one embodiment of the present invention will be described below with reference to fig1 through 10 . as shown in fig1 the baking oven of the present invention includes an oven main body 10 , a heating means 20 which creates a high - temperature atmosphere inside the oven main body 10 , a magazine 35 which accommodates therein lead frames 1 with the lead frames being stacked with a predetermined space between them , a magazine width adjustment means 40 which adjusts the width of the magazine 35 , and a magazine raising and lowering means 60 which moves the magazine 35 in a vertical direction . as shown in fig1 through 3 , the oven main body 10 is a three - dimensional box , and the outer walls are covered with a heat insulating material , such as adiabatic material , for instance . an entrance opening 10a through which each lead frame 1 and a pusher 12 for pushing the lead frames 1 advance into the main body 10 is formed on the entry side of a lead frame conveying path 11 . an exit opening 10b from which the lead frames 1 are discharged is formed on the exit side of the conveying path 11 of the oven main body 10 . as seen from fig7 two slots 10d are formed vertically in one side plate 10c of the oven main body 10 which is perpendicular to the conveying path 31 so that two pairs of magazine shafts 37a and 37b which support the magazine 35 ( to be described later ) can move up and down . flexible elastic plates 13 and 14 made of , for example , rubber plates are attached to the side plate 10c so that the elastic plates 13 and 14 close off the slots 10d from both ( right and left in fig4 ) sides . the heating means 20 comprises a heating block 22 and a gas blowing assembly 24 which is connected to a gas supply or a gas source ( not shown ). the heating block 22 is installed on the bottom surface of the oven main body 10 and has two cartridge heaters 21 inside . the gas blowing assembly 24 blows a heated gas 23 into the oven main body 10 as a convection current . the gas blowing assembly 24 includes two delivery pipes 25 provided beneath the heating block 22 . couplings 26 are connected to the delivery pipes 25 , and a gas 27 such as dry air or nitrogen , etc . is supplied to the couplings 26 from the outside . a front convection pipe 28 is connected to the front or operator side 31 of the delivery pipes 25 , and numerous blowing holes 28a opened upwardly are formed in the front convection pipe 28 . furthermore , a rear convection pipe 30 is connected to the rear ends of the delivery pipes 25 via vertical connecting pipes 29 , and numerous blowing holes 30a which face the upper surface of the heating block 22 are formed in the rear convection pipe 30 . as shown in fig4 the magazine 35 is installed above the heating means 20 inside the oven main body 10 and includes a pair of stocker plates 36a and 36b . the stocker plates 36a and 36b are vertically installed so as to face each other and are parallel to the conveying path 11 . a multiple number of grooves 36a and 36b which hold both ends of each one of the lead frames 1 in a stacked fashion with a predetermined space between the lead frames as seen in fig4 are formed on the inner surfaces of the stocker plates 36a and 36b . the stocker plates 36a and 36b are supported by two pairs of upper and lower magazine shafts 37a and 37b as best seen in fig5 which are installed horizontally and parallel to each other . the magazine shafts 37a and 37b extend in a direction of right angles relative to the lead frame conveying path 11 . end portions of these magazine shafts 37a and 37b are brought into the oven main body 10 through the slots 10d ( see fig7 ) of the oven main body 10 . the lower magazine shafts 37b pass through holes 36c formed in the stocker plate 36a . the magazine width adjustment means 40 is best illustrated in fig4 through 6 . the magazine width adjustment means 40 includes a raising and lowering plate 41 which is located beneath the lower magazine shafts 37b , and a supporting plate 42 which is located between the upper magazine shafts 37a and the lower magazine shafts 37b . the supporting plate 42 is above the raising and lowering plate 41 by four supporting columns 43 . two upper guide blocks 44a and 45a are provided on the upper surface of the supporting plate 42 . the pairs of upper magazine shafts 37a are passed through these upper guide blocks 44a and 45a via linear bushes 46a interposed between the shafts 37a and the blocks 44a and 45a so that the upper magazine shafts 37a are slidable in the guide blocks 44a and 45a . a movable plate 47a is fastened at its both ends to the upper magazine shafts 37a and positioned between the two upper guide blocks 44a and 45a . a horizontal cylinder 48a having internal thread is provided at the center of the movable plate 47a , and a horizontal screw 51a having external thread engages with the horizontal cylinder 48a . the horizontal screw 51a is supported by the two upper guide blocks 44a and 45a via bearings 49a and 50a so that the horizontal screw is rotatable . two lower guide blocks 44b and 45b are , like the upper guide blocks 44a and 45a , provided on the upper surface of the raising and lowering plate 41 , and the pair of lower magazine shafts 37b are passed through these lower guide blocks 44b and 45b via linear bushes 46b interposed between the shafts 37b and the blocks 44b and 45b so that the lower