JPS6093473A - Copying device - Google Patents

Abstract

PURPOSE:To prevent fixing defects and fixing stop by controlling gap of supply papers in accordance with the size of transfer forms when a heat roller is used for fixing. CONSTITUTION:A voltage switching circuit is provided which designates the rotative speed of a driving motor of an optical system, which determines a returning speed VB, in accordance with a size l of a transfer paper P, and a returning voltage is set manually or automatically by insertion of a transfer form cassette or the like. The signal of arrival of the optical system at a limit point is inputted to the switching circuit, and a voltage circuit corresponding to a returning speed in which a fixing paper supply gap D which gives a sufficient restoration time of the temperature of the fixing roller is obtained is closed, and the circuit is switched to an electric circuit, which reverses a driving motor to give a going speed VP, by the signal indicating that the optical system reaches a base point.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an electrostatic copying apparatus, and more particularly to paper feed control in a dry transfer method for thermally fixing toner particles.

(Prior Art) In a copying method that uses toner as a recording image element, it is essential for record preservation that the toner be reliably fixed on the recording image carrier, generally plain paper (hereinafter referred to as transfer paper). It is a requirement.

The toner used in electrostatic copying is a two-component developer in which a thermoplastic resin such as an olefin resin, an acrylic resin, a vinyl resin, etc. is mixed with a colorant, generally carbon black, and a -component developer. A magnetic material such as iron powder is further mixed into the agent. The melting point of these toners varies depending on the amount of the above-mentioned admixture and the properties of the thermoplastic resin, but is generally in the range of 150 to 200°C. Therefore, it is necessary to maintain the temperature of the heat fixing roller at a temperature sufficient to provide the toner with the amount of heat necessary for melting the toner.

On the other hand, it is preferable that the temperature of the heat fixing roller be as low as possible from the viewpoint of preventing burning of the transfer paper, thermal failure of the apparatus, prevention of fire, and power saving.

U.S. Patents 3 and 6 in terms of fixing properties and copying running fast.
No. 39,245 discloses a technique related to adjusting the electrical resistance of toner, which has a reciprocal relationship with fixability, and Japanese Patent Application Laid-open No. 118656/1983 discloses a method for lowering the softening point of toner.

In addition, in response to the demand for mass copying and rapid copying, the speed of continuous copying has improved significantly, and the situation has come to be such that copies are made by digesting various original sizes (Japanese Patent Application Laid-Open No.
No. 4-116243, No. 56-114955, etc.).

Under these circumstances, the temperature of the heat fixing roller is now detected and controlled by a temperature detection element, etc., but even if temperature detection control measures are taken for the heat fixing roller, continuous Copying speed is actually determined by the relative reciprocating time of the imaging optical system with respect to the original in, for example, a slit exposure type copying device, and the standard for determining the copying speed of a copying device is the most frequently used one on the market. It is customary to use a high transfer paper thickness, such as No. 4 in A row, and the copying speed,
The fixing conditions for the number of sheets to be processed are fixed.

Therefore, if the paper size is smaller than the standard, such as No. 6 or No. 5 in 8 rows, it will tend to overheat unnecessarily, and if the paper is large, such as No. 4 in 8 rows or No. 3 in A row, a lot of heat will be carried away by the transfer paper. , the recording state is not perfect due to insufficient heat supply with the predetermined capacity of the heating device, or the recording state is not perfect due to defective fixing, or a copying pause occurs automatically to avoid defective fixing due to control of the temperature sensor. , which significantly impairs the smoothness of the copying work and the work connected to the copying work.

(Objective of the Invention) An object of the present invention is to provide a copying apparatus that uses heat roller fixing and does not cause fixing failures or fixing stoppages (copying stoppages).

Another object of the present invention is to provide a copying apparatus that compensates for heat removal from a heat fixing roller of a transfer sheet.

