JPS62262876A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent an influence exerted on a picture quality immediately after preparations is completed, and after an image forming device is left unattended for many hours, and to obtain a stable image, by controlling the surface temperature of a photosensitive body having the temperature dependency or the surrounding temperature of the photosensitive body corresponding to said temperature. CONSTITUTION:The temperature of a photosensitive body is detected by a thermistor 10, and its output is compared with a reference voltage through a comparator 11, and determined as a voltage signal corresponding to a temperature by temperature - voltage converting circuits R1-R5. In such way, a data brought to temperature - voltage conversion is given to a control part 1 one after another. In the same way, a fixing hot roller temperature is also sent to the control part 1, as a data converted to a voltage. In the control part 1, both data are monitored, and when the data which is sent is in an L level, it is decided that both of them are in a lower temperature than a set temperature, and also, a signal is applied to a power source 4 so that the power source is supplied continuously to a lamp heater 5 and a photosensitive body heating heater 6.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to an image forming apparatus (for example, a copying machine, a facsimile machine, a laser beam printer) that visualizes an electrostatic latent image formed on a photoreceptor. In particular, it is applied to an image forming apparatus having a heater for heating a photoreceptor.

(Prior Art) In conventional image forming apparatuses of this type, the determination as to whether each process is ready or not requires the most electrical energy consumption in these apparatuses; The determination is made only by whether or not the fixing device, which is said to have a critical effect on the image quality, has reached a temperature range that allows toner to be properly fixed under a predetermined pressure. Next, if the fixing device has reached the fixing temperature range, a signal indicating that the device is ready is sent from the control section of the main body of the device to the display section, and on this display section, the entire device shows the state of the W surface other than the fixing process. Regardless of the situation, a display was displayed indicating that the preparations were complete.

Therefore, there is a problem in that the image quality deteriorates significantly immediately after the preparation complete display is displayed or after the apparatus has not been operated for a long time.

(Problem to be solved by the invention) In recent years, photoconductors with better tactility than before, high-sensitivity photoconductors that are compatible with high-speed processing and energy saving, and photoconductors with narrow band gaps have been developed. As these photoreceptors have become more frequently used, they have become highly dependent on temperature.
Even a temperature difference of only 1 to 2 degrees Celsius affects the overall sensitivity including dark decay, and it is often necessary to minimize overshoot with respect to the set value at 4 temperatures. Therefore, a technique for precisely heating and maintaining the temperature within an appropriate range is required, and there is a technical background that makes it difficult to use a powerful heat source such as a fixing device that uses a lamp heater or the like.

The photoreceptor also needs to be appropriately kept warm to avoid abnormal images caused by condensation due to sudden changes in outside temperature.

Furthermore, in general, the diameter of the fixing hole 1 to F1 to
The photoreceptor has a large volume and surface area, a large heat capacity, and a tendency to emit a large amount of heat.In addition to being softly heated, the photoreceptor may also heat up when the outside temperature is low or after the entire device has not been used for a long time. For fixing devices that are good enough to intensively input a large amount of high thermal energy and exhibit a rapid start-up, there are frequent problems in which the process operation is performed in a hyperbolic manner until the appropriate temperature condition is reached due to a delay in the start-up response. Reasons such as heat accumulation during image formation at full speed (Due to variations in the temperature rise of the fixing device, the fixing temperature may rise several seconds earlier than the target value, and the temperature of the photoreceptor may not reach the appropriate value when preparation is complete. .

For this reason, the conventional preparation completion judgment C based only on fixing temperature detection is difficult to perform heating because the photoconductor often does not reach the lower limit of the appropriate fixing temperature range, especially immediately after the preparation completion display is displayed. Coupled with the characteristics of recent high-performance photoreceptors, in which sensitivity and dark decay become exponentially faster as the temperature advances, and charging performance often decreases at an accelerated rate, even a slightly lower temperature can significantly increase the surface potential of the latent image. Not affected.

Specifically, there is a problem in that the surface potential becomes higher than a predetermined level due to a four-temperature response delay in the photoreceptor temperature, and the image density becomes darker than necessary.

In particular, the density of halftone gradation or higher is intense, for example,
There was a problem in which the A original image, such as a photograph, deteriorated significantly.

The present invention has been made in view of the above, and an object of the present invention is to provide an image forming apparatus that notifies completion of preparation when the photoreceptor and fixing means are at an appropriate temperature.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object 1, the present invention includes: a photoconductor temperature detection means for detecting a fixing temperature for detecting the temperature of the fixing means or a temperature corresponding thereto; A control means receives detection signals from the fixing temperature detecting means and the photoconductor temperature detecting means and determines whether or not both have reached a predetermined temperature, respectively, and the fixing 4 is controlled by the control signal from the control means.
The present invention is characterized by comprising a display means for displaying that the apparatus main body is ready for image formation when the temperature of one means and the surface temperature of the photoreceptor or the corresponding temperature reach a predetermined temperature.

