurement result is lower than the predetermined temperature, the feeding interval of the recording material becomes long.

That is, if the recording material to be sequentially supplied is thin, the time interval for each fixing operation after the supply is short, and if the recording material is thick, the time interval for each fixing operation is long. Therefore, the image forming efficiency is improved.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an electrophotographic copying apparatus according to a first embodiment to which the present invention is applied.

FIG. 2 is a block diagram showing a main circuit configuration of the electrophotographic copying machine of FIG.

FIG. 3A is a graph showing the relationship between the fixing temperature and the sheet feeding time in the first embodiment, and FIG. 3B is a flow chart showing the operation of the embodiment.

FIG. 4A is another control method in the first embodiment, which is a graph showing the relationship between the fixing temperature and the sheet feeding time;
(B) is a flow chart showing the operation of the control method.

FIG. 5 is a schematic configuration diagram of a second embodiment in which the present invention is applied to a full-color laser printer.

FIG. 6 is a schematic configuration diagram of a conventional image forming apparatus.

[Explanation of symbols]

 1 Photosensitive Drum (Image Forming Means) 40 Fixing Means (Detecting Means) 46 Temperature Sensor 52 Thick Paper (Recording Material) 54 Feeding Roller (Supplying Means) 56 CPU (Control Means)

Claims (1)

[Claims] 1. A recording means for supplying a plurality of recording materials sequentially at predetermined intervals, an image forming means for forming an image on the supplied recording materials, and a recording means for fixing the formed images on the recording material. In an image forming apparatus having a fixing means for heating a material, a detecting means for measuring a temperature of the fixing means, and a supply interval of a supply means are set to be short when the measurement result is higher than a predetermined temperature, and the measurement is performed. An image forming apparatus comprising: a control unit that sets a supply interval of the supply unit to be long when the result is lower than a predetermined temperature.