(Structure of the Invention) The present invention is characterized in that a copying apparatus that performs heat roller fixing is configured to control the paper passing gap according to the size of the transfer paper, and the copying apparatus having this configuration can be used in accordance with the present invention. The goal can be reached.

An aspect of the present invention is to control and/or control the time interval between the end point of the forward movement and the starting point of the backward movement in the relative reciprocating movement time series of the imaging optical system with respect to the document, depending on the size of the transfer paper. There is a mode in which the dynamic speed is controlled.

Further, there is a mode in which the imaging and paper feeding time intervals are connected and controlled.

Furthermore, for practical purposes, standard paper number 4 in row A (55mm paper for ppc;
Based on the design specifications, no control is required for transfer paper of sizes below (Basic weight 65tt/lrl, thickness μm).
It is sufficient to apply the present invention to transfer sheets of sizes exceeding row No. 4.

Furthermore, control of the paper passing arrangement gap in the present invention is originally performed based on the heat capacity (size x thickness x specific heat) of the transfer paper, but the specific heat is! Since the thickness is constant and does not vary as much as the size, the size is treated as a representative index.

Next, the basis of the structure of the present invention will be explained with reference to the drawings.

FIG. 1 is an explanatory diagram for analyzing the copying operation from the reciprocating motion of the optical system to image fixing in time series and in a coordinate sequence.

In the figure, W indicates the placement position and size of a document of a predetermined size, for example, No. 4 in row A (hereinafter abbreviated as A4. The same applies to other sizes), which is placed on the flat glass G. Indicates the size. In the figure, the solid line is for A4 and the broken line is for A3.

Δl is a buffer type for the approach of the forward movement of the optical system 0 and the brake of the backward movement.

Also, V is optical, 1% 0 platten glass a (original f) N
) The reciprocating range M is shown. Vp is the forward movement speed of the optical system, and vB is the backward movement speed. It should be noted that the forward and backward speeds in the buffer type △l are expressed as vP and vB, respectively.

M is a copying apparatus according to the present invention, and only the main points regarding the configuration of the present invention are shown.

0 is an optical system, N is a light source using a sodium lamp or the like, M, , M, , M, and M4 are mirrors, and L is a lens. I is an image forming system including an image carrier S, etc., P
1 is a transfer sheet, C is a conveying device, and F is a heat fixing roller.

The forward movement speed Vp of the optical system 0 along the platen glass G ([11) surface] is equal to the circumferential speed and conveyance speed of the image carrier S.

Further, the circumferential speed My of the heat fixing roller F is determined separately from the above-mentioned Vp, and generally, Vp>VF.

Therefore, the conveying paper passing interval of transfer paper P @11 and the fixing paper passing interval @1l
The IDs are different from each other, and the general K VP ) vF is therefore the general −D(, z).

On the other hand, the fixing paper passes while the transfer paper P has a size of 71, 1i11D and VF, and the transport paper passes! If the operation is steady and continuous between @ct and vP, in the steady time series (1 + D
) / VF = (1+ d) / Vp ・-=
(2) From the Japanese formula (1) and formula (2), it is clear that in the design specifications under these conditions, the size of the transfer paper! As the number increases, the fixing paper passing gap becomes narrower.

Next, the effect of narrowing the fixing paper passing gap will be explained with reference to FIG.

In the figure, the vertical axis indicates the temperature θ of the heat fixing roller F, θ0 is the upper limit of the appropriate fixing range, and θ is the lower limit, which is controlled by a signal from a temperature detector. The horizontal axis represents time t in the continuous fixing process time series.

to is the end of warming up of the heat fixing roller, θ
. is the roller temperature at the time, and θ is the roller temperature. and θ1.

t4 is the start and end time of fixing the first sheet of transfer paper of a predetermined size, and θ1 and θC are the roller temperatures at t, t'lK. From then on t1. θtbt'ttM,...
・Generally, ``in'', θ5, gin, and soi are the second paper, and are generally defined as having the same meaning as the first paper.

