JPS6247060A - Image recorder - Google Patents

Abstract

PURPOSE:To eliminate the occurrence of transfer defects in high-humidity conditions by ejecting a prescribed number of recording sheets without recording if the humidity of the outside air or recording sheets exceeds a specified value. CONSTITUTION:A device 100 is so constituted that a sheet 10a on the top is directly ejected out of the deviuce 100 without recording an image by a high humidity signal from a humidity sensor 200. Each device related to image formation is operated after the sheet 10a of the top passes a resist roll 13 or a transfer charger 5, thereby making this constitution possible. When the device 100 is left in high-humidity conditions for a relatively long period the sheet 10a of the top and several following sheet may absorb moisture to cause transfer defects. Then, the number of sheets which are directly ejected out of the device without recording can be determined in accordance with the degree of humidity and the length of the leaving time.

Description

[Detailed Description of the Invention] Industrial Application Field This invention is applicable to electrophotographic devices, electrostatic recording devices, etc.
The present invention relates to an image recording apparatus that obtains a recorded matter by transferring a developed image formed on a latent image carrier such as a photoreceptor or a dielectric onto a recording sheet.

BACKGROUND OF THE INVENTION FIG. 5 shows an example of a conventional transfer type electrophotographic apparatus. A photoconductive insulating layer is formed on the surface of the drum-shaped photoreceptor 1 . Around the photoreceptor 1, along the clockwise rotation direction, there are a charger 2, an exposure device 3,
A developing device 4, a transfer charger 5, a separation charger 6, a cleaning device 7, and a static eliminator 8# are arranged.

The photoconductive surface of the photoreceptor 1 is uniformly charged in advance to a predetermined polarity by a charging charger 2 . Then, when the exposure device 3 projects light reflected from the original or light according to the image signal, the charges on the photoreceptor 1 are selectively erased, and the electrostatic latent image of the image to be reproduced is removed there. An image is formed. This electrostatic latent image is developed by being supplied with developer 9 containing colored fine particles called toner from the next developing device 4 . The developing device 4 includes a magnet roller 4& and a non-magnetic sleeve 4b around the magnetic roller 4&, and as the two rotate relative to each other, the developer 9 on the surface of the non-magnetic sleeve 4b is conveyed. Due to friction with the magnetic carrier in the developer 9, the toner is tribo-electrified to the opposite polarity to the latent image polarity in the case of regular development, and to the same polarity as the latent image polarity in the case of reversal development, respectively, forming an electrostatic latent image. It adheres to the image area. A recording sheet 10 is placed over the developed toner image 9a, and by being charged from behind by a transfer charger 5 with a polarity opposite to that of the toner, the toner image 9a is transferred onto the recording sheet 1o. The recording sheet 1o is statically removed by the separation charger 6 and the photoreceptor 1
It is separated from the surface and transported toward a fixing device (not shown). On the surface of one photoconductor 1, residual toner is removed by a cleaning device 7, and residual potential is removed by a static eliminator 8.

In the case of an electrostatic recording device, a dielectric material is used as a latent image carrier, and an electrostatic latent image is formed directly on the surface of the dielectric material using a multi-needle electrode, and development is performed by attaching toner to this. The developed toner image is transferred to the recording sheet.

Problems to be Solved by the Invention In such a transfer type image recording apparatus, the transfer characteristics are influenced by the humidity conditions of the outside air.

Specifically, when the humidity increases, the density of the transferred image decreases and the transferred image becomes distorted. This is because when the humidity increases, the recording sheet absorbs moisture and its electrical resistance value decreases.
This is because the charged charges leak when being charged by the transfer charger.

In order to prevent such transfer defects due to moisture, a heat roll is installed in the recording sheet feeding section, and when the humidity is high, this heat roll heats the recording sheet to bring its electrical resistance back to the normal value. One way is to increase it. However, heating with a heat roll requires a rising time to reach a constant temperature, and constant heating increases power consumption and poses a risk of overheating.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an improved image recording apparatus that can eliminate transfer defects at times of high humidity using a simple method.