magazine shafts 37b are slidable in the guide blocks 44b and 45b . a movable plate 47b is at its both ends attached to the pair of magazine shafts 37b and positioned between the two lower guide blocks 44b and 45b . a horizontal cylinder 48b having an internal thread is provided at the center of the movable plate 47b , and a horizontal screw 51b having an external thread engages with the two lower guide blocks 44b and 45b via bearings 49b and 50b so that the horizontal screw 51b is rotatable . width adjustment motors 55a and 55b are mounted on the upper surface of the raising and lowering plate 41 via brackets 56a and 56b , respectively . a timing pulley 57a is attached to the output shaft of the width adjustment motor 55a , and another timing pulley 57b is attached to the output shaft of the width adjustment motor 55b . a timing pulley 58a is attached to the end of the upper horizontal screw 51a at the position facing the timing pulley 57a , and another timing pulley 58b is attached to the end of the lower horizontal screw 51b so as to face the timing pulley 57b . a timing belt 59a is mounted between the timing pulleys 57a and 58a , and another timing belt 59b is mounted between the timing pulleys 57b and 58b . the magazine raising and lowering means 60 is best shown in fig4 and 8 , and it is installed beneath the raising and lowering plate 41 . more specifically , a frame 62 of the magazine raising and lowering means 60 is mounted to the upper surface of a base plate 61 , and two guide rods 63 are vertically installed in the frame 62 . the upper and lower ends of the guide rods 63 are secured to the frame 62 . a vertical screw shaft 64 having an internal thread is installed between the two guide rods 63 so that the vertical screw shaft 64 is parallel to the guide rods 63 . the vertical screw shaft 64 is supported in the frame 62 via upper and lower bearings 65 in a rotatable fashion . a timing pulley 66 is attached to the upper end of the vertical screw shaft 64 . as seen in fig4 a raising and lowering drive motor 67 that has a timing pulley 68 fastened to its output shaft is secured to the under surface of the upper plate 62a of the frame 62 , and a timing belt 69 is mounted between the timing pulley 66 of the vertical screw shaft 64 and the timing pulley 68 of the motor 67 . a movable cylinder 70 having an internal thread , as best shown in fig8 engages with the vertical screw shaft 64 , and a wing plate 71 is attached to this movable cylinder 70 . two pushing rods 73 are passed through the upper plate 62a of the frame 62 via bearings 72 so that the pushing rods 73 can move up and down , and the bottom ends of the pushing rods 73 are connected to the wing plate 71 , and the upper ends of the pushing rods 73 are connected to the raising and lowering plate 41 . fig9 shows the width adjustment circuit for the magazine 35 which comprises the pair of stocker plates 36a and 36b facing each other . the width of lead frames varies depending upon the type of the lead frame . thus , a particular width value of lead frames to be processed is stored beforehand in a memory circuit 82 by an input means 80 via a control circuit 81 so that the space of the stocker plates 36a and 36b matches the width size of the particular type of lead frame to be processed . the control circuit 81 actuates the width adjustment motors 55a and 55b via a driving circuit 83 . first , a high - temperature atmosphere is created inside the oven main body 10 . more specifically , the cartridge heaters 21 of the heating block 22 are turned on , and as shown in fig3 the gas 27 is supplied via the couplings 26 . the gas 27 supplied via the couplings 26 is fed to the front convection pipe 28 via the delivery pipes 25 and to the rear convection pipe 30 via the delivery pipes 25 and connecting pipes 29 . as a result , the gas is blown out of the blowing holes 28a of the front convection pipe 28 and also out of the blowing holes 30a of the rear convection pipe 30 . thus , the heated gas 23 , as seen in fig3 being subjected to forced convection inside the oven main body 10 is generated , and a uniform heating atmosphere is created in the oven main body 10 . in the following description , it is assumed that the width of the magazine 35 ( or the space between the stocker plates 36a and 36b ) matches the width of a lead frames to be accommodated . first , the lead frames 1 are fed into the magazine 35 . fig4 shows the magazine 35 at its lowest position and being empty . the magazine 35 is , from this position , raised as indicated by the two - dot chain line by the magazine raising and lowering means 60 so that the grooves 36a and 36b of the first ( or the lowest ) stage of the stocker plates 36a and 36b are positioned at the conveying path level 11a . then , the accommodation of lead frames into the magazine 35 starts . in other words , when the first lead frame 1 ( to which an insulating tape 2 has been bonded ) is conveyed to the entrance opening 10a of the oven main body 10 , the pusher 12 is actuated so as to make a reciprocating movement so that the first lead frame is pushed into the grooves 36a and 36b of the first stage of the magazine 35 . next , the raising and lowering drive motor 67 is actuated so that the grooves 36a and 36b of the second stage ( i . e ., second stage from bottom ) of the magazine 35 are positioned at the level of the