Here, ti-t- is the fixed paper passing period, and L'i ”
'-ti+1 corresponds to TILED during fixing paper passing, and is a recovery period of the roller temperature.

As shown in Figure 2 (a), depending on the design specifications of the copying machine, in the continuous fixing process time series for a given transfer paper size, for example A4, θ1, θ-, etc. are generally always fixed on numbers 0 and θ-. Appropriate range θ. ~θ, even if the size of the transfer paper is larger, such as 10.10′ for A3, generally 1
0, 'θ' has a large size, so a lot of heat is taken out,
Generally large size 16. ′/ and small size θ,,1
In between, ('θ-1θ')>(θ, -θ;), the roller temperature decreases significantly due to fixing.

Furthermore, as described above, since the fixing paper passing distance 11D is narrow, the roller temperature recovery period is short, and (j+10-10') <(e;+1-θ;).

Therefore, if the size of the transfer paper is large, the above-mentioned 2
As shown in Figure 2, the fixing start temperature 1θ in continuous processing of large-sized transfer paper gradually decreases due to the accumulation of these two effects, and gradually increases
. ~θ, the image falls below the proper fixing range, resulting in poor fixing and fixing suspension (copying suspension).

The present invention breaks the vicious chain between the heat loss caused by the increase in transfer paper size and the roller temperature recovery period, adjusts the roller temperature recovery period to suit the transfer paper size, and compensates for heat loss one by one. This consists of ensuring complete fixation and smooth copying operations.

There are various embodiments that satisfy the essence of the present invention described above5.
However, preferred embodiments of the present invention will be explained by examples.

The copying device starts from the base point where the optical system for imaging the yA document is in a regular state and is waiting for imaging, and images the entire area of the document of a predetermined size while imaging the document as it moves forward. One cycle is completed by arriving at the final point, then returning to the base point, and arriving at the base point.During this time, the paper is fed in alignment with the formed image, and the image is again formed on the surface of the image carrier. This is then carried over to the alignment timing system for the next cycle in which the transfer paper is fed in such a manner that it is regularly aligned at the position. Further, even when the system is in operation and when the neutralization ship is not in use, the image carrier and the transport device are continuously operated at the constant speed Vp, and the fixing device is continuously operated at the constant speed vF.

In this case, even if the same value of the same dimension is added to both sides of equation (3), the condition for regular steady continuous operation will not be lost. Therefore, Dτ=■τr, d
If we put τ=vPτ, then the fixing paper passing time @D becomes D+τ corresponding to the conveyance paper passing time @ettxei, +tiT.

As is clear from the above equation (1), τ1 is the backward movement speed v
Since it is one number of B, it can be given by a change in VB, or it can be given regardless of VB.

Therefore, in a preferred embodiment of the present invention in constant speed continuous operation, (I) between the time when the optical system reaches the limit point and the time when it ends at the base point, (G1) increase or decrease VB in the above formula (1); Then, the conveying paper passing gap is set to dsd±dτ, thereby making the fixing paper passing gap D±.
(I-b) A pause timing τ1 is inserted between the time of arrival at the limit point and the time of return to the base point, and the fixing paper passing interval 11D is set to D10p.
(n) A mode of inserting a pause timing τ between the end of the cycle at the base point and the start of the next cycle, and (m) the leading or trailing edge of the paper feed of the front cycle of the alignment timing system. There is a mode in which a timing τ for adding dKdr is determined according to the size lK of the transfer paper by detecting the transfer paper size lK, and a start signal is input to the alignment timing system.

In addition, the conveying paper passing gap d in the case of a transfer paper of size l can be determined from the relationship i = eio +:etT for the transfer paper used as the standard for the design of the copying device, so the reference transfer paper is used as the transfer paper or the standard transfer paper size, for example, A
4) The following is a delay mode, that is, c4 = d, +σ', (tt, > o
) can be used.