Means for Solving the Problems The image recording apparatus according to the present invention includes a means for detecting the humidity of the outside air or the recording sheet, and a signal from the humidity detecting means to record a predetermined number of sheets when the humidity exceeds a certain value. When the operating humidity detection means detects high humidity, a predetermined number of recording sheets from the start of recording are ejected from the apparatus without recording images. is directly discharged.

Embodiment FIG. 1 shows an embodiment of the present invention. 6th
The reference numerals used in the explanation of the figures are used for similar parts. This electrophotographic apparatus 10o employs a reversal development method. The surface of the photoreceptor 1, which has been uniformly charged to a predetermined polarity by the charger 2, is irradiated with light corresponding to an image signal from the exposure device 3. This image signal is obtained by scanning the original image, and the image portion of the original image serves as the output signal. Therefore, when light is irradiated from the exposure device 3 in accordance with the image portion signal, the charged charges on the portions where the light has hit are erased, and the charged charges remain on the portions where the light has not hit as non-image portions. In such an electrostatic latent image, the potential of the image area is around zero V, so if regular development is performed, toner will adhere to the non-image area and a negative image will be formed.

Therefore, a bias voltage is applied to the non-magnetic sleeve 4b of the developing device 4, and the developing bias potential is set to be slightly lower than the potential of the non-image area of the latent image, and the toner in the developer 9 is Charge to the same polarity as the image polarity. By doing this, the potential difference with the sleeve 4b is higher in the image area than in the non-image area of the latent image.
, zotai<”9゛-.

adheres to the image area and a positive image is obtained. In the case of an electrostatic recording device, an electrostatic latent image is formed by sequentially placing charges on a dielectric material from a multi-needle electrode according to the image area signal, so a positive image can be created by simply depositing toner. can get.

The top sheet 101L of the recording sheets 10 stacked in the cassette 11 is fed by the paper feed roller 12 and the registration roller 13, and is superimposed on the toner image e& on the photoreceptor 1. The toner image 9a is transferred onto the recording paper 10 by being charged by the transfer charger 6 with a polarity opposite to that of the toner image. After the recording paper 1o is neutralized by the separation charger 6, it is separated from the surface of the photoreceptor 1, fixed by the fixing roller 14, and discharged to the outside of the apparatus 1oo. On the surface of one photoreceptor 1, residual toner is removed by a cleaning device 7, and residual potential is removed by a static eliminator 8.

As described above, when the humidity increases, the recording paper 10 absorbs moisture, causing transfer defects. However, when the recording papers 10 are stacked and housed in the cassette 11 as shown in FIG.
Although it varies depending on the paper thickness etc., the top sheet is 1 oa.
Only this often causes transfer defects. Therefore, in one embodiment, a high humidity signal from a humidity sensor 200 provided inside or outside of this recording device is used to discharge only the top sheet 10& directly to the outside of the device 1oo without performing image recording. configured to do so. This can be done by activating each device related to image formation after the uppermost sheet 102L passes through the registration rollers 13 or the transfer charger 5.

However, if the apparatus 10o is left under high humidity conditions for a relatively long period of time, several sheets from the top sheet 10& may also absorb moisture, causing transfer defects. Therefore, the number of sheets to be ejected directly from the apparatus without being recorded can be determined in accordance with the level of humidity and the length of standing time. On the other hand, no matter how high the humidity is, if the next recording operation is performed after a short interval, it is considered that even the top sheet 101L does not absorb enough moisture to cause transfer defects. In such a case, it is necessary to prohibit the direct ejection operation of the recording paper, and pressurize the device 1oo to directly eject it after a certain period of time has elapsed without use.

Whether or not the uppermost sheet 1otL on the cassette 11 has absorbed enough moisture to cause transfer defects can be determined by checking the IQ! rather than detecting the humidity of the outside air. It is preferable to directly detect the moisture absorption of L. An example of this type of device is shown in FIG. On the back side of the top cover 111 of the recording paper cassette 11, two electrodes 112 and 113 are provided in parallel with each other at an appropriate distance and are capable of contacting the uppermost sheet 10& of the recording paper 1o stored therein. . By inserting the leading end of the cassette 11 into the cassette hole 1o1 of the apparatus 100, the bottom receiving plate rises and the uppermost sheet 1o2L comes into pressure contact with the paper feed roller 12 in FIG. At this time, the top sea)
10& is the electrode 112, 1131C of the cassette top lid 111
Constructed to press into contact.