(Function) Conventionally, when a photoconductor is heated to a certain temperature with the intention of preventing abnormal images due to dew condensation and improving overall sensitivity, including dark attenuation of the photoconductor,
In contrast to the conventional method, which determines that preparation is complete and avoids starting the image process only by determining whether or not the temperature of the fixing system is at an appropriate level, regardless of the temperature of the photoconductor, the present invention includes each of the above-mentioned means. Therefore, when not only the fixing temperature but also the photoreceptor temperature have reached appropriate conditions, it is possible to display that the system is ready and to start operating the apparatus. Moreover, it also has the effect of improving the accuracy of detection and accuracy of control, thereby improving the controllability and responsiveness of the entire device. Specifically, when the fixing temperature is appropriate but the photoconductor temperature is not, wait until the photoconductor temperature becomes appropriate, and when the temperature reaches the appropriate temperature, the preparation is completed and the image forming process is started. On the other hand, if the fixing temperature is insufficient for some reason, preparation is completed when both the fixing temperature reaches the appropriate conditions. For this reason, there is an effect that, even if one of them is in an insufficient temperature state, for example, it is not determined that preparation is complete based only on the fixing temperature and the image forming operation is not proceeded.

(Example) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the basic configuration and technical features of the present invention. As soon as the power is turned on, the control unit 1 is independently operated by the heat roller temperature detection unit 2 and the photoreceptor surface temperature detection unit 3. Data is given as a voltage signal.

FIG. 2 is a basic layout configuration diagram showing an embodiment of the present invention, in which 6 is a cylindrical heater that heats the photoreceptor 8 from the inside through air, and 12 is in contact with the non-image area of the surface layer of the photoreceptor. The thermistor serves as a temperature sensor, and is fixed to a member 13 that controls elasticity such as a plate spring with a fastening mechanical element 16 such as a screw or the like to the housing part or cleaner unit 13. 5 is a lamp heater that heats the fixing hot roller [1-rough], and 7'' is a pressure backup row that conveys the transfer paper while pressurizing it.Here, 15 is in contact with the fixing hot roller 7 and detects the temperature of the surface of C. This is a thermosket that I use.

Conventionally, the temperature of the flange portion of the cylindrical photoreceptor 8 was detected,
There are configurations that detect the temperature of the atmosphere near the photoreceptor, but 7
In lunge temperature detection, there is a difference in response between the temperature of the photosensitive layer itself and the temperature of the photosensitive layer itself, and the width of this difference also varies depending on the outside temperature and operating conditions. What also detects the ambient temperature is the state of air flow around the photoreceptor! Response delays, overshoes, etc. have occurred due to external disturbances such as the temperature level of the photoconductor and whether or not it has just been run, but in an embodiment of the present invention in which direct contact is made, it is possible to more accurately determine the photoconductor temperature and fixing temperature. Detection and control become possible. By this method of direct contact, in addition to the plate spring 13, the thermistor itself is embedded in an elastic body for a sponge, or the thermistor is covered with a Teflon tape with good sliding properties, both in the image area of the photoconductor J1 and in the fixing area. etc.,
It is possible to reduce the degree of scratches. Now, control part 1
The data given to ? is shown in Figure 4. 1) The temperature detection circuit independently indicates the completion of the readiness state in terms of the temperature of the photoreceptor system. That is, the temperature of the photoreceptor is detected by the thermistor 10, and its output is compared with a reference voltage through the amplifier 11, and the temperature is determined by R1-R5.
A voltage conversion circuit determines a voltage signal corresponding to the temperature. The resistors R3 and R4 have the function of applying a reference voltage E+ to the converter 11. On the other hand, the resistors R1, R
2 and the input voltage E2 provided by the thermistor 10
changes depending on the photoreceptor surface temperature. When the surface temperature of the photoreceptor becomes high, heat transfer occurs in order to maintain thermal equilibrium by contacting the non-image area of the photoreceptor, and the resistance value of the 4-no-mister 10 decreases.

As a result, the input voltage F2 becomes smaller. This input voltage F
If the value of 2 becomes smaller than the reference voltage [1], the output Fo of the comparator 11 is maintained at the level of 1F. Conversely, if the surface temperature of the photoreceptor decreases, the input voltage E2 increases, and if the value of F2 becomes larger than the reference voltage E1, the output "0" is maintained at 11 lvl.

The data subjected to temperature-voltage conversion in this manner is sequentially given to the control section 1. Similarly, the fixing hot roller temperature is also converted into voltage and sent to the control section 1 as data.