Figure 3 shows the mechanism of reciprocating movement of the optical system. The symbols in FIG. 1A have the same meanings as those in FIG. 1 above. Also in the same figure (b
) shows a perspective view of an example of an optical system reciprocating mechanism. In this example, Ro is a drive pulley R1, R2, R1 connected to a DC motor (not shown) whose rotation speed can be increased or decreased by voltage control.
The circles and circles are fixed pulleys, and Rd is a movable pulley. wire W
is fixed at both ends to the locking member f and fIK, and f+ -R
It is stretched between d -& -L -&-R4-Rt -Rs -Rf.

The light source N and the first mirror M1 described above are locked to the wire W, and the second mirror M and the third mirror M3 are connected to the movable pulley R,
It is locked to.

The matching timing system applies voltage to the drive motor (in this example the DC motor), and when the bird rotates, the wire W or the movable pulley R.

The optical system member locked to performs a predetermined reciprocating motion.

In this case, the speed of movement of the movable pulley within the same time; therefore, the amount of movement is wire 〇〇, so the optical path length from the W and W4 surfaces to the surface of the image carrier is kept constant during the reciprocating movement of the optical system.

An embodiment of the present invention is such that the reciprocating movement between the reference point for imaging of the optical system and the limit point corresponding to the size l of the transfer paper is performed in steady continuous operation with reference transfer paper having a size l as target. The appropriate temperature range θ for the fusing roller that does not cause fusing failure or fusing stoppage (copying stoppage). Maintaining the fixing paper passing interval BIID (transporting paper passing interval tltd) that constantly provides a temperature recovery period (the above tI, -tt+1) sufficient to keep the ~θLVc roller temperature,
and D, which provides a necessary and sufficient temperature recovery period in response to fluctuations in the size l of the transfer paper, and is aimed at an alignment timing system that provides image consistency l between the image carrier and the fed transfer paper. Therefore, it incorporates an intervention control system that adapts d.

One of the embodiments of the embodiment (G1) of the present invention is a changeover switch system that specifies the rotational speed of the drive motor of the optical system that determines the backward movement speed VB in accordance with the size l of the transfer paper, for example, the voltage. A switching circuit is provided to set the reverse voltage manually or automatically by inserting a transfer paper cassette, etc., and input the arrival signal at the blocking point of the optical system into the switching switch system to ensure sufficient recovery of the fusing roller temperature. period (the above tl~
ti+i) during fixing paper passing @D+Dτ vBτ
The voltage circuit for the motor is closed, and the circuit is switched to an electric circuit that reverses the rotation of the drive motor and provides a forward speed Vp in response to a terminal signal to the base point.

One of the embodiments of embodiment (I-b) is such that the arrival signal at the stopping point of the optical system stops the drive motor and starts counting a timer, e.g. Return control to the system.

FIG. 4 shows an encoder as an example of a timer.

FIG. 5A is a perspective view of the encoder E, where El is an encode plate, E3 is an encoder photosensor, and E3 is an encoder mounting plate. The same figure (false) is Enfood W E
l, rl is the mountain diameter, and r! is the valley diameter, and ψ is the pitch angle of one count. FIG. 3(a) shows a voltage pulse signal from the encoder photosensor.

Further, FIG. 5 shows a time chart of the embodiment (I-b). τP is the forward movement time of the optical system at the speed Vp,
τB is the return time at Vn, and τ is the pause time intervening between the time of arrival at the blocking point and the time of explosion from the blocking point in order to compensate for the recovery of the roller temperature.

In the same figure (a), the size of the standard transfer paper is A4,
4 or less, in which τi is the start point of the first cycle (referred to as cycle 1; the same applies to the others) and the end of cycle il in continuous operation. It's also a point in time. b is the time of arrival at the blocking point corresponding to A4 and the time of explosion. τj+1 is the starting point of the next cycle 1+1 and the ending point of the cycle l.