Then, an appropriate voltage is applied between the electrodes 112 and 113, and if, for example, a current exceeding a certain level flows, the sheet 101L is determined to be defective and is directly discharged from the apparatus 100. By directly detecting the moisture absorption of the recording paper 1 in this way, it is possible to prevent wasteful ejection of paper under any usage or environmental conditions, and conversely, it can be Good image recording can always be carried out even in the above conditions. In addition, instead of measuring the surface resistance of the recording paper 1o, for example, the registration roller 13 shown in FIG.
The upper and lower rollers are used as electrodes, and the recording paper 1 passes between both rollers.
Alternatively, a volume resistance of 0 may be measured.

Another embodiment of the invention is shown in FIG. In this embodiment, the guide plate 15 for changing the course of the recording paper 1o after the registration rollers 13 is attached to the hinge 1.
It is rotatably arranged around 5a. Under normal conditions, the guide plate 16 is positioned at the position shown by the solid line, and the recording paper 10 receives image transfer from the registration rollers 13 and is ejected from the fixing roller 14 to the outside of the apparatus 10o. When a high humidity condition is detected in the manner described above, the guide plate 16
is rotated to the position indicated by the broken line, and the transfer paper 10 absorbs moisture.
is guided from the registration roller 13 to a guide plate 15 and another guide plate 16 following it, and is discharged to the outside of the apparatus 10o. In this way, the recording paper 10 that has absorbed moisture is immediately transferred to the device 1.
Recording paper 1 that has absorbed moisture due to being ejected outside
Problems such as paper jams that are likely to occur when 0 passes through the normal route can be prevented. At the same time, since the recording paper 10 that has absorbed moisture does not touch the surface of the photoreceptor 1, this also serves as a measure to prevent crystallization of the surface of the photoreceptor 1.

In yet another embodiment of the invention shown in FIG.
A roll recording paper 17 is used as the recording paper 10.

In the case of roll recording paper, the areas that tend to absorb moisture are the areas from roll recording paper 1 to cutter 18, and roll recording paper 17.
This is the -turn of the outermost surface of . Therefore, when a high humidity condition is detected, the recording paper 10 corresponding to that length is directly ejected from the apparatus 100. In this case as well, a guide plate 15 as shown in FIG. 3 may be provided to allow the registration rollers 13 to directly discharge the material to the outside of the apparatus 100. Furthermore, as described above, the moisture absorption level of the recording paper 10 may be detected, and all portions of the recording paper whose moisture absorption exceeds a certain level may be ejected.

Effects of the Invention As described above, the image recording apparatus according to the present invention includes a means for detecting the humidity of the outside air or the recording sheet, and a signal from the humidity detecting means when the humidity exceeds a certain value to print a predetermined number of sheets. Since the recording sheet is provided with a means for ejecting the recording sheet without performing recording, good recording can always be performed without causing transfer defects under high humidity conditions.

Therefore, if the image recording apparatus according to the present invention is used in a device such as a facsimile machine that receives and records in an unattended state, the reliability and reliability of recording can be dramatically improved.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of an image recording apparatus according to an embodiment of the invention, FIG. 2 is a perspective view of a recording paper cassette according to another embodiment of the invention, and FIG. 3 is a still another embodiment of the invention. FIG. 4 is a schematic configuration diagram of an electrophotographic apparatus showing still another embodiment of the present invention,
FIG. 6 is a schematic diagram of a conventional electrophotographic apparatus. 1... Photoreceptor, 2... Charger, 3... Exposure device, 4... Development device,
5... Transfer charger, 6... Separation charger, 7... Cleaning device, 8...
... Static eliminator, 9... Developer, 10...
... Recording paper, 200 ... Humidity sensor. Figure 1 Tow Prestige Salary J-11 Table 1 Copy - Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] a recording sheet for transferring the developed image formed on the latent image carrier; a means for detecting outside air or humidity of the recording sheet;
an image recording apparatus comprising means for ejecting a predetermined number of recording sheets without performing recording in response to a signal from the humidity detection means when the humidity exceeds a certain value.