The control unit 1 monitors both data and determines that if the sent data is at the rLJ level, the temperature is lower than the erroneously determined temperature, and further turns on the lamp heater 5 and the photoreceptor heater 6. A signal is given to the power supply 4 to continue supplying power to the

On the other hand, when the temperature of the hot fixing roller rises to 200°C or higher or the surface temperature of the photoreceptor rises to 250°C or higher, the resistance value of the thermistor 10 decreases, causing the input voltage of the comparator 11 to become lower than the reference voltage. It is set to .

Therefore, when the output Eo of the comparator 11 reaches rl-1,1, the control section 1 uses this signal to control the heater lamp 5 of the heat roller 7 or the photoreceptor 8 which has reached the rHJ level.
The power of the photoreceptor heater 6 is turned off. At this time, even if one of them reaches the set temperature first, if the other does not reach the set temperature, rREADYJ will not be displayed, and both will reach the set temperature. It is only when you reach the [[(
[D Y j is displayed.

For this reason, an AND circuit that performs a logical sum is arranged inside the control section 1, and at the same time the output reaches the l-1-IJ level, the control section 1 displays the rRFAD Y on the display section 9.
, 1 are displayed.

Therefore, the photoconductor surface temperature and the fixing roller heating stone have two independent heating and control systems. FIG. 3 shows a flowchart of the above-described specific operation.

As described above, when the main power switch is turned on, the lamp heater switch is turned on, and the lamp heater placed inside the fixing roller 7 starts heating.
Set point: Thirst begins to rise rapidly. The heater inside the photoreceptor is also used to maintain the electrostatic properties of the photoreceptor by keeping the temperature of the photoreceptor within a predetermined range. Start heating. To avoid both hot offset and cold offset, the supply of electrical energy to the heat source lamp 5 is controlled depending on whether the surface temperature of the defined hot roller 7 is within an appropriate temperature range exceeding at least the minimum temperature required for fixing.

When the fixing heat source is ON, it is determined whether the photoconductor surface temperature is within the target range, and if it is, the photoconductor heater 6 is turned on.
is turned off, and the lamp heater 5 is turned on until the fixing conditions reach appropriate values at the same time. Only when the fixing dryness 1σ condition is controlled to an appropriate value and the photoreceptor temperature condition is also controlled to an appropriate value, it is determined that the preparation is complete, and the image forming process is started from the start.

In one embodiment of the invention, the lemister 12 or 15 is
A means of contacting the photoconductor surface and the fixing hot roller surface is used, but in order to avoid streaks and other abnormal images due to scratches in the circumferential direction during contact sliding, the temperature, correspondence, and functional relationship of these are determined. The structure that detects the degree of contact in areas such as the photoconductor side system and inside the cleaner unit 13 where the image will be affected even if there is a scratch reduces the occurrence of streaks (white streaks, black streaks), etc. on the image. At the same time, the object of the present invention can be achieved.

〔Effect of the invention〕

As explained above, according to the present invention, by controlling the temperature-dependent surface temperature of the photoreceptor or the corresponding temperature around the photoreceptor, it is possible to control the Preventing the impact on image quality and obtaining more stable images by increasing the temperature of the detection unit in Celsius,
The purpose of the present invention can be achieved.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the technical features of the present invention, FIG. 2 is a basic layout configuration diagram according to an embodiment of the present invention, and FIG. 3 is a block diagram showing the operation corresponding to the block diagram of FIG. 1. flowchart. FIG. 4 is a temperature-voltage conversion circuit diagram of the 12-temperature detection section. 1... Control section 2, 3... Detection section 6.
...Photoconductor heater 8...Photoconductor 9...Display section Fig. 3 Fig. 4

Claims (2)

[Claims] (1) In an apparatus that performs image formation by once forming a developed image on a photoreceptor, transferring this developed image to a transfer material, and then thermally fixing the image transferred to the transfer material by a fixing means, the fixing means a photoreceptor temperature detection means for detecting a fixing temperature or a temperature corresponding thereto; and a photoreceptor temperature detection means for detecting a temperature corresponding to the fixing temperature, and a means for receiving detection signals from the fixing temperature detection means and the photoreceptor temperature detection means to determine whether each of them has reached a predetermined temperature. If the temperature of the fixing means and the surface temperature of the photoreceptor, or the temperature corresponding thereto, reach a predetermined temperature, according to a control means for determining whether or not the fixing means and a control signal from the control means,
An image forming apparatus characterized by comprising a display means for displaying that the apparatus main body is in a state in which image formation is possible. (2) The image forming apparatus according to claim 1, wherein the photoreceptor temperature detection means is connected to the surface of the photoreceptor.