The figure (b) shows a size larger than the standard size A4, for example, A3.
This is a time chart for the case. 'τ' is the start point of cycle 1 (end point of cycle 1) in continuous operation at A3, 'τ' is the arrival time at the corresponding stopping point of A3 K, and the intervening pause time τ.

'τ' is the point of exit from the rest period and the point of explosion from the stopping point to the starting point.

The intervention τ, is controlled by an encoder. '+1τ is the end point of cycle 1 (start time of cycle 1+1), and control is returned to the matching timing system by this end signal. By setting τa+τB, time is given for the roller temperature to recover to an appropriate temperature, and the fixing paper passing gap becomes D+Dτ.

One of the embodiments of Embodiment (2) is similar to the time chart of the embodiment (1-b) in FIG. The connection of τB is τP - τB
- τ2 connection, the final signal is put into a timer, for example, an encoder, and the count end signal of intervention τ7 is used as the starting input of the next cycle of the matching timing system, and the effect is the same as (I-b) above. .

Embodiments I and (2) above can be used together.

Next, embodiment (2) is different from embodiments (2) and (2) in that an intervention control system is incorporated into the operation of the optical system, and the conveying paper passing time @Id corresponding to the fixing paper passing time @D required for roller temperature recovery is directly controlled. An intervention control system built into the conveyance path is incorporated into the paper feeding system.

As an example of embodiment (2), the size of the standard transfer paper is YA4, and in the alignment timing system in which no intervention control is required when the size is A4 or smaller, the transfer paper P is fed at the alignment timing. A detector is provided to detect the leading or trailing edge of paper fed from the registration rollers, and the detection signal is once input to a timer, for example, an encoder, and is matched with a count end signal from the encoder corresponding to transfer paper larger than A4, for example, A3. The start signal of the system is generated by using the end signal of the timing system as an AND circuit.

If the system is to detect both the leading edge and the trailing edge of the paper feed, constantly check the size l of the transfer paper, and make the transport paper passing gap tik required for l follow the trailing edge of the transfer paper, the embodiment (2) is as follows.
Even when documents of various sizes are automatically fed and transfer sheets corresponding to the sizes are selectively fed, poor fixing and fixing suspension (copying suspension) can be avoided.

(Effects of the Invention) The inconveniences of poor fixing and suspension of fixing, which are the objectives of the present invention, can be eliminated, smooth copying work is guaranteed, and unmanned operation can be further promoted.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the copying operation, Fig. 2 is a diagram showing temperature fluctuations during continuous operation of the fixing roller, Fig. 3 is an explanatory diagram of the reciprocating mechanism of the optical system, and Fig. 4 is an explanatory diagram of the encoder. be. Further, FIG. 5 is a reciprocating time chart of the optical system. Vp...Optical system forward movement speed, Vn...Optical system backward movement speed, V,...Fixing conveyance speed, τP...Optical system forward movement time, τB...Optical system return movement time, τ1 ...Optical system down time, d...Transportation paper passing gap, D...Fixing paper passing gap, θ
. , θi, θtS'θ and 10'...Fixing roller temperature. Agent Kanmi Kuwahara 61 Kunisai 20 (a) G6) θ Figure 5 (α) Mo 4 Ward (C) Den 5 (0-) φ)

Claims (4)

[Claims] (1) A copying apparatus that performs heat roller fixing and is characterized in that the paper passing gap is controlled according to the size of the transfer paper. (2) In the time series of the reciprocating movement relative to ms of the imaging optical system of the copying apparatus, the interval between the end point of the forward movement and the explosion point of the return movement is controlled according to the size of the transfer paper. A copying apparatus according to claim 1, characterized in that: (3) The percentage feedback return speed of the relative reciprocating movement of the imaging optical system of the copying apparatus with respect to the document is controlled according to the size of the transfer paper. Copying device described in Section 1. (4) Claim 1, characterized in that the paper feed interval is controlled according to the size of the transfer paper, and the paper passing gap is controlled.
Copying device as described in section.