conveying path 11 . more specifically , when the raising and lowering drive motor 67 is driven , the vertical screw shaft 64 is rotated via the timing pulley 68 , timing belt 69 and timing pulley 66 so that the movable cylinder 70 along with wing plate 71 are lowered by the rotating vertical screw shaft 64 . since the raising and lowering plate 41 is connected to the wing plate 71 via the pushing rods 73 , and since the magazine shafts 37a and 37b are provided on the raising and lowering plate 41 , the magazine 35 is lowered when the wing plate 71 is lowered . when the grooves 36a and 36b of the second stage of the magazine 35 are positioned at the conveying path level 11a , and the next or second lead frame is conveyed to the entrance opening 10a of the magazine 35 , the pusher 12 again makes a reciprocating movement , pushing the second lead frame into the grooves 36a and 36b of the second stage of the magazine 35 . lead frames are thus accommodated in all of the grooves 36a and 36b up to the uppermost stage of the magazine 35 by repeating the above - described operation . when the lead frames 1 are thus being fed into the magazine 35 , the lead frames 1 and the insulating tapes 2 bonded to the lead frames 1 are dehumidified ( pre - baked ), starting with the first - stage ( or the bottom ) lead frame 1 inside the magazine 35 by the heating atmosphere created inside the oven main body 10 . when the transfer of the lead frames 1 into the magazine 35 is completed , the raising and lowering drive motor 67 is rotated in the opposite direction so as to raise the magazine 35 until the grooves 36a and 36b of the first stage of the magazine 35 are positioned at the conveying path level 11a . next , the pusher 12 reciprocates so that the first - stage lead frame 1 in the magazine 35 is pushed out through the exit opening 10b into the feeder section of a chip bonding machine ( not shown ) which performs the next process to the pushed out lead frame 1 . afterward , a new lead frame 1 is fed to the entrance opening 10a of the magazine 35 , and then the pusher 12 pushes the new lead frame 1 into the empty grooves 36a and 36b of the magazine 35 . after this , the raising and lowering drive motor 67 is rotated so that the grooves 36a and 36b of the second stage of the magazine 35 are positioned at the conveying path level 11a . then , when there is a demand of a lead frame from the next process , the second - stage lead frame 1 is pushed out to the feeder section as described above , and a new lead frame is pushed into the grooves 36a and 36b of the second stage . afterward , the grooves 36a and 36b of the third stage are positioned at the conveying path level 11a . subsequently , the operation described above is repeated . the lead frames which have been pushed out from the oven main body 10 to the feeder section are forwarded to the bonding section of a chip bonding machine by the feeder section as in conventional methods , and the semiconductor chips 3 are subjected to chip bonding to the lead frames and then stored in a storage magazine ( not shown ). when the type , and therefore the size , of the lead frame to be processed is changed , the width of the magazine 35 is adjusted . as seen from fig5 the width adjustment motor 55a is actuated , and the horizontal screw 51a is rotated via the timing pulley 58a , timing belt 59a and timing pulley 57a . as a result , the horizontal cylinder 48a and movable plate 47a are moved in the direction indicated by the arrow . since the pair of upper magazine shafts 37a are attached to the movable plate 47a , and the stocker plate 36a is secured to the upper magazine shafts 37a , the stocker plate 36a is moved in the same direction . likewise , as shown in fig6 when the width adjustment motor 55b is actuated , the horizontal screw 51b is rotated via the timing pulley 58b , timing belt 59b and timing pulley 57b , so that the horizontal cylinder 48b , movable plate 47b , lower magazine shafts 37b and stocker plate 36b are moved in the direction indicated by the arrow . in this way , the space between the stocker plates 36a and 36b ( or the width of the magazine 35 ) is changed . the width adjustment motors 55a and 55b are driven so as to move the stocker plates 36a and 36b by equal amounts in the opposite directions ; thus the center line between the stocker plates 36a and 36b is prevented from shifting . as seen from fig9 when information of the lead frame to be processed is inputted into the input means 80 , the control circuit 81 reads out the corresponding type data stored beforehand in the memory circuit 82 and drives the width adjustment motors 55a and 55b via the driving circuit 83 so that the width of the magazine 35 is automatically adjusted to the lead frame to be processed . in the above embodiment , the lead frames 1 with bonded insulating tapes are processed . the present invention of course is applicable to lead frames applied with an adhesive agent , so that the adhesive agent is baked after it is chip bonded to the semiconductor chips 3 . as seen from the above , according to the present invention , the lead frame accommodating capacity can be high , and it is possible to set a long pre - baking or baking time . in addition , the size of the oven main body can be reduced . furthermore , the baking oven can meet changes in the width of lead frames to be processed .